I can't recall what the Federal Trade Commission (FTC) specified when it cracked down on audio amplifier power claims back in the late '70s. But I always took it to mean watts calculated from the continuous RMS voltage of a sine wave, all channels driven, at the specified distortion, measured for all frequencies claimed in the frequency response, within one decibel. The output load was also specified. That was the performance I would shoot for when designing a power amplifier for a given "RMS power". Now, RMS voltage depends on the waveform being analyzed. For a sine wave, it's root 2 over 2 times the peak voltage, or approximately 0.707. For a square wave, it's 1 times the peak voltage. For real music, it's... who knows? How loud are you playing it? How efficient are your speakers? How was it compressed, peak limited and clipped? Even the musical style, the amount of dynamic range contained in the original performance, and subsequently, how it was mixed and processed makes a big difference in the amount of actual power needed to reproduce it accurately and at a realistic volume. Of course, a lot of the fidelity may have been lost before it ever even hit the vinyl or CD.
Wow, such a controversy .... The standard measurement used by most technicians and not a few engineers is to drive an amplifier up to clipping, back it down by 1%, read the RMS voltage across a dummy load then apply P = (V x V) / R to get the wattage. 20 volts RMS on 8 ohms will get you (20 x 20) /8 = 400/8 == 50 watts RMS. The notation "Watts RMS" very simply means "wattage calculated using RMS voltage". If I calculated using Peak voltage I would say... Watts Peak If I calculated using Peak to Peak voltage I would say... Watts Peak to Peak When I calculate using RMS voltage I say... Watts RMS The "using" is implied ... as in "Watts _using_ Peak voltage" becomes Watts Peak. Why do people have so much trouble with that???
@@glpilpi6209 Yes, and? It wasn't "fancy hifi artisans" who designed the current testing procedure... it was design engineers looking for a standardized test that could be administered easily. The old hot resistor test relied too heavily upon the heat dissipation of the load... which even with "matched" resistors could vary over a wide range with variations in humidity, ambient temperature, airflow etc. The test described above only cares what the ohmic value of the dummy load is.
Yeah, your right It's a standardised way of comparing different amplifiers. And that's what counts! Ideally it should include declaration for distortion measured at the claimed power output along with impedance. So 100w RMS per channel @ 8ohm with (say) 1% distortion. Knowing level of Distortion and when it occurs is essential for comparison. It should be declared as false advertising for power output claims that fail to mention important specifics. And that's where the fudge factor takes off with the cheap chip amps. It's absolutely ridiculous how the established method is disgarded. Example: quoted output can be doubled (2x channels) the load is lowered to 4ohms and most crazy of all, peak power is used at a Tweeter popping 10% distortion. Lower distortion values on these amps are capable of typically appear on a different line on the spec list, at an unknown output level. Only clue you will get towards realising they have no relation at the claimed max output.
@@SuperBicycleRepairMan I agree ... and when I write wattage I always include both impedance and distortion as part of the spec. The best way with these chip-amps is to look up the spec sheets for the chips. If you don't have the measuring equipment to verify outputs, this will at least get you into the ballpark. For example if you search for "TPA3255 Spec Sheet" you will discover a world of detail about any amp containing the TPA3255 chip... It behaves the same way no matter what brand or price of amplifier it's in. (Of course substitute other part numbers for other chips... 😉)
Dummy loads are resistive loads unless I'm miles off here no? Speakers are capacitive loads (potentially huge impedance (resistance really ie if you took a snap shot in time)).. they also generate electricity via inductance. Ie back EMF. There is soooo much more.to it than voltage/current output into a given resistance (yes, ie dummy.load). Damping factor? Slew rate? Power supply reserve capacitance? Buy an 20+ year old BSS EPC series amp 760 or 780 which I have. It benches at 1625w rms.@ 2ohms sustained over enormous time frames... yes ohms law etc... However LISTEN to the amp perform.. you don't even need high end speakers, mediocre ones will suffice. There is an immediacy, impact, slam, grip, and sheer effortlessness to the sound yet at the same time a silky smooth, soft, subtle, jaw dropping delivery to the mids and highs. I agree with the video author however MY amp is definately not average lol. Fun fact.. these amps were chosen for.the turbosound flash and floodlight PA systems in the 90s and built at a loss to be the best amps in the world.
None of this really matters long as you have a good strong Poweramp to drive your speakers at the SPL that you're comfortable with without blowing your speakers and if your amplifier has enough in the power rails that it doesn't sag during high-powered transients
I listen to music the majority of the time at levels less than 1 watt. If I turn it up, I bump maybe 2 watts. Prolonged periods at those levels would challenge longterm hearing health.
Exactly , most of the time an amp is ticking over , if the rest the of the chain is property matched . If you need to listen at a high volume something isn't right or you have horrendously inefficient speakers.
The value of RMS is derived from squaring the values of the sine wave, (the negative side climbers up), finding the area of the new wave form and divide it by the length (an integral) In such case sine waves will show a ratio of 0.707 of the amplitude. The average value of the sine wave without squaring the values is 0.623 I hope I remember the average ratio correctly, been ages since I learned this and no one uses the avarage ratio, only RMS is used for obvious reasons
If your amplifiers output is sag'ing The cause is usually that its Power Supply is failing to deliver the energy that the amps power output stage has demanded. Few domestic audio amplifiers are designed for continuous rating anywhere near their maximum transient power. This is possible because we don't need to generate a continuous sine wave at maximum power .. We are listening to music which ( unless overly processed) likely has an average power of about 30% of the amplifiers transient response power. ( therefore the designer does NOT need to design a Power Supply with the capacity to deliver the amplifier's " Full " rating continuously ) Hence if you attempt to obtain it's transient rating continuously.. it's output falls off ( sags ) 😊
Maybe we don't need to generate or listen to a full sinewave signal on our system, but, the fact is, we should be able to do it, if the following situation occurs: we are watching or listening to some musical material on TH-cam, near the maximum output of the amplifier, and, suddenly, its predictive listener experience algorithms drop a material about testing an amplifier continuous power output. You are not close enough to the be able to reduce the volume of your audio system and, suddenly, the test sinewaves, at 40 Hz , 400 Hz, 1 kHz, etc, used in the material start blasting through the system and you don't have a limiter deployed. Result: bye bye amplifier, bye bye tweeters, bye bye woofers. Fact: in today's world, the chance of encountering over processed/over compressed audio materials, especially on the streaming platforms, is very high. Conclusion: don't use any amplifier which is not able to withstand at least 5 minutes of 1 kHz full sinewave at full power output.
Back in the early 80’s I used to sell audio and we had Harmonic Kardon. One day one of the engineers paid us a visit and gave me a small little box, and in it was a nine cold battery and two RCA outputs. He told me that this was a better measurement of what an amplifier could do and would show current in an amp. It emited a pulse, the woofer would move back and forth. Every Harmon Kardon amp connected could push that woofer back and forth with no issue, even large ones. When I connected Japanese receivers or amplifiers the woofer would barely move. One day I’d like to know that current is also something that is recognized or these “high current” amps “there are some still” are as you say, audio phoolery 😮
It is even more complicated because the load of an amp normally not a resistor. A loudspeaker is a complex (reactive) load, the resistance of an '8 ohm' speaker can drop at some frequencies to 1 ohm!! Most amps can not deliver the current (and the 'rms' power) that is required at 1 ohm. It is better to have a modest power amp that is capable to deliver enough current! Keep going with your channel, you ar a very nice story teller (even for my age :) Rob (from Holland)
Now that I am an aging hipster, the volume control is normally set at 9 o’clock. If I can hear all the soft and loud musical bits, I am pleased. So my aging 37 wpc amp is a great companion.
Dear David. I have viewed this video a few times ( because I'm dutch and it take me a bit more effort to follow English, totally my fault ) and I looked at the info in the link. I believe it isn't that complicated. Let's use your example of 1 V rms over a 1 Ohm resistive load. Starting with 2.828 V p-p, divide it by 2 = 1.414 V p(peak). The current is 1.414 V p / 1 Ohm = 1.414A p(peak). Power is the multiplication of Voltage and Current. 1.414 V p * 1.414 A p = 2 W p(peak). Now we can say: to convert the peak voltage to rms divide the peak value by SQR2 ( 1.414 / SQR2=1 ) the same apply for current. This means that the conversion from Power-peak to rms is the following: P p / (SQR2 * SQR2 ) --> Power-peak / 2=power rms.
When looking at power amplifier output I look at how the power is quoted. If it’s just at 1 KHz and 10% THD with one channel driven it’s pretty safe to say that’s useless info. My NAD amplifier is quoted as continuous power output >50W at 20Hz - 20KHz, both channels driven at 8 ohms and 0.009% THD. That’s enough to say to me that under normal usage conditions with my 8 ohm 90 db/W/M speakers that I have more than enough clean usable power in my living room. I probably only peak at 1 or 2 watts of power output at the very most.
