well we all start from scratch at some point and dumb questions from newbies are unvoidable or there should be some writing license to only skilled persons
4 subwoofers centered at midpoints even in the height dimension seems to give the smoothest inroom response ever when simulated in rew, but this is still not my question
My room is 5x3x2.4m, all plaster on cinder block (I think that's what it's called - soft internal blocks less dense than brick or concrete but can be structural). Big window on one short wall, big Tannoys with good LF extension on the opposite short wall.
It sounded less than delightful, the usual boxy "small room" sound, with some horrid mid bass resonances.
Then, in order to soundproof one long party wall, I put up an independent (ie not fixed to existing wall, just floor) stud wall with a 100mm cavity filled with RWA45 rockwool. The improvement in sound was enormous, and doubly gratifying as it came about as a side effect of fixing a separate problem.
Try it, your neighbour will love it too.
Also: look out for articles by Ethan Winer. He was active on GS and has his own website. He sells acoustic treatment but doesn't keep secrets- lots of DIY designs on his site, and reliably BS-free articles.
It sounded less than delightful, the usual boxy "small room" sound, with some horrid mid bass resonances.
Then, in order to soundproof one long party wall, I put up an independent (ie not fixed to existing wall, just floor) stud wall with a 100mm cavity filled with RWA45 rockwool. The improvement in sound was enormous, and doubly gratifying as it came about as a side effect of fixing a separate problem.
Try it, your neighbour will love it too.
Also: look out for articles by Ethan Winer. He was active on GS and has his own website. He sells acoustic treatment but doesn't keep secrets- lots of DIY designs on his site, and reliably BS-free articles.
Celef,
Let put it differently: porous absorbers are great for let's say 200hz and up ( if you accept to have a 150/200mm gap between panel and walls which means 300mm total depth. Against a wall, depending on material and thickness i would say 600/700hz but more 1khz and up.
From there you can use it to perform 'bass' duty if 'corner loaded' ( superchunk). From this you can expect effectiveness in the 80hz and up.
Below those frequency then you'll have to use different approach: resonating membrane over cavities or helmotz resonator. Or change location of listening spot and or loudspeakers...The first include VPR and have the advantage to be 'wider range' than helmotz resonator which are tuned and higherQ.
I suppose the sonotube basstrap you owned were of this kind. If they were effective then i would try to replicate them. But before make a polar pressure map of where you plan to locate them to be sure they'll have an effect. Those will need prototype so be prepared.
Let put it differently: porous absorbers are great for let's say 200hz and up ( if you accept to have a 150/200mm gap between panel and walls which means 300mm total depth. Against a wall, depending on material and thickness i would say 600/700hz but more 1khz and up.
From there you can use it to perform 'bass' duty if 'corner loaded' ( superchunk). From this you can expect effectiveness in the 80hz and up.
Below those frequency then you'll have to use different approach: resonating membrane over cavities or helmotz resonator. Or change location of listening spot and or loudspeakers...The first include VPR and have the advantage to be 'wider range' than helmotz resonator which are tuned and higherQ.
I suppose the sonotube basstrap you owned were of this kind. If they were effective then i would try to replicate them. But before make a polar pressure map of where you plan to locate them to be sure they'll have an effect. Those will need prototype so be prepared.
..because bass has a long integration time anyway. If you seem to have too much bass why not try adding more to fill in the gaps.
Thank you, i think i need something similar, a highly lossy ”wall” in front of my concrete walls. I have built one section of masonite and less dense glass fiber, a type of panel absorber, but i need to simulate to know if it works, by hitting it it seems to be tuned very low
Ok, let say i have room for very large porous absorbers, where would you put them in the room for highest effiency, in the corners or along the walls or both or else?
my early traps where not sonotubes but very large pipe insulation wraps, very similar to original tube traps. My new traps are built in a similar way but of glass fiber sheets instead.
With fibrous absorbers i would use 'hangers': the way Hidley implemented them was an 'isorel' panel ( a kind of in between cardbox and paper material) on which is glued rockwool ( both sides).
Hangers are then 'spaced' and hanged at ceiling (the more the better).
From rooms i've seen implementing this your 'usable' post treatment room should be 1m width, 3meter length 1,8m height....
http://johnlsayers.com/phpBB2/viewtopic.php?f=2&t=12365&hilit=hanger+trap
https://gearspace.com/board/bass-tr...panels-energy-absorbers-what-they-called.html
Hangers are then 'spaced' and hanged at ceiling (the more the better).
