Bass Traps: Pressure vs Velocity - Which one should you get? - AcousticsInsider.com

[@gooshie3]

Aah...such a relief to hear someone who knows what they're talking about. Great content.

[@joelrichloow1021]

Omg what have I got myself into, I wanted to treat my room, so I search for help and now it feels that i’m studying rocket science. All this is insanely complicated. But your videos are the only ones that actually help me out to reach my goal!🙏🏼 Keep it up man!

[@wesselingaudiodesign5031]

For critical listening, Complicated? Yes and no. Not really, Just use lots of absorption.

[@joelrichloow1021]

@@wesselingaudiodesign5031 Yeah of coarse, but it’s insanely much information to be aware of about this topic. I got myself 4 foam bass traps from EQ Acoustics for about $100, I hear a slight improvement. But I’ll follow your advice, quantity over quality so I will build my own big thick panels which leads me to this question: What material is usually best to use for treating primarily low end but along that also improves the mid’s and high’s? Is it really rockwool that everybody else recommends? I don’t trust anybody else besides you right now😅

[@joelrichloow1021]

@@wesselingaudiodesign5031 Oh, I realized now that it wasn’t the guy in the video that answered to my comment, I thought it was, sorry🤣 But if you do have an answer anyway, please share it!

[@wesselingaudiodesign5031]

@@joelrichloow1021 Please, Don't buy foam, it doesn't work, absorption coefficient is extremely low and probably has no absorption at low frequencies. Use Rockboard 60 and diy the panels. - This is broadband. The stereo room in my old house was filled with it. I'm doing the same in the new house.. Guilford of maine for fabric covering. Thin polyfill cloth can cover the rockboard under the fabric.. wood frames. Plan for personal aesthetics.. I was hired to treat a Piano/practice room, this will have some quadratic diffusers and broadband absorption.

[@wesselingaudiodesign5031]

The guy in the video is Excellent!

[@PeterBatah]

Thank you for sharing your time and knowledge with us. Your presentation is clear and precise. Just what the audio doctor ordered. Keep up the great work!

[@jonlanghoff]

That one negative vote is from Dennis Foley.. :P

[@infinaneek]

😂😂😂😂😂😂😂 good one!

[@JonnyRocksAW]

I am so glad I found your channel before room treatment. I don't see this in-depth info elsewhere and learn something new every video. Small room home studio here, porous traps here I come.

[@nirniro1]

Thank you so much for this clarification. That will save me so much headache and money , I was almost about to get into membrane traps🤦🏽‍♂️

[@markp4044]

Thank you very much. You actually put a smile my face. Because I'm in this exact situation. And a certain guy on KZbin here is stressing me out with his videos that only catering for people with a lot of money. I guess he's a salesman at the end of the day.

[@RoyThompsonAudio]

Great video dude!! The bass trap guide is incredible -- you are gonna help a lot of people!

[@lucasloud]

Jesco! Can you tell us straight up: are Dennis Foley’s diaphragmatic absorbers voodoo? Please do a whole video with your thoughts on Acoustic Fields, we need that video badly!

[@ATOMIKDOG23]

Great to have it explained properly ....I downloaded your guide....thanks

[@raphaeldubois9107]

To cover down to 40Hz with a 50% coefficient you need 10 inches and to increase the effectiveness, you have to go up to about 2 feet deep so for small rooms I don't think it's as "flexible" as you said. Although, small rooms usually need velocity absorbers because they are most likely to have resonances at multiple frequencies that are close to each other (the whole low end). On the other hand, membrane traps or diaphragmatic absorbers take less space for the same frequency and will have more efficiency than velocity absorbers. Membrane traps or diaphragmatic absorbers can also be designed to work with larger Q factors.

[@xpulsar]

Totally! I think the 40hz claim he is stating in this video is very off from all of the actual technical research done by some very educated research departments. BBC , RCA etc..

[@plummetplum]

Are you going to do any videos on how you make your traps, plans etc? Thx

[@reading_fastandslow]

I like the idea of putting a diffuser front on your porous absorbers. Is there a particular way to design that?

[@citadelo5ricks]

I have found garment racks with stacks of 6" plastic wrapped insulation to be fantastic and moveable. My question is what about hanging MLV on a garment rack? Either in combination or alone?

[@graywyot]

Thank you so much for this super helpful video!

[@spyro5484]

basstrap guide is awesome!!! thank you!