Even if "Watts RMS" is wrong, at least it is a standard that can be easily applied to any number of amplifiers tested by the same method and then used to compare them. In other words, let's Keep doing it wrong so we don't have to Test Everything All Over Again to a Correct standard.
Agreed, it's like the published figures for fuel (or electrons) consumed by a car - meaningless in itself for the real world but useful to compare against others.
When you apply a sinusoidal voltage to an amplifier the output waveform is sinusoidal and so is the current through the load. However, when you multiply the voltage by the current and plot it on a graph you get the power waveform. The power waveform is a strange non-sinusoidal shape that obviously never goes negative. My college maths lecturer said that power is an imaginary quantity because the only real things present are voltage and current. The power amplifiers I built provide 46.6 volts RMS across an 8 ohm load just prior to clipping which is how I measure the output. No need to calculate the output power into imaginary units.
Why is power imaginary and why are voltage and current not? They are as much imaginary when you consider they represent the flow dynamics of electrons through atomic crystals, which are realer than current and voltage.
@@l.s.1709 Well if you consider current and voltage to be imaginary then the product of them must also be imaginary. Anyway, you can measure the voltage across a load and the current through it. Now if you want to multiply the current by the voltage you can call it power. However, it's really volt amps.
I have glossed over the replies to MC's vid, and I apologize if any comments were related to my post. First off, what kind of amps are we talking about? SS, hybrid or valve (tube). There topology is different when driving speakers (and what kind of speaker your driving). Speaker efficiency is paramount in tandem with the amplifier. Amplifier loading varies greatly. SS (solid state) amps (class A, AB and D) load voltage differently due to there topology. Tubes are stage gains in amplification (continuous power) through there rated transformers. Watts are only a combination of values (volts*amps* to 1J (W) over distance, ect.). Voltages (and current) are really the key factor when driving speakers. The input signal is DC current (0.4v to 3.0v max). The amplifier takes that signal voltage and "amplifies" that signal (0.4v = low gain to 3.0v = max gain or RMS). The truth about watts when it relates to current supplied to the speaker (volts/amps) is the speaker itself. @ 1 watt, the efficiency of the speaker will determine how that watt is driven. Low efficiency speakers will not produce much work (load) through the speaker. Where as high efficiency speakers will produce a more audible load. Less watts are needed to achieve higher gain (volume) loads on high efficiency speakers. @ 20watts, a 96db speaker will produce a high range of sound (decibels) than low efficiency speakers which require more current load (watts) to produce the same loudness gain. Even low efficiency speakers will use around 40 to 60 watts per channel to achieve high gains (loudness) with a good, stable power (driven) source. The basis for MC's video shows the actual (driven) loads required when using speakers as a load reference. If you have a good pair of speakers (depending on the efficiency) you would be hard pressed (and possibly go deaf) when driving your speakers @ 100w per channel continuous loads (even under extreme low end bass frequencies). Most speakers load at around 30 watts per channel comfortably and the gain is actually quite high. Low efficiency speakers do well at around 50 watts per channel. So, what do you even need a 1000 watt BS amp for? Even if that amp could produce 1000 watts, you will only be using a fraction of that power to drive your speakers comfortably.
I am neither an audiophile nor an electrical engineer,. I do know that when I run these two big speakers in my field (15" EV Woofers. JBL 2425 Drivers with Renkus Heinz lenses and some nondescript crossovers) with an old Sansui 661 (15w) or the Marantz 1060 (60w), I get beautiful clean deep tones at volumes that shake the neighbors before I hit the midway point on the volume pots. Still.... I find your talks entertaining and I'm even learning a little bit. Thanks for the insights.
Two big problems, First, whilst my main current main amp is rated at 40W RMS per channel, it will probably never produce that, that is unless I listen to lots of organ music, and then ride the volume control to maximise the output without hitting the clipping point, quite hard and kind of pointless. 95% of my music will never produce more than a handful of watts from that amp, assuming I keep it below clipping (Except my AC/DC tracks, where clipping is usually not noticeable, sometimes beneficial, excellent tweeter destructor) The other problem is 99% of speakers have a very dynamic impedance curve, and an amplifier has to be able to keep its set output signal voltage level even if the speaker's impedance drops from, say 8 ohms to 2 ohms. (which actually means the amp has to put out bursts of way more power, do the math but with 2 instead of 8 ohms) If it cannot hold the voltage level then one hears a pile of distortion as it's output crashes. This is the problem with a lot of those mini high power amps you find using Google, once you get past that bull quoted ratings, using something like PMPO rather than RMS, (and they add the two channels together for 2X, something real HiFi does not) you also have to then derate them an awful lot to allow for normal speaker impedance dynamics. they have NO margin for a load that drops it's impedance below the rates 4 or 8 ohms they quoted, so best of luck getting a good 10W out of that 600W mini beast you just ordered.
One small mistake, and it is small but in hi-fi and pedantry that's where the fun is: what you're trying to say is not "your power amp is average." you're trying to say "your amp power is an average."
I have thought for some time that power amps should be rated for continuous peak voltage at a given load value (which really should be more like 6 ohms resistive to account for 8 ohm nominal speakers, or 3 ohms resistive for 4 ohm nominal speakers). Also, it should be rated for continuous peak current. This type of rating would account for the true capability of the power supply, rather than transient ratings that occur before the storage capacitance is drained and the supply has sagged. A secondary transient rating could be given for a fixed time period (that ideally would be correlated to typical musical dynamics), because there is often significant headroom for fast transients in a typical supply, especially in a class AB amp biased nearer to B.
Quoting Watts RMS at a particular frequency is really a comparison (Who sits in front of the speakers, listening to a sinewave?) like the procedure for measuring the fuel consumption of a car or the range of an electric car it’s just a comparison and not necessarily representative of the real world. I guess another approach would be to have a standard musical track lasting say, five minutes that incorporates various types of uncompressed music. The total average power is measured, and then divided by the time to come out with a power number. Clipping would not be allowed. To get a more accurate number, you would have to include transient power and slew rate etcetera. But the true way of measuring power handling capability, it’s probably with a 2 tone and a 3 tone test and then to measure the intermodulation distortion. This is what we do with radio-frequency amplifiers to measure linearity for a given power level.
I not to up on it all but if you got 12v 6amp power supply input and the amplifier claims to be 90% efficient, what would be the true watts unclipped be about, based on a class D tda7498 chip?
My humble view is PA specifications should contain peak output power per channel (all available channels driven) with some predefined low level of distortion (let's say, THD below 0.1%) for unlimited time period. The average loudness will depend on input signal statistics - dynamic range, for example.
Every Electrical & Electronics Engineer knows that (1V × 1A) AC = 1W , which means it's the Rms value (& not something " derived from P-P) that is the electrical equivalent of thermal power / heat produced in a "purely" resistive load of 1 Ohm. , that produces THE SAME power consumption / heat generation when passing 1A of DC current from a 1V DC source through the same resistor. so the method of explaining by juggling P-P ac to show such end results is IMHO flawed. Hence "RMS watts" or " continuous rated power" is more correct in specifications , even if not technically accurate ... Yet the question of how much is wasted as heat & how much is converted to music is a different matter altogether.
Isn't average power what hifi mags used to refer to as "continuous power"? From what I remember, power amps can push out a lot more watts for very short bursts (dynamic power), but cannot maintain that power long term. The other important issue is with, say, 100 watts into 8 ohms, what is the power into 4 ohms? Ideally, it should be 200 watts, etc, but with lesser amps the power does not double as the resistance is halved.
I thought you had to include the distortion figure to make the Watts RMS figure valid too. Ie. That accepting 10% THD would allow you to measure a higher power level than specifying 0.1% THD. Could you explain that part?
Is power about in this case about work done? The amplifier could be rated on a steady-state sine-wave but that's not what is actuallu amplified in real-world use. The work done will vary with the frequency of the signal. The work done in terms of energy transferred per second at 1V amplitude at 100Hz vs 10,000Hz would be higher at the higher frequency. More energy is transferred per second at the higher frequency. More work would need to be done to move the mass of a speaker cone and the air that's loading it per second if it maintains the 1V amplitude but has to move backwards and forwards 100 times more per second. The area under the voltage vs time graph would be greater at the higher frequency. 100 times more Joules per second needed. The intensity of the two frequencies would be very different. An amplifier with a music signal only produces brief moments of a range of given frequencies at a time and the intensity and frequencies are for small fractions of each second. The amplifier will mostly be doing very little work at any given frequency during a music signal. Music is made of continually varying collections of frequencies for very short periods of time and each of those frequencies also continually varies in amplitude. The amplifier just needs to be capable of transferring the required amounts of Joules per second as collections of undistorted waves that can do work driving the cone masses of the loudspeaker.
