REW over-correction

[ILAN]

I have been using REW for many years, including 'Room Correction' and speakers response corrections.

Was working just great, till few days ago:

The equalization calculation and filters construction was perfect. REW says 'predicted response should be flat'

I created the filters text file, and imported it to Equalizer APO as a set of filters to correct my PC sound in real time. (same as in the past)

BUT: when I tested it with the filters assigned, using REW test, I realized that the filters did over correction, and the response was a mirror image of the uncorrected. See figure bellow.

My 'Brutal' fix was to go back to the filters and manually cut by half their gain. For all of them.

And when using with the corrected filters, I got the perfect correction the REW predicted.

Any idea why this happens?



Figure: red line- before correction, Green line - after using proposed filters REW calculated for me, Blue line- after I manually cut the gain for all filters by half.

 

[John Mulcahy]

Perhaps the filters are somehow loaded twice in eqAPO.

 

[ILAN]

Thnx, I will look into it.

 

[ILAN]

Dear John,
Thnx for the fast response,
I see no place where eqAPO can load the configuration file (with the correction filters) twice.
The APO software has no detailed settings options. It is a very simple module.
My frustration comes from the fact that the whole system worked perfect for many months.
The sudden change then might be that I unintentionally changed some setting....
But I could not find it...

 

[ILAN]

Problem solved.

John you were right.
The problem was the eqAPO, not REW.
When I installed the new APO version, it automatically checked boxes applying filters on both input and output audio.
So when I measured the REW filters in real time, it applied the filters twice !
Once I uncheked the input option, all was perfect.
My mistake not checking it.
Ilan.