How To Build Membrane Bass Traps (THEY WORK!)
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- เผยแพร่เมื่อ 23 ก.ค. 2024
- This Video shows the basic theory about membrane bass trap,
how to build them and some results for example
amcoustics.com/tools/amroc?l=...
gearspace.com/board/bass-trap...
www.acousticmodelling.com/8lay...
downloads.bbc.co.uk/rd/pubs/re...
0:00 what are membrane bass traps
1:02 some history
3:56 room modes
5:49 formulas
7:19 optional materials
9:38 calculation
14:31 the built
17:33 results
20:04 tip
20:25 more results
![รวมเพลงลูกทุ่ง 6 หนุ่มไทบ้าน ฮิตติดกระแส ชุดที่ 1 l มนต์แคน ไมค์ ไผ่ เสถียร ไหมไทย พี [Longplay]](http://i.ytimg.com/vi/GD2v1OjMw5I/mqdefault.jpg)
I built 12 modules of 3 sizes each - 36 in total - from the original designs on the gear space post by Tim Farrant that are referenced in this great video. I used the updated calculations suggested in the video, and the links to room mode and absorber depth calculators to arrive at the design. I then installed them in the room corners, roughly according to Tims layout plan.
I’m happy to tell you - they worked perfectly. I had a massive low end problem in my newly built control room, 50 hz particularly, and the modules totally solved it. Now very smooth all the way up to 120hz.
Things to note - the modules I built are much smaller than the one in the video, as per Tims original design. I did this for ease of installing them on the walls and ceiling and because Tim is a well respected audio designer (Buzz Audio) in my country (New Zealand) which gave me a bit more confidence that he knew what he was talking about.
They cost about $1000 NZD ($650 USD) and took about a weeks labor I would guess. I used the tec sound for the membrane, like in the video. I used 18mm MDF for the boxes. I used builders strap attached to the internal cavity by small metal angle brackets to hold the insulation in place,at the distance specified in the design calculator. I used a brad nail gun and glue to construct the boxes. There was a lot of stapling involved to attach the membrane thoroughly, which wasn’t much fun.
I used Pink Bats Ultra R2.6 Wall for the insulation (This won’t be useful to anyone outside New Zealand) which has a gas flow resistivity of 10,300 rayls. I found the whole gas flow resistivity thing confusing. The gear space thread on trying to find the data on common insulation materials is what I scoured through. Google ‘Common Gas Flow Resistivity numbers gear space’ and you should find it.
And for anyone is Asia/Pacific, what got me the information I needed in the end was a google drive link at the bottom of page 7 in that thread, by Paul the Sparky
From memory, what may have made it confusing was it took me ages to realise ‘rayls’ where the same measurement as kPa.s/m². So 10,300 rayls is 10.3 kPa.s/m². I may be remembering this incorrectly, so don’t quote me on this.
Other things to note if you are planning on building these - follow the instructions exactly and they will work. The sound sealant caulk is crucial, they need to be airtight. Apply the caulk with a caulk gun, then work it in with your finger to make sure the seal is good. The boxes should be made out of dense material - MDF or ply. I have not seen any suggestion of using less than 18mm. I only note this because I was initially deterred by a comment on here saying they didn’t work, but the person had used chip board (not dense enough) and only built 2 of the smaller modules (not enough to make any difference).
Thank you very much for this video and good luck to anyone who has found their way here - I researched some other options that were either insanely expensive (Acoustic Fields DIY charcoal design) or didn’t have enough before and after measurements to make me confident of efficacy (super chunk etc). Yours, Lord Echo.
Sounds like you did an amazing work both in research and building. thank you very much for the comment, I'm very happy to hear it actually helped someone.
Fuck yeah bro, thank you for sharing a 2nd scenario of then build. 🤝
Thank you for taking the time to explain this ! much appreciated !
Thank you, sir, for the priceless information and the resources.
Wow. The before and after is stunning. The power of low end absorption.
Amazing! I'm just starting out on this struggle to get the low end of my room under control. Thank you!
This video is GOLD. Thank you for sharing all your experience!
Welcome man 🙏
Exellent work! It was almost mission impossible
Thank You for the precious and detailed informations!!! You Rock!
Great video! They work really good👍
Wow the before and after is fantastic!
