here is some of my traps in building stage
may i ask what size your asc tube traps are? when looking att absorption coefficient charts for tube traps they do look much like what could be expected by plain porous absorbers of similar size, but asc traps has those reflectors and absorption curves goes down again at higher frequencies, so their traps looks to have a huge boost of effiency at bass frequencies. art noxon writes here that their tubes are much more efficent then a ball of fuzz https://www.acousticsciences.com/artblog/basstrap-sound-off-fuzzballs-vs-tubetraps/
may i ask what size your asc tube traps are? when looking att absorption coefficient charts for tube traps they do look much like what could be expected by plain porous absorbers of similar size, but asc traps has those reflectors and absorption curves goes down again at higher frequencies, so their traps looks to have a huge boost of effiency at bass frequencies. art noxon writes here that their tubes are much more efficent then a ball of fuzz https://www.acousticsciences.com/artblog/basstrap-sound-off-fuzzballs-vs-tubetraps/
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Hmmm.
I used things like that ( but it was Auralex products). The form factor is smart as it allow to have a reflective side ( for diffusion) and an absorber side. For mid high they probably are effective diffusors.
For low well, for me it is 'just' a Helmotz based resonator with increasing efficiency thanks to porous absorbers.
I might be wrong but i doubt it.
From the graph on ASC site i bet your homemade one would bring same results ( there is nothing exceptional from the graph and the use of a 'custom' scale and explanation sound like marketing blabla to me.
But i've not used these one so can't tell. Except it is incredibly overpriced! I can understand a nice Schroeder diffusor cost a lot but a sonotube covered in fabric forom 600 to 1500$...
Good business. If they sell cables too it must be very interesting.
About patent... in pro world there was one brand which patented the use of filters on sidechains of compressors... something done by anyone since the 'key input' appeared early 70's on this units...
I should patent hot water.
I used things like that ( but it was Auralex products). The form factor is smart as it allow to have a reflective side ( for diffusion) and an absorber side. For mid high they probably are effective diffusors.
For low well, for me it is 'just' a Helmotz based resonator with increasing efficiency thanks to porous absorbers.
I might be wrong but i doubt it.
From the graph on ASC site i bet your homemade one would bring same results ( there is nothing exceptional from the graph and the use of a 'custom' scale and explanation sound like marketing blabla to me.
But i've not used these one so can't tell. Except it is incredibly overpriced! I can understand a nice Schroeder diffusor cost a lot but a sonotube covered in fabric forom 600 to 1500$...
Good business. If they sell cables too it must be very interesting.
About patent... in pro world there was one brand which patented the use of filters on sidechains of compressors... something done by anyone since the 'key input' appeared early 70's on this units...
I should patent hot water.
My Tube traps look like this one best I can tell:
https://shop.acousticsciences.com/collections/pro-studio/products/isothermal-tubetraps-13x3
Bought mine a long time ago so they likely have changed a bit. I agree that they are more than a ball of fuzz.
Yes, so much high end stuff is insanely priced now days. I honestly would be doing some DIY stuff before paying so much for ASC traps. I don't remember what I paid for these in the late 90's but it wasn't that much.
Celef, what kind of traps are those that you built? I found these traps while searching bass resonator traps ...
https://gearspace.com/board/studio-building-acoustics/665657-diy-helmholtz-resonator-made-easy.html
They look similar to yours.
You know, I visited Boulder amplifiers in the early 90's when my dad and I went to listen to some Nelson/Reed 804B loudspeakers paired with their large subs. They had this DIY bass resonator in the back and a room walled with fiberglass. The room was smaller than ours but the system there had incredible bass, very clean and deep. The overall sound quality was really something. Love the ATC midrange on those speakers.
https://gearspace.com/board/studio-building-acoustics/665657-diy-helmholtz-resonator-made-easy.html
They look similar to yours.
