# How to adjust phase properly with a Continuously variable phase control circuits sub???



## alexa7x23 (Feb 21, 2012)

Okay..not really sure if this is possible or not, if it is I would greatly appreciate some steps to take on optimizing a home theater with Continuously variable phase control circuits. Alright I have two of the same subs in two different positions in my HT and both subs have Continuously variable phase control circuits meaning no phase control on either of the subs..how would you optimize these subs with the main tower with a external phase controler for each sub. I am using a miniDSP..is it even possible to aling them correctly??? And if so what to set the crossovers at and what to set the distance on the a/v processors before making adjustments.. Front sub is about 13'5" away from listening posting and rear sub is about 5'8" away..Please help!! can't really find any info on adjusting phase properly with Continuously variable phase control circuits and especially using two of them???!!

Thankx much
Alex


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## jackfish (Dec 27, 2006)

Make and model of the subs and other equipment expected to do processing would be helpful. Thanks.


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## alexa7x23 (Feb 21, 2012)

(reciever) Denon AVR1911 (both subs) def tech super cube 2000s (main towers) def tech bp10b (processor) minidsp in a box RevB


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## SAC (Dec 3, 2009)

You can at a particular point in space And we will ignore the codicil 'at a particular frequency').

Here is a rather two rather simple ways to do it using REW. Generate a full range sweep with both units driven and then convolve the impulse response.

Note polarity and time offset of the later signal. At this point you might disconnect one sub and rerun the sweep in order to determine which cub corresponds to each peak. Adjust the delay of the first arriving peak so that they are arriving as close to the same time as possible. (ideally you will want to know when your mains are arriving too, and make them _all_ coincident in time (in which case you would physically move or adjust both signals with delay so that they are coincident with the mains.)

One they are very close, you can either repeat the measurements using the phase control of one (the other set to zero) to make a small adjustment and note when the sum is coincident you will see an increases in the gain of the 'now single' impulse peak. 

It is also possible to do the same by playing pink noise and observing the intensity of the output signals in a continuous display RTA function. When in phase their sum will increase in gain accordingly.


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## alexa7x23 (Feb 21, 2012)

Okay couple questions..when you say adjust the first arriving signal do you mean left to right or right to left..and what do u recommend adjusting the distance setting on the reciever..the sum of both subs?????????? Note front sub is traveling on a 8 ft RCA cable and the back sub is traveling on a 50ft RCA cable(if that makes a difference)..front sub 13.6ft away at listening position and 5.8ft from listening position..and one last question when u say full sweep to mean a bass sweep or 20hz to 20khz...and when u do this sweet are u you disconnecting the mains to do this sweet and when measuring phase and impulse on mains are u disconnecting the subs????

Thankx for helping out so much!
Alex


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## alexa7x23 (Feb 21, 2012)

5.8ft on back sub from listening position


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## alexa7x23 (Feb 21, 2012)

Jackfish you still there??


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