Folks: I know Anthony personally, he did my Orange County townhouse acoustics. Horrid became quite good, for small money. I could have made it better with more money but it was good enough, and I’m picky! Wife and I have moved to the desert, buying more from him to fix some nasty tiny room acoustics. He’s a great guy and his knowledge and products are amazing! Buy from him without any fear.
Nice! SO much useful information. BTW, I do not have a PhD, and was never associated with NRC. I think Tony is rolling up Floyd Toole and me into one person. Floyd has the PhD, and worked at NRC for years before coming to Harman. I'm just a guy who was lucky enough to get paid (by Harman) to research this subwoofer stuff. I modelled a lot of scenarios and selected the best ones overall, then followed up by testing in real rooms. There are, however, no guarantees in any one particular real room. I think the general feedback is that the optimal rectangular room sub configs I recommend work well most of the time, if seat to seat consistency is your primary concern (as is probably should be). Kudos to Tony!
Hey Todd. Any day that you are confused for Floyd is a good day 😃 I do appreciate all the work you have done on research. Have you been involved in the headphone studies Harman has been doing?
Gene & Anthony, these three presentations on room acoustics have been amazing. What a treasure trove of very usefull information on the subject. Many thanks guys!
New to your channel and I have just discovered you guys. I just finished building 4 traps of my own. By far the best information I have seen. I love the fact that nothing is being sold, just old fashioned rap. I have really enjoyed it.
Grimani has helped me understand more about acoustics in the few videos that Gene at Audioholics has put on than a hundred other TH-cam clips I've watched. Very timely as I am building my Home Theater room right now. Also looking into multiple subs for the 50 hz and below range. Thank you guys!
Other random TH-cam videos are often published by material manufacturers and their recommendations seem intended to get you to buy as much of their stuff as possible.
I would definitely love a REW primer showing how to measure and what that means for types and placement of acoustic materials. I put some absorption panels on the first reflection points and the room measured worse. At least, I think it did. I’d like to understand what you can learn from the measurements and how that informs the placement and type of acoustic treatments. Thanks for doing these videos Gene!
I havd played with the idea of building a long living room, and dividing it with an absorber wall. So behind the absorber is physically a small, separate room, but acoustically it is still part of the living room. It's cool to see a "pro" teaching the same idea!
Good job hosting these gene. Tony is my new favorite in the audio world to listen to . I already feel like I've gained important insights from just a few hours of these videos today. Many thanks to you both. I have a lot more experimenting and research to do but feel like I know what avenues to walk down now.
Hey Gene. I’ve seen a few videos now where you mention the great idea of doing a REW video. Although I have a good grasp I’d love to see an hour or more on REW with you and AG etc. it would also be great for those new to the program. Please do it?!! Any plans in the near future? Always a pleasure to watch your videos. Truly a gift to all of us in the community, you should be proud which I’m sure you are.
34:41 Great video so far, only a small improvement suggestion from me. Here you are talking about porous absorbers that work well in high velocity regions but you’re showing the pressure behaviour of a standing wave mode (not velocity). At the 1/4 way pressure dip (as shown here) will be a velocity peak. The reason for positioning an absorber in that location is so that you can use that high velocity to force air through the material and dissipate its energy as heat, thereby mechanically removing that energy from the sound field. I think it would be more intuitive if the graphic was updated to show the velocity behaviour instead. Thanks!
It is not about Boyle's law (and what you stated was the ideal gas law), it is about Euler's equation of motion relating the derivative of pressure with velocity; at pressure null you have the highest derivatives.
Don't understand why you'd put traps in corners when the whole wall is the problem, assuming you have flexibility with space. Modal pressure is strongest between two parallel surfaces not corners.
I've been watching these series from Anthony Grimani, very good info. I have recently subscribed, but would like to know if he goes over any info on setting up REW and how to measure and to look at?
After a TBI + epilepsy which equates to chronic migraines and the tip for relief, is get the volume over 120dB and low Hz helps plenty - love to have a go being your test pig 🐷
Secret internet tip for Audioholics! Put your modem/router on a transformer! My router’s internet connection comes into the house very close to my electrical service, the modem/router’s circuit is only like 6’ long to the breaker box, we have whole home surge protector at the breaker box, but still our lights flicker from time to time, I believe that internet interruptions are correlated with light flickery. I use a few incandescent lightbulbs in my chill spot because of some color spectrum curve preferences I have, but they show flickering voltage shifts way more than my other led bulbs. I believe because LED’s have switch mode power supplies inside them. When I put my incandescent lamps on transformers, no flickers at all, when they’re on my other surge protector products (of which I have many) lol they flicker from time to time. My recommendation is exactly what I use on my router, a “OneAc Condition One transformer with the OneGround feature giving it a virtual kelvin ground” www.gryphon-inc.com/Spec%20Sheets/917155C%20ConditionOne%20Series.pdf Since installing it, it has Eliminated my internet hiccups! It’s a small
Both Gene and Anthony sound good. Anthony's level is stronger than Gene's but not distorted. A decent mic. I am sure my office bass trap is a drop ceiling of over a foot and 20 x 15 feet long it should act as a nice bass trap I will send a schematic when completed taking out the divider walls. The Cornwall between two Klipshorns sounds amazing and I turned the Outlaw to forward-facing because of distortion of the down-facing mode. Trying to keep up to 3 15" Klipsch speakers it has its work cut out for it. I just set it to 80Hz and will calculate the dimensions of my bass trap. The sub I have closed both traps but have to increase the gain to keep with thee three 15" transducers. We Will experiment with an SPM and software to be purchased as both Gene and Anthony have it in their reading lists. cheers guys great segment.
Spikes and dips are consequences of phase cancellation. So the dip is caused by a frequence that IS there, as far as I know. If I understand it correctly, if you damp the problematic standing wave, there won't be so much dip any more, because there is no more cancellation.