[@frankroobaert808]

I’m in office acoustics and recently my son asked me to treat his home music studio, I learned a lot from your videos and it’s a totally different business but we managed thanks to YOU !

[@dewaldomusic]

PSI AVAA solves many issues associated with pressure traps. My room transformed after adding 5

[@perthomasthorsager9544]

Wow , this was great. I am a subscriber now and finally my work towards soundnirvana is getting closer I think. Thank you sir. Just ordered 8 X 20cm deep rockwool insulation .. as a start.

[@jorgeandreozzi4945]

great great work!! as usual..

[@sickmessiah]

I wonder if passive radiators could be built into a box and tuned for bass absorption.

[@plummetplum]

Hi my room at the longest length is 3.6m is it worth having a small primitive root diffuser at the back or just have some absorption with wooden slats over them to stop the room being too dead? Thx.

[@QuangNguyen-nh2oc]

Amazing amount of great info! Would an acoustic guitar works as a Hemholtz resonator absorber? If so, would it absorb in the fundamental frequency range of the guitar?

[@PanosLa]

This video does a great job explaining that, but I can't stop thinking of the claim about the 40Hz porous absorber. Usually, in small rooms 10-15m2 in surface, the issues are usually the 1st and second harmonic of each axial mode (hopefully the room dimension ratio gives an even distribution of the oblique and tangential modes). So, if a dimension is 3m the first axial mode is like 57Hz (ish) and the second 114Hz. How are you going to treat that 114Hz (which is usually rings most) when the quarter wavelength is like 37cm? Assuming that you put a set of porous absorbers at 37cm on both ends of this axial mode, you are losing a total of 74cm. That is almost 25% of your space. Although the challenges to building a pressure absorber (of any kind) are true, they can still have a wide Q and hit "two birds with one stone". Not exactly ideal, but if you have a "non-ideal" room, to begin with, it's pointless to assume that you will have an ideal acoustic treatment... So I am kinda thrown off by the idea that pressure absorbers are impractical. I already built my studio in a terribly wrong room for that purpose (3.1x3.4x2.8) and I managed to get very decent acoustics using mostly Helmholtz absorbers. That room was in my own house, but now I have moved (because of work) and I am planning to treat my room (in a non-destructive way... ). My design showed that I need 3.6m2 for an 80Hz Helmholtz absorber and 1.8m2 for a 160Hz one. That is not much for 30m2 of free available vertical surface that I have available (excluding doors, windows, radiators, ceiling, floor)

[@dougleydorite]

Do you have any knowledge of GIK Scopus membranes?

[@PanosLa]

@@dougleydorite I just googled them. What about them?

[@jamesmoore4827]

My brain hurt just reading this, and all I want is my hi fi system to sound good in my room! lol.

[@d.andresvaldes7659]

keep up the good work man! I really appreciate it!

[@saardean4481]

Hey there. Would love for you to make a video on building Helmholtz resonators and how to tune them

[@justinbraun8003]

PSI Avaa 20 is a pressure trap that circumvents all of these issues apart from cost.

[@kentwood2914]

Is a diaphragmatic absorber a pressure absorber which is a resonance absorber, which is a membrane trap?

[@perrysmiles60]

Hello Master Jesco, In my case, it's for a home theatre and I don't have the ability or equipment to do measurements as you mention in this video. And because my home theatre is also my living room, corner bass traps are not ideal. So if I'm to use made from a supplier, rigid fibreglass panels (6 lbs/cubic foot) covered with an acoustic tissue, can I treat my front wall with 5 or 6 inch thick panels of 2' x 4', placing 2 behind my L & R mains and 2 behind my large screen TV, all evenly spaced as a good start to treating my space? And will this control necessary low to mid frequencies to help improve my listening experience? I cannot treat side wall reflections because of my layout... only front wall, back wall and ceiling. I do have a thick rug on the floor between my MLP and the centre channel. My living room space is 20' W x 25' L x 12' H. I'm running a 5.1.4 set-up. Your advice would be Greatly appreciated. Anyone reading and that has experience on the topic, please feel free to share your comments as well on my situation. Cheers to all my fellow enthusiasts! 🙂

What do you think about a live end/dead end setup for the studio room ?

[@davidasher22]

Love this channel!

[@hexial]

This is really interesting. I'm so glad I've discovered your channel! Do you plan on doing a video about how to treat very low frequencies using velocity traps as mentioned in this video?

