Is this a good bass trap design?

This is not a basstrap :? This is just a Broadbandabsorber, which may absorb also some low end. It could be used in corners , to absorb a little more bass, but it is still a broadband absorber. cheers Mika

I entirely agree Mika - but for some reason people have started calling panels like that bass absorbers!!

Ah ok well is it a good broadband absorber then? I'm using Isover Sonepanel, 10 cm thick. From all the DIY absorbers I see on the web these seem the easiest to build and the prettiest. My gut says these are very effective (with the gap behind it etc but I just wanted to check with you guys :).

Yep that a broad band absorber yes it is a good broad band absorber if you want better bass results us diaphragmatic or Helmholtz design with out killing (deadening) your room too much it depends on your application. fibrous material work better were high velocity movement is occurring and that's not at close to the wall positions diaphragmatic and Helmholtz work better in hi pressure points that is close to the walls.

fibrous material work better were high velocity movement is occurring and that's not at close to the wall positions

Well, that's only true for waves that approach a wall totally perpendicular to it (come in head on, at 90°). For waves running parallel to a wall, there can indeed be very high velocity right next to the wall. And for all angles in between, there will be intermediate velocities right next to the wall. Since most of the energy in a room beyond the critical distance is resonant field, not direct field, then most of the waves are NOT perpendicular to the walls. And even for the direct field, those waves coming straight out of the speaker and hitting the side walls are doing so at very low angles, much closer to parallel than to perpendicular. So it's safe to say that for any given small room, there is a large amount of high-speed particle motion very close to the wall surfaces. Which is part of the reason why we can get away with fairly thin absorption (just a few inches thick) mounted on or close to the walls. If you think about it, if all waves were normal to the wall (perpendicular) then we'd need absorption several feet thick to do the job... I seem to recall some research somewhere, from Eric Dessart I think, showing that you only need absorption the thickness of something like 5 to 10% of a wave's length in order to absorb it effectively, in an average studio. I'll see if I can find a link to that. - Stuart -

it seams very interesting to read that paper if you can tell me where to get it still with the same reasoning the is as an average more high velocity away from the walls than near the walls remember that in small rooms there is never a diffuse field

seem to recall some research somewhere, from Eric Dessart I think, showing that you only need absorption the thickness of something like 5 to 10% of a wave's length in order to absorb it effectively,

5% to 10% of 50Hz is more than 12" to 24" of material and many of the spaces spoken here do not have that luxury.

Soundman2020 wrote:

I seem to recall some research somewhere, from Eric Dessart I think, showing that you only need absorption the thickness of something like 5 to 10% of a wave's length in order to absorb it effectively, in an average studio. I'll see if I can find a link to that.

Here is the link: http://johnlsayers.com/phpBB2/viewtopic.php?t=562&highlight= It is typical Eric work that helped me learn to study as much available data as possible, for information before jumping to conclusions. Thank you Eric. Greatfuly, Andre

Thanks i have read it

Thanks Andre! I might have guessed you would have the link. :) - Stuart -