HI Alan

(Copy of my email)

I Have been to Kevin's place as he ask me to help set up his JBL horns and Rel Sub using his new DEQX 4.
All went good but I was not quiet happy with the result but I will go back as he is getting new amps and cables and whatever.....Anyway
I have encounter a problem which I have never have had before.......I will try to be as direct as possible -not to confuse you .

Configuration - Bi-amp with mono sub
When I do ROOM measurement (L&R&Sub) I always end up -10db on the horns
(Picture 01)
When I do ROOM Measurement (L&R) without Sub it measure fine
(Picture 02)
(Pls note I do not make any change whatsoever basically just taking 2 measurement one with sub the other without and always when I do include the subs it will drop the main speaker -10db.(I have adjusted the volume equal for main and sub)

NOW: At the end I came out with solution just basically measure them separately
then drag both measurements to one window for eq
(Picture 03) shows final setup with eq in place.

MY question would you know why do I get the difference when measure both speakers and Subs.

I have never have had this issue in my previous setups (Bi-am with stereo subs) Just last week I was at Mark's Morel place and also not issue at all using (Bi-am with stereo subs)
The only differences between theses setups and Kevin's is (Bi-am with stereo subs)vs(Bi-am with mono subs) Also the FR Crossover point at Kevin's is 40 hz from main to sub with our setup the cross would be higher at 80-100 hz
Anyway if you have any info/direction in this regard pls let me know


Picture (01)

Picture (02)

Picture (03)