Oof, the PV=nRT explanation at around 36:00. It's not enough of a blunder to make me doubt your expertise, but you should really go back to the textbooks before repeating that one again. Wondering after a quick Google search if this tidbit came from the Jay Kadis paper "Acoustics: the study of sound waves" since he also mistakenly refers to the ideal gas law as Boyle's law and then misrepresents its applicability. Hopefully the rest of the info in this paper is more accurate than the gas law portion. At least he correctly identified the V as volume (of the container, not SPL volume) and not velocity. That said, I still feel this has been a very valuable video series. Thanks guys!
I just REWd my setup last night. Two subs between tv and Speakers. Massive ~20db drip around 42hz. Moved to the corner and got worse. Added sub to the rear and created another sharp dip at like 50hz. I was able to correct some with EQ on the SVS PB-1000 Pros, but guess I need to keep working on it tonight :(
Funny I've always been a "bass guy" and made sure my systems always had the best quality bass possible. I'm also a chocolate snob lol. Great information guys, thanks!
Multi subs is good for having a more even bass response in multiple positions throughout the room. It is unnecessary and can even be detrimental to a studio nearfield listening environment where the frequency response is optimized for only 1 general listening position. Context matters a lot. :)
thank you both for such great info! i wish someone would speak more to non-rectangular rooms. working on an L shaped multi-purpose entertainment room that by my calculation is about 7400 cubic feet with a HT set up on one short wall. looking to replace two weak 12 inch subwoofers with something more appropriate but don't really want to do the spend on multiple jtr rs1/rs2 subwoofers! considering a pair of the new monolith 16 thx. can only use two due to other room constraints. also need to think about bass traps and other wall acoustic treatments.
Hello Gene. Multi sub with acoustic bass treatments is OK, but when will Audioholics do the current subwoofer state of the art video on Double Bass Arrays? Why not explore a superior subwoofer system that uses the benefits of multi sub without the need of extensive acoustic bass treatments?
Ported subs are slower in the sense that the sub itself has a longer decay time. It doesnt stop outputting energy when the signal stops. Thats because it amplifies the very lows via the bass reflex tube, which is essentially a resonator, and resonators are designed to resonate. So yeh. Kinda ironic how people care about decay in acoustics, but not the device creating the energy itself. But dang these guys give soo good info.
In a well-made ported enclosure, surely the resonance should stop at most half a cycle after the driver stops its motion (when the back wave excites the air in the enclosure and it exits through the port), so at 20 Hz that would be 25 milliseconds, which in terms of group delay isn't bad for such low frequencies. So in absolute terms it's slower, but as far as audibility goes I don't think it's a concern.
@@TokeBoisen Yeah. Fair enough. I just think along the lines of, if the sound designer, mixing engineer etc wanted some decay to the sound, they'd program that into the signal. Aka, if I were to want to make a hyperrealistic sounding movie, I'd care if the gunshot sounds(open air shooting) had proper low end punch to them, without pretty much any tail to it. Also, if there is quite a bit of effort put into controlling the bass in the room in terms of acoustics, might as well consider the group delay of the sub itself. But I aint no expert on the subject, which is why Im here learning. :D Gotta say, amazing knowledge they pass on here.
Gene and Tony. Really enjoying this series. Amazing how little I know about any of this. Question: this might come up in the next video but I'm wondering what suggestions you have for multi sub integration. Most AV processors or receivers are going to have at best 2 sub output hopefully separate. The AVM90 is supposed to have 4 but also costs 7G+. Do you suggest integrating 4 subs through splitters, daisy chaining, mini dsp, some wireless solution, etc? Is there an amp-procesor channel reassignment I don't know about? Thanks for any info!
Gene did a video about mini-dsp, I think you run 1 sub in and 4 out then you can delay, eq, level adjust each independently. I think Tony uses a better pro level ashly dsp. You have to be able to measure and adjust though which requires some experience and tools. Tony uses an average of 4 positions in the room not just the money seat as us amateurs would do to figure out everything.
@@dm17nc17 thank you. Yes you're right I think ideally you run the mini dsp with the 1 in and 4 outs to 4 subs and then adjust each accordingly. Truth be told I have the umic and the mini but I haven't gotten around to it. I tried once and couldn't get stuff working so got frustrated and quit. I do want to get to it. I've seen tutorials it's just not that easy to do imo.
@@jliu2222 Home Theater Gamer and Home Theater Gurus have some pretty good guides for how to setup subs with miniDSP using just REW. Personally I found that with a lot of tinkering I got some really good results using MSO (multi sub optimizer) as that allows you to put in multiple seats measurements per sub and optimize it for seat to seat response across more than the MLP and every sub gets it's own unique PEQ filters so they ultimately combine better in my experience with a really challenging room since one corner is missing since it goes to the rest of my house.
@@TylerStout thank you. I agree. I've seen those videos and they are really good. I think I need to just commit one weekend to this to feel more comfortable with it. The high learning curve makes it difficult to just jump in. I agree tho I think the minidsp is going to be a game changer in my house when I get to it!
So a trick I heard was to place a speaker in the listening position and walk around the room to find the sweet spot. That's where to place the speaker. No idea if it works or not.
Does adding damping panels in a room give the impression of less bass below 100hz? If the rooms damped, are your ears hearing less bass? Sorry had to ask twice, hard to describe ;)
The Telecoms do updates in the middle of the night! so it just have to deal with the odd drop out at this night owl period for us in the USA and I am EST time. cheers agiain
In the example where you put the bass trap 5ft from back wall to fix the null in the bass, could you build a 2x6 wall with insulation, mount an acoustically transparent screen to it (possibly in wall speakers as well) and use that 5ft space behind the wall to even out your bass?
Unless you maintain placement along an arc being the same distance from speakers to listener, wouldn't you be introducing phase issues as the sub wavelengths would hit your ears before of after your mains dependent on placement in from orfor behind that arc line?
