What is the best Port size?
ฝัง
- เผยแพร่เมื่อ 13 พ.ค. 2024
- In this video I go through what port size is best and why, and how to design a box around it.
TIMESTAMPS:
0:00 Introduction
1:00 - Problems with small ports
3:35 - Problems with big ports
4:46 - Conclusion
6:30 - Sources
7:21 - Discussion - วิทยาศาสตร์และเทคโนโลยี
If you wanna know what LENGTH your port should have, check out:
"What is the best Port length?"
th-cam.com/video/RDEEm-JW7ic/w-d-xo.html
Thank you lol 🙏🏾
Dude, something is completely off here... with that calculation, a tiny *ss box with 5,45L would need a 5cm port in diameter, which makes 0 sense. What makes even LESS sense, is a 6,8cm port would match with a 10L box, while both the industry and knowledgeable DIY builders use a singular one of that size for 30+ L boxes. I don't buy this.............
Finally the youtube algorithm suggest something i WANT to see
heh cheers
this is a good video
Lol. Yup
😂😂😂
Bro I had to look this shit up
I only watched a few of your videos yet, but so far i love them. I love how u break things down and go into depth on subjects. It really has taught me alot. Keep the videos comming and I will keep watching. Thanks for all the advice.
Found this video while trying to tune the port on my 2x10 Ampeg (copy) bass cabinet, 50L. Did the math, it sounds spot on. Thanks!
Finally something I actually want to watch.. Thank you
Very accurate, great detail and description. Good video bro. Keep it up.
ported enclosure sounds good on bigger speakers but I always like the passive radiators in motion also it only need less box size.
Thanks dude, this was incredibly informative, like most of your vids ofc!!
Below the tuning frequency, ported system acts like open back enclosure. To maintain some back pressure on the driver I find keeping port area to be 1/4 to 1/8 of the driver cone area works the best. Of course there're systems like Altec A7 where port is much bigger than the driver ( but driver has reasonably stiff suspension that supports the driver cone )
This video is infinitely easier to follow than the others. Thanks!
i would like to see experimentation with adjustable port size to demonstrate it, with various musics and tones.
Great Video, and thank you kindly.🌺
The information here has been proven over and over and never fails. I’ve seen videos of these kids with these new subs with higher power and they think they need a bigger port.
Depending on the subwoofer.
kilamanjaro Mountain yeah, not by much though. The Thiel small parameters are different from sub to sub, but as far as the box size to port size is minimal. Certain subs play better in different box tuning but for the most of it you build a box for 2 12” subs with box volume 4.25 with a slotted port of 16W/3H/22L you will be in the ballpark of a tuning of 32HZ give or take a frequency or 2.
I have one DS12 EVL. In a 2.7c box I want another one though. What's the best ported box for spl I can make. ?
Mark Godfrey it’s not the port size to the sub, it’s the box size. He even showed that 2 different manufacturers are using the same formula.
Mark Godfrey exactly. Certain subs perform in different size boxes than others, but the formula for port area is the same
I built a 100L sub tuned to 20hz, and used a 9.9cm/ 3.875" diameter port. Then I built a second version using 2 ports that were the same 9.9cm diameter. Comparing the two, the single port design had noticeable low frequency compression @80dB+, and the THD measurement showed a peak of 10%+ from 20-30hz. The 2 port design had no compression at 80dB, and THD was 2% at 80dB. (The sub is built into a full range floor standing speaker, so I have vertical height for tubes the full length of the port.)
Heya. Valuable info. The technology came forward a lot, and nowadays if you know what you´re doing, and use high end drivers, you can use the port very differently. No need to optimize the port itself for best accoustical performance anymore. Golden ages. Now I can afford to optimize the port for impedance shape, for cooling, Group Delay and transient response (boomyness) and such. It is great helper to make efficient compact system now, instead of desperate need for speaker to produce any SPL at the bas region. That way I can afford to put a 21" speaker into compact 230l box, measuring 58x58x76cm including feet, handle and 100mm casters, load two into european sized car, and make quite loud gig for 150-200 people. Hope IPAL and M-force technology comes forward some more, so we increase the power density even more.
Yeah, M-Force looks really cool, though from what I've found its quite expensive. Would be cool to see more companies adopt a moving magnet/stationary coil system.