I think whatever way you measure the watts the most important thing is to have an amp matched to the speakers maybe with a slight cushion. 500 watt amp driving 500 watt speakers. NEVER crank the amp all the way it can spike over peak and damage speakers. Lastly if it sounds good it is good…. To you. 😃
Music laypersons like me have to have a consistent number to begin comparing amplifiers. I don't think any manufacturer should even be quoting X rms watts at 10% distortion 1 channel driven as its not how the product will ever be used. This is especially true of Home Theatre recievers !!! 🙄 🇬🇧
You have the right idea ... a standard measurement as a basis of comparison. That's why yardsticks are all the same length! Unfortunately a lot of manufacturers do cheat... they will measure up to the panic shutdown of the amplifier, or take readings at 10% distortion, or worse still there is the magic number of "Music Power" which is always way bigger. Big numbers sell products.
@@Douglas_Blake_579( ...all amp manuf ... & others) , ..all have been educated in similar ways and its only those who are able to think ..( & more so ) DO OUTSIDE THE BOX may present or produce something extraordinary /revolutionary that becomes a successful alternative.
Your channel is very fine. Its a prove for taste , profession and knowledge. - One question i do have : you used some harp- music in one of your videos. Where can i get this and can i get mor of it ? This music was so beautiful that my mind instantly stood still an was banned. Like in Einaudis´s music. This is no compliment. Its my feeling .
music is not a sine wave, music is NOT RMS it is actually a wave with very high peaks and valleys and a much lower average "work or heat" power, which makes peak to peak power (or output current in Amperes ), a more valuable number for music, HOW MUCH HEADROOM - do I have above average "heat power". while RMS is useful mostly for knowing how DURABLE is that amp, and ditto RMS if especially important for not burning your loudspeakers. how much "heat or work power" can it handle without over heating, (note if you push music signals into RMS average "heat power", you must be clipping)
A few years ago I starting gigging and needed a bass combo that I could drag around the London Underground. I chose a Hartke Kickback 12. Is it light and loud. Perfect. On the front, it stated it was a 500W amp. I was so embarrassed by this assertion that I immediately took a piece of gaffa tape and covered that bit of the faceplate.
Bass amps went class D a few years ago. I'm pretty certain digital watts have much less umph than analogue class AB watts. I think they were taking the power amp modules from car stereos and using them directly in bass amps, complete with the fictitious peak power claims.
In audio specification a Watt seems to be that piece of string that my physics teacher was talking about when he posed the question "How long is a piece of string?". ps I'm thinking of ditching the electric fire and listening to hot jazz instead.
Does my 160 wpc $80 Aiyima a07 give me deep, effortless, natural bass, rich mids and sparkling highs and do it loudly? No. Does my 150 wpc Emotiva? Yes. Are they both great for their price? Yes. In my limited experience, my receivers didn't sound as good as my amps. Maybe it was the low price I paid. To get the same sound quality, I would guess an integrated amp would cost 25% to 50% more than a similarly powerful amplifier.
Never look at the advertised watt rating for inexpensive class D because those are rated at 10% THD. Check out the real testing results like this: archimago.blogspot.com/2023/08/review-measurements-aiyima-a08-pro-ti.html
I think that the Number that manufacturers print on their boxes and in their brochures is pretty much pointless and only gives you an indication of how it is build. And with how it is build I don't mean good or bad but about their circuit philosophy. I categorize amps in 3 categories, 1 below 20w, 20-100w, above 100w. The point is, when listening music at home you will use something between 1-5 watts with over 90% of the speakers available, there are only very few speakers available that need more power like magnetostatic speakers or these kinds of things, but over 90% range between 85-90db efficiency therefore more than 5w starts to be pointless. The more interesting question is about the damping of the amp (damping means how much control your amp has over your speakers). It is a little counter-intuitive, but more damping does not equal better. There are speakers where more damping equals better and there are speaker where more equals worse. A B&W 801 with it's fairly heavy 12-inch woofer needs some control so an amp with high damping is very good but one of these vintage Tannoys with a very light 12-inch paper cone woofer does not want high damping so you could drive it with a tube amp (these amps have basically zero damping). In general you want an amp with as little amplification as possible but if you build a 10w amp then unfortunately it will not have any damping so even though more amplification equals worse sound quality in order to control your speaker a 100w amp might work better even if you are only using 5w
I did read one review of a speaker (can't remember which, some bookshelf job, I think) that "soaks up watts like an acoustic sponge". That description has stuck with me for decades! 🙂
@@stevemawer848 yes these kinds of speakers do exist, like a BBC 3/5 this legendary nearfield studio monitor. But it is an exception and not the average.
?? My brain hurts. Been buying hifi gear for 50 years. For me I have always found to buy gear where the amp power matches speaker capability ( using RMS quoted numbers ). Test the gear out in the shop in a room similar to your listening room size. Turn the volume knob up to 9 or 10 o'clock for normal personal listening levels, up to 12 noon to test for when you have just come back from the pub, or into the afternoon regions of 2 or 3 o'clock for party levels. Does this basic approach fill audiophiles with dread ?
I've seen a new budget pair of 8ohm bookshelf speakers from a manufacturer that also makes high end speakers with a claimed low impedance value of 6.4 ohms.! A few positive reviews Inc 1 on U tube about how musical they are for the price (£349 🇬🇧 pair) I assume these could be driven well by even the most "average" amplifier
I've never been too fussed about big numbers on amplifiers, you need low distortion with a flat frequency response for the dB volume you like to listen at.
Interesting subject, but I guess the gist of it is that 'rms' power as is often quoted in the manufacturers literature is the same as 'average' power, even though it's technically incorrect. More important is that doubling your power output only gives you a 3db increase in volume, which is audible, but just barely.
There actually is a standardized testing procedure that most (credible) manufacturers follow. As I explained in an earlier comment... Watts RMS simply means "watts calculated using RMS voltage" ... It amazes me that people can't figure that out.
I was looking at some amp specs following this. Don’t ask me why I went to McIntosh. They quote watts but don’t specify what type! If the type isn’t specified then what are they assumed to be?
My amp is not average Audio note ongaku And a beautiful hand made valve amp built by my dad who’s an ex radioham 1000 watt per channel used for nightclubs in the 80’s using tt21 valves ten of them on each bank no joke anyone who knows how to build amps will understand what I have is an amazing home hifi amp and one I cannot use as it’s brutal and would bring down a concrete ceiling
RMS or AVG. it does not matter to the ears...thats only for mathematical definition and clarity... As long as the loudspeaker system can handle the power outputted to it by the amp. , without annoying audible distortion to the listener and without it getting damaged or detoirating it's performance, it should not matter how much power is lost in heat or how much power is converted to sound energy , as long as the owner/listener is convinced that he/she is happy with it.
Why would you care about bandwidth beyond just over 20kHz as humans? You're not going to hear it and in fact some of that ultrasonic stuff can distort into the audible range.
I collect old Ghetto Blasters, The JVC DC-33L with Turntable has high power output for a Portable System, its 11w RMS X2 but sounds truely awful and not very loud, the original speakers are what lets this system down, 3.2ohm i think, there not even 2 way, the mock tweeter is bass port, speaker cones so stiff they hardly move, it doesn't sound very powerful for the output power but when you connect up some better bookshelf speakers this unit comes alive and sounds wonderful for what it is
Can I just point out that Audiophil works at Cheshire Audio in Crewe, and he doesn't sport anything like as much hair as the imposter in your video's :.) Oh and the last thing I would call myself is an audiophile and my power amp says Naim on the front, and it is far from average - it shows me all the cock-ups made in recording studio's all over the world every single day. Love the channel - I learn something from every video. Thanks.
Hello, are you there? I'm Watt. Yes, who are you? What's _What's your name name? Watt's my name. Yes, what's _\es, _\es, what's your name name? My name is John Watt. John what? Yes. Are you Jones? No. I'm Knott, Will you tell me your name then? Will Knott, Why not? My name is Knott, Not what? Not Watt, Knott.
That's not true. The Average Intelligence Level is the level that the majority of the population are assumed to be on, or very close to, at any given time. A much smaller number than 50% of people measure either above or below the Average on random IQ tests. Overall IQ levels of any large population are based on fuzzy, generalised estimates that are made unreliable by various factors, such as: What is actually being measured (testing methods and sample selection are not always consistent) and the fact that most people have never been measured for their IQ level.
@@donjohnstone3707 Grab a dictionary and look up "humour" ... Also you should know that the "average IQ" (not intelligence) is deliberately manipulated to be 100 ... half the word scores higher the other half score lower.
Another great video. What the figures actually represent is somewhat irrelevant, people who love hifi equipment have built a general expectation of what the figures should bring and that expectation is generally met. Most enthusiasts can spot a BS wattage figure quoted. Price and presentation are obvious giveaways.
@@obscurazone Vague terms may be endemic but they have to be since the outcomes are always subjective and we all have different ears (it'd be embarrassing to have to share just one!) and sound processing capabilities.
