Small Room Acoustics

pinkphiloyd

New member
Small Room Acoustics and appropriate treatment.

The floor is excluded and since I am mentioning floors; All studio rooms should have hard floors...


Why is this? I'm not questioning you in any way, shape, or form, but it seems that everything else I've read suggests the opposite.
 

jhbrandt

Acoustic Design
pinkphiloyd,

:D You ARE questioning me and THAT'S A GOOD THING!
Now, not to answer with another question... but what is your 'everything else' that you've read?

The reason why we need hardwood, concrete, tile, or laminate in a studio is because floor bounce is something that we have naturally occurring in our environment every day. A cello just doesn't sound good on a rug! Many times an acoustic guitar doesn't either. You'll find that the drum kit sounds quite differently with and without a rug. There are instances where it is useful and needed to have a rug under an instrument and that's FINE.. it's all about creating a sound.

But in a control room, you do NOT want to have a carpet or rug anywhere in the front of the room! Any sound reflecting off the floor will have the 2 kHz band removed while all the other bands reflect. This will create a skewed response. Not a good thing. If you want to eliminate the floor bounce in a control room, you need to create a huge, deep trap in front of the listener. And by deep, I mean about 4 to 6 feet deep, filled with absorption and wave guides. ;)

But psycho-acoustic research relating to localization has been done under anechoic conditions. We are not used to listening and determining distance to a sounding object in anechoic surroundings. The clues that could possibly be given by the interference dips due to sound reflections by the floor in normal rooms will be absent. This is the way that all humans perceive their surroundings, blind or sighted. In other words, some rooms 'feel' different due to the floor and wall treatment.

It is important to create an atmosphere that is conducive to accurate mixing when designing a control room. For more information read my paper, "Who Needs a Haas Kicker" found on my publications page.

I welcome more of your questions. :thumbs up:
"Question Everything!"

Cheers,
John
 

BroKen_H

Re-member
"Question Everything!" My psych profs call to arms...Guy was constantly saying that. "They say people whistle because they're happy...but you can't whistle and smile at the same time." My favorite quote from said professor. :)
 
4

4tracker

Guest
Someone should make a thread like this for apartments that you can't modify at all.

Also, why should studios have hard floors? I have carpeting and it sounds fine, though maybe not since I don't have a comparison point.

Edit: NM, just read the response above. But that goes back to my main point -- what if you have no other option but carpeting?
 

jhbrandt

Acoustic Design
4tracker,

If you can't modify the room and it has carpet, you can always bring in some 3/4" (18 mm) plywood to lay on the floor for more natural sounding recordings.

You can always build trapping units so that they are free-standing.. with feet or hinged together so that they support themselves.
Cheers,
John
 

sausy1981

New member
Hi guys, I did a measurement of my room today using REW and I was wondering if I could get an interpretation of the graphs from people more knowledgeable than me. here are the graphs
10000 to 20000 waterfall.jpg5000 to 10000 waterfall.jpg2500 to 5000 waterfall.jpg500 to 2500 waterfall.jpg20 to 500 waterfall.jpg
Thanks a million guys.
 

Bob Amser

New member
Like those waterfall graphs, but can't help you.

Folks, it's 2016. There must be an app out there that will measure the acoustics in my room and give some (at least basic) guidance of how many 'sabins' of absorption at different frequencies, or where you can put in your absorber's frequency range and get told how many to put up or, at the very least, give you an idea of what frequencies are needing extra treatment.

Anyone know of any such thing?!
 

jhbrandt

Acoustic Design
Like those waterfall graphs, but can't help you.

Folks, it's 2016. There must be an app out there that will measure the acoustics in my room and give some (at least basic) guidance of how many 'sabins' of absorption at different frequencies, or where you can put in your absorber's frequency range and get told how many to put up or, at the very least, give you an idea of what frequencies are needing extra treatment.

Anyone know of any such thing?!

Yes.

It's all on my room mode calculators... you'll find them on my resources page. If you need help, let me know.
Cheers,
John
 

bLUiVORY

= Mojo Worker =
'Got a question...

I have FINALLY gotten to the point of acoustic panel installation. I posted about my room waaaay back in November, 2014.

Here's my Lil' Breast of studio space:
Studio Dims.jpg

(orig. post about my room is back on page 11 of this thread).

So I've got a bunch of OC 703. The local source here, N. of Detroit, will not break bundles of 12. So that's what I've got - 12 panels of 2' x 4' x 2" 703.

As recommended during my original series of posts, I've relocated the business end of my studio to the end with the 6'5" h wall. I'm sitting back at 59" (my 38% mark). And it just so happens that I have just enough 703 at his time to "wrap" my entire workspace at this end of the studio - cover left and right side walls from desk top up to 48", the entire 6'5 wall I'm facing from desktop to top of 6'5" wall, and just about ALL of the sloped ceiling above me from top of 6'5" wall to just about 16" in front of my nose. I think this would be tits. Any thoughts? Anybody even participating in this thread anymore?