What is like to know is if I had 2 big subs at the rear of the room because I don't have space at the front of the room for them being so tall can I use 2 smaller subs at the front to help with smoothing? A.G. did say the smaller subs run out of steam first but I already have one big ported sub and want a second the same to match and they will have to go to the back. If I find out that I still have modes to deal with can I put 2 smaller ported from the same manufacturer at the front of the room to assist and fix the issue and then blend them in with eq?
Anthony- if having a less flexible wall is desirebale re bass, wouldn’t that suggest some advantage of steel studs versus wood ? What about mounting yoru drywall on resilient channel ? Or screw through a rubber washer to buffer the stud/drywall interface ?
Both mics sounds great! Hearing you fine on my phone sitting outside on the patio with some endangered species 72% dark chocolate with tart raspberries, goes good with Romeo y Julieta 1875 cigar 😁👍
I've heard this works well for how to place a sub. It is recommended by my local HIFI-klubben: Place your sub at the listening position, then move yourself around the room, and place your head, where the sub can potentially be placed. The place where your sub sounds greatest, is the place to place your sub.
Timepoint 37.25: Anthony, Gene was confused by your diagram (I imagine other people were too). I respectfully suggest that a 3D image would have helped, or alternatively an additional top-down view to put the side-on view into context. On its own it is not obvious what that image is supposed to represent IMHO
How about a video bring all this together but giving ideas of how to economically for those of us on fixed budget. I want to make my room the best icon for what I can afford.
Build your own panels or bass traps. You can get a sheet of mdf cut to the size you want for bass traps or panels. Roxul safe n sound for 50 bucks. Hobby lobby for some fabrics, and you can basically have all the absorption you want for around 10 dollars per panel. UA acoustics has diffuser panels that are pretty cheap on Amazon or eBay. I think this would be the best bang for your buck..They can actually look pretty good too. I'm on a budget myself, this is the way I went.
Anthony- re number of subwoofers, ie 2 better than 1, 3 better than 2, and 4 better than 3, ceteris parabis, ie good placement, same subs, “decent” room (ie not large (ie
Thank you for the guidance. However, most of the recommended materials are above the average person pay grade. I am creating entertainment room with the following dimensions: 17’(L)x11’(D or W)x9. I am planing to achieve correct environment for the 5.2.2 Dolby Atmos surround system by having utilizing second subwoofer, placing pictures, wall furniture, coffee table, couch, area heavy rug and heavy black curtains over the window and door to mitigate sound problems. I will be utilizing AVR software with the microphone to create the best possible room acoustic. I do not expect a miracle, but I am hoping to achieve great sound; separation, fidelity, etc by having the second subwoofer and taking my time; tizing try and error method to acchieve best possible results.🤞🏻
My basement has a large open wall on rt side. An a ceiling only 7 feet. Any advice , my room is 30L/18w ..Thx much…. I have 1 big sub and small sub.. Pb 16, Klipsch 12 inch😎😊
Guys, really nice job on bass absorption. About your question Anthony on why you get video dropouts, I spent 21 years in IT solely working on computer and network performance, and I can probably help you understand why and how you are seeing dropouts. If you want to follow up on it, let me know and I can email you my email address and we can talk about it.
I run a 8" ported with a 60 w amp and not a lot of room so made a bigger box around the sub and got some rockwool in the outer box with air gap. Diy ass f.. just a mcgyver fix as i save up to get new sub's
So according to the science, would I be better off with 4 smaller subwoofers like SVS PB-1000 in the corners instead of two larger ones in front like dual PB-3000 or dual V1812?
From my own experience, a lot of it depends on how many seats you are trying to accommodate . The more seats you have in the room the more you benefit from 4 subs. This is because the 4 subs are going to distribute the bass more evenly throughout the room than one sub, meaning that if you time align them properly, each sub will fill in the dips and smooth out the peaks in the frequency range within which they operate. With fewer subs you can have great bass at your main listening position but that bass might disappear in other seats around the room. If you decide to go with just 2 subs, the science and my own real world tests have shown that placing them directly across from each other either at the front and back of the room mid-wall, or the side walls mid walls can work best. But you still need to have a way of properly time aligning them, and for that you can use REW to measure and MiniDSP to make the timing adjustments. Once you've done that, you now integrate the combined sub with the rest of your system.
@@wells2671 Yes I think in theory starting with 2 PB-1000 Pros in a 14x20room is where I will start as I only have 4 seats. That should be plenty loud but I can always get 2 more if needed. Tony has diagrams from Welti's work showing the best layouts, either 2 on middle of opposite walls (either front to back or side to side) or 4 in the corners. Gene's testing data of the PB-1000 Pros should guide to how loud in what size room they work because they seem amazingly good for not much $$. Tony had a test case where 4 10's worked so much better than one huge 15 as far as similar bass in each seat for a six seat room.
@@dm17nc17 I went from 1 to 2 to 3 and now 4 subs. All SVS SB12-NSD. Even with 1 properly placed sub, if you only had 1 or 2 seats you would be fine(assuming you could EQ the peaks down). But once you start to go into multiple seats and multiple rows, 1 sub will not give the same experience at all seats. Just bear in mind these 2 points... 1st one is that when you add subs you're not necessarily assigning 1 sub to each seating location, but rather you are creating the effect of having a more efficient sub (by combining them) which forms a larger and more even field of sound for the room. The 2nd point is that more subs don't necessarily equate to more volume (loudness) although they do increase the headroom of your system. So each sub doesn't have to work as hard individually.
Can you detect the frequency of the standing wave problem with a frequency generator (app or website) (frequency sweep) and listening at what frequencies aproximately it's unnaturally loud?
$100?…..$80?…..90?…..TRY $140 for the Sonitus Decotrap!! And you must buy them in packages of 2, so that’s a minimum of $280. Also, they, along with all of their other bass traps, have been out of stock for ages, which seems odd, considering it’s only a piece of foam and a sliver of wood. Also, while Anthony states that he doesn’t want to call his Sonitus Low Killer a bass trap, on the Sonitus web site it is named, “LowKiller Acoustical Bass Trap.” It makes me curious as to who is actually running Sonitus.