There is no such thing as Watts rms. It's a term used by marketing people with no technical background. RMS only applies to volts to convert ac signals to an equivalent dc value. It does not apply to Watts. The various miscalculations shown are just that, miscalculations. There is only 1 valid calculation from a sine wave voltage to Watts. The confusion with amplifier specifications come about because of continuous vs instantaneous or peak (music) power. Many amplifier circuits can output more power than their power supply can provide continuously so their continuous power is set by the power supply. Also be careful of multichannel amps. 1 channel may be rated at say 100W (100W power supply), but if all say all 5 channels are operating, the 100W has to be shared between the 5 channels. Peak power is much more deceptive. The power supply has output capacitors that can provide a short burst of much higher power, the shorter the burst, the higher the power. This is useful for loud bangs, gun shots or bass drum thumps, but cannot be simply specified. This is where the 100W continuous amp gets a headlining 1000W peak music power spec. Good amps will be spec'd at XXX Watts continuous @ 1kHz, both channels driven. This can be used to compare amp performance.
_" There is only 1 valid calculation from a sine wave voltage to Watts."_ Which voltage would that be? Peak, Peak to Peak, DC equivalent or, oh gosh, could it be RMS voltage? "Watts RMS" is engineering shorthand for "Wattage calculated using RMS voltage"... It's not a complex concept.
By the way, there is also the problem of phase shift between voltage and current when the resistance drops (or elevates). This is also of great influence in the delivery of power!
Yeah who cares about numbers and letters. Does it sound good, that's all that matters, put whatever numbers and letters you want on it I couldn't care less
You cannot produce an even slightly meaningful power figure by squaring the peak-to-peak voltage and dividing it by the resistance, even as a peak. There is never, ever, a voltage over the load from a pure sine wave of that sort with respect to the central point of the waveform so it is meaningless in that context. The only time where it could have a meaning is if the two outputs of an amplifier are operating in what is called "bridge mode", whereby the output of one is a mirror image (180 degrees out of phase) of the other. Then the load will see peaks which are equal to the peak-to-peak voltage, but if that is the case, it's necessary to show both (180 degree out of phase) sine waves, or if you just want absolute values, the difference between the two voltages. In effect, if the two sine waves are " a * sin(ωt)" and "a * sin(ωt+π)" where "a" is the amplitude (half the peak-to-peak voltage), ω is the frequency in radians per second and t is the time in seconds, then the signal across the load will be "a * (sin(ωt) - sin(ωt+π))" which equals "2a * sin(ωt)". So that does yield a sin wave with twice the peak to peak voltage, but only by taking the differential voltage of two power amps 180 degrees out out of phase. Note that another term for this is "differential mode", and there are amplifiers that do work like that. There are a lot of class "D" amplifiers that do, and they have 4 channels where they can be operated such that there are pairs operating in bridge mode. It's very useful where the DC voltage is low, such as in a car, as the power output can be quadrupled. However, when sketching out the signal output from the power amplifier, you can't have it both ways. That is draw a simple sine wave and claim that the peak power output is the square of the peak-to-peak voltage divided by the resistance. You either show both sine waves, or the output of the bridged output which will have double the amplitude. The peak output is never, ever, the square of the peak-to-peak voltage (double the amplitude) of a sine wave across the load. As far as what we hear, it isn't watts, it's sound pressure and that is conventionally measured in dBA, which is a logarithmic scale weighted according to the human ear's responses to different frequencies. Just what that means in terms of amplifier output wattage depends on a large number of other factors, such as the location of the speakers, their efficiencies, the nature of the acoustic environment and so on.
These some of the ones we studied (in a previous lifetime or at least it seems like it). en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws but after that I was more interested in soldered circuits together to make stuff. Anyhow Ohm's law has to be modified for music because its frequencies change things. Measure the decibels from your speakers with a smartphone these days.
Personally, and from memory during my decades long romantic affair with Hifi and the countless magazines that I had bought and read.....not to mention as many trips to Hifi dealerships, if at the halfway volume knob setting: my speakers sound too loud.....my amp has enough Ooomph and whatever square or root of its power, for my ears and is good enough! My "miserable" 15 Watts of power Quad II valve monoblocks can kick up more dust and put out more sound through my Quad ESL57s than the neighbours can bear! I rest my case!
I might stretch it some more in Photoshop next time. The sad fact is though that TH-cam rewards 'goofy face' thumbnails. I'd rather not be in them at all. DM
Let's cut to the point. I don't care if RMS is an inaccurate way of measuring power. Is not two different amps of the same rms the same power roughly. It's seems to me your argument is my weight of 183 pounds is wrong because I need to weigh myself by kilos! Yes I understand that a five hundred watt tube amp can be driven harder than a solid state or even class D, but all three have sufficient headroom to play cleanly at a low volume. I've got an old knight pa tube amp rated 50 watts. I guy scoped it and said it's really 60 watts but breaks up at fifty.
Interesting you should come across power output for cyclists. On a good day I can average 180 watts and peak 550-600 watts. Is it RMS though? 🤷♂️ No, in cycling terms it is usually measured on watts per kilo. For a 77kg chap like me that's around 2.34 watts per kilo. TDF riders are usually 3 times this.
I would guess that the aim would be to measure the equivalent heating power, same as in audio. Whether cycling power meters actually do this I shall leave for more dedicated cyclists than I to worry about. DM
In my opinion, we should not bother. Reason .....My NAD doesn't say, and my Denon does, but it massively exceeds watt goes in. So why bother. They are, however, both loud enough to upset my tinnitus and for the wife to say, " Turn that shit off "
You need to drive your speakers (quoted SPL at "1 watt" [what watt?] ) WITHOUT DISTORTION. The impedence of a speaker changes at different frequences too, not many I suspect listen to music comprised of a 1kHz tone. Did someone say inductance of a crossover? Is the rule of thumb to have an amplifier more powerful than the rated handling of the speakers, and "be careful" not turning it up to 11.
Saying that amp power is "average" is sort of "mean."
I see watt you did there. 😆
Genius. 😂
Ohm my God, clever....
@@bhidtrSw.65qqhwtsloUtDeklbne15 He did'nt have as much junk test equipment sitting around
That's getting to the root of it.
I can't recall what the Federal Trade Commission (FTC) specified when it cracked down on audio amplifier power claims back in the late '70s. But I always took it to mean watts calculated from the continuous RMS voltage of a sine wave, all channels driven, at the specified distortion, measured for all frequencies claimed in the frequency response, within one decibel. The output load was also specified. That was the performance I would shoot for when designing a power amplifier for a given "RMS power".
Now, RMS voltage depends on the waveform being analyzed. For a sine wave, it's root 2 over 2 times the peak voltage, or approximately 0.707. For a square wave, it's 1 times the peak voltage. For real music, it's... who knows? How loud are you playing it? How efficient are your speakers? How was it compressed, peak limited and clipped? Even the musical style, the amount of dynamic range contained in the original performance, and subsequently, how it was mixed and processed makes a big difference in the amount of actual power needed to reproduce it accurately and at a realistic volume. Of course, a lot of the fidelity may have been lost before it ever even hit the vinyl or CD.
Great answer.
Wow, such a controversy ....
The standard measurement used by most technicians and not a few engineers is to drive an amplifier up to clipping, back it down by 1%, read the RMS voltage across a dummy load then apply P = (V x V) / R to get the wattage.
20 volts RMS on 8 ohms will get you (20 x 20) /8 = 400/8 == 50 watts RMS.
The notation "Watts RMS" very simply means "wattage calculated using RMS voltage".
If I calculated using Peak voltage I would say... Watts Peak
If I calculated using Peak to Peak voltage I would say... Watts Peak to Peak
When I calculate using RMS voltage I say... Watts RMS
The "using" is implied ... as in "Watts _using_ Peak voltage" becomes Watts Peak.
Why do people have so much trouble with that???
We used to to it the DC heating effect in watts Before fancy hifi artisans decided to baffle the public with nonsense.
@@glpilpi6209
Yes, and?
It wasn't "fancy hifi artisans" who designed the current testing procedure... it was design engineers looking for a standardized test that could be administered easily.
The old hot resistor test relied too heavily upon the heat dissipation of the load... which even with "matched" resistors could vary over a wide range with variations in humidity, ambient temperature, airflow etc.
The test described above only cares what the ohmic value of the dummy load is.
Yeah, your right
It's a standardised way of comparing different amplifiers. And that's what counts!
Ideally it should include declaration for distortion measured at the claimed power output along with impedance. So 100w RMS per channel @ 8ohm with (say) 1% distortion. Knowing level of Distortion and when it occurs is essential for comparison. It should be declared as false advertising for power output claims that fail to mention important specifics. And that's where the fudge factor takes off with the cheap chip amps. It's absolutely ridiculous how the established method is disgarded. Example: quoted output can be doubled (2x channels) the load is lowered to 4ohms and most crazy of all, peak power is used at a Tweeter popping 10% distortion. Lower distortion values on these amps are capable of typically appear on a different line on the spec list, at an unknown output level. Only clue you will get towards realising they have no relation at the claimed max output.
@@SuperBicycleRepairMan
I agree ... and when I write wattage I always include both impedance and distortion as part of the spec.
