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Phase Control on SVS sub

post #1 of 22
Thread Starter 
I have a Phase Control knob on my SVS SB12-plus. It has been all the way to the left (on zero) since I got the sub a few weeks ago. What is the significance of this setting? The owners manual has a brief paragraph about it but it does not tell me anything useful. Is it recommended to move this knob to another position for movies or music?
post #2 of 22
The phase adjustment has nothing to do with a movies or music dependent setting. It has to do with how your sub and your main speakers blend at the area of the crossover. The easiest way to properly set the phase would be to play a test tone that is close in frequency to the crossover point. Slowly turn the phase knob to the point at which the output is the loudest. That could very well be at "0", but not necessarily.
post #3 of 22
Quote:
Originally Posted by mojomike View Post

The phase adjustment has nothing to do with a movies or music dependent setting. It has to do with how your sub and your main speakers blend at the area of the crossover. The easiest way to properly set the phase would be to play a test tone that is close in frequency to the crossover point. Slowly turn the phase knob to the point at which the output is the loudest. That could very well be at "0", but not necessarily.

its a little more easier in my opinion to reverse the black and red wires to your fronts and then play the test tone and look for the output to be lowest. then put the speakers wire back correctly and you will be set. well, that was easiest for me, it was hard to find the loudest point in my opinion.
post #4 of 22
Either of the above methods works fine, but don't try to do it by ear. Get an SPL meter to measure the output, then follow either of the 2 methods above.


Tim
post #5 of 22
Thread Starter 
Quote:
Originally Posted by mojomike View Post

The phase adjustment has nothing to do with a movies or music dependent setting. It has to do with how your sub and your main speakers blend at the area of the crossover. The easiest way to properly set the phase would be to play a test tone that is close in frequency to the crossover point. Slowly turn the phase knob to the point at which the output is the loudest. That could very well be at "0", but not necessarily.

So if I were to persue this, I would need one of those calibration discs people often mention on here in order to get a test tone in the desired frequency? In other words, the generic test tone from my Onkyo 705 receiver wouldn't probably be the desired frequency to start with.
post #6 of 22
You can download the test tone that you need form here:
http://www.ronelmm.com/tones/

Then you can burn it to a disc and run it through your system. A word of caution: When using sine waves or test tones, make sure they are used at reasonably low levels so you don't damage anything. 80db is a safe level.
post #7 of 22
Thread Starter 
Quote:
Originally Posted by mojomike View Post

You can download the test tone that you need form here:
http://www.ronelmm.com/tones/

Then you can burn it to a disc and run it through your system. A word of caution: When using sine waves or test tones, make sure they are used at reasonably low levels so you don't damage anything. 80db is a safe level.

You have a lot of faith in me.
post #8 of 22
C'mon. You can do it.
post #9 of 22
Is it logical for me to assume that using either of these methods for phase control (loudest/softest) that the mains are set to SMALL in the pre/pro?

This sounds like a great tweak for my new PC Ultra 13. Perhaps a little more pace and rhythm from my system.
post #10 of 22
Thread Starter 
Quote:
Originally Posted by chartwel View Post

its a little more easier in my opinion to reverse the black and red wires to your fronts and then play the test tone and look for the output to be lowest. then put the speakers wire back correctly and you will be set. well, that was easiest for me, it was hard to find the loudest point in my opinion.

If I do this, will I be listening for the subwoofer to be at its softest point. Should I be listening for any cues coming from the fronts (assuming it is even safe to cross black/red lines like that)? I can only imagine the theory behind this....how does this sound....by "messing up" the sound of the fronts, and lining up the sub to be at its weakest point, then this somehow puts the fronts and sub in proper sync or phase or whatever
post #11 of 22
Quote:
Originally Posted by chartwel View Post

its a little more easier in my opinion to reverse the black and red wires to your fronts and then play the test tone and look for the output to be lowest. then put the speakers wire back correctly and you will be set. well, that was easiest for me, it was hard to find the loudest point in my opinion.

Or you can leave the speakers wired "normally", adjust the output to be lowest, then add or subtract (whichever is appropriate) 180° from the result and adjust the knob accordingly.