You know, I visited Boulder amplifiers in the early 90's when my dad and I went to listen to some Nelson/Reed 804B loudspeakers paired with their large subs. They had this DIY bass resonator in the back and a room walled with fiberglass. The room was smaller than ours but the system there had incredible bass, very clean and deep. The overall sound quality was really something. Love the ATC midrange on those speakers.
maybe asc exaggerate a bit about how their tube traps work and how effective they are, but i guess there must be some substance to it.
just to be clear, tube traps are not sonotubes. sonotubes are tubes made out of hard pressed paper that is often used as concrete forms.
tube traps are made of glass wool pipe insulation, i find it to be quite smart to use these. these premade pipe form structure is quite robust and they have an decorative apperience too.
Hi Celef,
I'm exagerating a bit too i must concede.
As i said i've not seen nor used them so i don't know, maybe they are onto something.
I've seen some modular 'gobo' ( you had absorber, diffusion on each side so you could mix and match to the needs, very clever) used in studio which were probably based on same approach and they were effective at what they did.
Have you experimented with other location than behind you and corners?
I'm exagerating a bit too i must concede.
As i said i've not seen nor used them so i don't know, maybe they are onto something.
I've seen some modular 'gobo' ( you had absorber, diffusion on each side so you could mix and match to the needs, very clever) used in studio which were probably based on same approach and they were effective at what they did.
Have you experimented with other location than behind you and corners?
my diy tower traps works exactly like your original tube traps, or that was my intention anyway, https://www.acousticsciences.com/product/towertrap/
i tried at first to get the correct tube insulation wraps but it was just not possible, it is easy to get small dimension pipe insulation but the huge ones used for bass traps where for me impossible, so i built my tube traps square, and asc calls their square tube traps for tower traps so i call mine for tower traps too, but with a diy prefix 🙂
Fence forced into cylindrical shape could work as frame, then with 1,2m length for standard tile you could do up to 35cm radius i think.
Then you have multiple of 60cm for height: 60cm, 1,2m, 1,8m...
I suppose they use some different layers of absorbing materials. What they call reflector is the perforated metal layer covering half the tube?
About price: a market is a market. If customers are ok to pay for something (price justified or not) then it is ok. This is how the price of your car is determined. Works or materials involved is a secondary concern...
Then you have multiple of 60cm for height: 60cm, 1,2m, 1,8m...
I suppose they use some different layers of absorbing materials. What they call reflector is the perforated metal layer covering half the tube?
About price: a market is a market. If customers are ok to pay for something (price justified or not) then it is ok. This is how the price of your car is determined. Works or materials involved is a secondary concern...
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no i have not tried any other locations yet, but i will, i had hoped that the recommendation setups from asc could work for me too https://www.acousticsciences.com/hifi/
those sheets of glass wool used in traps like these are very difficult to bend, they are quite hard or stiff so if you try to make a curve out of them they will collapse and the sheet folds
the reflector is a limp mass sheet, they have a specific density and hole sizes to let low frequencies in and reflects frequencyis above some target point, above 400-600 hz if i recall
asc seems to like to call their traps equivalent to an electric lcr filter, where l the reflector, c is the size of the trap, and r is the acoustic damping
I think they do, but what they don't tell is that Config 3 is the minimum ( in my view and from my experience with porous absorbers).
Once you start to absorb this is difficult to stop: because you changed the natural 'eq' profile of your room ( attenuated let's say 100 to 400hz freq band) you'll need to attenuate the 400 to 1600 and so on...).
Once you start to absorb this is difficult to stop: because you changed the natural 'eq' profile of your room ( attenuated let's say 100 to 400hz freq band) you'll need to attenuate the 400 to 1600 and so on...).
Ha ok you used some compressed sheets!
They are not needed. Well no, this is what is used on ceiling and side walls to create RFZ by attenuation in the control room i've built/ been. As rule of thumb those are the "1khz and up" absorbers i already talked about (once located on wall).