The best way with these chip-amps is to look up the spec sheets for the chips. If you don't have the measuring equipment to verify outputs, this will at least get you into the ballpark.
For example if you search for "TPA3255 Spec Sheet" you will discover a world of detail about any amp containing the TPA3255 chip... It behaves the same way no matter what brand or price of amplifier it's in. (Of course substitute other part numbers for other chips... 😉)
Dummy loads are resistive loads unless I'm miles off here no?
Speakers are capacitive loads (potentially huge impedance (resistance really ie if you took a snap shot in time)).. they also generate electricity via inductance. Ie back EMF.
There is soooo much more.to it than voltage/current output into a given resistance (yes, ie dummy.load).
Damping factor?
Slew rate?
Power supply reserve capacitance?
Buy an 20+ year old BSS EPC series amp 760 or 780 which I have. It benches at 1625w rms.@ 2ohms sustained over enormous time frames... yes ohms law etc...
However LISTEN to the amp perform.. you don't even need high end speakers, mediocre ones will suffice. There is an immediacy, impact, slam, grip, and sheer effortlessness to the sound yet at the same time a silky smooth, soft, subtle, jaw dropping delivery to the mids and highs.
I agree with the video author however MY amp is definately not average lol.
Fun fact.. these amps were chosen for.the turbosound flash and floodlight PA systems in the 90s and built at a loss to be the best amps in the world.
None of this really matters long as you have a good strong Poweramp to drive your speakers at the SPL that you're comfortable with without blowing your speakers and if your amplifier has enough in the power rails that it doesn't sag during high-powered transients
I listen to music the majority of the time at levels less than 1 watt. If I turn it up, I bump maybe 2 watts. Prolonged periods at those levels would challenge longterm hearing health.
Yep.10 Watts is bloody loud.
😢
@@fatfreddy8089 That rather depends on the efficiency of your speakers, Shirley?
Exactly , most of the time an amp is ticking over , if the rest the of the chain is property matched . If you need to listen at a high volume something isn't right or you have horrendously inefficient speakers.
This is relative to listening distance and room size though. Concert at 1 watt would sure be a pitty even 30 feet away aye
The value of RMS is derived from squaring the values of the sine wave, (the negative side climbers up), finding the area of the new wave form and divide it by the length (an integral) In such case sine waves will show a ratio of 0.707 of the amplitude.
The average value of the sine wave without squaring the values is 0.623
I hope I remember the average ratio correctly, been ages since I learned this and no one uses the avarage ratio, only RMS is used for obvious reasons
If your amplifiers output is sag'ing
The cause is usually that its Power Supply is failing to deliver the energy that the amps power output stage has demanded.
Few domestic audio amplifiers are designed for continuous rating anywhere near their maximum transient power.
This is possible because we don't need to generate a continuous sine wave at maximum power ..
We are listening to music which ( unless overly processed) likely has an average power of about 30% of the amplifiers transient response power.
( therefore the designer does NOT need to design a Power Supply with the capacity to deliver the amplifier's " Full " rating continuously )
Hence if you attempt to obtain it's transient rating continuously.. it's output falls off ( sags ) 😊
Maybe we don't need to generate or listen to a full sinewave signal on our system, but, the fact is, we should be able to do it, if the following situation occurs: we are watching or listening to some musical material on TH-cam, near the maximum output of the amplifier, and, suddenly, its predictive listener experience algorithms drop a material about testing an amplifier continuous power output.
You are not close enough to the be able to reduce the volume of your audio system and, suddenly, the test sinewaves, at 40 Hz , 400 Hz, 1 kHz, etc, used in the material start blasting through the system and you don't have a limiter deployed.
Result: bye bye amplifier, bye bye tweeters, bye bye woofers.
Fact: in today's world, the chance of encountering over processed/over compressed audio materials, especially on the streaming platforms, is very high.
Conclusion: don't use any amplifier which is not able to withstand at least 5 minutes of 1 kHz full sinewave at full power output.
Back in the early 80’s I used to sell audio and we had Harmonic Kardon. One day one of the engineers paid us a visit and gave me a small little box, and in it was a nine cold battery and two RCA outputs. He told me that this was a better measurement of what an amplifier could do and would show current in an amp. It emited a pulse, the woofer would move back and forth. Every Harmon Kardon amp connected could push that woofer back and forth with no issue, even large ones. When I connected Japanese receivers or amplifiers the woofer would barely move. One day I’d like to know that current is also something that is recognized or these “high current” amps “there are some still” are as you say, audio phoolery 😮
It is even more complicated because the load of an amp normally not a resistor. A loudspeaker is a complex (reactive) load, the resistance of an '8 ohm' speaker can drop at some frequencies to 1 ohm!! Most amps can not deliver the current (and the 'rms' power) that is required at 1 ohm. It is better to have a modest power amp that is capable to deliver enough current! Keep going with your channel, you ar a very nice story teller (even for my age :)
Rob (from Holland)
Now that I am an aging hipster, the volume control is normally set at 9 o’clock. If I can hear all the soft and loud musical bits, I am pleased. So my aging 37 wpc amp is a great companion.
The volume control is really just an indication of the strength of the input signal rather than a measure of how loud things sound.
Dear David. I have viewed this video a few times ( because I'm dutch and it take me a bit more effort to follow English, totally my fault ) and I looked at the info in the link. I believe it isn't that complicated. Let's use your example of 1 V rms over a 1 Ohm resistive load. Starting with 2.828 V p-p, divide it by 2 = 1.414 V p(peak). The current is 1.414 V p / 1 Ohm = 1.414A p(peak). Power is the multiplication of Voltage and Current. 1.414 V p * 1.414 A p = 2 W p(peak). Now we can say: to convert the peak voltage to rms divide the peak value by SQR2 ( 1.414 / SQR2=1 ) the same apply for current. This means that the conversion from Power-peak to rms is the following: P p / (SQR2 * SQR2 ) --> Power-peak / 2=power rms.
I'm finding it difficult to fault your logic. Perhaps other mathematical brains can join in this thread. DM
When looking at power amplifier output I look at how the power is quoted. If it’s just at 1 KHz and 10% THD with one channel driven it’s pretty safe to say that’s useless info.
My NAD amplifier is quoted as continuous power output >50W at 20Hz - 20KHz, both channels driven at 8 ohms and 0.009% THD.
That’s enough to say to me that under normal usage conditions with my 8 ohm 90 db/W/M speakers that I have more than enough clean usable power in my living room. I probably only peak at 1 or 2 watts of power output at the very most.
Even if "Watts RMS" is wrong, at least it is a standard that can be easily applied to
any number of amplifiers tested by the same method and then used to compare them.
In other words, let's Keep doing it wrong so we don't have to Test Everything All Over Again to a Correct standard.
Agreed, it's like the published figures for fuel (or electrons) consumed by a car - meaningless in itself for the real world but useful to compare against others.
When you apply a sinusoidal voltage to an amplifier the output waveform is sinusoidal and so is the current through the load. However, when you multiply the voltage by the current and plot it on a graph you get the power waveform. The power waveform is a strange non-sinusoidal shape that obviously never goes negative. My college maths lecturer said that power is an imaginary quantity because the only real things present are voltage and current.
The power amplifiers I built provide 46.6 volts RMS across an 8 ohm load just prior to clipping which is how I measure the output. No need to calculate the output power into imaginary units.
Why is power imaginary and why are voltage and current not? They are as much imaginary when you consider they represent the flow dynamics of electrons through atomic crystals, which are realer than current and voltage.
@@l.s.1709 Well if you consider current and voltage to be imaginary then the product of them must also be imaginary. Anyway, you can measure the voltage across a load and the current through it. Now if you want to multiply the current by the voltage you can call it power. However, it's really volt amps.
@@jimdavis5230you're reinforcing my point.
I have glossed over the replies to MC's vid, and I apologize if any comments were related to my post. First off, what kind of amps are we talking about? SS, hybrid or valve (tube). There topology is different when driving speakers (and what kind of speaker your driving). Speaker efficiency is paramount in tandem with the amplifier. Amplifier loading varies greatly. SS (solid state) amps (class A, AB and D) load voltage differently due to there topology. Tubes are stage gains in amplification (continuous power) through there rated transformers. Watts are only a combination of values (volts*amps* to 1J (W) over distance, ect.). Voltages (and current) are really the key factor when driving speakers. The input signal is DC current (0.4v to 3.0v max). The amplifier takes that signal voltage and "amplifies" that signal (0.4v = low gain to 3.0v = max gain or RMS). The truth about watts when it relates to current supplied to the speaker (volts/amps) is the speaker itself. @ 1 watt, the efficiency of the speaker will determine how that watt is driven. Low efficiency speakers will not produce much work (load) through the speaker. Where as high efficiency speakers will produce a more audible load. Less watts are needed to achieve higher gain (volume) loads on high efficiency speakers. @ 20watts, a 96db speaker will produce a high range of sound (decibels) than low efficiency speakers which require more current load (watts) to produce the same loudness gain. Even low efficiency speakers will use around 40 to 60 watts per channel to achieve high gains (loudness) with a good, stable power (driven) source. The basis for MC's video shows the actual (driven) loads required when using speakers as a load reference. If you have a good pair of speakers (depending on the efficiency) you would be hard pressed (and possibly go deaf) when driving your speakers @ 100w per channel continuous loads (even under extreme low end bass frequencies). Most speakers load at around 30 watts per channel comfortably and the gain is actually quite high. Low efficiency speakers do well at around 50 watts per channel. So, what do you even need a 1000 watt BS amp for? Even if that amp could produce 1000 watts, you will only be using a fraction of that power to drive your speakers comfortably.