Long live the BOSS,finally I got what I need,god bless u
yes there's a math to the correct port size .. I owned a custom car stereo business back in 80s 90s we built hundreds of sub boxes we called it tuning the box ..the port is crucial to the specs of the box and cubic internal air space also is crucial also depending on the speaker used
You sound like you know what you are talking about bro..
Would u recommend pairing the JBL S2 1224 subwoofer with the GS PT 112 Ground shaker Box- slanted ported ?
Thanks for this information brother. I truly know how This sound travel makes a big difference. Brace on the port. Again thank you ✌✌✌✌✊✊✊✊👍👍
This really helped. Thanks man!
... definitely one of those critical aspects, often overlooked in DIY's...
Thanks for this tutorial
Medium ports have been good to me! “commented before I watched” thanks man I build probably 10 to 12 box’s a year an have always wondered but just used common since to keep it strong an quiet!
Perfectly reasonable, learning from experience is a great way to learn things you don't forget.
at 5:00 am I do not understand the comparison, and what is the meaning of the medium port?
Good explanation thank you
I am trying to build my first subwoofer box on my own with the help of my father-in-law who is your carpenter and has the tools to do all the round do you know flares and 45s and everything else you need to get the air flowing properly I’m also looking in on how to build more complex boxes like fourth order six order stuff like that but you kept it simple which is what I need and give me information on where I can find the dimensions I need for my subwoofer thank you very much I subscribed and liked your video because it is awesome keep up the good work.
Cheers, good luck on your future projects!
@@Dakoustics thanks man. It’s an art in my eyes. Like geometry meets physics.
hey man, love your info. I have two of bowers & wilkins ccm382, i like to make my own speakers for each side of my TV, how can i calculate how big the speaker box should be?
I've gone by the enclosure volume to determine port area but I've heard about using cone displacement as well to calculate it as well. Both can be applied and I think it all boils down to the application and skill level.
I've heard cone area for 4th order port area
For a ported box or 4th order bass reflex box 16 cubic inches is great but that number is different for other boxes like a 4th order bandpass box where you would want more like 20 sq inches of cone area.
Im building a 5.25" pc drive bay speaker out of styrene plastic and 2x 3w creative drivers out of a creative travelsound 400, im opting to rear port it and am going to make it rectangular as these seem to work best in my experience, the port will be exactly half the width of the enclosure. these little drivers sound absolutely beautiful with a PAM8403 5V class D amp, the amps are tiny and pack a punch, ideal for drive bays.
Thx from Italy 🙌🏻
Good video. Also. If you go for say 3 smaller round ports instead of 2 larger round ports the 1st order port resonance goes up
But would it give you a longer bass hit
I like the sound of an overly long port. In fact, I mounted some tiny speaker cones at the end of some wrapping paper tubes, and it sorta sounded good! (A little echoed though.) the resonance frequency of the smaller one that I had was 58hz. I could not tell the bigger one though.
I noticed this too in different port set ups that I heard
if i have an 18 "speaker ... how to determine the box volume and port on the speaker box ... according to the data on the speaker ... thanks
Below are some notes I would like to make. I'm aware it is essentially a novel in length, but when you're passionate about a hobby that is just what happens. lol
1.) Xmax is normally a figure of one-way travel, not Peak-to-Peak, also not to be confused with Xmech for those who are curious.
2.) The ports themselves shouldn't generate 'wind' (Air Flow) or essentially displace air from the port volume, it usually occurs below fundamental tuning due to the rise in velocity prior to the reduction after once you've extended well below fundamental tuning. Rather the most idealistic scenario is limiting vent velocity so that the column of air within the port resonates with minimal surface/ cross-sectional area resistance which would cause turbulence.
3.) Port Area's relation to Resonance is correct, though what is largely important is driver selection, this will be covered after the next statement. There is a caveat here, where you move into the B.V.R. [Big Vent Reflex] territory. This is a hybrid between a Bass Reflex, and Quarter Wave Pipe where you're coupling the net volume, chamber length, port volume, and port length for the fundamental tuning which if done correctly will significantly increase damping apposed to an average net volume and less lengthy port than a BVR. Within Horn Response, you can view the Impulse Response, or export the Impulse Response to a .Wav file and make an audible comparison between enclosure adjustments to get a rough idea for Impulse attack, sustain, decay and release. Prior to doing so, it is best to use the Filter Wizard to set the theoretical subsonic filter and low pass filter to get a more accurate representation of the transient response.
