Seeking Your Approval

Hi everyone, Just finished planning the acoustics for my bedroom studio. I'm hoping to get into constructing these panels when my university semester is finally over in a month. For now i just wanted to check if anyone thought there were changes i should make.? Currently i think the room sounds pretty bad. To my (untrained) ears there are problems with bass/low-mids. Definate peaks and nulls showed up in the bass range when playing sine waves through my speakers (again by ear, without measuring equipment). No doubt reflections are also going to be an issue. Basically as you can see from the sketchup pics below, i've got: 6 panels on the side walls to tame reflections. 50mm thick with 25mm air gap behind. 2 front bass traps (wall-wall). 100mm thick 2 side bass traps (wall-ceiling). 100mm thick 1 ceiling cloud 100mm thick (attempting to fit it between the speakers and the listening position as per Ethan's documentation, but that a/c vent makes it tricky) Now, the back wall has been giving me plenty of troubles, because it's not a solid wall, the majority of it is the two sliding doors of my built-in wardrobe and the other part needs to be clear so the door can still open. With that in mind i thought of this hanging bass trap idea. Essentially it's just a curtain rod fixed to the ceiling and from that hangs a bass trap measuring 1000mm(H) x900mm(L) x100mm(W). Question: Is this going to be an effective bass trap? I'm going DIY using rigid glasswool. I want to get this right so i'm willing to stretch the budget if the benefit is there. For the side panels i'm copying the mounting suggestions gullfo gave in thisthread Almost forget my room dimensions: 3.6m(L) x 2.8m(W) x 2.4m(H) Rather than overload everyone with any more information, feel free to ask me questions.

I think that trap on the back wall will work just fine. Now for the back corners: traps on stands maybe? Mobile corner traps? Frank

Thanks for the reply Frank Those back corners definitely have me a bit stumped. Main problem is I don't have a great deal of floor space to play around with, so that's why I devised the hanging rear panel. Maybe some stand mounted panels that I could also use for tracking instruments or a bit of a quasi vocal booth when I'm not mixing. Better make my way over to sketchup. Anyone else care to weigh in? Once i fix the rear corners, anything left? All replies appreciated, and also a big thanks to everyone who posts in this forum, your knowledge has been incredibly valuable.

Seems like bedding on one side and reflective furniture on the other side of your ears will continue to have a skewed effect on what you are hearing.

Seems like bedding on one side and reflective furniture on the other side of your ears will continue to have a skewed effect on what you are hearing.

I see your point, but isn't that the effectiveness of the panels hanging on the right wall, to make that surface more absorbing? I would have thought that only putting panels on the right hand wall and not the left, to counter the effects of the furniture would be a worse idea than treating the room equally?

I'm not sure I'd worry about furniture either. It's a fact of life for all of us whether it's a bed, a console, couche(s), racks of gear behind us or to the side...you can minimize the comb filtering effects, but not eliminate them. Frank

Excellent, nice to get some validation. Weasel, as you can see below i added some stand mounted panels at the rear. they're pretty much 100mm thick like the other corner absorbers. not really a true "bass trap" but i think given the limitations of my room its a good step. I might consider making them triangular (like a superchunk on a stand) if i have some spare glasswool but with the current design it means i can save space by having them right up against a wall. I guess that's the concession i make. I'm liking the the pointers too, keep them coming.

jamesoz88 wrote:

Excellent, nice to get some validation. Weasel, as you can see below i added some stand mounted panels at the rear. they're pretty much 100mm thick like the other corner absorbers. not really a true "bass trap" but i think given the limitations of my room its a good step. I might consider making them triangular (like a superchunk on a stand) if i have some spare glasswool but with the current design it means i can save space by having them right up against a wall. I guess that's the concession i make. I'm liking the the pointers too, keep them coming.

I'm liking the superchunk idea...I'd keep them at 100mm thickness if at all possible though. What did you say the density was? That will determine how well they'll work in that critical sub-100Hz range, especially if you go below 100mm thickness. Frank

density is 48kg/m3 Manufacturer's specs (for 50mm sheets) don't give any indication of sub-100HZ but they do say 125Hz = 0.33, 250 = 0.74, 500Hz = 1.18.

Weasel9992 wrote:

I'm liking the superchunk idea...I'd keep them at 100mm thickness if at all possible though. What did you say the density was? That will determine how well they'll work in that critical sub-100Hz range, especially if you go below 100mm thickness.

Density and sound absorption are not related in an obvious way. This thread is lenghty but it explains the relationship as well as any I seen. Executive summary: the thicker the absorber, the lighter and cheaper the best material is. Andre

Density and sound absorption are not related in an obvious way.

I think i know what you mean, just from reading the specs of rockwool/glasswool/fiberglass i have seen products at 48kg/m3 have better absorption properties than some 90kg/m3 products. Not very scientific i know. Just to be clear you're not arguing with the idea of thickness being related to absorption, just density?

the thicker the absorber, the lighter and cheaper the best material is.

could you expand on this, I'm not quite sure i understand your meaning?

jamesoz88 wrote:

Density and sound absorption are not related in an obvious way.

I think i know what you mean, just from reading the specs of rockwool/glasswool/fiberglass i have seen products at 48kg/m3 have better absorption properties than some 90kg/m3 products.

Your getting the idea.

Not very scientific i know.

It is scientific. What it is not is intuitive

Just to be clear you're not arguing with the idea of thickness being related to absorption, just density?

I' am not clear on what you mean.

the thicker the absorber, the lighter and cheaper the best material is.

could you expand on this, I'm not quite sure i understand your meaning?

From what I have read of your posts, you have done research in this area. The best I can offer but it does get technical at points is this thread and post number 29 for as a summary as good as any I have read about the subject. Andre

Hi AVare, thanks that thread was pretty helpful, a bit hard to get my head around at parts but some interesting points. In regard to my point about thickness related to absorption...i was checking that you didn't disagree with the idea that, Regardless of the type of material (Rockwool, glasswool, etc.) and the density of the material being used, a 100mm panel is going to do a better job at absorbing low frequencies that a 50mm panel. Yes? James

jamesoz88 wrote:

In regard to my point about thickness related to absorption...i was checking that you didn't disagree with the idea that, Regardless of the type of material (Rockwool, glasswool, etc.) and the density of the material being used, a 100mm panel is going to do a better job at absorbing low frequencies that a 50mm panel. Yes?

Yes, I agree with the idea. Andre

Thanks to all who have commented. Good news...my budget just got an increase because my parents are paying for my room treatment as my birthday present. Fantastic!

Nice!! How would your parents feel about adopting a 38-year-old? Frank

Long trip to Australia Frank? Pretty sure we're maxed out for space as it is though. I mean, have you seen the size of the space im working with!

I'm cool with that. My wife and kids might freak though. Frank