[jlucas]

I have an opposed dual driver servo sub in an H frame powered by a A370PEQ.
I've double check the wiring per here https://www.audiocircle.com/index.php?topic=149708.0

Sub was played on music (not test tones) for a week with middle vol & 60 hz settings on the plate amp.
Now when I'm trying to dial in the response, changing the frequency cutoff is only changing the amplitude.
Here is measurement with crossover set at 25hz (yellow), 50 hz (blue), and 80hz (purple) setting and the volume the same for each measurement (PEQ off).  There is a mid 50s null showing up in both the sub & speaker (not shown) measurements but that is not my current question.
Why is changing the crossover only changing amplitude?


Wiring pictures

[Danny Richie]

Turning that crossover dial is doing what it is supposed to do.

The huge peak and the dip that follows is room related. So try moving that sub and your speakers further out into the room and see what happens. You need to keep moving them around until you find their happy spot. If it is there in your main speakers and in the sub then it is likely that they are the same distance from the front wall.

Once you find where they work best then you can use the rest of the settings on the plate amp to get just about any response that you want.