We used Rockfon tiles ( brand's intended use for ceilling). ( this one but in black, walls and ceiling): https://www.ceilingtilesuk.co.uk/product/rockfon-artic-a-600-x-600mm-square-edge-ceiling-tiles/ )
Once you introduce some airgap and cover a lot of area, they behave like a very large 'membrane' absorbers ( and this is what they do when you use them as their intended use : ceiling). With 20cm plenum ( airgap) i think it was ok to 100/150hz in the one i implemented. And the standardized size enable the use of diffusors tile above and below listening spot : http://www.akustar.com/tech/053_d_ds710.htm )
If you are willing to experiment try circular, with noncompressed rockwool ( your lungs will thank you longterm and it won't itch as much when manipulated).
Mlv ( mass loaded vinyl, limp mass) is available through Auralex ( Sound Barrier) and the likes but it'll need some strong frame ( it is mass loaded).
They are not needed. Well no, this is what is used on ceiling and side walls to create RFZ by attenuation in the control room i've built/ been. As rule of thumb those are the "1khz and up" absorbers i already talked about (once located on wall).
We used Rockfon tiles ( brand's intended use for ceilling). ( this one but in black, walls and ceiling): https://www.ceilingtilesuk.co.uk/product/rockfon-artic-a-600-x-600mm-square-edge-ceiling-tiles/ )
Once you introduce some airgap and cover a lot of area, they behave like a very large 'membrane' absorbers ( and this is what they do when you use them as their intended use : ceiling). With 20cm plenum ( airgap) i think it was ok to 100/150hz in the one i implemented. And the standardized size enable the use of diffusors tile above and below listening spot : http://www.akustar.com/tech/053_d_ds710.htm )
If you are willing to experiment try circular, with noncompressed rockwool ( your lungs will thank you longterm and it won't itch as much when manipulated).
Mlv ( mass loaded vinyl, limp mass) is available through Auralex ( Sound Barrier) and the likes but it'll need some strong frame ( it is mass loaded).
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yes i think i need to aim for the stage 3 config, but i also need to build bigger traps, i guess that if i go for 60x60cm square size, that would give a whopping 80cm diagonally, i could cure some of the 50 hz peaks, i wish and i hope 🙂
when dealing with porous absorbers there seems to be some rules to follow, one can either choose to use a thin wall absorber with a large airspace behind it, in this way you must use a high density mineral wool with a high air flow resistance. the opposite to thin wall absorber is the super chunk and these use a low density mineral wool with a low air flow resistance, and this absorbers are very thick with no airspace.
if you have not done it yet you can simulate multilayer absorbers with this tool http://www.acousticmodelling.com/8layers/multi.php
only question is which model to use, the most recent one: komatsu or the default one, or else?
and you can use this graph for air flow resistance guidance
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I agree there is rules.
I disagree about the spaced panels requiring compressed tiles, you'll have same effect with unpacked material, the issue is in bulk. When you 'eat' (20cm depth of rockwool +20cm of plenum) 40cm each side of room, you expect high efficiency and in lower freq range.
Remember the 1/4 wavelength rule: use it in this context and 'll see why space is needed. 😉
For mid/high freq you can use compressed material against a wall, no issue it'll work. But don't expect results in bass as the material is too much packed. There is too much flow resistivity ( Metisse have same issue, it is less effective for low end).
It's naive explanation but for bass treatment against wall you try to increase 'viscosity' of air. So unpacked material works better.
This is in part what is behind 'hangers' ( but it behave too as a membrane absorber)...
I disagree about the spaced panels requiring compressed tiles, you'll have same effect with unpacked material, the issue is in bulk. When you 'eat' (20cm depth of rockwool +20cm of plenum) 40cm each side of room, you expect high efficiency and in lower freq range.
Remember the 1/4 wavelength rule: use it in this context and 'll see why space is needed. 😉
For mid/high freq you can use compressed material against a wall, no issue it'll work. But don't expect results in bass as the material is too much packed. There is too much flow resistivity ( Metisse have same issue, it is less effective for low end).