From rooms i've seen implementing this your 'usable' post treatment room should be 1m width, 3meter length 1,8m height....
http://johnlsayers.com/phpBB2/viewtopic.php?f=2&t=12365&hilit=hanger+trap
https://gearspace.com/board/bass-tr...panels-energy-absorbers-what-they-called.html
thank you, i will look those hangers up. some panel absorbers seems to use a heavy steel plate between two sheets of absorbers, what i have read is that they are dependent on spl, and need high spl to come "active", i do not know if there is any truth to it though
but still, from simulations it seems that i could aim for an absorber with lower absorption coefficient but using two, one on each opposing walls
what do you think of the absorber setup suggested by asc tube traps: https://www.acousticsciences.com/wp-content/uploads/2020/10/HiFi-3.1.jpg
but still, from simulations it seems that i could aim for an absorber with lower absorption coefficient but using two, one on each opposing walls
what do you think of the absorber setup suggested by asc tube traps: https://www.acousticsciences.com/wp-content/uploads/2020/10/HiFi-3.1.jpg
I don't know what to think of sketch like that. I don't know if the items does what they are supposed to do too ( what i've seen for low end was always HUGE for things below 60hz...). I'm careful about not known on pro circle brands for acoustics treatments: so many placebo.
What you describe ( sheet of metal and absorber) is a VPR ( Fraunhofer initially developed the concept, was then adapted by others after).
BS about spl ( this is what happen when people look at a plate reverb and think it must works the same because it more or less look alike... but no it's different.).
They works whatever the spl and are more location tolerant ime than other 'bass traps'.
What you describe ( sheet of metal and absorber) is a VPR ( Fraunhofer initially developed the concept, was then adapted by others after).
BS about spl ( this is what happen when people look at a plate reverb and think it must works the same because it more or less look alike... but no it's different.).
They works whatever the spl and are more location tolerant ime than other 'bass traps'.
Then metal plate absorbers might be what i want, but the size and weight of a large metal plate do scares me of a bit, do you know if they must be in one large single piece or could they be sliced up in strips?
I know they weight a bit yes.
That said Audiothings install some on ceiling so he found a way to hang them in a safe way. The one i used had a very simple way to attach them to wall but it was planned from the start ( we had reinforcement on the structural rail for taking into account the weight).
Yes these are 'membrane' based so are tuned ( so their size is relative to freq of interest) but they are wide band nonetheless. I think i've seen from 30hz as the lowest.
I will try to link to Auiothing's threads at Gearslutz he explain some things about them.
I would follow Adhoc1 advice too.
That said Audiothings install some on ceiling so he found a way to hang them in a safe way. The one i used had a very simple way to attach them to wall but it was planned from the start ( we had reinforcement on the structural rail for taking into account the weight).
Yes these are 'membrane' based so are tuned ( so their size is relative to freq of interest) but they are wide band nonetheless. I think i've seen from 30hz as the lowest.
I will try to link to Auiothing's threads at Gearslutz he explain some things about them.
I would follow Adhoc1 advice too.
Last edited:
thank you very much for your time, i really apppreciate it.
thank you, but i feel a bit like being in a restaurant and asking the waiter which juicy steak i should choose, and the waiter keeps telling me to choose the fish...
Just from personal experience with my listening room ... I had a big dip in the 50-60 Hz range. Placing the speakers along the long longest wall solved that and the bass is very good along that wall. I like a bit of a bump up in the 60 Hz and lower range. Given your problem, you may prefer placing your speaker along the short wall? Sounds like you have tried this, but if not might give it a shot. My listening room is bit larger at 5.5m x 4.5m x 2.5m.
Speaker placement makes a big difference and placing the speakers closer to the wall reinforces the bass, while pulling them out reduces bass response typically. I have a dedicated listening room, so I have lot of control over where I put stuff.
Looks like you've been offered lots of good advice ... I think that good active room correction with subwoofers might be your best bet here. It is easy to null your bass peaks that way, with good subwoofer eq. I've done this with my speakers placed along the long wall of our room and had really nice results.
I use corner absorbers as well, don't do much for the 60 Hz peak but greatly improved overall bass sound quality.