[@laaldonk4357]

is there anywhere else to asscess the guide? ive gone thru the steps twice with a 3 day span with no luck

[@EckhardRotte]

What about passive, disconnected (maybe electronically) bass cabs? The resonance frequency may be listet in the specs and might be adjusted by an adjustable bass reflex tube.

[@KirkYardley]

Can anyone help me with this… In regards to recording (not mixing) where would one put the diffusers? If the front wall is the wall I’m facing when I’m on the mic. (Assuming walls are thoroughly covered with velocity panels.)

[@chrissymostuy]

Can you please comment on Output's new bass traps? They look amazing, but it makes me wonder if they actually work...

[@hamooddyy]

Wat is your opinion about ekustik bass trap they claim it absorbs from 40 to 80 hz!

[@infinaneek]

Great videos

[@couchcamperTM]

Ok this video convinced me I need another hobby or headphones xD

[@anttiniku5223]

Great approach to bass trapping that makes a lot of sense. What is your take to constructing the entire walls for handling low frequency and reflection control? Philip Newell presents some of the wall designs in his book about building recording studios. Typically you would have several layers of materials / air (e.g. sandwiched drywall with dead sheet in between, porous absorption, dead sheet membranes etc., which is not tuned so keeping it intentionally lossy to have a broader band effect.

[@GurvanBHC7]

Hey, the most broadband TRUE bass trap is Slat resonator (idealy all your front wall with your speaker build in the resonator). For targeting not just one narrow frequency, you can angle the resonator on the outside to target more frequency. Please read the paper of « AndyMacDoor », a french acousticien who has study these trap for about 7 years and now he working on huge french studio and also small home studio and all his theory work in real word. You just need Google traduction :)

[@C--A]

@@GurvanBHC7 Hi get in touch with AndyMacDoor as you seem to know him. And get him to send Jesco his slat resonator and also his other products - diffusers etc. So we can see if they actually do perform better than similar equivalent products on the market. His acoustic room treatment products on his website do look very interesting unique. But we need detailed measurements from Jesco to determine if they actually work as claimed.

[@flawlessbeautyil]

Hola Hermano. What is the best pressure trap? Helmholz? membrane? diaphragmatic?

[@danyar91]

what is flow resistivity ?

[@CynicEidolon]

As an audio and solar professional, I love your analogy, sir. Haha.

[@staffanolofsson8342]

You talk about the depth of the trap is important, but what about an air gap between the trap and the corner? Some say that it's enough whith 15 cm of actual trap, but it's important that there is a big air gap between the trap and the corner. Is that true?

[@snapascrew]

A tube trap is a velocity trap then? (ie: ASC tube trap)

[@christianmeza4529]

What brands carry velocity traps?

[@WinslowOfSouris]

Hi Jesco, first off I really like your practical approach to acoustic treatment. Most of us have to work with what we have rather than being able to build perfect rooms from scratch. I have a question about flow resistivity: at 1:50 in this video, as you adjust the absorber thickness you also change the flow resistivity value. Is there somewhere someone without a masters degree in physics can look to better understand that? I just want to model some very simple traps, but if 100mm is 10,000 pa/m2, but 200mm is 8000, and 300 is 5000 for the same material, how am *I* supposed to figure things like that out? All these calculators require a flow resisivity value, so how do I get that for my material? I can get the weight per m3 (which you've also mentioned elsewhere), but how does that translate for using something like the acoustic modelling calculator you often use? I don't if you'll see the comment on a year+ old video, but figured I'd ask anyway. Maybe someone in the community can help as well! All the best!

[@nikolaudio]

If your gas flow resistivity is lets say 3000pa*s/m2, you MAX out the absorption coefficient of the absorber somewhere around 60cm thick. IF you take that same material and make it now 100cm thick, it wont absorb anymore/any deeper of the frequencies. In order to absorb anything deeper, you need to select another material with a LOWER gas flow resistivity, and THEN you could go up to 100cm thick and it WILL absorb deeper/more. Thats why as he lowers the gas flow resistivity, he increases the thickness of the material because they are related in that aspect^. There is nothing stoping you however from having a 10 foot thick absorber of a 10,000pa*s/m2 material - its just pointless.

[@joker927]

I have a 25db room mode at 100hz. It's very annoying as I cannot move my listening position nor my speakers. It sounds like without a major investment I might not have any options.

Awesome video! :)

[@carolinegaudeoso6798]

Do you have more info on velocity absorber? I am still kind of questioning how to reach 40Hz only with porous material. Great explanation btw!