It's naive explanation but for bass treatment against wall you try to increase 'viscosity' of air. So unpacked material works better.
This is in part what is behind 'hangers' ( but it behave too as a membrane absorber)...
what i am trying to say is that the thinner fibrous sheet you use (with an airspace behind it or not) the higher air flow resistivity it needs to be, on the other side, the thicker sheet you use the lower air flow resistivity it needs to be. the 1/4 wavelength rule is a safe recommendation, but mineral wools seems to be effective already at 1/8 wavelengths
Yes i agree Celef.
And in no way i want to discourage you about using absorbers. There is many things to be gained but not nescessarely in the area you would expect.
The thing is have you some measurement of the room without treatments?
It would help to determine what have to be done and from there have a target, because by try and error you'll have spent a large amount of cash before aiming at 'good'/adapted treatments for the room.
The 'pressure' map could be very handy too: it will tell you where to locate for low room mode ( and you might be surprised corners are not always the 'best' place).
This takes a bit of time but it is really worth it, if you need i can explain you how i do.
I still suspect that for sub range ( below 60hz) to be treated you'll need something different than porous absorbers.
Have a little fun with this in // to your own experiments:
http://mh-audio.nl/Acoustics/PResonator.html
With a 60/180/ 7,5 and a 25kg panel i achieve around 40hz.
The panel could be some nice plywood with MLV layer(s) glued to it ( alternatively you could use lead sheets (if still availlable, i think Rohs baned the use... still for x ray it is used for shielding so it should be findable. The issue here is to glue it to panel... but it open to 'heavy panels so sub freq range. 2 panel like that, if correctly located would greatly help with modes). And as it is basically a flat surface if you are a painting artist ( or your other half is) it wont hurt the eye. Could printbanything on fabrics and wrap it too.
You could locate them behind your porous absorbers as they are not this deep.
And in no way i want to discourage you about using absorbers. There is many things to be gained but not nescessarely in the area you would expect.
The thing is have you some measurement of the room without treatments?
It would help to determine what have to be done and from there have a target, because by try and error you'll have spent a large amount of cash before aiming at 'good'/adapted treatments for the room.
The 'pressure' map could be very handy too: it will tell you where to locate for low room mode ( and you might be surprised corners are not always the 'best' place).
This takes a bit of time but it is really worth it, if you need i can explain you how i do.
I still suspect that for sub range ( below 60hz) to be treated you'll need something different than porous absorbers.
Have a little fun with this in // to your own experiments:
http://mh-audio.nl/Acoustics/PResonator.html
With a 60/180/ 7,5 and a 25kg panel i achieve around 40hz.
The panel could be some nice plywood with MLV layer(s) glued to it ( alternatively you could use lead sheets (if still availlable, i think Rohs baned the use... still for x ray it is used for shielding so it should be findable. The issue here is to glue it to panel... but it open to 'heavy panels so sub freq range. 2 panel like that, if correctly located would greatly help with modes). And as it is basically a flat surface if you are a painting artist ( or your other half is) it wont hurt the eye. Could printbanything on fabrics and wrap it too.
You could locate them behind your porous absorbers as they are not this deep.
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I can't remember if anyone linked to the video of Earl Geddes and how he describe low frequency absorption? But he mentions that to dampen low frequencies, you have to absorb the sound waves in a big membrane, then dampen that membrane, to transfer acoustical energy into physical movement and then into heat(the damping material around the membrane). Simply putting tons of damping material around the room... never proved to do anything for low frequencies. This is why multiple subwoofers actually is still the better way to deal with it, in many cases where you can't dedicate an entire wall to absorb bass.
The first part ( description of membrane absorbers - which are transducers like a mic or loudspeaker) i agree.
The second not. But it can't be translated to a domestic room:
Non Environment control rooms are based around the (heavy) use of porous absorbers ( through hangers).