Wow such a video .. thank you so much 🙏 that’s a whole school semester . I will repeat this video until I will understand and learn everything in it
❤️🙏🥃🥃
Glad it was helpful!
Awesome!
Been collecting information like a 24" absorber, this was really nicely compiled and easily followable.
As I just moved in a new home, I've taken a side-quest to treat the living room in a way it would make a great listening room. As it's almost a square box with one wall consisting of terrace doors and windows for the whole wall, it'll be a challenge. But an interesting one, no doubt.
Tip for the DIYers - place a comfy chair in the listening sweet spot, have your other half sit in the chair and close their eyes. And play them something really nice. 8 out of 10 would open to the idea of you building bass traps, diffusers and acoustic panels to decorate the living room =D
I have never built a membrane trap before. I've known a bit about them, and learned a whole lot more from your video. Good job 👍🏻great video. well explained.
pleasure mate, yes there is definitely lots to learn about it (: we learn it both from theory and of course while trial and error in reality, through building and placing. good luck with the built if you're gonna build some !
Nice
That final image... that's it... that illustrates the best element of bass trapping, the time domain, ie., damping down room decay times.
As you showed, the freq domain is addressed, but knocking down those ringing decay times across the board is immensely powerful in subjective tightness and bass clarity, ... tones are easier to delineate, and of course, that 55hz-65hz range is directly in the "punch" region... so leading edge transient components aren't obscured by resonant energy lagging around.
Also, it's worth noting, when Art Noxon speaks... everyone should listen. His interviews, technical savvy, combined with decades of hands on knowledge, just legit.
Well done. Thank you.
This is that one video what i need.Thanks !!
Great job, mate!
That was really top notch. Thank you.
Shoutout to Rod Gervais and his book Build it like the pro's which I bought somewhere around 2009. I have a very dear memory of mine where I built a "panel trap" with the same mathematics involved like Tim's document, only with a rigid wood panel instead as membrane. As I built it I listened to music, when I fastened the last like 4-5 screws I could hear the shift in air pressure within the room, tightening up the measured problematic frequency I aimed at targeting with each screw I screwed in. The panel were spot on. Thanks for a great video!
What did the "rigid wood panel" consist of? And how thick?
@@Tazmanian_Ninja plywood, 1/4" thickness. Then combined with the depth of the trap and you can calculate to find the resonant frequency.
Thanks for sharing. I have problems with my neighbours because of the low bass frequencies. I’m gonna try this!
First video about membrane resonator absorbers I see on YT. Unfortunately subtitles are not available but I will watch it several times to understand it better. I'm about to make one of these for myself. Greetings from Rosario, Argentina
By far the best before and after results I have seen on TH-cam. Pretty amazing.I watched a review of the PSIAudioAVAAC20 active bass traps. 2 of them in a small room. Price now is $6400 and the before and after results didn't even come close to your results.I watched before and after results from acoustic insider with velocity traps. Not even close to your results. By the way I find it almost impossible too to find information on Flow Resistivity. The only useful one I found is on Jochen Schulz blog with a list of different insulation products.I was gonna stay away from trying to build Membrane traps but after your video I might try it.Can't find Tecsound 50in the US though. Thanks for this great information and congratulations !
Thank you greatly, I'm glad that it inspired you. I'm sure it'll be worth it if you take the effort to build those. If you can not locate the tecsound 50, any other heavy MLV will do, just weight it to check its kg/meter weight and adjust the depth based on the mass. About flow resistivity, very tough to get reliable info, if you're using ecose by knauf, I've mentioned the info in the video, you can use it. If other, try to email the supplier.
Good luck!!
Very important; thanks
Great video! Did you check what formula Acoustic modelling uses on limp membrane? It might be a bug in the calculator that if you have the insulation on back, it will give low result. In theory velocity is low on the back, but that probably does not apply to sealed resonator as most ppl seem to put insulation on the back without air behind and get great results. Thanks for sharing this!
Thank you so much
Hey Ram! Your video is amazing, thank you very much. I don't speak English very well, so I might not understand some useful things about the membrane. Could you answer the question.
Can ordinary plywood be used as a membrane? (I want to absorb 48 hertz using a 6 kg/m2 membrane). Or should I use MLV?
How thick should a membrane be to resonate at 48 hertz?
Thanks!