47:10 Hmm, so would it be possible to build tunable panels by having 2 perforated boards, one sliding behind the other so that the size of the holes varies? Can these "holes" even be square so that when the 2 boards are aligned there is a huge total "hole" area (low frequency I assume) and as we slide that board they become rectangular "holes", progressively smaller for higher frequencies. Would that make sense? Then we can put that panel on casters and easily tune a room whenever we move to a new place for example (by measuring w/ a mic of course). Can anyone knowledgeable tell me if this would work?
Awesome video! Too bad you mentioned multi sub without touching on double bass array (dba). It seams to be almost unknown although it is state of the art for home theater in Germany for years.
@@xavdeman well of course it isnt cheap but neither are the alternatives. And I don't think it is more expensive or difficult than using Helmholtz resonators. In smaller rooms you perfect results with four subs in the front and four in the back. If you built it yourself you can buy good chassis for 250-500$ each + a stereo dsp amp + building material. So the entire thing is around 5000$ and probably gives you in an rectangular room the best bass you can get with the same result for every person in the room. If your room isn't perfectly rectangular, a single bass array might be an alternative.
Re multi subs - is it a real problem to have a mix of different subs (driver size, manufacturer, amp etc) or is the critical thing just not mixing ported and sealed subs ?
Question, When these soundwaves stretch from the front of the room to the back of the room for a certain frequency (based on the length of the room)does the height and width of the room also affect that particular frequency, or is it only specifically tied to the length of the room? In other words if that room was the same length but half the height would the soundwave/frequency be the same and would it affect the room in the same way?
In a rectangular room there are at least 3 room modes corresponding to each spatial dimension as low frequencies propagate equally in all directions. If either of the room dimensions are of the same length, or close to being the same, the amplitude of a room mode at one particular frequency will be greater. However, In the real world it can be hard to predict these things exactly. Ideally you'll want a rectangular room with varying dimensions so that any one particular mode isn't too powerful, thus easier to deal with.
Yeah, that's what I've read, and I've used the Harman room mode calculator to get a rough idea of what the Room modes could be in my own Room. I am always curious about the sound waves hitting one wall and then bouncing back, and how having a ceiling that varies in height can affect the room modes between the other surfaces. It seems like most of these calculators assume that all surfaces a parallel. I'm wondering how (if you had a barn shaped Room) those calculations for the length get affected by the different heights of the ceiling or if they get affected at all since that is a different direction?
R.e.w. has a room sim where you can place 2 speakers and up to 4 subs and see how up to 200hz should respond to any listening position. Great graphical interface.
I've wanted to know about bass yes with about ten years because my living room is awful. I have a subwoofer but it doesn't give me as much bass as it should. My room is 11' x 13' with carpet down. I am extremely limited to where I can put the subwoofer. So I was going to try some bass traps in the room but I'm not sure if it will work. Also there's a problem with standing waves from two of the walls.
Very sus that Anthony doesn't show a single measurement of the Sonitus Decotrap he sells. Espeacially after an hour of explaining why other types of bass traps have disadvantages by showing graphs and measurements. He doesn't even remark to which flatness in dB this 60-500 Hz range corresponds.
Folks: I know Anthony personally, he did my Orange County townhouse acoustics. Horrid became quite good, for small money. I could have made it better with more money but it was good enough, and I’m picky! Wife and I have moved to the desert, buying more from him to fix some nasty tiny room acoustics. He’s a great guy and his knowledge and products are amazing! Buy from him without any fear.
In person or? And if you don’t mind me asking, how much did it cost?
Nice! SO much useful information. BTW, I do not have a PhD, and was never associated with NRC. I think Tony is rolling up Floyd Toole and me into one person. Floyd has the PhD, and worked at NRC for years before coming to Harman. I'm just a guy who was lucky enough to get paid (by Harman) to research this subwoofer stuff. I modelled a lot of scenarios and selected the best ones overall, then followed up by testing in real rooms. There are, however, no guarantees in any one particular real room. I think the general feedback is that the optimal rectangular room sub configs I recommend work well most of the time, if seat to seat consistency is your primary concern (as is probably should be). Kudos to Tony!
Good to see you here Todd.
Hey Todd. Any day that you are confused for Floyd is a good day 😃 I do appreciate all the work you have done on research. Have you been involved in the headphone studies Harman has been doing?
I have watched this series 3 times now. So much info in here, can't believe its free!Thanks Audioholics and Grimani.
There is more to life than Audio😮 😅great video series, I’ve watched all three on absorption, diffusion and bass traps. Thanks gentlemen!
Because his information is so good, I will more than likely be purchasing his products for my new theater room at the end of the year
Gene & Anthony, these three presentations on room acoustics have been amazing. What a treasure trove of very usefull information on the subject. Many thanks guys!
I just love these talks on room acoustics so much! I could listen to you and Anthony talk for hours. Informative and entertaining on so many levels.
New to your channel and I have just discovered you guys. I just finished building 4 traps of my own. By far the best information I have seen. I love the fact that nothing is being sold, just old fashioned rap. I have really enjoyed it.
Antony is simply the BOSS i love that Guy !🔥 can hear him explaining all day long 🔥
Grimani has helped me understand more about acoustics in the few videos that Gene at Audioholics has put on than a hundred other TH-cam clips I've watched. Very timely as I am building my Home Theater room right now. Also looking into multiple subs for the 50 hz and below range. Thank you guys!
Other random TH-cam videos are often published by material manufacturers and their recommendations seem intended to get you to buy as much of their stuff as possible.
Really impressed with Anthony of all your guest speakers....!
I can listen to Anthony all day.
I would definitely love a REW primer showing how to measure and what that means for types and placement of acoustic materials. I put some absorption panels on the first reflection points and the room measured worse. At least, I think it did. I’d like to understand what you can learn from the measurements and how that informs the placement and type of acoustic treatments. Thanks for doing these videos Gene!