Back to the statement about driver selection mention prior. The drivers' damping factor is incredibly important for more accurate transient response achieving less of a muddy/ boomy response near tuning, though a note to make is that you have to also account for Lossy Inductance [Lossy Le] which for most mobile audio drivers impact them heavily having a rather high Le:Re ratio. The higher the inductance is in relation to the Impedance of the driver the more resonant the driver will become due to the back EMF generated by the coil. Though, 'most' Home Audio, and Professional Audio drivers feature shorting rings, pole sleeves, bifilar winding types for the coil and/or non-conductive coil formers to limit the amount of inductance present.
4.) Though a suggested 'Golden Rule' for In² per Ft³ isn't a bad start, if the program used to simulate/ design the enclosure is capable of it, keeping tabs on Group Delay, Vent Velocity, and Diaphram Displacement, keeping each as low as possible while maintaining a more linear acoustic power profile is most ideal for most applications outside of SPL.
As an addendum on the topic relating back to Lossy Inductance, this will shift most mobile audio drivers largely off of what would be optimal without taking it into consideration. It isn't a perfect method but has been measured via RTA in 1/2 Space Radiation in comparison to the simulated result and from our findings, it closely follows the trace with Lossy Inductance calculated. With the additional driver resonance, the enclosure usually has to sacrifice its smaller footprint to increase the net volume, counteracting the peak above fundamental tuning that is caused by the abundance of driver resonance. This also makes many drivers fall outside of the acceptable EBP region to be 'ideal' for a bass reflex alignment, and for those shooting for a 0.707 Qtc Sealed enclosure, it can actually be impossible in some cases.
Just here to clarify a few things and present some ideas that most are not aware of. I'm not trying to step on any toes, just explaining what I've gathered over the years since I have been pushing to learn as much as possible within the acoustic engineering field. At the very least it'll steer those who are less technically inclined in the right direction not to overshoot or undershoot port area either because they aren't aware of the effects, or they've been told by others to do one way or the other and end up with poor results. So for that, thank you.
DJ Slow N Throw damn what language is that!? Lol I hope I will know what your talking about one day. I’m learning as much as I can. But I love your music btw!
This proves that making rebassed musinc is not as simple as it looks,you have to know every single aspect of both the driver and the enclosure. A great lesson from djsnt!
Love it DJSNT!! A comment just as accurate as his beats!
@@THESUBZILLA Just the language of a passionate audio enthusiast. The reason music hasn't been coming out is that I'm sufficiently enthralled in enclosure engineering as Subsonic Center Enclosure Engineering. I have been producing music in the background though, should have some new videos in the future.
@@DJSNT Wow, that's awesome!! are you gonna start a box design business?! also is there a website I can find your rebassed/slowed music aswell?
I think it all depends on your goals ur driver and vehicle, if u r firing into an open cabin jt will vary then if u have it dead against a back gate
Yup people always forget about the vehicle which itself is an enclosure. So you should tune your box to the vehicle size.
@@ASSOpid finally someone mentioned it.
Thank you brother for very informative vedio 🙏
4:22 Mmmmmm~~~~~ Thank you man, I really enjoy the video. highly appreciated.
Thanks brother from India
Actually i didn't understand.
Tell me if i want to make an enclosure of 1.5 cubic feet to tune it at 32 Hz.
What will be the dimensions for both round ported box and slot ported box?
can you make a video on how to design a subwoofer box?
I've been doing alot of wondering about my port size I built my box with a tuned to 35/36 with 129.5ci port area (7"x18.5") for 2 American Bass XR15s on a 2k amp, the box is around 6.75cf and on the low low bass it sounds killer smooth,clean and hard hitting but the long test tone higher frequency notes I get a ton of nastyy muddy boominess that is unpleasant and uncontrolled sounding, I plugged the port and it sounded Awsome but I lost about half my output... unacceptable. I also screwed up when building my box I put the port in the center vs off to one side like the plans and took the 12" rear leg and made two 6" opposing legs but forgot to make the width half so each side leg has the same port area as main center port making my tuning 35/36 vs 29. Any input would be appreciated...