I am neither an audiophile nor an electrical engineer,. I do know that when I run these two big speakers in my field (15" EV Woofers. JBL 2425 Drivers with Renkus Heinz lenses and some nondescript crossovers) with an old Sansui 661 (15w) or the Marantz 1060 (60w), I get beautiful clean deep tones at volumes that shake the neighbors before I hit the midway point on the volume pots. Still.... I find your talks entertaining and I'm even learning a little bit. Thanks for the insights.
Two big problems, First, whilst my main current main amp is rated at 40W RMS per channel, it will probably never produce that, that is unless I listen to lots of organ music, and then ride the volume control to maximise the output without hitting the clipping point, quite hard and kind of pointless. 95% of my music will never produce more than a handful of watts from that amp, assuming I keep it below clipping (Except my AC/DC tracks, where clipping is usually not noticeable, sometimes beneficial, excellent tweeter destructor)
The other problem is 99% of speakers have a very dynamic impedance curve, and an amplifier has to be able to keep its set output signal voltage level even if the speaker's impedance drops from, say 8 ohms to 2 ohms. (which actually means the amp has to put out bursts of way more power, do the math but with 2 instead of 8 ohms) If it cannot hold the voltage level then one hears a pile of distortion as it's output crashes.
This is the problem with a lot of those mini high power amps you find using Google, once you get past that bull quoted ratings, using something like PMPO rather than RMS, (and they add the two channels together for 2X, something real HiFi does not) you also have to then derate them an awful lot to allow for normal speaker impedance dynamics. they have NO margin for a load that drops it's impedance below the rates 4 or 8 ohms they quoted, so best of luck getting a good 10W out of that 600W mini beast you just ordered.
One small mistake, and it is small but in hi-fi and pedantry that's where the fun is: what you're trying to say is not "your power amp is average." you're trying to say "your amp power is an average."
Yeh, but that is not click bait (for audiophiles)
I have thought for some time that power amps should be rated for continuous peak voltage at a given load value (which really should be more like 6 ohms resistive to account for 8 ohm nominal speakers, or 3 ohms resistive for 4 ohm nominal speakers). Also, it should be rated for continuous peak current. This type of rating would account for the true capability of the power supply, rather than transient ratings that occur before the storage capacitance is drained and the supply has sagged. A secondary transient rating could be given for a fixed time period (that ideally would be correlated to typical musical dynamics), because there is often significant headroom for fast transients in a typical supply, especially in a class AB amp biased nearer to B.
Love these comments.
On a side note, I thought was just here to compare notes.
Think I learned something today.
Quoting Watts RMS at a particular frequency is really a comparison (Who sits in front of the speakers, listening to a sinewave?) like the procedure for measuring the fuel consumption of a car or the range of an electric car it’s just a comparison and not necessarily representative of the real world.
I guess another approach would be to have a standard musical track lasting say, five minutes that incorporates various types of uncompressed music. The total average power is measured, and then divided by the time to come out with a power number. Clipping would not be allowed.
To get a more accurate number, you would have to include transient power and slew rate etcetera.
But the true way of measuring power handling capability, it’s probably with a 2 tone and a 3 tone test and then to measure the intermodulation distortion. This is what we do with radio-frequency amplifiers to measure linearity for a given power level.
I not to up on it all but if you got 12v 6amp power supply input and the amplifier claims to be 90% efficient, what would be the true watts unclipped be about, based on a class D tda7498 chip?
Many AVR's and budget class D amps really go overboard on faking true output.
My humble view is PA specifications should contain peak output power per channel (all available channels driven) with some predefined low level of distortion (let's say, THD below 0.1%) for unlimited time period. The average loudness will depend on input signal statistics - dynamic range, for example.
Every Electrical & Electronics Engineer knows that
(1V × 1A) AC = 1W , which means it's the Rms value (& not something " derived from P-P) that is
the electrical equivalent of thermal power / heat produced in a "purely" resistive load of 1 Ohm. , that produces THE SAME power consumption / heat generation when passing 1A of DC current from a 1V DC source through the same resistor. so the method of explaining by juggling P-P ac
to show such end results is
IMHO flawed.
Hence "RMS watts" or
" continuous rated power" is more correct in specifications , even if not technically accurate ...
Yet the question of how much is wasted as heat & how much is converted to music is a different matter altogether.
Isn't average power what hifi mags used to refer to as "continuous power"? From what I remember, power amps can push out a lot more watts for very short bursts (dynamic power), but cannot maintain that power long term. The other important issue is with, say, 100 watts into 8 ohms, what is the power into 4 ohms? Ideally, it should be 200 watts, etc, but with lesser amps the power does not double as the resistance is halved.
Specs should be stated: X Watts with a signal of 1000 Hz at an input of Y Volts output in Z Ohms.
One of my sweetest sounding amps IN NEAR FIELD has a max output of 0.75w through reasonably sensitive Castle monitors (71A diy SET).
Thanks this is a good start to that Amplifier power video I asked about : P Legend !
I thought you had to include the distortion figure to make the Watts RMS figure valid too. Ie. That accepting 10% THD would allow you to measure a higher power level than specifying 0.1% THD. Could you explain that part?
Is it any coincidence that audio Phil looks like a typical salesman at a high end audio shop between '75 and '85?
Is power about in this case about work done? The amplifier could be rated on a steady-state sine-wave but that's not what is actuallu amplified in real-world use. The work done will vary with the frequency of the signal. The work done in terms of energy transferred per second at 1V amplitude at 100Hz vs 10,000Hz would be higher at the higher frequency. More energy is transferred per second at the higher frequency. More work would need to be done to move the mass of a speaker cone and the air that's loading it per second if it maintains the 1V amplitude but has to move backwards and forwards 100 times more per second. The area under the voltage vs time graph would be greater at the higher frequency. 100 times more Joules per second needed. The intensity of the two frequencies would be very different. An amplifier with a music signal only produces brief moments of a range of given frequencies at a time and the intensity and frequencies are for small fractions of each second. The amplifier will mostly be doing very little work at any given frequency during a music signal. Music is made of continually varying collections of frequencies for very short periods of time and each of those frequencies also continually varies in amplitude. The amplifier just needs to be capable of transferring the required amounts of Joules per second as collections of undistorted waves that can do work driving the cone masses of the loudspeaker.
I think whatever way you measure the watts the most important thing is to have an amp matched to the speakers maybe with a slight cushion. 500 watt amp driving 500 watt speakers. NEVER crank the amp all the way it can spike over peak and damage speakers. Lastly if it sounds good it is good…. To you. 😃
What is a 500 watt speaker?
@@cubemerula5264 It's a colloquial way of saying a speaker capable of handling a 500 watt input without being destroyed.
Music laypersons like me have to have a consistent number to begin comparing amplifiers.
I don't think any manufacturer should even be quoting X rms watts at 10% distortion 1 channel driven as its not how the product will ever be used.
This is especially true of Home Theatre recievers !!! 🙄 🇬🇧
You have the right idea ... a standard measurement as a basis of comparison. That's why yardsticks are all the same length!
Unfortunately a lot of manufacturers do cheat... they will measure up to the panic shutdown of the amplifier, or take readings at 10% distortion, or worse still there is the magic number of "Music Power" which is always way bigger.
Big numbers sell products.
How you arrive at a particular value is interesting in itself but is not too useful unless all the amp manufacturers are using that same method.
For the most part ... they are.
@@Douglas_Blake_579( ...all amp manuf ... & others) , ..all have been educated in similar ways and its only those who are able to think ..( & more so )
DO OUTSIDE THE BOX may present or produce something extraordinary /revolutionary that becomes a successful alternative.
@@analoghardwaretops3976
Hey ... aren't you the guy who invented the 16 inch yardstick?
@@Douglas_Blake_579 YEAH YEAH YEAH...for that 16 " yardstick ..each inch was
B.S. 2.25" long..