[@sonnenklang6925]

Maybe replace a roomwall with an velo. absorber :)

[@mikemcguinness1304]

You can't. Jesco is talking shit

[@pnkk787]

He's the Vsauce of acoustics

[@eddieruddock7014]

Or is he 🤔

[@LQ-gaming]

ALREADY have two orders of base traps, dang ! :P

[@sh91899]

So with a 12x18x8’room and a $5000 budget... $2500 for an AVAA and $2500 for porous first, second, and ceiling reflections and diffusers on the back wall (12’ wall)? AVAA is 14-150Hz and placed in the corner behind the sub which is located off the corner 3-4 feet.

[@dougleydorite]

Have you tried the AVAA?

[@sh91899]

I have not, but I understand the concept/construction and reviews say it works magic.

[@dougleydorite]

@@sh91899 I have not seen any acoustician recommend it and the two reviews on KZbin are a bit “sponsored” feeling and the before and after on those vids don’t show hardly any difference. But, if you go to forums, so many people say that it is a huge difference and definitely worth the money

[@sh91899]

@@dougleydorite Yeah, the face converts the velocity wave into pressure and a mic feeds directly into the amp then driver without any DSP which inverts to cancel the pressure out. I'm considering making my own... (MSEE)

[@painstruck01]

brilliant video. you've convinced me to pay someone who knows what they're doing, to do it for me.

[@jmpsmash]

What would it take to build a velocity trap that goes down to 40Hz?

[@ClintMoody]

About 7 ft of absorptive materials

[@sh91899]

Quarter wave, which is location of max velocity from the wall, is 7 feet but that doesn’t mean you need 7 feet of porous material. You can use 4-8” of material positioned 7 feet off the wall. If you place them diagonal across a corner then you’d attach the absorbers 5 feet from the corner along both adjacent walls. The center of the absorber would be 7 feet from the corner but the diagonal would give you broadband bass absorption because the trapping frequency increases as you move towards the wall in both directions. Like he says in the video, it’s not practical for smaller studios and could be pretty expensive.

[@plummetplum]

@@sh91899 At that point it's time for headphones and Sonarworks calibration software.

[@joeblow1229]

Man this guys gets it. Finally someone saying what needs to be said. Newsflash: this is all physics, and you can’t argue against this. You wanna absorb bass below 100hz? Good luck. It’s just reality. Unless your panels are 5 feet thick ( literally).

[@CyberBeep_kenshi]

The more i hear the less i am inclined to start lol. Its my livingroom, no room for huge traps lol Is a big L shaped couch a good absorber? 😆

[@amosluyk]

Now I'm thinking I'll buy a really great set of headphones and headphone amp....

[@matsudakodo]

Under 100 Hz, just use subs and EQ. Much more effective, and...bass!

[@3DaysTillGrace]

EQ won’t reduce the ringing in the time domain. The best thing to do is try to improve the room a bit with bass traps, and then further improve the frequency response with multiple subs and EQ.

[@matsudakodo]

@@3DaysTillGrace absorption is not very effective under 100 Hz, which is why subs and EQ are the most powerful solution.

[@3DaysTillGrace]

@@matsudakodoabsorption-style bass traps might not be super effective, but at least they help a little (which means that they help in both the frequency and the time domain). Multiple subs and EQ only helps in the frequency domain. The best solution is to use resonance-tuned bass traps since they are more effective than regular absorption-style bass traps. Just to be clear, regardless of if the person is using any room treatment or not, I think 2 subs and maybe even EQ is a must. I’m just saying that room treatment AND multiple subs is best because the room treatment reduces ringing in the time domain. Multiple subs and EQ can create a somewhat flat frequency response in a couple listening positions, but it can’t make the bass fast or clear in the time domain. I hate muddy bass so much that I’d rather hear less bass than muddy bass.

[@matsudakodo]

No disagreement that a combined approach is best. I am doing that now, with absorption effective down to 80 Hz with GIK 244 traps. I don't plan on doing any tuned traps as those are more location-specific and it's a really small room.

[@nkenchington6575]

Fuck me, just buy headphones!

[@davelassell]

FFAAAAACCTTTSSS!!!!!! I mean you're crushing my hopes and dreams, but I'd rather start with the truth instead of pretending that things will just work by magic.

[@JesusChristSaves2024]

When it comes to bass management, Bass traps aren't all that effective and definitely aren't worth the cost and space. The solution is relatively simple, Is cheaper and most importantly is actually effective. That is multi sub-woofer set up and DSP correction.