[braidkid]

Hello,

Please look at my attached room frequency response. I measured from 20Hz up to 2kHz out of the right channel only using a RS SPL meter for mic. The mic was placed in the main listening position. I have heard the RS SPL is not reliable above 500Hz, but still this graph has me depressed. Is this comb filtering? Is it as bad as it looks or are most rooms in worse shape? The deep null at 140Hz has me really worried. I don't think it's a sub phase issue as it shows up even with the subs turned off. How does one fix this kind of nasty response?

 

[JohnPM]

That doesn't look like a valid measurement, would need to see the scope plot and the impulse response to be sure. If you wait a few hours there'll be a version of the wizard that allows the graph to be saved as a jpg for easier posting, or you can save the measurement data and send me the (zipped) .mdat file to check.

 

[Ethan Winer]

BK,


> Is this comb filtering? Is it as bad as it looks The deep null at 140Hz has me really worried. How does one fix this kind of nasty response?

 

[braidkid]

I guess I know better to ask how to fix this. Generally, how high do bass traps absorb?


I was wondering if speaker placement would help smooth the response but unfortunately don't know where to begin.


Guess there comes a point where you need to stop worrying and enjoy the music.

 

[JohnPM]

I really think you do not have a proper measurement in that plot, rooms just don't come with responses flat to within a dB or 2 from 20 to 100Hz as shown in the graph you posted.

 

[braidkid]

John,

That measurement is with bass traps and eq for the low end. Hence why it is semi flat in the low end. I think it is showing everything accurately.

 

[Jonomega]

My graph came out kinda similar to yours. I simply deleted the graph and pretended that I never took those measurements.

 

[braidkid]

Quote:

Originally Posted by Jonomega My graph came out kinda similar to yours. I simply deleted the graph and pretended that I never took those measurements.

HAHA That's exactly what I've done Jonomega!!! This hobby can sure drive you to madness can't it?


Merry Christmas

 

[JohnPM]

Quote:

Originally Posted by braidkid John, That measurement is with bass traps and eq for the low end. Hence why it is semi flat in the low end. I think it is showing everything accurately.

Nice job then!

 

[Jonomega]

Quote:

Originally Posted by braidkid HAHA That's exactly what I've done Jonomega!!! This hobby can sure drive you to madness can't it? Merry Christmas

BTW, I have a large peak at 140hz and I lowered it by 14dB by corner loading my speakers. For me, this gave me better imaging as well. My room is 12'x12.5' though so I have little room to play with already. This caused me to get a +6dB increase at 90dB. To me, the better stereo imaging is worth it.


Merry Christmas to you too!

 

[bobgpsr]

Below is a TrueRTA plot of the left and right speakers in an untreated room (unfinished basement).


I used a LinearX M31 calibrated mic with a M-Audio Firewire 410 (soundcard equivalent). The mic was on a stand about 1 meter from each speaker in turn. The major purpose was to check out tweeter replacements in my very old Wharfedale 312's. I supose I should install L-Pads to bring the tweeters down 10 dB, but to my 53 year old ears they sound good.


The left speaker was in a corner and the 312's have a rear facing port. What a diff in base output! Good to see the pink noise and quick sweep responses match freq response so well.