Your channel is very fine. Its a prove for taste , profession and knowledge. - One question i do have : you used some harp- music in one of your videos. Where can i get this and can i get mor of it ? This music was so beautiful that my mind instantly stood still an was banned. Like in Einaudis´s music. This is no compliment. Its my feeling .
open.spotify.com/track/1TWcWgeiPKdG0rPVB3YC26?si=0be3604ae6c44d21
Fun stuff, once again
I have a Parasound 2350 with 600 x 2. I don't worry about enough power.
music is not a sine wave, music is NOT RMS
it is actually a wave with very high peaks and valleys and a much lower average "work or heat" power,
which makes peak to peak power (or output current in Amperes ), a more valuable number for music,
HOW MUCH HEADROOM -
do I have above average "heat power". while RMS is useful mostly for knowing how DURABLE is that amp, and ditto RMS if especially important for not burning your loudspeakers.
how much "heat or work power" can it handle without over heating, (note if you push music signals into RMS average "heat power", you must be clipping)
A few years ago I starting gigging and needed a bass combo that I could drag around the London Underground.
I chose a Hartke Kickback 12. Is it light and loud. Perfect.
On the front, it stated it was a 500W amp. I was so embarrassed by this assertion that I immediately took a piece of gaffa tape and covered that bit of the faceplate.
Bass amps went class D a few years ago. I'm pretty certain digital watts have much less umph than analogue class AB watts.
I think they were taking the power amp modules from car stereos and using them directly in bass amps, complete with the fictitious peak power claims.
In audio specification a Watt seems to be that piece of string that my physics teacher was talking about when he posed the question "How long is a piece of string?". ps I'm thinking of ditching the electric fire and listening to hot jazz instead.
Does my 160 wpc $80 Aiyima a07 give me deep, effortless, natural bass, rich mids and sparkling highs and do it loudly? No. Does my 150 wpc Emotiva? Yes. Are they both great for their price? Yes. In my limited experience, my receivers didn't sound as good as my amps. Maybe it was the low price I paid. To get the same sound quality, I would guess an integrated amp would cost 25% to 50% more than a similarly powerful amplifier.
That's probably because the Aiyima is only 50 watts per channel.
Do a search for the "tpa3255 spec sheet" you'll see...
Never look at the advertised watt rating for inexpensive class D because those are rated at 10% THD. Check out the real testing results like this:
archimago.blogspot.com/2023/08/review-measurements-aiyima-a08-pro-ti.html
I think you should give audio Phil a break. He spent more money on his stereo than I spent on my education, and it shows.
I think that the Number that manufacturers print on their boxes and in their brochures is pretty much pointless and only gives you an indication of how it is build. And with how it is build I don't mean good or bad but about their circuit philosophy. I categorize amps in 3 categories, 1 below 20w, 20-100w, above 100w. The point is, when listening music at home you will use something between 1-5 watts with over 90% of the speakers available, there are only very few speakers available that need more power like magnetostatic speakers or these kinds of things, but over 90% range between 85-90db efficiency therefore more than 5w starts to be pointless.
The more interesting question is about the damping of the amp (damping means how much control your amp has over your speakers). It is a little counter-intuitive, but more damping does not equal better. There are speakers where more damping equals better and there are speaker where more equals worse. A B&W 801 with it's fairly heavy 12-inch woofer needs some control so an amp with high damping is very good but one of these vintage Tannoys with a very light 12-inch paper cone woofer does not want high damping so you could drive it with a tube amp (these amps have basically zero damping).
In general you want an amp with as little amplification as possible but if you build a 10w amp then unfortunately it will not have any damping so even though more amplification equals worse sound quality in order to control your speaker a 100w amp might work better even if you are only using 5w
I did read one review of a speaker (can't remember which, some bookshelf job, I think) that "soaks up watts like an acoustic sponge". That description has stuck with me for decades! 🙂
@@stevemawer848 yes these kinds of speakers do exist, like a BBC 3/5 this legendary nearfield studio monitor. But it is an exception and not the average.
@@snakeoilaudio That rings a bell! Made by Rogers, if memory serves.
@@stevemawer848 yes, the design was licensed to 7 different manufacturers, Rodgers, Spendor, Harbeth etc
Nice microphone!
AKG C414 EB. Diaphragm needs a clean.
Thats a hell of an audio room.
Green screen
?? My brain hurts. Been buying hifi gear for 50 years. For me I have always found to buy gear where the amp power matches speaker capability ( using RMS quoted numbers ). Test the gear out in the shop in a room similar to your listening room size. Turn the volume knob up to 9 or 10 o'clock for normal personal listening levels, up to 12 noon to test for when you have just come back from the pub, or into the afternoon regions of 2 or 3 o'clock for party levels. Does this basic approach fill audiophiles with dread ?
No.
I have a class D amplifier which never heats so much. I guess it is very efficient.
Music is an uneven load. Loud parts and silent parts. Is it not what is buffered in the capacitors that matters?
Is it April 1st already?😉
I've seen a new budget pair of 8ohm bookshelf speakers from a manufacturer that also makes high end speakers with a claimed low impedance value of 6.4 ohms.!
A few positive reviews Inc 1 on U tube about how musical they are for the price (£349 🇬🇧 pair)
I assume these could be driven well by even the most "average" amplifier
I've never been too fussed about big numbers on amplifiers, you need low distortion with a flat frequency response for the dB volume you like to listen at.
Interesting subject, but I guess the gist of it is that 'rms' power as is often quoted in the manufacturers literature is the same as 'average' power, even though it's technically incorrect. More important is that doubling your power output only gives you a 3db increase in volume, which is audible, but just barely.
There actually is a standardized testing procedure that most (credible) manufacturers follow.
As I explained in an earlier comment... Watts RMS simply means "watts calculated using RMS voltage" ... It amazes me that people can't figure that out.
I was looking at some amp specs following this. Don’t ask me why I went to McIntosh. They quote watts but don’t specify what type! If the type isn’t specified then what are they assumed to be?
The assumed default is watts calculated from RMS voltage.... Watts RMS
My amp is not average
Audio note ongaku
And a beautiful hand made valve amp built by my dad who’s an ex radioham 1000 watt per channel used for nightclubs in the 80’s using tt21 valves ten of them on each bank no joke anyone who knows how to build amps will understand what I have is an amazing home hifi amp and one I cannot use as it’s brutal and would bring down a concrete ceiling
RMS or AVG. it does not matter to the ears...thats only for mathematical definition and clarity...
As long as the loudspeaker system can handle the power outputted to it by the amp. , without annoying audible distortion to the listener and without it getting damaged or detoirating it's performance, it should not matter how much power is lost in heat or how much power is converted to sound energy , as long as the
owner/listener is convinced that he/she is happy with it.
Oh, there are different types of power?
I've always thought that power is the product of voltage and amperage.
Oh, thanks.😮
Rotel RB 1582MKII is my power amp and I LOVE it! It easily drives my B&W 802D2's and it's damping factor of 800 is also very nice. Cheers.
So if my T+A PA3100HV integrated has a manufacture's rating of: RMS output per channel into 8 Ohms: 300 watts
RMS output per channel into 4 Ohms: 500 watts
Peak output into 8 Ohms: 380 watts
Peak output into 4 Ohms: 700 watts
Power bandwidth: 1Hz - 150kHz
Frequency response + 0 / - 3 dB: 0.5Hz - 180kHz
Slew guess: 60V/µs
Damping factor: > 65
Signal/noise ratio: > 115dB
Total harmonic distortion:
Who cares, all that matters is that it sounds good
Put whatever numbers and letters you like on it, I couldn't care less
@@crazyprayingmantis5596 I am just wonder what the math works out to be.
so my amp is average? just like your videos😁
Hmm, I've looked at my TH-cam statistics and, by inference, your amp is actually doing pretty well. DM
@@AudioMasterclasspretty well,average… Potato, potahto😂. keep up the good work😊👍🏻
A own 2 class D mono amplifiers . For me its really not interesting if it's in real life 25%. 25% of 1200W is still more than enough
To me , a full bandwith (5-50k) is a better indicator of what’s at hand.
Why would you care about bandwidth beyond just over 20kHz as humans? You're not going to hear it and in fact some of that ultrasonic stuff can distort into the audible range.
I collect old Ghetto Blasters, The JVC DC-33L with Turntable has high power output for a Portable System, its 11w RMS X2 but sounds truely awful and not very loud, the original speakers are what lets this system down, 3.2ohm i think, there not even 2 way, the mock tweeter is bass port, speaker cones so stiff they hardly move, it doesn't sound very powerful for the output power but when you connect up some better bookshelf speakers this unit comes alive and sounds wonderful for what it is
Can I just point out that Audiophil works at Cheshire Audio in Crewe, and he doesn't sport anything like as much hair as the imposter in your video's :.)
Oh and the last thing I would call myself is an audiophile and my power amp says Naim on the front, and it is far from average - it shows me all the cock-ups made in recording studio's all over the world every single day.
Love the channel - I learn something from every video. Thanks.
Sounds good to Me!
Hello, are you there? I'm Watt. Yes, who are you? What's _What's your name name? Watt's my name. Yes, what's _\es, _\es, what's your name name? My name is John Watt. John what? Yes. Are you Jones? No. I'm Knott, Will you tell me your name then? Will Knott, Why not? My name is Knott, Not what? Not Watt, Knott.
Speaking of "average" ... we do live in a world where 50% of the population has a below average IQ.
