treating 80Hz

abraxxus · Post by **abraxxus** » Fri May 13, 2005 12:56 am

Hey guys!

I got my room built out, Tested it, and had a problem around 80Hz, after talking it over with ppl, I put in soffits, Room sounds better! but I still have this problem around 80-85Hz.

So my question is... What are my options for treating these freqs? Helmholtz, panels?

Ive seen quite a few sites and studios that have port type Helmholtz resonators. They seem like they could be easy to build, with holes drilled in them, instead of the slots...

Other question, If I build the slot type Helmholtz, Does it matter where they go in the room? or can I put them in the convienint spot? =) Ideal place (for practicality of space) would be front of room, between the monitors, I have about 5'x4' area up there I could build these. Looks like they have to be about 9" deep for the freq's Im looking at.

any other ideas, links to posts? knightfly, Got any tricks? =)

Thanks again! Im slacking on getting my pix up, but heres what I have so far for anyone that remembers me durring my build.
http://www.mantisrecording.com/gallery

-Abraxxus

drfrankencopter · Post by **drfrankencopter** » Fri May 13, 2005 1:11 am

80 Hz eh? Let me guess...ceiling height is around 8'? Are you sitting in a null of the ceiling's first axial harmonic (i.e. half the ceiling height)?

I took a brief look at your site, and I think you need more than just a spot treatment at 80 Hz (though it's not a bad idea to target 80). Do you have any bass traps in the corners? That's probably a good place to start...just use the generic panel, corner type with insulation to acheive a low Q bass absorber for overall mode control.

If you put the helmholz on the front wall, then it's going to work on the axial modes along the length of the room, and if that's not what's causing your 80Hz hole, then it won't help too much.

Best to find out what room dimension is causing the hole, and target it specifically (once the general purpose bass trapping is done).

That's what I'd do, anyways....

Kris

Post by **John Sayers** » Fri May 13, 2005 8:06 am

Abraxxus - am I correct in reading your pics that the onlt treatment in your control room is two corner traps?? It appears the rest of the room is painted drywall.

cheers
john

abraxxus · Post by **abraxxus** » Fri May 13, 2005 11:10 pm

Yea John, I havent put up any new pix, I have put up first reflection stuff since then.
And yes, painted drywall. alot of the wall space is still painted drywall. The FR absorbers are 2' X 4', so they take up some of the space...

http://www.mantisrecording.com/gallery/ ... x00?full=1

on the left of this pic you can kinda make out one of the first reflection absorbers

In the rear corners I have traps, And now that I am thinking about it, I dont remember where I got the idea for these, But this is what they are: bassicly Johns Corner Absorbers without the slats, So I have 2 layers of rockwool angled in the corner just as the Wall Unit page shows, and a cloth covering across the whole corner.

After some discussion with bgiles, we decided to put soffits in the front. These are pretty much to Johns specs. They have a thin cloth covering over them.

First reflection: 2' x 4' x 6" boxes, open back 3" rockwool on the front face with cloth coverings. I have 4 of these in the room, 2 just on the sides of mix position, and 2 on the side walls near the rear of the room at first reflection points.

Thanks in advance anyone =)
-Abraxxus