+1
Mr grimani’s knowledge goes above genes head when grimani talks
@@TheSpeedyr6 the content on this channel goes above yours.
Just love these chats with Mr. Grimmani
a good video would be examples where people often get ripped of and what to look out for :)
+1
I havd played with the idea of building a long living room, and dividing it with an absorber wall. So behind the absorber is physically a small, separate room, but acoustically it is still part of the living room. It's cool to see a "pro" teaching the same idea!
Greetings to Anthony from Poland
Good job hosting these gene. Tony is my new favorite in the audio world to listen to . I already feel like I've gained important insights from just a few hours of these videos today.
Many thanks to you both. I have a lot more experimenting and research to do but feel like I know what avenues to walk down now.
Hey Gene. I’ve seen a few videos now where you mention the great idea of doing a REW video. Although I have a good grasp I’d love to see an hour or more on REW with you and AG etc. it would also be great for those new to the program.
Please do it?!! Any plans in the near future?
Always a pleasure to watch your videos. Truly a gift to all of us in the community, you should be proud which I’m sure you are.
Love these. Just when I think I’m starting to learn, this dude comes in and reminds me I know nothing
Thanks Anthony from Italy
My dedicated 11x13 theater/music room is starting to sound way too small. 😆 Always learning with these videos.
Thanks guys from Australia
Meters 👍 was waiting for the live show but ended up in the dreem world
Haha. I told the GF, 11pm is a live stream and I was out cold by 10. 🤣🤣
I really wanted to be on this as my room is 148sq ft.
Timeless gems!
Thanks for the video! Would be great if you guys could to a walkthrough of a Dirac calibration :)
34:41 Great video so far, only a small improvement suggestion from me. Here you are talking about porous absorbers that work well in high velocity regions but you’re showing the pressure behaviour of a standing wave mode (not velocity). At the 1/4 way pressure dip (as shown here) will be a velocity peak. The reason for positioning an absorber in that location is so that you can use that high velocity to force air through the material and dissipate its energy as heat, thereby mechanically removing that energy from the sound field.
I think it would be more intuitive if the graphic was updated to show the velocity behaviour instead. Thanks!
@Anthony Grimani...you're absolutely right about meters and feet..i totally agree.. :-)
It is not about Boyle's law (and what you stated was the ideal gas law), it is about Euler's equation of motion relating the derivative of pressure with velocity; at pressure null you have the highest derivatives.
Don't understand why you'd put traps in corners when the whole wall is the problem, assuming you have flexibility with space.
Modal pressure is strongest between two parallel surfaces not corners.
I've been watching these series from Anthony Grimani, very good info. I have recently subscribed, but would like to know if he goes over any info on setting up REW and how to measure and to look at?
After a TBI + epilepsy which equates to chronic migraines and the tip for relief, is get the volume over 120dB and low Hz helps plenty - love to have a go being your test pig 🐷
Secret internet tip for Audioholics! Put your modem/router on a transformer! My router’s internet connection comes into the house very close to my electrical service, the modem/router’s circuit is only like 6’ long to the breaker box, we have whole home surge protector at the breaker box, but still our lights flicker from time to time, I believe that internet interruptions are correlated with light flickery. I use a few incandescent lightbulbs in my chill spot because of some color spectrum curve preferences I have, but they show flickering voltage shifts way more than my other led bulbs. I believe because LED’s have switch mode power supplies inside them. When I put my incandescent lamps on transformers, no flickers at all, when they’re on my other surge protector products (of which I have many) lol they flicker from time to time. My recommendation is exactly what I use on my router, a “OneAc Condition One transformer with the OneGround feature giving it a virtual kelvin ground” www.gryphon-inc.com/Spec%20Sheets/917155C%20ConditionOne%20Series.pdf Since installing it, it has Eliminated my internet hiccups! It’s a small
Both Gene and Anthony sound good. Anthony's level is stronger than Gene's but not distorted. A decent mic. I am sure my office bass trap is a drop ceiling of over a foot and 20 x 15 feet long it should act as a nice bass trap I will send a schematic when completed taking out the divider walls. The Cornwall between two Klipshorns sounds amazing and I turned the Outlaw to forward-facing because of distortion of the down-facing mode. Trying to keep up to 3 15" Klipsch speakers it has its work cut out for it. I just set it to 80Hz and will calculate the dimensions of my bass trap. The sub I have closed both traps but have to increase the gain to keep with thee three 15" transducers. We Will experiment with an SPM and software to be purchased as both Gene and Anthony have it in their reading lists.
cheers guys great segment.
If you have a rectangular room , make a single bass array (SBA) or a double bass array (DBA) that’s how we build home cinema rooms here in germany.
Bass traps only solves spikes but not dips, and you can easily attenuate spikes with the AVR’s DSP
Whats up FOMO?? Didnt know you did home theater!
I've recently bought GIK bass traps and measured with REW and it helped the drips and peaks by 2 db.
Spikes and dips are consequences of phase cancellation. So the dip is caused by a frequence that IS there, as far as I know. If I understand it correctly, if you damp the problematic standing wave, there won't be so much dip any more, because there is no more cancellation.
Thanks for the clarification I didn’t expect traps to help with dips!
@@bgallagrr heck yeah, I have a huge upgrade to my 3500H this spring
Excellent video!!
Oof, the PV=nRT explanation at around 36:00. It's not enough of a blunder to make me doubt your expertise, but you should really go back to the textbooks before repeating that one again.
Wondering after a quick Google search if this tidbit came from the Jay Kadis paper "Acoustics: the study of sound waves" since he also mistakenly refers to the ideal gas law as Boyle's law and then misrepresents its applicability. Hopefully the rest of the info in this paper is more accurate than the gas law portion. At least he correctly identified the V as volume (of the container, not SPL volume) and not velocity.
That said, I still feel this has been a very valuable video series. Thanks guys!
Video topic recommendation: REW deep dive with Grimani
Do you sell the fabric over the acoustic treatment - With the marvel characters?