Could you please clarify the section between 15:22 and 15:52? From my understanding it is: sit the frame on the floor (so the 120cm height of the unit is lying on the ground) and apply glue to frame, sit the Tecsound on it (how long should you leave it on without stapling?) and after it is settled, sitting on the ground the same way as before, apply a ton of staples, then stand up vertically?
Thanks!
It's just a comfortable way of doin it mate, so it won't fall once it stands.. You don't need to wait, put glue only there first and staples right after. then, let it to stand up and keep placing the glue and the staples. G. Luck!
This is so useful, thank you for taking the time and sharing your process in such detail. One question… why do you use such light insulation rather than more dense slabs like RW3 or RW5? Is there a reason you used less dense mineral wool? Thank you.
Thank you Matthew, because of flow resistivity. those rockwool materials you're referring to have a higher Pa*s/m² value.
try to put in acousticmodeling.com calculator 2 traps, one of then with 10K Pa*s/m², and one with 15 , 20 or 40K and you'll see (:
Ram, great video. I've been struggling with this. How do I calculate for my room which has vaulted ceilings? It has 8 ft. sides then angles up to 12ft. It's 16 ft. deep by 18 ft. wide. I also wondered if these would work as a cloud suspended up in the apex? Thanks.
Very cool. Did you then go on to treat higher freqs as well?
Fantastic video and applaud the effort you put into making it, the theory, the construction, the results. What strikes me though, is this 174dB measurement. How did you measure that loud and what did you measure it with??? Perhaps some extreme offset setting at overlays? It's an honest question, as I've never seen anything like this before. Hope to hear from you soon. Again, congrats on the content.
Thank you mate! glad you liked it. It's just a random measurement done with rew fireface interface and a presonus measure mic. It wasn't calibrated in volume that's why you see this 174 db, sound from speakers is probably about 60-90db in the room
Wow thanks so much Ram, that's the most useful video I've seen yet. One question though: Do I need to pull the membrane tight or should it just "hang loose"? I'd think that it should make a difference to the effected frequency, no, so I wonder how much tightness/looseness is the exact right measure? Cheers and thanks again!
Hi man, thanks for watching and the kind feedback. about the membrane, you don't want it too tight and also not too loose with visible waves. Goal is straight looks and not too tight. Just put the glue and the staples on the upper side, let it fall naturally by itself, connect the rest and you'll be good. If you'll tighten it too much, less of the area will vibrate eventually, and if it's not even, than the depth is not the same allover, so....
I love the way you've put it together. A couple of doubts, here in my country they usually use MDF for the membrane, from 6 to 8 mm they had told me that it was better than one of 3 mm. Supposedly it would act better, is this relevant or does it simply matter the mass of the membrane? Then, the frame to cover the front of the membrane without touching it... how did you do it? is it attached to the resonator frame? How tall and wide is it? How is the rear wall sealed well so that air can escape?
Thank you for watching! All the details are there, pay attention and watch again. MDF membranes are different than loaded vinyl, this built here is different, and will work for sure. Using mdf, you'll have to make your own trial and error and create a new build.
Sizes and way of assembly are also described. good luck!!
@@ramelijah thanks for your answer! I was referring to if you ever used mdf as a membrane, instead of tecsound.
Thank You.
How does it SOUND to your ears?
Hi ram this will work also if put foam as absorber amd not the glass wool?
Hi, what kind of knauf wool did you use exactly?
do the tacsound need to have contact with the wall to work? or just near the wall is ok? thx
Great video, how limp did you make the tecsound, Rod asks that on the original Gear/S thread?
Thanks mate, I'm glad you enjoyed it!
From my experience, the techsound should be not too stretched and not too Limp. You should try to get to an even appearance without waves in it and yet to allow 3-5mm movement to each side. cut it ahead to the excat size, connect the top, let it fall, connect the rest and you'll be good
Can we see pics or video of all your treatment?
Thank you very much for your very helpful and very well explained video.
I have a question, does the absorber have to be fixed to the wall later or does it work just as well if it stands a few centimeters in front of the wall?
Best regards from Germany
From my experience, it's not a must, more important is that you're in the right spot for the frequency pressure-wise in the room. There are small ones hangged on the wall, large ones standing or even small ones laying on the floor facing upwards, it's a matter of placement based on pressure
@@ramelijah okay , i understand ! thank you very much ! You have helped me a lot
What always confuses me about the amroc calculus and modes is this. So do you only hear the issues if you are listening at the location of the modes?