A large or small port depends on Thiele-Small parameters of the speaker and what frequency Yuit want the box tuned to. Flared ports are always helpful.
Very good video. I tend to like 12 to 13 sq" of port space when I'm tuning for deep bass 29 to 32 hz. If I'm tuning a little higher I'll shoot for 14 to 15 sq". But to each their own. It's a matter of what works for you. And just to help those out that don't know you just simply multiply width times the height of your port to get the square inch of it. If you want 12sq " of port space for example you will have a 3 inch wide by 4 inch tall port if you had 1 cubic inch of airspace in your box.
good day sir thanks for a knowledgeable video. may I ask what is the best dimension for an 12" L ported box design?
it depends on what the sub specs are and what vehicle its going into. for example if the sub needs 2.5 cubes and you were given a box dimension thats too big to fit in your trunk then it would be useless. you will need to give measurements of the opening of the trunk (LxW) and the depth of the trunk to have an idea and lastly what frequency do you want your box tuned to
Is there any difference between the resonance frequency of the port itself and the resonance frequency of the system (i.e., the box plus the port)? I have come across some texts that describe them as distinct frequencies. Thanks for your help!
Good work
Hello , port square inches should be calculated per net internal volume or total internal volume
Actually WinISD shows the air speed at different frequencies so you can change the diameter and check the speed so no more calculations is needed
Good job thank you
Thats to get you in the ballpark. Actually ideal port area is based on xmax, power and tuning you want to model it out vs taking a blind guess based on general recommendations.
I got amazing results by mounting a full range 4 ohm 5" dia. speaker in a thick cardboard tube fully sealed. Powered by a 5 watts per channel 8 track tape deck (Muntz brand).
great video ... can you please also explain in your coming videos what will have the influence if a large diameter port need to be very long in order to tune the box low? i mean any adverse effect it would cause? thanks
Longer the vent, the worse the group delay xx
Does the position of the speaker upright, slanted, or flat ,has an effect on the sound, especially the bass?
Question this is great for sound quality and I'm not into SPL but I do you like to move hair. Can having certain size ports increase my chances of having a standing frequency in the vehicle for hair tricks? I know this might be a little vague of a question but any input would be welcomed. I would like to do it with ported boxes because I don't have spacing to do anything but I one-to-one fourth order inside of my cab
Bigger the car, the harder it'll be to achieve a hair trick. The main thing is moving as much air at as low frequency as possible, or at least below the tuning of the car. Cars with open windows act more like 4th orders themselves, so playing slightly below the resonance of the car is the best way to move air through a window. Standing waves are more important for SPL. Something I'd suggest, is make a ported box as big as possible. Put 2 ports into it, where it's tuned to something like 30Hz for musicality, and when you want wind plug one of the ports to tune it closer to 20Hz.
Thanks for the info! May i email you with some questions? Thanks
The primary issue with using a ratio of vent area to box volume is that it ignores the volume displacement of the cone. It doesn't take a lot of thought to see that a 6.5" woofer and a 10" woofer in the same 1cuft box might require different diameter vents. Even if driver diameter is kept constant, Xmax varies wildly from driver to driver, also affecting the total volume displaced by the cone.
A better calculation would be Sv = 0.02032* Fb * Vd where Sv is the vent area in square inches, Fb is the vent tuning frequency (yes it actually makes a difference what the tuning frequency is) and Vd is the volume displaced by the cone in cubic inches (Sd x Xmax). 0.02032 is a constant that will result in a vent area to keep air speed in the vent to ~ 5% mach, or about 57feet/second. This is good for a quiet environment like in a house. In a car, and especially one where the enclosure is in a trunk, higher speeds (more chuff) can be tolerated but should not exceed about 9%mach (100fps).
Ah, nice to see some algebra in an example. I've had theories tuning frequency affected vent diameter, though not seeing solid examples elsewhere online. One thing to note, is tuning chokes the driver, and makes it much more difficult for it to reach Xmax at standard power, although the 0.02032 may already consider that.
Learn alot from this vid thanks
Hello i m from india
Which is best low and loud frequency enclosure size and port size please suggest me.....
I have 2 sub 530 rms Svc parrelel 2ohm to sony Mono Amp 750 rms 2 ohm......