And Brandt - if you're around, I hope you had a great birthday (it was Feb. 25, y'all).
 

mjbphotos

What?!?
Are you tracking in this room, or just mixing? Do your monitors have rear-firing bass ports?
For true bass trapping (really all frequencies), you want your traps to be at least 4" thick. 2" is ok for ceiling cloud and side wall point-of-first reflection panels.
Most important at this stage is the corner bass trapping - so doubling up to 4", 6 of your OC will(almost) do the front corners. If you use 2 panels for a ceiling cloud over your mixing position, that leaves 4 panels - I'd use them for the side walls, and then buy more panels for the rear wall corners and wall-ceiling corner.
 

bLUiVORY

= Mojo Worker =
Hey, Mike. How've you been?

99% mixing.

As of right now - no rear-firing ports - but who knows the future may bring.

Inadvertently omitted detail - all 703 is being installed so as to stand-off 2" from wall.

My current intention is to follow-up the 703 installation by covering the lower 5' of rear wall with thick 705 (possibly FRK) trapping.
 

mjbphotos

What?!?
Hey, Mike. How've you been?

99% mixing.

As of right now - no rear-firing ports - but who knows the future may bring.

Inadvertently omitted detail - all 703 is being installed so as to stand-off 2" from wall.

My current intention is to follow-up the 703 installation by covering the lower 5' of rear wall with thick 705 (possibly FRK) trapping.

My advice still applies - 4" thick is what you want for bass trapping.
 

jhbrandt

Acoustic Design
Wow! You guys are STILL using the dense, reflective 703 and even 705!! When lightweight (GFR = 5000 mk/rayls) is far superior?

Advice: Never, ever use 703 thicker than 2" and just NEVER use 705 for acoustic treatment... unless it is in pre-packaged panels bought from a panel manufacturer. (because it is what it is...)
Also, 8" of trapping is NOT bass trapping, because it barely gets to 150 Hz at 0 deg incidence.
Corner trapping is just the tip of the iceberg.
Putting panels on reflection points is dipping your toes in the water.

Come on boys! Jump IN! Do it right... do it once.

Check out my resources page and YouTube channel.
All the best!
Cheers,
John
 

mjbphotos

What?!?
Great info in your videos - specially for those who are in the construction phase of their studio room. For those of us using a pre-existing room, not so much. Our rooms are the dimensions we've got. And 'small' is relative, too. Your room mode demo video, for example - almost a 12' ceiling. I wish I had 12 feet in any dimension in my room. Membrane traps? Great, again, if you've got room for them. If i put as many thick traps as you show in my room, I wouldn't have room for the desk or chair to sit in!
 

bLUiVORY

= Mojo Worker =
Wow! You guys are STILL using the dense, reflective 703 and even 705!! When lightweight (GFR = 5000 mk/rayls) is far superior?

Advice: Never, ever use 703 thicker than 2" and just NEVER use 705 for acoustic treatment... unless it is in pre-packaged panels bought from a panel manufacturer. (because it is what it is...)
Also, 8" of trapping is NOT bass trapping, because it barely gets to 150 Hz at 0 deg incidence.
Corner trapping is just the tip of the iceberg.
Putting panels on reflection points is dipping your toes in the water.

Come on boys! Jump IN! Do it right... do it once.

Check out my resources page and YouTube channel.
All the best!
Cheers,
John

Hi John.

Well, since I've ended-up with a 12-pack bundle, I am intending on covering just about 100% of walls of the 'business' end of my little project studio with 2" 703 stood-off the wall 2". The info I've seen indicates this should handle pretty well everything from 250hz up.

I'll have four panels remaining at this point. Vascilating between installing on the sloped ceiling or on the back wall.

For bass-trapping, not sure - pink fluffy corner traps?
 

jhbrandt

Acoustic Design
Great info in your videos - specially for those who are in the construction phase of their studio room. For those of us using a pre-existing room, not so much. Our rooms are the dimensions we've got. And 'small' is relative, too. Your room mode demo video, for example - almost a 12' ceiling. I wish I had 12 feet in any dimension in my room. Membrane traps? Great, again, if you've got room for them. If i put as many thick traps as you show in my room, I wouldn't have room for the desk or chair to sit in!

I know, I know.... I understand. :P

Hi John.

Well, since I've ended-up with a 12-pack bundle, I am intending on covering just about 100% of walls of the 'business' end of my little project studio with 2" 703 stood-off the wall 2". The info I've seen indicates this should handle pretty well everything from 250hz up.

I'll have four panels remaining at this point. Vascilating between installing on the sloped ceiling or on the back wall.

For bass-trapping, not sure - pink fluffy corner traps?

Pink fluffy, of course! If you're not sure, you should do more research. Here's a good online calculator - Multi-layer Absorber Calculator
The info you've seen is pretty close to correct, but the thing is: The MAIN thing you need to do is from 350 Hz and DOWN. Below 250 Hz are basically ALL THE PROBLEMS! and you've done absolutely nothing for that. Above 250, is really, really easy to correct. It's the bass that is very difficult to control and most people miss it.

I'm just sayin...
And as Richard Prior used to say in stand up 'drunk hoodlum to space alien that landed in the Bronx' - "you got to give up d' flyin' saucer baby..." - You've got to give up some space for trapping if you're going to actually 'do any good'. Don't waste your time or money.

All the best.
Cheers,
John
 
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