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Can you adjust the phase between subs and mains?

After building my speakers, I realized I couldn't adjust the phase relationship between my subs and the three front speakers. Even the high end processors only adjust for distance but not phase.

I just bought a gadget called the "phazer." I saw it in Tape Op magazine. It's a pure class A, discrete , solid state device and does what I need. I bought it two months ago but haven't connected it yet, a personal flaw I can't seem to get rid of .

Radial Engineering, made in Canada. It cost only $300 bucks so I need to get my but in gear to see how it works, or , wait to hear from one of you as to how good it is.

It's my hope to finish one of the projects I've started, but then, what's next?

regards, Ken
kftool
martykl
3,578 posts
 
I'll second the Velodyne SMS for the same reason as Kal. I'd also note that the 2 controls on the SMS; "phase" and "polarity" (I'm not sure how 180 degrees of phase differs from polarity) were absolutely critical to achieving smooth integration of subs and mains in my system. I was PEqing and tweaking the x-over points/slopes trying my way toward a flat response on video and couldn't get it quite right until I flipped polarity. Instantly, I got a great, almost flat line through the x-over frequency and the results are dramatically audibly superior to the earlier settings.

Marty
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kr4's avatar
kr4
3,720 posts
 
"I'm not sure how 180 degrees of phase differs from polarity."

"Dumb question, but what's the difference? Don't they both insert a time delay?"

Polarity is a simple inversion of the electrical signal across all frequencies and is either 0deg or 180deg. All of the signals are inverted in phase with this.

Phase, however, is frequency sensitive in that delaying a signal by a finite time will change differently the phase of each frequency, measured in degrees. For example, delaying a signal such that a particular frequency F is shifted 90deg with respect to the original signal will shift by 180deg the signal at 2F and by 45deg the signal at 0.5F.

Kal
martykl
3,578 posts
 
Kal,

That explains my experience in which the offset 180 degree phase setting and inverted polarity setting on the SMS yielded very different results.

Marty
kr4's avatar
kr4
3,720 posts
 
Yes. The phase shift adjustment is, afaik, centered on 80Hz, the nominal crossover but the phase change would be different below that. With a polarity inversion, everything would be 180deg changed.

Kal
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