Please help me with 40 hz room problem

[fulltato]

Hello Everybody .

I am recording engineer form Caracas Venezuela and i just build a production and mixing room but i am having a very hard time getting it to sound right, my biggest problem is a resonance i have around 41 hz that is driving me mad , if i play a 41hz tone and mute it suddenly, i can hear a 1 sec tail in that frequency and it resonates around all the room being worst at the front and back areas of the room.. The room is 13’7” L 10’8” w 7’5” (4,20 3,30 2,30 meters) I have carpeted floor all around , I also made broadband wood acoustic panels with fiberglass inside and covered in burlap. I used mdf panels in corners covered with 3 inch acoustic foam (please see the pictures to see the configuration. I know the ratios and parallels walls of the room are anything but ideal but is what i have for now, please let me know any advice that you would have to improve the acoustics and get rid of the 40 hz problem... thanks in advance everybody, This forum is great

[nosebleedaudio]

You need at least 8" of 703 or equv. on the back wall.
565/13.5 = 41.85Hz...
Is one of those a pic of the rear wall?

[Ethan Winer]

You also need to put bass traps in as many corners as possible. Including where the walls meet the ceiling and floor if you can manage. Real bass traps. Big thick bass traps.

--Ethan

[Weasel9992]

Yep...your problem is glaringly obvious. The back wall is bare and the corners are essentially untreated. Foam doesn't do much in the corners.

Frank

[fulltato]

thank you very much for yout time

[fulltato]

Can i use Rockwool to make basstraps and solve this problem???

[Weasel9992]

Originally Posted by nosebleedaudio

You need at least 8" of 703 or equv. on the back wall.
565/13.5 = 41.85Hz...
Is one of those a pic of the rear wall?

That's the right answer. I'd even go with 12", and you'll need a heck of a lot of it too.

Frank

[Glenn Kuras]

Originally Posted by fulltato

Can i use Rockwool to make basstraps and solve this problem???

Yes rockwool works GREAT.

Glenn

[fulltato]

Thank everybody who posted here i will keep you informed

[JAMES L KOVACS]

[quote=fulltato;3663575]Hello Everybody .

Epale, hermanito !fuuck
Ok, cool to find you here, we already got in touch directo...
Anyway, obviously you got strong STANDING WAVES GOING THERE !
Your wall dimensions are mathematical multiples, and you get this great Standing Wave just cooking between parallel walls.

I would=
A. de-parallel them walls (and with some care, create tuned Helmholtz resonator chambers in the cavities)...
B. work on that ceiling some, maybe some clouds ?
C. DEFINITELY work on that rear wall.... lots can be done here.
First, however, it is good if you decide what kind of monitoring environment you are going for.... I would recommend LEDE (live end dead end) for your space.............
we have talked, but I am at jimkovacs7@gmail.com
PLEASE OTHERS REFRAIN UNLESS YOU ARE IN THE NEIGHBOURHOOD OR ARE WILLING TO COVER MY TRAVEL EXPENSES....... GOD BLESS YOU !

[JAMES L KOVACS]

HEY ETHAN, WOW,SAY HI TO THE CAT ! (I have 4 now in my old age).

between us cat folks, this seems to need some real Helmoltz units. Rockwool (not even available here) will do NOTHIN for them LOW FREQUENCIES.
You got to design a Resonator...! With a Q of maybe 0.5, broadband.. around 50 Hz fundamental, and with some fun for the first harmonics (100, 200 Hz).
Does anyone remember how to do that ?
Ahhhh, this is where the fun starts !
This can be done at home anywhere if you know the physics........ and can find a good carpenter !!!
Be good...

[Glenn Kuras]

between us cat folks, this seems to need some real Helmoltz units. Rockwool (not even available here) will do NOTHIN for them LOW FREQUENCIES.

If you cut the rockwool into 17"x17"x24" triangles, stack them floor to ceiling it does VERY well down to 50hz.

Glenn

[nukmusic]

Originally Posted by Glenn Kuras

If you cut the rockwool into 17"x17"x24" triangles, stack them floor to ceiling it does VERY well down to 50hz.

Glenn

what about cutting/mounting the rockwall like this?

John Sayers' Recording Studio Design • View topic - The Corner Trap

sort of like a "modified Super Chunk"