Please suggest me size ...
To eliminate all the above problems use a sealed baffle.
what about for a 2x15 Guitar cabinet??? it has 3" holes ...... 2 of them. Seems way to much air escaping, what do you think?
I made a box container a subwoofer, all-range speakers and a pair of tweeters.
I have 2 ports where air goes out/in, but the pressure from the subwoofer seems to push the all-range speakers out also.
Not noticing any effect on the sound though, but would it be a massive problem those move along?
If so, would just add another port to release pressure be the best option? Or would it sacrifice the bass?
Best option is to make chambers behind the speakers being pushed out. It can be hard to tell a difference in the sound, though if the speaker is pushed too far it could burn out. Adding another port will only change the frequency they are damaged at, not reduce it completely. Making a bigger box can help, though best way is to not use the shared air space.
Which port is best for deep bass Subwoofer
So say I'd want 5-8cm wide flared ports on a Celestion TF0818. What length is ideal?
If I were to use dual ports, would I be correct in thinking 2 ports of 23mm or 1×30mm? Sounds wrong.
Can you give me some measurements for a box. I need a box for my Escalade. I'm putting 2 15 inch subs and they need 10 cubic feet of air volume. Can you send me some measurements please sir. I'd really appreciate you
Does this apply to 4th order bandpass boxes for cars?
Thanks man, my 400 pages Book on how to make your loudspeakers wasn't that clear
Can i use 4ohm 30w subwoofer instead of 3ohm 10w woofer (stock) in speaker?
Is the box area example before or after adding the port?
Degital design chart for the port? Is that for sound qaulity bass or spl bass?
Thank you.
Anyone know if the woofer diameter matters? I have different online calculators saying one 4" port should be from 3.8" to over 100 inches to get 25hz in 8 cubic feet. They cannot all be correct. None ask about the driver itself. Is a 10" sub going to have the same response as an 18?
If you use WinISD or any other program that can estimate port velocity, try to keep it under 30 m/s (100 ft/s)
100 ft/sec is much too high! It should be no more than about 55 ft/sec. Port compression occurs well befor chuffing becomes evident.
@@marthax.korver3401 for most people I doub't it will be a problem. Could you perhaps show some tests?
@@FSXgta Some actual tests.... facebook.com/DIYRM/posts/1212863525554986?hc_location=ufi
I designed ported and 6th order bandpass and for a full power signal at tuning, the port velocity is usually around 25-30m/s but it will rarely see this value on music. It's basically the lowest value I could get with reasonable sized ports that fit in the box for the tunings I want. I also prefer to have port lengths and box depths less than a quarter wave of the highest frequency of the subwoofer to avoid organ pipe and back wall response anomalies.
For subwoofer duty, when you consider the capabilities of today's drivers, it's difficult to stick to that 1/4 wave limit and still use vent vents that are large enough to reduce compression and chuffing within the driver's linear capabilities. This is why I've shifted to using offset TLs instead of simple vented designs because with that type of design I have a lot more control over the impact of those 1/4 wave resonances. I haven't designed or built a bandpass design in a while, but the last one that I retuned was able to minimize the impact of the first 1/4 wave resonance, the result was a build that had the out of band noise around 15dB below the passband.
Thank you
My method is to use 2 or even 4 ports, I think that this is a solution to mix pros of both methodes. It working very good. ;)
Simply.....
Which one produce good bass effect????
5:03 16 square inches per cubic foot, or 100 square cm per 28 litres. Change the length of the port to get the right tuning.
My subs only have (15" planet audio)13mm and (10" power acoustik) 15mm of excursion. That huge port may have been recommended because of your giant excursion # ? Though I'm mindful of subs specs I lean towards the larger port size, My rough general rule For 10s and 12s I use 4" and for 15s I use 6" ports or close combo equivalent. When building slot ported boxes I keep the general size rule in design but can be bigger or smaller depending on the so many factors . Also I prefer my built auto sub enclosures tuned around 31hz to 34hz , so my ports are a big factor . I'm currently pondering a single 15" with 2×6" ports that will be like 30+ inches long each that will be mostly external and a part of the exterior design for minimal box size(still 3+cu.ft.net.) and a unique look without skimping (I'm bored with plain old gray/black undersized generic prefabs). Let the subs breath DEEP! I'm "BRAINS over brand " in Tacoma Wa .
