Odd goings on in my CR

[dnafe]

Hi All

Been a while

Today I ran the Real Trap test tone CD (10 - 300hz tones in 1 hz increments measured by a RS SPL meter at the listening position) in my CR room and the numbers came back looking quite good.

The odd thing was there were a couple of groups of frequencies that made the audio appear to be coming from just the right side of the room and some made the audio appear to be on the left sideof the room.

Almost like light to heavy panning and then back to center.

I've included the layout of the room.

Any explanation and possible solutions would be appreciated

thanks

Don

[dnafe]

a bit more info for you

The corner panels are 2 Roxul RX40 3" thick 2'X4' batts stacked floor to ceiling with empty space behind them.

The wall panels are single Roxul RX40 3' thick batts hung 35.5" from floor and ceiling and mounted 3" off the wall

The ceiling clouds are the same as the wall panels but hung 3" from the ceiling

DOn

[Ethan Winer]

Don,

> The odd thing was there were a couple of groups of frequencies that made the audio appear to be coming from just the right side of the room and some made the audio appear to be on the left sideof the room. <

I see a lack of symmetry from the video monitor on the right. That might affect mid and high frequencies more than bass though.

--Ethan

[dnafe]

well so far I've removed all non essential gear (that monitor) furniture and stuff from the front 2/3 rds of the room and there is no change...just not as pronounced (15% less I'm guessing)

Tomorrow the rest of the room gets emptied and I'll check again.

Do you think the windows behind the acoustic panels could be part of the problem...they're single pane casement windows (with aluminum casement windows on the exterior of the house) approximately 5" behind the acoustic panels

Don

[Tonio]

dnafe,
I bet (ok I won't bet) guess that its the furniture and keys, monitor on your right. I have witnessed that but not as drastic. More about the snare fluctuating from the center a tad. doe sit have that effect when you move your head up and down/side to side slowly?
If you have'nt be sure to calibrate the monitoring chain.
Are those monitors(CRT?) the same size / hz refresh? I would try to move closer to the front wall if possible, since you will get some reflection.

T

[dnafe]

I'm not sure exactly what you're asking but I have no problems with stereo imaging in a mix or wandering instruments (solo'd or not) when I move my head around.

The speaker and listening position were based on a couple of things...first the manufactuterer's recommendations, second Barefoot's 2D wall bounce calculator recommendations and third and most importantly listening tests over a period of three weeks.

I can say that the most noticeble movement of the sound happens between 120 and 129 hz, the tones appear to move right around the room from right front to right rear to left rear to left front...very interesting effect


Don

edit The 17" CRT monitors are the same model with the same settings

[dnafe]

For photo's of the room go to:

http://recforums.prosoundweb.com/index.php/t/13325/946/

they're at the bottom of page 1 and the top of page 2

Don

[dnafe]

well today I cleared out absolutely everything that was nonessential and lo and behold the phenomenon is still there albiet less pronounced...I can only assume it is a function of the difference in wall construction and the windows because with the exception of my DAW, the desk it's on and the panels the room was empty.

Moving the panels altered things a tad but less than removing the misc stuff in the room...interesting

Bottom line is I don't hear it when I'm mixing so it's of no great importance but it was interesting to see how removing the stuff in the room effected this phenomenon.

Anyway next step is to ETF the room and see what the results are.

DOn

[dnafe]

Damn double posts....sorry