It’s something I’ve been looking for
My wife hates my only sub. I let it to your imagination what is going to happen when she comes back home from work and suddenly finds four of them.
Stacked? :)
Silly problems. My room my say. Don't like it stay out.
I got four now 🥳
@@Harald-MacGerhard You either single or your den is well off your wife's routine.
@@benjaminqilafku5714 Thx a lot for your concern .... my better half wants subwoofers and she helped design bass traps 😂
I just REWd my setup last night. Two subs between tv and Speakers. Massive ~20db drip around 42hz. Moved to the corner and got worse. Added sub to the rear and created another sharp dip at like 50hz. I was able to correct some with EQ on the SVS PB-1000 Pros, but guess I need to keep working on it tonight :(
Funny I've always been a "bass guy" and made sure my systems always had the best quality bass possible. I'm also a chocolate snob lol. Great information guys, thanks!
Multi subs is good for having a more even bass response in multiple positions throughout the room. It is unnecessary and can even be detrimental to a studio nearfield listening environment where the frequency response is optimized for only 1 general listening position. Context matters a lot. :)
Waiting for R.E.W program!!!
thank you both for such great info! i wish someone would speak more to non-rectangular rooms. working on an L shaped multi-purpose entertainment room that by my calculation is about 7400 cubic feet with a HT set up on one short wall. looking to replace two weak 12 inch subwoofers with something more appropriate but don't really want to do the spend on multiple jtr rs1/rs2 subwoofers! considering a pair of the new monolith 16 thx. can only use two due to other room constraints. also need to think about bass traps and other wall acoustic treatments.
Thank You !!!
Hello Gene. Multi sub with acoustic bass treatments is OK, but when will Audioholics do the current subwoofer state of the art video on Double Bass Arrays? Why not explore a superior subwoofer system that uses the benefits of multi sub without the need of extensive acoustic bass treatments?
Ported subs are slower in the sense that the sub itself has a longer decay time. It doesnt stop outputting energy when the signal stops. Thats because it amplifies the very lows via the bass reflex tube, which is essentially a resonator, and resonators are designed to resonate. So yeh. Kinda ironic how people care about decay in acoustics, but not the device creating the energy itself. But dang these guys give soo good info.
In a well-made ported enclosure, surely the resonance should stop at most half a cycle after the driver stops its motion (when the back wave excites the air in the enclosure and it exits through the port), so at 20 Hz that would be 25 milliseconds, which in terms of group delay isn't bad for such low frequencies. So in absolute terms it's slower, but as far as audibility goes I don't think it's a concern.
@@TokeBoisen Yeah. Fair enough. I just think along the lines of, if the sound designer, mixing engineer etc wanted some decay to the sound, they'd program that into the signal.
Aka, if I were to want to make a hyperrealistic sounding movie, I'd care if the gunshot sounds(open air shooting) had proper low end punch to them, without pretty much any tail to it.
Also, if there is quite a bit of effort put into controlling the bass in the room in terms of acoustics, might as well consider the group delay of the sub itself.
But I aint no expert on the subject, which is why Im here learning. :D Gotta say, amazing knowledge they pass on here.
@@rist98 Audioholics actually have a great video on the topic of ported vs sealed subs on the channel.
But if the reflex tube is tuned to 10hz then it’s a moot point no?
@@stopthefomo in practice, yes. The port has little influence in a properly constructed sub above its tuning.
Gene and Tony. Really enjoying this series. Amazing how little I know about any of this. Question: this might come up in the next video but I'm wondering what suggestions you have for multi sub integration. Most AV processors or receivers are going to have at best 2 sub output hopefully separate. The AVM90 is supposed to have 4 but also costs 7G+. Do you suggest integrating 4 subs through splitters, daisy chaining, mini dsp, some wireless solution, etc? Is there an amp-procesor channel reassignment I don't know about? Thanks for any info!
Gene did a video about mini-dsp, I think you run 1 sub in and 4 out then you can delay, eq, level adjust each independently. I think Tony uses a better pro level ashly dsp. You have to be able to measure and adjust though which requires some experience and tools. Tony uses an average of 4 positions in the room not just the money seat as us amateurs would do to figure out everything.
@@dm17nc17 thank you. Yes you're right I think ideally you run the mini dsp with the 1 in and 4 outs to 4 subs and then adjust each accordingly. Truth be told I have the umic and the mini but I haven't gotten around to it. I tried once and couldn't get stuff working so got frustrated and quit. I do want to get to it. I've seen tutorials it's just not that easy to do imo.
@@jliu2222 Home Theater Gamer and Home Theater Gurus have some pretty good guides for how to setup subs with miniDSP using just REW. Personally I found that with a lot of tinkering I got some really good results using MSO (multi sub optimizer) as that allows you to put in multiple seats measurements per sub and optimize it for seat to seat response across more than the MLP and every sub gets it's own unique PEQ filters so they ultimately combine better in my experience with a really challenging room since one corner is missing since it goes to the rest of my house.
@@TylerStout thank you. I agree. I've seen those videos and they are really good. I think I need to just commit one weekend to this to feel more comfortable with it. The high learning curve makes it difficult to just jump in. I agree tho I think the minidsp is going to be a game changer in my house when I get to it!
So a trick I heard was to place a speaker in the listening position and walk around the room to find the sweet spot. That's where to place the speaker. No idea if it works or not.
Does adding damping panels in a room give the impression of less bass below 100hz? If the rooms damped, are your ears hearing less bass? Sorry had to ask twice, hard to describe ;)
God bless Lord Grimani! I need some Grimani clothing now (Fck Armani) as well so my clothes don't mess up the acoustics when i'm listening.
The Telecoms do updates in the middle of the night! so it just have to deal with the odd drop out at this night owl period for us in the USA and I am EST time. cheers agiain
In the example where you put the bass trap 5ft from back wall to fix the null in the bass, could you build a 2x6 wall with insulation, mount an acoustically transparent screen to it (possibly in wall speakers as well) and use that 5ft space behind the wall to even out your bass?