Thanks for the good video, but isn't a flat long rectangular port the best option, for it allows enough cross section surface while offering good damping, thanks to a high side wall surface to cross section ratio?
First time I heard a speaker with a so called "lamellar flow" wide thin and deep port, it struck me how deep the bass frequencies were reaching, without any boominess or ringing.
In essence, since round ports have less resistance, they are designed with a smaller cross section, so the air moves faster, which is what results in drag/damping
@@Dakoustics ok I get that, but wouldn't a thin rectangular port offer both low air speed and high dampening?
@@paolozak3014 damping is a factor of velocity squared, so it doesn't do as much damping as you might think, a very thin rectangular port would, but consider too much damping reduces output, and the point of a port is to increase output, all about the ideal compromise.
But yes, if SQ is the goal, maximising port area and having a ton of internal damping can reduce the need for port flaring, meaning less noise from turbulence due to the low velocity, and lower ringing.
@@Dakoustics sure enough damping is a factor of velocity squared, but also a factor of wall surface : a thin rectangle (x depth) can easily have 2x the surface of a cylinder of same section area. This means that using a thin rectangle shape vent with twice the section of a circle would cut the air speed in half but since the wall surfaces are 2x2=4x higher, it results in equal damping factor yet at half the speed, thus a more relaxed and still tight deep bass response. After several builds, what I notice is that - to.my ears - flat rectangular vents just do sound better. Perhaps a better phase coherence?
I have a 4 inch subwoofer of home theatre. I want to design a enclosure for it. (0.35 ft3 is the enclosure volume) . Can I use a 1 inch diameter pipe with it?
1" is a bit small, but often with such a small enclosure compromises must be made in order for the enclosure not to be enormous, which would defeat the purpose of a small driver. Give it a shot, if it doesn't sound great, could try running 2 1" ports, or a single 2" diameter port.
@@Dakoustics Thank you, sir.
Sir just correct me if i am wrong. Example i have a total 2.75cu.ft of the box. Am i right? My port wide is 2.75” and lenght of 26”? Just correct me sir if i am wrong of my coputatuon for my width 2.75” width?
Is this the same for normal speakers (not subwoofers)? I am building a custom bluetooth speaker and am trying to calculate the correct port length. My driver is 4" diameter, with a enclosure volume of 0.21 ft cubed and a resonant frequency of 81.4 hz
yeah, it should work for any tuning frequency
Dakoustics awesome thanks
Thanks!
How would I find my ports displacement?
🔴Does 16 sq inches per cubic foot also apply to aero ports, if not is there another number.
what is the best port lenght?
You can make 3x 5-7cm small port's, if is a big port not possible to make or the sound are not that what you want.
A little bit longer time to work, but the result Convincing.
I'm testing it passive radiator with 3x 7.5cm ports and my reaction to the first sound was only a "WoW", it was not possible to make one big port, not enough space/distance from speaker magnet to the back side of the speaker box with the ports, in the middle not possible to make a port, but 3x small port's like triangle around the magnet.
Have you ever done a video on port length, port shape and port placement/location?
From what I understand, port placement is not relevant due to the extreme wavelengths that travel through the port.
+1 for info regarding port length tho
I do know that ur supposed to keep ports 3-4" from any exterior walls, thats including when the port extends into the enclosure at the point the air is leaving the port. I believe also stay away 4-5" from any interior walls. Kinda rule of thumb. Port placement is kinda important. Enclosure size and quality and ur port is what makes a good sounding enclosure. Just sayin.
καλησπέρα σας να σας κάνω μία ερώτηση αν το μεγάφωνο των τοποθετούσατε ανάποδα ο μαγνήτης έξω από την κούτα είναι σωστό ή λάθος ....ευχαριστώ πολύ εκ των προτέρων
Is it possible to devide the area of the port.
How do you calculate your port length... im goning for spl and have read not to be any longer than 8- 10 inches ... problem is with my port area being right at 8-10 inches in winisd im getting my tuning higher than I would like?? Wanting a spl box with good bandwidth in a accord wagon
I've not heard of a limit for port length before, but you've got 2 options I'd recommend- If you're at or near Xmax, make the port longer. If you're not, make the enclosure volume slightly larger to get the desired tuning.