Quote:
Originally Posted by sourbeef View Post

If I do this, will I be listening for the subwoofer to be at its softest point. Should I be listening for any cues coming from the fronts (assuming it is even safe to cross black/red lines like that)? I can only imagine the theory behind this....how does this sound....by "messing up" the sound of the fronts, and lining up the sub to be at its weakest point, then this somehow puts the fronts and sub in proper sync or phase or whatever

The idea in this case, sourbeef, is to intentionally wire the speakers out-of-phase, set the knob to the setting that produces the LOWEST output, then flip the speaker's polarity back to "normal", which should then realign the sub and speakers' phase properly, and (in theory) provide the highest output.
post #12 of 22
Thread Starter 
Quote:
Originally Posted by sivadselim View Post

Or you can leave the speakers wired "normally", adjust the output to be lowest, then add or subtract (whichever is appropriate) 180° from the result and adjust the knob accordingly.


The idea in this case, sourbeef, is to intentionally wire the speakers out-of-phase, set the knob to the setting that produces the LOWEST output, then flip the speaker's polarity back to "normal", which should then realign the sub and speakers' phase properly, and (in theory) provide the highest output.

This is what I need clarification on. After I switch the red/black wires on the fronts to put them out of phase, what am I listening to or for? A test tone only to the subwoofer
to be at its weakest point? I guess I should also ask, does it matter which end of the speaker wire I switch, the red/black end that goes into the speakers, or the red/black end that is connected to the receiver?
post #13 of 22
Thread Starter 
Quote:
Originally Posted by sivadselim View Post

Or you can leave the speakers wired "normally", adjust the output to be lowest, then add or subtract (whichever is appropriate) 180° from the result and adjust the knob accordingly.


The idea in this case, sourbeef, is to intentionally wire the speakers out-of-phase, set the knob to the setting that produces the LOWEST output, then flip the speaker's polarity back to "normal", which should then realign the sub and speakers' phase properly, and (in theory) provide the highest output.

Not that I doubt your word on this, but this goes against the conventional wisdom which says.... 2 wrongs don't make a right
post #14 of 22
Thread Starter 
Ed Mullen, if you are out there, can you or one of your techs address this?
post #15 of 22
If you type setting phase on subwoofer in google. Almost every page gives the same advice that sivadselim gives.
post #16 of 22
Thread Starter 
Quote:
Originally Posted by Hot Grits View Post

If you type setting phase on subwoofer in google. Almost every page gives the same advice that sivadselim gives.

Like I said I do not doubt he knows what he is talking about. But I still like to do things that make sense to me before I do them.
post #17 of 22
Quote:
Originally Posted by mojomike View Post

You can download the test tone that you need form here:
http://www.ronelmm.com/tones/

Then you can burn it to a disc and run it through your system. A word of caution: When using sine waves or test tones, make sure they are used at reasonably low levels so you don't damage anything. 80db is a safe level.

which test tones do you recomend using? Everything in the 20 - 80 hz range?
post #18 of 22
For phase setting, it's best to use a tone that is close or the same as the crossover frequency.
post #19 of 22
Quote:
Originally Posted by mojomike View Post

For phase setting, it's best to use a tone that is close or the same as the crossover frequency.

Thanks for the quick reply. Burning this in mp3 format to a cd would work fine?
post #20 of 22
Quote:
Originally Posted by Hot Grits View Post

Thanks for the quick reply. Burning this in mp3 format to a cd would work fine?

If your CD or DVD player plays Mp3 files, you can burn it as a data file. If not, burn it as an audio CD which will play on anything that plays CDs.
post #21 of 22
Quote:
Originally Posted by sourbeef View Post

But I still like to do things that make sense to me before I do them.

So, do your own research so that it will "make sense" to you.


Quote:
Originally Posted by sourbeef View Post

Ed Mullen, if you are out there, can you or one of your techs address this?

Why don't you go straight to the source and email SVS?
post #22 of 22
Quote:
Originally Posted by sivadselim View Post

Why don't you go straight to the source and email SVS?

Yep - whenever I e-mail them - they always get back to me ASAP. SUPERB customer service.
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