60 Hz null at mix position

[PoorGlory]

I have a nice 60z vaccuum right where I sit at my console. I constructed this room by hand earlier this year, and it sounds nice acoustically... much better than I thought it would. Anyway, due to certain contraints, I have to have the console where it is in the room, and there is a support column behind mix position so I can't move the console out into the room any more than it already is. The room is treated with some strategically placed ATS acoustic panels.

Question: Am I screwed? I can't put bass traps vertically in the corners because there is really only one corner (right of mix position) and there are water pipes in the way (no, not the ones for smoking dope... ) To the left of mix there is a short hallway that I've deadened with homemade absorbers. I've placed two 2'x2' panels, 4 inches thick, straddled across the area where the wall meets the ceiling directly above mix position. There are two 4'x2' panels on either side of mix position angled to create sort of a "band shell" type design. Everything sounds great, except for this 60hz problem... any suggestions? Here are a couple pics and an early Sketchup rendering.

Not the prettiest space in the world, but these pics were taken right after everything was hooked up and tested, so looks weren't a priority at the time. And yes, the ceiling is pretty low. Completely treated with fiberglass batts covered in burlap between all ceiling joists.

[dnaflr2]

I have a very similar issue with nulls. My room is 11'X12'X10', and filled with real traps. Sometimes there comes a point where you can't really do anymore given the dimensions of the room.

I have found that by moving my mix position I have found a point where it is best in the room, however still a compromise. Looks like you are limited with positioning due to console though.

[lowfreq33]

Can you move your console and monitors back into the room a bit? That's way too close to the wall. Ideally the mix position should be about 1/3 the room length from the front wall. A couple of Tube Traps might help also, and since they're portable you can move them out of the way when you need to go down the hall.

[PoorGlory]

It may look weird from the pictures, but where I am sitting at mix in the room is about 1/3 of the way back. Can't go back because of the aforementioned support column. The back of the console is roughly almost 2 feet from the wall.

[lowfreq33]

Is the column treated?

[PoorGlory]

The column is solid cinderblock, about 1.5' by 1'. I have a carpet wrapped around it, but that's more for look and comfort (increase someone scrapes up against it). There's not enough surface area for this thing to really make any sort of difference, especially in the low frequencies.

[matucha]

I'm afraid that the only solution is to move your setup around... it is very hard to guess what's possible with those photos... can you for ex turn your setup 90°? Placement of things is the most important, followed by right amount of acoustic treatment... or better said those go hand-in-hand.

Ah, sorry I forgot about the sketchup picture.

Your solution is spacialy the most reasonable, but if it doesn't work acoucticaly, I'd suggest to try to put the desk in the corner (turning your setup 45° to the right) and than full 90° turn. The column will always be a problem ;(. Other thing I see in your current position that is less then desirable is you don't have a symetry around your speakers because of that corridor (entrance) on your left. That have to skew your stereo image a bit.

[nosebleedaudio]

First is it all speakers?
I would if all possible move the near fields away from the wall as much as possible and have 2 to 4" of 703 right behind them, esp. if their rear ported.
More bass traps might help.

[PoorGlory]

If I move 6' to the right or left, the 60hz comes back, but I'm out of the sweet spot big time. Maybe I could try treating the area where the floor meets the wall under the console.... every time I get under there to fix some wiring, I notice theres a ton of low end there.

[Ethan Winer]

Originally Posted by PoorGlory

I have a nice 60z vaccuum right where I sit at my console.

This is very common, and is usually caused by reflections from the wall behind you. As I'm sure you know, the solution is yet more bass trapping. Once all the corners are filled, and this means wall-ceiling and even wall-floor corners too, the next line of attack is traps on the entire rear wall.

Also, since you bought panels from ATS, you should ask them for advice. A good treatment vendor will know how to solve these problems, and should be willing to spend time with you on the phone or in email.

--Ethan

[Glenn Kuras]

Originally Posted by Ethan Winer

This is very common, and is usually caused by reflections from the wall behind you. As I'm sure you know, the solution is yet more bass trapping. Once all the corners are filled, and this means wall-ceiling and even wall-floor corners too, the next line of attack is traps on the entire rear wall.

Also, since you bought panels from ATS, you should ask them for advice. A good treatment vendor will know how to solve these problems, and should be willing to spend time with you on the phone or in email.

--Ethan

I am with you Ethan on this one. One thing to add is just plan wrapped 4" panels do work but (from the data I have seen) it does start to fall off at 100hz so I am not sure how much absorption you are really getting at 60Hz.

Glenn

[Wayne]

If you move to the right or left and it goes away doesn't that mean it's a room width issue? Would side wall treatment help?
Over at John Sayer's site I learned that avoidance of the width mode (typically?) takes second priority to side to side symmetry in monitor/listening placement.
So in the spirit of true Low End Theory may I offer...

Before reaching for eq decisions down there, do what I do -Take a little walk around.
(-or in your case scoot over a bit.

We can (and do) overcome.

[jwl]

I highly recommend reading this thread at the John L Sayers forum.