I have noticed this. I had a Yamaha surround speaker with two tiny ports, less than an inch wide, and 2 inches long. It had a 4 inch woofer. The issue: not tuned well. Muddy sound, port chuffing. The ports are literally cardboard tubes glued to the front particle board panel, so the ports even have a little lip on them that is smaller around than the port itself, which just makes it worse. Same thing with many Onkyo surrounds. Funny thing is, the ports on the speakers from many of the cheap “all in one units” mini stereo systems from the 90s and early 2000s (Sony, Aiwa, Jvc, etc.) are actually tuned extremely well!
Yeah, some can be good. Its possible they started high, and work their way down with cost cutting until consumers start to complain, possibly they were still getting good reviews. A video will be coming out soon with me complaining about typical modern ported subs if you're interested.
Also, regarding the tube, it'd work as a quarter wave transmission line if you haven't heard of transmission line enclosures. Basically, they tune around:
340 / (length in metres* 4)
So, for a 2 metre transmission line, it'd be 340/(2x4, or 8) which is ~42Hz.
@@Dakoustics I’m familiar with most of this. My favorite subwoofer is a 10 inch front firing driver with an extremely low resonance, heavy cone. It’s in a box that measures approx. 34.3x 34.3 x 38 cm on the outside. Approx. 3.8cm should be subtracted from each of these values due to wood thickness. Flared rear port measures around 7.5cm wide, 16.8cm long. It goes down to 28hz cleanly, but perhaps not super loudly. It’s great in a 3x3 meter room, but not much larger than that.
Do all these measurements work out?
Video topic suggestions: restive port and passive radiator :)
I'd like to give a resistive port a try, which I assume you mean the one which is like a big flat panel. Also I have an old sub which blew, and I was going to make a passive radiator box for it, but I might wait and get some proper passive radiators for a sound quality sub build some time in the future, budget permitting. Cheers for suggestions!
The info you got there from DD about cubic feet and port calculations. Is that before sub and port displacement or after?
Best advice you could give the people
if you're increasing the area of the port.. doesn't this also affect the length as well... if so what ratio?
surface area to length ratio should remain the same, so if you increase surface area by 25%, make the port 25% longer.
Is varation of subwoofer how ohm is and watts but im with big port because have more bass port is Air when sub breathe in Explorer bass exurcion
So which is better bass
What if we like extended bass notes?
What would be the best for sq?
how about with elbow aeroport?
Doesn't total surface area of the diaphragm combined with x max have anything to do with port area? One website I went to said I should go with a short two and a half inch port, well another website suggests that I use a very long 6-in port. But both suggest that these ports will result in 34 Hertz tuning. How can that be? Doesn't Port area also affect tuning along with diameter and length? I have everything I need to put this sub together. But I am absolutely befuzzled by Port area. Trying to do a 1.25 Cube box tuned at 34 HZ for a single low budget 10-in sub, to be installed in a single cab pickup truck. Port area dramatically affects the external dimensions of the box. And my space is tight.
Rules of thumb:
Start with port area equal to Sd and work backwards until it fits in the box.
Port length should not exceed twice its diameter.
Port should be circular with appropriate flares at both ends.
Port termination should be similar at both ends to reduce port rectification.
Enclosure and port size are closely interrelated and change dramatically with desired F3 and the driver TS parameters.
Don't expect high efficiency at low frequencies from a small enclosure.
can you please give us a simple chart like 8 inch speaker then the box should be length in to breath the port should be dia and length. if the speaker is 12 inches the box should be length into breath with a port hole in size. it could be approximate to get the best with what we have. regard from India
What's the calculator link address (at 41secs) please?? I had this, but lost due to computer failure. Thanks.
I don't know if I'm wrong but when you used the vent diameter calculator you entered 60mm for Xmax which is insane because that means there is 60mm of excursion in either direction giving total of 120mm and mechanical limit would be absolutely insane. Xmax of 30mm would be much more logical.
yeah, derped on that one lmao, but I know of 3 subs capable of such a feat, Ground Zero GZPW 15Xmax, I've seen the MTX 22" Jackhammer do it from memory, and possibly custom Sundown Audio Team Neo 18".