[TomW16]

I am building a pair of subwoofers that will be dedicated to home theater duty only.  They will be powered by a Crown XLR pro amp.  The crossover duties will be handled by the processor but I don't think that there is a variable phase control function in the processor.  How important is a phase control for the subs in a home theater set up?

If I were to use the subs for music duty with the mains (which I am not), I would go through the trouble of ensuring that the subs were in phase with the main speakers, however, when the subs will be used in a home theater and there are 7 separate speakers, what are the chances that a phase control would help with multiple channels?

Thanks.
Tom

[Kevin Haskins]

I am building a pair of subwoofers that will be dedicated to home theater duty only.  They will be powered by a Crown XLR pro amp.  The crossover duties will be handled by the processor but I don't think that there is a variable phase control function in the processor.  How important is a phase control for the subs in a home theater set up?

If I were to use the subs for music duty with the mains (which I am not), I would go through the trouble of ensuring that the subs were in phase with the main speakers, however, when the subs will be used in a home theater and there are 7 separate speakers, what are the chances that a phase control would help with multiple channels?

Thanks.
Tom

Most plate amps with variable phase only swap it 180 degrees, they don't really offer continuous adjustment.   In fact, I've not measured one that does.   The exception is DSP based devices that perform all the signal processing in the digital world.

So... all you really need to emulate the phase control that you would typically have on a plate amp would be swapping the cables to the driver.    That will give you 180 degrees of phase control.     

[TomW16]

Thanks for the quick response Kevin!  I am not interested in the 180 degree phase switch since, as you mentioned, it really is only a convenience feature that switches the speaker leads.

I believe that my old Keiga 5150 plate amp had a continuously variable phase adjustment knob from 0 to 180 degrees but I am wondering if I even need to worry about phase with 7 channels noting that most plate amps have just a phase switch.

Cheers,
Tom

[Kevin Haskins]

Even the ones with variable knobs typically just swap it.    Don't know the reason for the knob other than they want to imply more functionality than it really has.

I wouldn't say you need it.   If you want more control buy a Velodyne SMS-1.   It will give you pretty much complete control over what can be done electronically.    It also has the Mic & test tones built-in so you can get instant measurements and results. 

[bpape]

If you can get variable phase control (real phase adjustment) go for it.  Having phase adjustment (variable) is so handy when trying to integrate mains into sub(s).  I can't tell you how nice it is to have a REAL phase adjustment - almost as good as a parametric EQ.

Bryan

[TomW16]

Thanks Keven and Bryan for the responses.  I didn't realize that the knob on a plate amp only switched the phase 180 degrees and wasn't completely variable.  Based on your responses, I'll go without a phase adjustment (of course I can switch the speaker leads if it integrates better) initially. 

Bryan, I have full range speakers for stereo music (crossover designed by Dennis Murphy) so the subs are only required for home theater.  I'll keep the parametric EQ on my wish list 

Thanks again guys!

Tom

[bpape]

Many cheap plate amps are really nothing more than 0 or 180.  The better plates have real adjustable phase - just remember that absolute phase can only be at one frequency - everything else is no more than a way to EQ the blend between mains and subs.

Bryan