BBC R&D were fantastic. Still are good, but much smaller now.
Hi, very interesting video! Quick question: I have a whole wall or which I can add 2cm of whatever I want (behind projector screen). I am thinking of sticking absorbers designed as follows: a piece of perforated metal (6 mm holes), then some kind of viscoelastic material, then another perforated metal (4mm holes), again viscoelastic material, then final metal sheet (2mm holes) and viscoelastic material on the wall. In front of those sheets 1cm of bassotect foam.The idea is that pressure will push these sheets and the viscoelastic material will absorb the movement into heat. Also the holes should cause some of the sound to disperse sideways and thus deep in the viscoelastic material. The foam in front of it will hopefully catch some of the higher frequencies. What do you think? Will it work? I am asking since I noted your comment that unless the box is soundproof it will not work. Many thanks!
Thanks for the great video!
A question though, can the membrane be stapled directly on the outer edges of the sealed box? And let's say for example my box is 1m by 1m, should the membrane be exactly this size? Or slightly bigger to avoid tension?
Staples should be straight on the edge of the MDF. When you cut the membrane cut it to the exact size and you'll be fine
Hey Ram, thanks for the explanation. How about the area of the trap? Is it related to the effiency of the trap? Bests
Of course that the more surface you have covered, the stronger the action of them... For each individual trap, If you go too small, there's less vibrating area of the membrane (wide mdf frame eating room), if you go too big it's harder to attach the membrane and the more waves you'll get..
40/60 is the smallest I would go personally, and 120/60 biggest
Bonjour , nouvel abonne !
Bien sur , vous êtes au top !!! Avec les bons matériaux .... 👍
Que donnerait le même cadre rempli de mousse à matelas ??? Privilégier une mousse dure ou plus souple ?
Ex : fond en mousse dure et plus souple sur l'avant ? Peut être plus d'epaisseur de mousse pour faire le même job ?
Ou ce sera vraiment sans bon resultat ?
Doit on y ajouter une membrane comme sur les dessins , ça fonctionnera quand même avec de la mousse derrière ?
Des liens pour acheter la membrane ?
J'aurais un plan pour de la mousse pas chère .... habitant à Mayotte (vers madagascar) , les commandes internet + le transport et les douanes et l'octroi de mer finissent par rajouter pas mal !!! J'aimerai trouver une solution locale !!!
Merci pour vos réponses et désolé si mes questions sont stupides , je n'ai pas un fort bagage dans ce domaine !!! 🤔😂
I have 12 Rigid Fiberglass Board, 2 Inch, 3 lb. Does this insulation work?
Because if it works I won't have to buy the other one. Thank you
Hey Ram good tutorial. I am trying to reproduce your results. Spent a lot of time with Tim's smaller boxes and got nothing worth mentioning.
How come your SPL is so high? 170db is crazy
Thank you for watching, i'm sure you'll do well if you follow this built. using only small boxes can work, but you need a lot of them in many different places. alternatively you can combine both larger traps like presented here and smaller ones. for example, in this studio this same built was done also in ~40/60cm small boxes, to treat other modes, alongside the larger traps. the small ones are great and work well too, if you place them specifically where their target frequency pressure is very high in the room.
spl that you see was not recorded at 170db, it was just calibrated over there for presentation
@@ramelijah hey man thanks for the reply.
I did make two small boxes with 20mm thick chipboard (to prototype). After a lot of trail and error the best they could do was 1db reduction at 70hz.. I understand you need a lot more but these were mere prototypes. The best successes I seen were like your larger box. I make them adjustable too.
One thing I would really like to know is do you actually see the tecsound moving back and forth? I only seen/felt mere vibrations.
@@garethjohnston3486 if you'll play a sign wave of the target frequency and place your finger on the membrane, you'll feel it vibrating. not something that your eyes can see ..
it’s not the absorption coefficient that you need to focus on when building a membrane based “trap” but the amount of dampening the “trap” can produce at the specified frequency to reduce the pressure building up in the room around that particular mode - unlike panel traps that are all about reducing velocity.
Using the same calculator you used, you need to look for the dampening effect at the frequency. Anything below 1.0 the effect on the pressure build up will be low. Anything over about 1.5 will be a good level of dampening reached. It these type of traps where you are going to be using the thinnest amount of absorption material then it’s time to use a much higher density/GFR ie >40,000. I use 60,000 otherwise you don’t truly get the spring effect.
