Soffit mount in a bombshelter

[Bodega113]

So,

About a year ago I redid my studio and control-room that is literally located inside of a bomb-shelter.
I am underground and walls and ceilings are very irregular and all stone/cement.

The control room actually sound pretty good although it could improve. I def get some standing waves in the lo´s. Rocking a pair of dynaudio bm15a with a adam sub12 as my mains now and feel they are to small for my room which is around 20-25 square meters with the ceilings varying at around 2.5-3 meters in height.

My plan is to get something like the Genelec 1038a or b (dream would be the ATC scm150´s, but way outta budget at this moment).
I want to soffit mount them using the Barefoot method so I´m going to build the framing and put them on stands instead of framing since the floors are a 7-10 cm thick conrete slab with some flooring right onto it.
Then build the framing to fill with absorbent and finally put some cloth or some kind of reflective on top to get a surface that diffuse sound at the front.
If I put a hard material in front I´m guessing it needs to be pretty solid? If not I guess it can start vibrating? Thinking of maybe leaving small gaps so sound can go "into" the absorbing wall.
Any suggestions on this? or should I just put some kind of cloth instead? Looking to get the best out of my room of course! Not scared of the work just need to do things right!

Here´s some pictures so you can get an idea!

aleksiberget.jpg

2018-09-16 10.22.28.jpg

shajeiberget.jpeg

[Soundman2020]

Hi. Please read the forum rules for posting (click here). You seem to be missing a couple of things!

The control room actually sound pretty good although it could improve.

To find out how good it is, and what is wrong with it that needs fixing BEFORE you buy new speakers or soffit-mount your current speakers, first TEST the room: How to calibrate and use REW to test ant tune your room acoustics

Rocking a pair of dynaudio bm15a with a adam sub12 as my mains now and feel they are to small for my room which is around 20-25 square meters with the ceilings varying at around 2.5-3 meters in height

That size room should not be a problem for the speakers you mention. If you have the sensation that they are not powerful enough for the room, then the room is probably not treated properly. You have more htna enough power and quality with those speakers.

I want to soffit mount them using the Barefoot method so I´m going to build the framing and put them on stands instead of framing

You still need framing! To support the front baffle of the soffit, which must be rigid, massive, and very heavy. Plus, if you out your speakers on stands inside the soffit, then the stand takes up all the space that you need for good bass trapping, under the speaker...

Then build the framing to fill with absorbent and finally put some cloth or some kind of reflective on top to get a surface that diffuse sound at the front.

What design concept are you using for your room? I have never heard of any design concept that makes the front wall diffuse. With most design concepts, the front wall is either reflective, or it is absorptive. Why would you want the front wall to be diffuse? And how would you combine that with soffit-mounted speakers?

If I put a hard material in front I´m guessing it needs to be pretty solid?

It's not a matter of "if" you do it: The front baffles of the soffit mounts MUST be hard, solid, rigid, massive, thick. Because that's the way soffit mounting works. Some people make their baffles from several layers of heavy wood, and others have been known to make them from concrete, brick, or stone.

Thinking of maybe leaving small gaps so sound can go "into" the absorbing wall.

The front wall is not absorptive: It is reflective. Yes it does also have substantial bass trapping in it, if built correctly, but that is ONLY meant for the bass. It is not meant to be general broad-band absorption.

Any suggestions on this? or should I just put some kind of cloth instead? Looking to get the best out of my room of course! Not scared of the work just need to do things right!

To learn how to treat a control room properly, and to see how soffits should be built, take a look at this thread: building and tuning a control room


- Stuart -