Unless you maintain placement along an arc being the same distance from speakers to listener, wouldn't you be introducing phase issues as the sub wavelengths would hit your ears before of after your mains dependent on placement in from orfor behind that arc line?
What is like to know is if I had 2 big subs at the rear of the room because I don't have space at the front of the room for them being so tall can I use 2 smaller subs at the front to help with smoothing?
A.G. did say the smaller subs run out of steam first but I already have one big ported sub and want a second the same to match and they will have to go to the back. If I find out that I still have modes to deal with can I put 2 smaller ported from the same manufacturer at the front of the room to assist and fix the issue and then blend them in with eq?
Anthony- if having a less flexible wall is desirebale re bass, wouldn’t that suggest some advantage of steel studs versus wood ? What about mounting yoru drywall on resilient channel ? Or screw through a rubber washer to buffer the stud/drywall interface ?
What is an ideal shaped and size room for two channel listening?
Both mics sounds great! Hearing you fine on my phone sitting outside on the patio with some endangered species 72% dark chocolate with tart raspberries, goes good with Romeo y Julieta 1875 cigar 😁👍
But of course you don't appreciate the finer things in life! :-) I'm drooling just reading it
I've heard this works well for how to place a sub. It is recommended by my local HIFI-klubben:
Place your sub at the listening position, then move yourself around the room, and place your head, where the sub can potentially be placed.
The place where your sub sounds greatest, is the place to place your sub.
Could you use passive radiators in a box for bass traps
Timepoint 37.25: Anthony, Gene was confused by your diagram (I imagine other people were too). I respectfully suggest that a 3D image would have helped, or alternatively an additional top-down view to put the side-on view into context. On its own it is not obvious what that image is supposed to represent IMHO
How about a video bring all this together but giving ideas of how to economically for those of us on fixed budget. I want to make my room the best icon for what I can afford.
This. It's all great theory, but what can we practically do that doesn't cost more than the system?
Build your own panels or bass traps. You can get a sheet of mdf cut to the size you want for bass traps or panels. Roxul safe n sound for 50 bucks. Hobby lobby for some fabrics, and you can basically have all the absorption you want for around 10 dollars per panel. UA acoustics has diffuser panels that are pretty cheap on Amazon or eBay. I think this would be the best bang for your buck..They can actually look pretty good too. I'm on a budget myself, this is the way I went.
Anthony- re number of subwoofers, ie 2 better than 1, 3 better than 2, and 4 better than 3,
ceteris parabis, ie good placement, same subs, “decent” room (ie not large (ie
Thank you for the guidance. However, most of the recommended materials are above the average person pay grade.
I am creating entertainment room with the following dimensions: 17’(L)x11’(D or W)x9.
I am planing to achieve correct environment for the 5.2.2 Dolby Atmos surround system by having utilizing second subwoofer, placing pictures, wall furniture, coffee table, couch, area heavy rug and heavy black curtains over the window and door to mitigate sound problems. I will be utilizing AVR software with the microphone to create the best possible room acoustic.
I do not expect a miracle, but I am hoping to achieve great sound; separation, fidelity, etc by having the second subwoofer and taking my time; tizing try and error method to acchieve best possible results.🤞🏻
I'm looking for Tod Welke and coming up with nothing. Could you provide a link?
What about near field subs, for instance, 2 subs in close proximity to the main listening position?
does open grass land make it ideal listening space?
My basement has a large open wall on rt side. An a ceiling only 7 feet. Any advice , my room is 30L/18w ..Thx much…. I have 1 big sub and small sub..
Pb 16, Klipsch 12 inch😎😊
Are you saying that a sub in the corner of a room that’s 121sf would be enough?
Guys, really nice job on bass absorption. About your question Anthony on why you get video dropouts, I spent 21 years in IT solely working on computer and network performance, and I can probably help you understand why and how you are seeing dropouts. If you want to follow up on it, let me know and I can email you my email address and we can talk about it.
Hi Stewart, I would live to hear your insights. Agrimani@pmiltd.com
Love it!
Are there any companies in South florida that come to your home to give ideas on what acoustics you need?
Best fucking video. Very good. Helpful. Fucking wonderful.
In the drawing @ 38:02 why not put that absorber on the back of the chair?
I run a 8" ported with a 60 w amp and not a lot of room so made a bigger box around the sub and got some rockwool in the outer box with air gap. Diy ass f.. just a mcgyver fix as i save up to get new sub's
When you look at most of the listening rooms I've seen would simply benefit from furniture, soft fittings and some books, pictures on the walls etc.
Would love to know what furniture would solve the theoretical 50hz issue exampled throughout this lecture.
So according to the science, would I be better off with 4 smaller subwoofers like SVS PB-1000 in the corners instead of two larger ones in front like dual PB-3000 or dual V1812?
From my own experience, a lot of it depends on how many seats you are trying to accommodate . The more seats you have in the room the more you benefit from 4 subs. This is because the 4 subs are going to distribute the bass more evenly throughout the room than one sub, meaning that if you time align them properly, each sub will fill in the dips and smooth out the peaks in the frequency range within which they operate. With fewer subs you can have great bass at your main listening position but that bass might disappear in other seats around the room. If you decide to go with just 2 subs, the science and my own real world tests have shown that placing them directly across from each other either at the front and back of the room mid-wall, or the side walls mid walls can work best. But you still need to have a way of properly time aligning them, and for that you can use REW to measure and MiniDSP to make the timing adjustments. Once you've done that, you now integrate the combined sub with the rest of your system.
@@wells2671 Yes I think in theory starting with 2 PB-1000 Pros in a 14x20room is where I will start as I only have 4 seats. That should be plenty loud but I can always get 2 more if needed. Tony has diagrams from Welti's work showing the best layouts, either 2 on middle of opposite walls (either front to back or side to side) or 4 in the corners. Gene's testing data of the PB-1000 Pros should guide to how loud in what size room they work because they seem amazingly good for not much $$. Tony had a test case where 4 10's worked so much better than one huge 15 as far as similar bass in each seat for a six seat room.