You’ll find you achieve a much higher dampening of the sound pressure especially if you place the traps where the pressure is physically building up in the room.
Thank you for the comment, I'm glad you took the time to watch and to share !
as I said, I presented here my own way to build and calculate those traps, which works great and was tested on lots of modes and spaces.
If you are used to use higher flow resistivity materials or to focus on damping instead, do a follow up video of your own build, calculations and results and comment it here, so everyone can gain more knowledge, try out different builds and choose what works best for them.
About placing, you are right mate, it is better (if possible) to place a membrane trap in a corner or an area with higher pressure for the specific mode
Exactly
All modal resonances terminate in corners.
Hi Ram,
Just a question to see if I'm correct or missing something.
I have looked at your interessting video to learn about Membrame Traps.
I have found a EPDM sheet of 8mm thick that has a mass of 12.8 kg/M2. I used the calculators and found that I needed a cabinet (about 1500x600mm) with this membrame an airgap (20mm) and 70mm of glass wool (f.r. = 5000) to get to the +/-49Hz centerfreq of 'filtering'. Will this work (when properly airtide build) or am I makening a misstake here ??? I'm thinking about 4 panels for my about 3x3x2,5m room just for adressing the 49Hz issue.
Thanks
It's all about trial and error man. Apparently your calculation is right, but dig in to the video and understand the micro details in this built, like trapping the wool between 2 air gaps and building an adjustable back etc. Good luck!
@@ramelijah thanks, I understand that it's trail and error.
I did dig into the video and calculated a lot of variations and got quite interessing results. this was the best to safe as much space in the room. I was only wondering if I would make a mistake with a membrame of this thickness and weight. According to the calculation it should work but maybe there are other thing I need to take in account.
@@roloftilanus1933 as long as the room can not take a thicker trap, then it's worth the try of working with a denser memberane.. Only Harder to install... Good luck!
@@ramelijah ok, in theory it should work than. I will give it a try to see if it will work in reality. Thanks !!
Is there a link to the bbc paper?
Sure, I've added it to the description
Great Video, but can you explaind about 82mm air gap of layer 4. 11:21
Thanks man, here there's a minimum air gap of 3cm between the membrane and the ecose and there's another air gap of 8.2cm between the ecose and the back wall of the cavity. the total depth determines the target frequency. If you stay with 10cm ecose and 3mm front gap, you can just change the 8.2cm gap based on your wanted frequency. just play with the numbers in the calculator.
@@ramelijah Thanks!🙂👍🏽))
@@ramelijah Hello, how about temperature change, Does it affect the tensions of the membrane that make the frequency shifting?
@@Mythbuster42 I'm sure it does in theory, but from my experience - you don't need to worry about it. the membrane is so thick and heavy and the tension is not as tight as you think
@@ramelijah One more question, the box you created has a volume of 1.2 x 0.6 x 0.212 = 15.26m3. Does the volume affect the desired target frequency, and does the calculator automatically calculate it?
Thanks
What alternatives can be to replace the tecsound?
MLV
@@ramelijah what about thin MDF like 4-6 mm??
@@TheChromaticz355 there are builds out there that use thin mdf. But think about its lack of ability to move... That's why those who use metal sheets, implement them inside rubber
Isn't the membrane becomes loose after a while? it's an elastic material
Tecsound 50 isn't that elastic, it's a very dense, thick and heavy sheet. As long as it's connected the right way to the cavity, it will be good for years to come
how to build a limp mass membrane tubetrap?
I think there is confusion with these because people just use some material. when it needs to be sort of like a balloon with a small opening.. Id make an air tight box with a port and then put a large balloon over the prot and then addjust dimensions to suit frequency.. I think people just put a flat piece of plastic in-between some rockwool and slats of wood and wonder why it does nothing. the air just goes right around it..
This is an excellent idea.
th-cam.com/video/WqnA4qpaaNQ/w-d-xo.html
מדהים 🫶
Do you have an instagram or anything? I'm gonna follow this guide but I'd like to be able to quickly ask to make sure I understand correctly once every blue moon.
If you check out the Gearsource forum mentioned in the video... there's a vast community of information and help... on this exact topic.