Finally hooked up a PC13-Ultra to partner the resident PB13-Ultra yesterday. Result is not as what I hope for. There is a certain cancellation happening as well as sounds muddy

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Did the calibration via AS-EQ1 this morning. 1 input and 2 sub outputs. As usual, EQ1 will get the desired dB from one of the front channels. Then, set the sub A's gain level to match it and continue by Sub B. After that, it's measuring process. The initial subwoofers matching is important.
Sweep tone to the front first, followed by Sub A and then Sub B. After that both sub together. Then, continued to do the rest of position. This time the sweep tone for the sub only 1 time (since it is being 'integrated' at position 1) for the rest of the positions. AS-EQ1 can do up to 32 positions.
Once it was done, I have to do channel level check again to get 75dB across all channels. it's time for some movies' test scenes. Tested Ip Man 2, TS, DTG and DF & Friends. In ULF heavy scene such as DTG's restaurant fight, TS' 7 Eleven, Kung Fu Panda, TDK as well as DH4.0 .

In TS' 7 Eleven, the robot stomping the ground has so much weight and floor rumbling. The door was being pushed open. It happens again for Ip Man2, DTG and Kung Fu Panda.
My customers were

with its sheer power. The atmosphere..... ambiance would be the ideal word, certainly up a notch. The bass is so crazy tight and powerful even at -12dB to -15dB. At my LP, I can feel that my shirt moved

Glad to see things working much better after the AS-EQ1. Yeah, having it would make integrating 2 subs much easier. If not integrated well, having 2 subs can adversely affect bass quality.
Maybe gotta borrow it again to see how it can integrate my 2 subs.