@@dm17nc17 I went from 1 to 2 to 3 and now 4 subs. All SVS SB12-NSD. Even with 1 properly placed sub, if you only had 1 or 2 seats you would be fine(assuming you could EQ the peaks down). But once you start to go into multiple seats and multiple rows, 1 sub will not give the same experience at all seats. Just bear in mind these 2 points... 1st one is that when you add subs you're not necessarily assigning 1 sub to each seating location, but rather you are creating the effect of having a more efficient sub (by combining them) which forms a larger and more even field of sound for the room. The 2nd point is that more subs don't necessarily equate to more volume (loudness) although they do increase the headroom of your system. So each sub doesn't have to work as hard individually.
Thanks Gene and Anthony ! Been following Gene for over 20 years dam That's a long time 😆
thanks for reminding me that I'm old ;)
I thought Gene had a baby seal on his TV shirt. If you zoom, it is actually Yoda.
Can you detect the frequency of the standing wave problem with a frequency generator (app or website) (frequency sweep) and listening at what frequencies aproximately it's unnaturally loud?
$100?…..$80?…..90?…..TRY $140 for the Sonitus Decotrap!! And you must buy them in packages of 2, so that’s a minimum of $280. Also, they, along with all of their other bass traps, have been out of stock for ages, which seems odd, considering it’s only a piece of foam and a sliver of wood.
Also, while Anthony states that he doesn’t want to call his Sonitus Low Killer a bass trap, on the Sonitus web site it is named, “LowKiller Acoustical Bass Trap.” It makes me curious as to who is actually running Sonitus.
47:10 Hmm, so would it be possible to build tunable panels by having 2 perforated boards, one sliding behind the other so that the size of the holes varies? Can these "holes" even be square so that when the 2 boards are aligned there is a huge total "hole" area (low frequency I assume) and as we slide that board they become rectangular "holes", progressively smaller for higher frequencies. Would that make sense?
Then we can put that panel on casters and easily tune a room whenever we move to a new place for example (by measuring w/ a mic of course).
Can anyone knowledgeable tell me if this would work?
Awesome video! Too bad you mentioned multi sub without touching on double bass array (dba). It seams to be almost unknown although it is state of the art for home theater in Germany for years.
Maybe you could get to dba when you talk about subwoofer placement.
Bass array is difficult to pull off and expensive right?
@@xavdeman well of course it isnt cheap but neither are the alternatives. And I don't think it is more expensive or difficult than using Helmholtz resonators.
In smaller rooms you perfect results with four subs in the front and four in the back. If you built it yourself you can buy good chassis for 250-500$ each + a stereo dsp amp + building material. So the entire thing is around 5000$ and probably gives you in an rectangular room the best bass you can get with the same result for every person in the room.
If your room isn't perfectly rectangular, a single bass array might be an alternative.
Re multi subs - is it a real problem to have a mix of different subs (driver size, manufacturer, amp etc) or is the critical thing just not mixing ported and sealed subs ?
I dont think so. Gene current room has different brands
Question, When these soundwaves stretch from the front of the room to the back of the room for a certain frequency (based on the length of the room)does the height and width of the room also affect that particular frequency, or is it only specifically tied to the length of the room? In other words if that room was the same length but half the height would the soundwave/frequency be the same and would it affect the room in the same way?
In a rectangular room there are at least 3 room modes corresponding to each spatial dimension as low frequencies propagate equally in all directions. If either of the room dimensions are of the same length, or close to being the same, the amplitude of a room mode at one particular frequency will be greater. However, In the real world it can be hard to predict these things exactly. Ideally you'll want a rectangular room with varying dimensions so that any one particular mode isn't too powerful, thus easier to deal with.
Yeah, that's what I've read, and I've used the Harman room mode calculator to get a rough idea of what the Room modes could be in my own Room. I am always curious about the sound waves hitting one wall and then bouncing back, and how having a ceiling that varies in height can affect the room modes between the other surfaces. It seems like most of these calculators assume that all surfaces a parallel. I'm wondering how (if you had a barn shaped Room) those calculations for the length get affected by the different heights of the ceiling or if they get affected at all since that is a different direction?
Is there an estimating program that takes in dimensions and surface types of a room and suggests placement of speakers and audio control surfaces?
R.e.w. has a room sim where you can place 2 speakers and up to 4 subs and see how up to 200hz should respond to any listening position. Great graphical interface.
I'm from the UK although we use imperial and metric, metric is much better.
Anyone using that Sonitus Decotrap Quad in smaller rooms? :) What are your experiences?
please explain 20% material far panels
boomy bass does minidsp helps
You can't just get 3db from power alone , I like that I currently use 3 i might try 4 . Hmmm
Would like to know preferred room measurements for new build. W x L x H
I've wanted to know about bass yes with about ten years because my living room is awful. I have a subwoofer but it doesn't give me as much bass as it should. My room is 11' x 13' with carpet down. I am extremely limited to where I can put the subwoofer.
So I was going to try some bass traps in the room but I'm not sure if it will work.
Also there's a problem with standing waves from two of the walls.
Acoustic treatment and eq
@@thatchinaboi1 hair dryer and water. Come back to me when you can elaborate with more than four words.
How do you compare 2 SVS pb 2000 pro vs 4 SVS pb 1000?
Either 4 1000s or 4 2000s😂
I find the best bass trap is just stacking more subs in the corner
Very sus that Anthony doesn't show a single measurement of the Sonitus Decotrap he sells. Espeacially after an hour of explaining why other types of bass traps have disadvantages by showing graphs and measurements. He doesn't even remark to which flatness in dB this 60-500 Hz range corresponds.
How come commercial cinemas get good bass with only front stage pro subwoofers
because the room size is enermous and the standing waves are in very very low frequencies only, like way beyond 20hz.