John Sayers' Recording Studio Design Forum Archive

I decided my room could sound better than simply cherckerboarding foam on the walls and foam bass traps so I got some 4" 4'x2' panels.

The room is stripped of all except what is in the cieling (drops 1ft from fromt to back) and the tiles are stuffed behind with as much pink cotton insulation as I could fit. The rear has no treatment but is pretty diffuse, and inside the closet at the rear I have my Lenrd traps (8 of them). I also have foam bass traps in the rear of the room in place of the rear right and left tile. I plan to place a frame covered with speaker cloth where the panels would go.

The room consists of drywall, sound deadening board on the left and front, and all is covered with t-111 wood panels. the wood helps take care of the highs (evident based on RT60 in the higher regions).


So I added the forst two traps in the front corners at 45 degrees, where the Lenrds were. I noticed with no additional wall treatment the room sounded pretty freakin' nice. The bass was tight and everything was pretty smooth sounding.

Since I don't have rear corners available (closet and entrance door) I decided to go for the second best mounting place on the second pair of traps....the right and left walls, 45 degrees to the cieling. In the pictures below you can see I had to use hinges and wire to mount them, since I didn't want the weight pullung on the cieling frame. they are plenty sturdy.

The problem is, now things sound worse than with just the two traps. Why I can't imagine. There is now some serious ringing in the midrange area, I'd have to guess 2-3K without an RTA. It is very edgy and peaky and scratches at my ears. i gave a day to rest...but still the issue.

The traps are rigid fiberglass, covered in canvas and are pretty linear from 150 up to 8k as far as the mfgr. specifies. I can't imagine the traps are causing this.

I want to solve this before I put the sonex wedges back up. Is this just not the place for the other 2 traps?

I can also mount them vertically, 4" off the wall, but I wanted to ask here first. It was a pain mounting them where they are and if that is the ideal location I'd like them to stay.

If I end up wall mounting them, should I do it towards the front of the desk, or directly to the sides of the listening position? If it would be better, I may spring for a few of the 2" 4'x2' panels too, instead of using the foam to treat the rest of the room. My plan was just to checkerboard the foam judiciously in the spaces around the traps, and invert the pattern on the opposing wall.

Here are some pix. the room is 12.5 length by 11.8 width. The cieling is 8' in front, and 7' in the back. Also, the cieling slopes slightly on the right and left side too to further minimize reflection.

http://www.pbase.com/sbushman/image/52376030.jpg

http://www.pbase.com/sbushman/image/52376019.jpg

http://www.pbase.com/sbushman/image/52376011.jpg

Thanks in advance for any help guys. This all started when Lynn, Bill, and Dan suggested my mixing volume was too loud. I am trying to go back and nip the issue at its' source.

I am friends with Tom Graeffe, and he will come check out the fft and RT60 with the RTA again, but I don't want to overuse his generosity so i'd like to get in better shape before he comes back.

Certainly it "could" be the glass. I am thinking it might also be ringing from the taught wire that is holding the traps. Heck, even the metal frame of the light has a bit of audible ringing if you get close to it (in the hand clap test anyway).

The weird thing about this is that things were sounding pretty smooth, punchy and focused before the side traps got mounted. They caused an instant degradation of sound. I was hoping it was just unmasking another issue, but I am thinking now it has to do with where or how the panels are mounted.

The ceiling would have been a fantastic place to mount some tiles, but unfortunately there isn't enough space behind it because the traditional cieling is back there. That's also the reason we crammed as much insulation back there as we could, to get "some" absorption.

I am thinking I should first pull down the side traps and mount them in the primary and secondary reflection points as suggested. Good idea? I will mount them 4" off the wall to get the bass absorption extended.

Perhaps I will also get 2 more 4" and a pair of 2" absorbers too. If I remove the wooden frame from one of them I will be able to mount it on the door in the back of the room.

Then, I won't have any use for the foam...but the panels should really take care of most of what the foam would help with anyway, right?

The traps are letting you know what is really going on with your mids.... By killing some of the low end bouncing around in the room. I am sure the LF problems were masking your Midrange issues (so far as what you were hearing was concerned.)

Have you visited Johns DIY page. I would recommend some Side wall resonators for all theat midrange ringing you are finally noticeing.

Looking at your room I am sure anything done made it Appear to sound better, but you have not addresse the standing waves, etc.......

The basics of good acusitcal control onb a budget on on the high end are nestlked in this Forum. This has been addressed a number of times......

Check out the SAE site......Just absorbing some highs mids and lows will not correct a wrong room.....

First, what's inside those panels, exatly?

Second, you have neither the ceiling over the mix position nor the first reflection points on sidewalls absorbed, so you're right about moving the wall/ceiling panels down to the sides. For your ceiling, I'd put at least 4' x 6' 2" thick 3 PCF absorbent (rockwool, mineral wool, 703, etc) centered over the mix area and spaced off the ceiling by at least 2".

It's also possible that your mounts are causing at least part of the problem; I once had a nasty 6.3 kHz ringing in one of my rooms, traced it down to a freakin' luxo lamp (articulated, springs, etc)

http://www.johnlsayers.com/HR/index1.htm

This gives a basic idea of the things discussed... Steve