That's not true. The Average Intelligence Level is the level that the majority of the population are assumed to be on, or very close to, at any given time. A much smaller number than 50% of people measure either above or below the Average on random IQ tests. Overall IQ levels of any large population are based on fuzzy, generalised estimates that are made unreliable by various factors, such as: What is actually being measured (testing methods and sample selection are not always consistent) and the fact that most people have never been measured for their IQ level.
The really great news is that 50% of the population have above average IQ.
@@donjohnstone3707
Grab a dictionary and look up "humour" ...
Also you should know that the "average IQ" (not intelligence) is deliberately manipulated to be 100 ... half the word scores higher the other half score lower.
Speaking of statistics - most people have more than the average number of legs.
@@rogerking7258 and arms
Another great video.
What the figures actually represent is somewhat irrelevant, people who love hifi equipment have built a general expectation of what the figures should bring and that expectation is generally met. Most enthusiasts can spot a BS wattage figure quoted. Price and presentation are obvious giveaways.
Why doesn't my Marantz surround receiver sound as good (two channel) as my BasX even though it cost over three times as much?
Because Marantz is overpriced Denon
What do you mean when you say "doesnt sound as good"? Vague terms are endemic in hifi land.
Because it is surround, how many amplifiers on the tits of one puny power supply?
@@obscurazone Vague terms may be endemic but they have to be since the outcomes are always subjective and we all have different ears (it'd be embarrassing to have to share just one!) and sound processing capabilities.
@@obscurazone To me, it sounds warmer and less dynamic whereas my BasX sounds more neutral with crisper highs and upper mids.
There is no such thing as Watts rms. It's a term used by marketing people with no technical background. RMS only applies to volts to convert ac signals to an equivalent dc value. It does not apply to Watts. The various miscalculations shown are just that, miscalculations. There is only 1 valid calculation from a sine wave voltage to Watts. The confusion with amplifier specifications come about because of continuous vs instantaneous or peak (music) power. Many amplifier circuits can output more power than their power supply can provide continuously so their continuous power is set by the power supply. Also be careful of multichannel amps. 1 channel may be rated at say 100W (100W power supply), but if all say all 5 channels are operating, the 100W has to be shared between the 5 channels. Peak power is much more deceptive. The power supply has output capacitors that can provide a short burst of much higher power, the shorter the burst, the higher the power. This is useful for loud bangs, gun shots or bass drum thumps, but cannot be simply specified. This is where the 100W continuous amp gets a headlining 1000W peak music power spec. Good amps will be spec'd at XXX Watts continuous @ 1kHz, both channels driven. This can be used to compare amp performance.
_" There is only 1 valid calculation from a sine wave voltage to Watts."_
Which voltage would that be? Peak, Peak to Peak, DC equivalent or, oh gosh, could it be RMS voltage?
"Watts RMS" is engineering shorthand for "Wattage calculated using RMS voltage"... It's not a complex concept.
None of this makes much difference if you married a volume control ☹
Why don't audiofools just get a pair of studio monitors?
I was well gel of your lounge set up , but it wasn’t your lounge 😂
By the way, there is also the problem of phase shift between voltage and current when the resistance drops (or elevates). This is also of great influence in the delivery of power!
Put whatever numbers and letters you like on it, i couldn't care less, all that matters is if it sounds good in your room
Is there anything sensible about the often heard comment that Tube watts offer more of that oomph
This is a topic I may address in a future video. Also why British watts are more powerful than American watts. DM
Just listen to it
Yeah who cares about numbers and letters.
Does it sound good, that's all that matters, put whatever numbers and letters you want on it I couldn't care less
Sorry missed out the 2, 🤔
You cannot produce an even slightly meaningful power figure by squaring the peak-to-peak voltage and dividing it by the resistance, even as a peak. There is never, ever, a voltage over the load from a pure sine wave of that sort with respect to the central point of the waveform so it is meaningless in that context.
The only time where it could have a meaning is if the two outputs of an amplifier are operating in what is called "bridge mode", whereby the output of one is a mirror image (180 degrees out of phase) of the other. Then the load will see peaks which are equal to the peak-to-peak voltage, but if that is the case, it's necessary to show both (180 degree out of phase) sine waves, or if you just want absolute values, the difference between the two voltages. In effect, if the two sine waves are " a * sin(ωt)" and "a * sin(ωt+π)" where "a" is the amplitude (half the peak-to-peak voltage), ω is the frequency in radians per second and t is the time in seconds, then the signal across the load will be "a * (sin(ωt) - sin(ωt+π))" which equals "2a * sin(ωt)". So that does yield a sin wave with twice the peak to peak voltage, but only by taking the differential voltage of two power amps 180 degrees out out of phase.
Note that another term for this is "differential mode", and there are amplifiers that do work like that. There are a lot of class "D" amplifiers that do, and they have 4 channels where they can be operated such that there are pairs operating in bridge mode. It's very useful where the DC voltage is low, such as in a car, as the power output can be quadrupled.
However, when sketching out the signal output from the power amplifier, you can't have it both ways. That is draw a simple sine wave and claim that the peak power output is the square of the peak-to-peak voltage divided by the resistance. You either show both sine waves, or the output of the bridged output which will have double the amplitude. The peak output is never, ever, the square of the peak-to-peak voltage (double the amplitude) of a sine wave across the load.
As far as what we hear, it isn't watts, it's sound pressure and that is conventionally measured in dBA, which is a logarithmic scale weighted according to the human ear's responses to different frequencies. Just what that means in terms of amplifier output wattage depends on a large number of other factors, such as the location of the speakers, their efficiencies, the nature of the acoustic environment and so on.
What's a Watt?
one Joule per second.
Also 1 amp on 1 volt for one second.
No peak to peak no noise from speaker
nice
I'm going revisit this vid, 🎹
Ok..interesting 🧐
I just run a headphone setup.
2 watts and I’m good .
Bryston BHA-1 ..I’m good 😊
Have a Mark Levinson dual mono amp 100wpc 8 ohms, rated down to 2 ohms - 400wpc. It’s 104lbs. However my 6wpc custom tube amp is my preferred amp.
My brain hurts.
Not as much as mine making this vid. DM
The true power of an amp is the equivalent of the DC power it could deliver
These some of the ones we studied (in a previous lifetime or at least it seems like it). en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws but after that I was more interested in soldered circuits together to make stuff. Anyhow Ohm's law has to be modified for music because its frequencies change things. Measure the decibels from your speakers with a smartphone these days.
So i need to connect my amp to my bicycle and see how fast/far it goes to know the true wattage 😮 got it😊
Average is okay, or at least it's predictable lol.
Personally, and from memory during my decades long romantic affair with Hifi and the countless magazines that I had bought and read.....not to mention as many trips to Hifi dealerships, if at the halfway volume knob setting: my speakers sound too loud.....my amp has enough Ooomph and whatever square or root of its power, for my ears and is good enough!
My "miserable" 15 Watts of power Quad II valve monoblocks can kick up more dust and put out more sound through my Quad ESL57s than the neighbours can bear! I rest my case!
That must be the longest index finger in living history😂 Had to say before I watch .. d''oòhooooo❤😂
I might stretch it some more in Photoshop next time. The sad fact is though that TH-cam rewards 'goofy face' thumbnails. I'd rather not be in them at all. DM
Let's cut to the point.
I don't care if RMS is an inaccurate way of measuring power. Is not two different amps of the same rms the same power roughly.
It's seems to me your argument is my weight of 183 pounds is wrong because I need to weigh myself by kilos!
Yes I understand that a five hundred watt tube amp can be driven harder than a solid state or even class D, but all three have sufficient headroom to play cleanly at a low volume.
I've got an old knight pa tube amp rated 50 watts.
I guy scoped it and said it's really 60 watts but breaks up at fifty.
so many strong opinions from people whove never built a single electric circuit in thier lives😂
Interesting you should come across power output for cyclists. On a good day I can average 180 watts and peak 550-600 watts. Is it RMS though? 🤷♂️ No, in cycling terms it is usually measured on watts per kilo. For a 77kg chap like me that's around 2.34 watts per kilo. TDF riders are usually 3 times this.
I would guess that the aim would be to measure the equivalent heating power, same as in audio. Whether cycling power meters actually do this I shall leave for more dedicated cyclists than I to worry about. DM
This guy could be Paul McCartney’s twin, just needs a bit more hair.
In my opinion, we should not bother. Reason .....My NAD doesn't say, and my Denon does, but it massively exceeds watt goes in.
So why bother.
They are, however, both loud enough to upset my tinnitus and for the wife to say, " Turn that shit off "
You need to drive your speakers (quoted SPL at "1 watt" [what watt?] ) WITHOUT DISTORTION. The impedence of a speaker changes at different frequences too, not many I suspect listen to music comprised of a 1kHz tone. Did someone say inductance of a crossover? Is the rule of thumb to have an amplifier more powerful than the rated handling of the speakers, and "be careful" not turning it up to 11.
All eye know is that my current speakers eat a lot of volume nob