Speaker placement makes a big difference and placing the speakers closer to the wall reinforces the bass, while pulling them out reduces bass response typically. I have a dedicated listening room, so I have lot of control over where I put stuff.
Looks like you've been offered lots of good advice ... I think that good active room correction with subwoofers might be your best bet here. It is easy to null your bass peaks that way, with good subwoofer eq. I've done this with my speakers placed along the long wall of our room and had really nice results.
I use corner absorbers as well, don't do much for the 60 Hz peak but greatly improved overall bass sound quality.
out of frustration i moved all my diy tower traps out and built a wall with them behind my listening chair, i fired up some torture test tracks, patricia barbers first three tracks on her album clique, oh jee this sounded horrible, the double bass sounds like a hard hitting bangs, or a slap in my face! my diy corner traps do after all make a huge difference, not as good as i would like but they sure works, i guess i "just" need to make them 50% bigger
thank you for posting! i might give multiple subs a chance, i have almost everything at hands, i only miss the eq, can you recommend any?
please can you tell some about your corner traps?
Yes give multi sub a try. It won't be lost time whatever is the outcome.
Celef do you get the implied difference between velocity and pressure absorbers?
Here is a superchunk example:
http://www.ayoung.ca/basstraps.php
Of course your panel are effective Celef, the problem being are they efficient in the bandwidth of interest for the room. And not sure doubling their depth will help.
To me what you describe with all of them at your back is a symptom they are effective outside the band of interest: by 'cleaning up' an octave too high, they send an improper balance at listening point.
Or they revealed an other mode which was 'hidden' before ( it happened to me once, you treat one and it is worst after because there was some masking at play. Axial treated, tangential was put into light... i've read a documented situation like this not too long ago on web too...).
Example of commercial offer VPR:
http://www.rpgeurope.com/products/product/modexplate.html
Celef do you get the implied difference between velocity and pressure absorbers?
Here is a superchunk example:
http://www.ayoung.ca/basstraps.php
Of course your panel are effective Celef, the problem being are they efficient in the bandwidth of interest for the room. And not sure doubling their depth will help.
To me what you describe with all of them at your back is a symptom they are effective outside the band of interest: by 'cleaning up' an octave too high, they send an improper balance at listening point.
Or they revealed an other mode which was 'hidden' before ( it happened to me once, you treat one and it is worst after because there was some masking at play. Axial treated, tangential was put into light... i've read a documented situation like this not too long ago on web too...).
Example of commercial offer VPR:
http://www.rpgeurope.com/products/product/modexplate.html
Last edited:
yes i have a hunch of the differencies between pressure and velocity absorbers. mine diy traps works for most part (as it seems*) as plain velocity absorbers just like superchunks. but my traps are built a bit differently, instead of using a thick layer of material i use a thin layer but with a large air space behind it. the glass fiber used is therefore different to the one used in superchunks.
panel absorbers to look interesting, i have material to do some testing but no metal sheets though only masonite, i wonder if limp mass absorbers calculators can be used to calculate panel absorbers as well?
*asc tube traps have their absorbers patented, and they claim that their absorbers works differently than normal velocity absorbers; they are velocity absorbers designed to work and be used in pressure zones, and i have tried to mimic that, but i must have failed because they do not offer the absorption i where after
panel absorbers to look interesting, i have material to do some testing but no metal sheets though only masonite, i wonder if limp mass absorbers calculators can be used to calculate panel absorbers as well?
*asc tube traps have their absorbers patented, and they claim that their absorbers works differently than normal velocity absorbers; they are velocity absorbers designed to work and be used in pressure zones, and i have tried to mimic that, but i must have failed because they do not offer the absorption i where after
I have four ASC bass tube taps in the four corners of my room. They really do a good job at cleaning up the bass subjectively, but didn't do much in the 50-60 Hz room modes.
I used the Behringer Ultra-Drive Pro loudspeaker management crossover. Since my speakers are bi-amped I could just crossover from the subs to the woofers in my large three way speakers, so not to affect the highs and mids. It is a great tool but you don't want to run this in the highs and mids as it will color the sound some. You can use it just with the subs and then use a passive 2nd order RC high pass filter before your main loudspeaker amp. The Behringer gives you almost complete control over your subs ... crossover slope, shape, Q, boost or null a couple frequencies and so on. It is really hands on though and requires some experimentation and measurement capability, to get the best sound.
Behringer Ultra-Drive Pro