This was paradigm shift Hidley's approach 80's.
It evolved to what T.Jouanjean from Northward acoustics now call 'progressive acoustic' iirc. Basically an N.E. approach ( reflective front wall with absorbers for the whole room except above listening point and back wall where 2d diffusor ( Schroeders) are located. The one above listening point are there for comfort of operator mainly ( but not only). The issue with very damped rooms is they are oppressive longterm.
Those rooms are ( usually) way bigger than typical domestic room ( 200m3 is a lower limit for Hidley's room). So yes i think multisub is the answer in domestic room.
But improving 'wide band' absorption in lows ( 80hz to a bit above Schroeder freq) will definitely help. But not below that. You then enter membrane and tuned resonator territory.
What Earl describe is the use of the structural walls as panels absorbers. It is from the one i've built ( it have to be calculated to be sure it target frequency you need to treat so can change with different rooms): ba18+ba13 ( plasterboard in 18mm and 13mm srewed together) then a layer of MLV ( glued) then another ba13 on top of that.
Rails ( metal, structural frame) is decoupled of floor and ceiling by the use of neoprene 'cushion' ( closed cell foam, act like a shock absorber) which are glued in place ( no screws used!). Better have the vertical given the weight of walls... of course each layer must be offsetted to not have coincident joint ( less possible leakage allowed) and each joint have to be closed by use of silicon or typical strips ( be careful with silicone/MLV potential interaction, can be naughty with MLV liquify when silicon cures!).
If the room is not rectangular ( which is typical for control room) even for a three motivated guy team it is like... pyramid build! But you got an absorber and you increased sound isolation if floor ( and ceilling) is decoupled too. Very effective.
Non Environment with plans to understand the volume needed (the orange strips are Hangers):
https://www.soundonsound.com/music-business/bop-studios-story
Northward Acoustics requirements:
https://www.northwardacoustics.com/services/
The second not. But it can't be translated to a domestic room:
Non Environment control rooms are based around the (heavy) use of porous absorbers ( through hangers).
This was paradigm shift Hidley's approach 80's.
It evolved to what T.Jouanjean from Northward acoustics now call 'progressive acoustic' iirc. Basically an N.E. approach ( reflective front wall with absorbers for the whole room except above listening point and back wall where 2d diffusor ( Schroeders) are located. The one above listening point are there for comfort of operator mainly ( but not only). The issue with very damped rooms is they are oppressive longterm.
Those rooms are ( usually) way bigger than typical domestic room ( 200m3 is a lower limit for Hidley's room). So yes i think multisub is the answer in domestic room.
But improving 'wide band' absorption in lows ( 80hz to a bit above Schroeder freq) will definitely help. But not below that. You then enter membrane and tuned resonator territory.
What Earl describe is the use of the structural walls as panels absorbers. It is from the one i've built ( it have to be calculated to be sure it target frequency you need to treat so can change with different rooms): ba18+ba13 ( plasterboard in 18mm and 13mm srewed together) then a layer of MLV ( glued) then another ba13 on top of that.
Rails ( metal, structural frame) is decoupled of floor and ceiling by the use of neoprene 'cushion' ( closed cell foam, act like a shock absorber) which are glued in place ( no screws used!). Better have the vertical given the weight of walls... of course each layer must be offsetted to not have coincident joint ( less possible leakage allowed) and each joint have to be closed by use of silicon or typical strips ( be careful with silicone/MLV potential interaction, can be naughty with MLV liquify when silicon cures!).
If the room is not rectangular ( which is typical for control room) even for a three motivated guy team it is like... pyramid build! But you got an absorber and you increased sound isolation if floor ( and ceilling) is decoupled too. Very effective.
Non Environment with plans to understand the volume needed (the orange strips are Hangers):
https://www.soundonsound.com/music-business/bop-studios-story
Northward Acoustics requirements:
https://www.northwardacoustics.com/services/
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