How do YOU setup phase? - AVS Forum
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Old 02-20-2013, 05:40 PM - Thread Starter
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OK, so I read a useful article the other day that helped me understand how one might dial in the phase setting on the subwoofer.

My setup:
HK 3490 (stereo receiver)
Monitor Audio Bronze BX2 (ported, flat down to 42hz according to spec)
Behringer DCX 2496 Processor
Behringer EPX2000

My subwoofer enclosure is turned to 28Hz.

According to the article, which uses a HT Receiver in the example, one must set the subwoofer crossover point on the receiver to 80Hz, and play an 80Hz test tone, and dial in the phase to the setting that sounds the loudest. This would be the point that the woofers are working together, in theory, because the crossover point would be the point at which the response is -3dB. So it would be filling in the 3dB of loss.

My problem is that my stereo receiver doesn't have that setting, but using the fact that my speakers are theoretically flat down to 42Hz, could I set my subwoofer crossover to 42Hz, and play a 42Hz test tone, and dial in phase until it sounds the loudest? Is that the same idea, or am I missing something?
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Old 02-20-2013, 06:50 PM
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Use the DCX2496 to set the crossover points and then use the delay settings to blend the sub with the speakers.

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Old 02-20-2013, 07:20 PM - Thread Starter
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OK, but what about the phase setting? leave it at 0?
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Old 02-20-2013, 08:28 PM
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Originally Posted by w00b3r View Post

OK, but what about the phase setting? leave it at 0?
Phase setting on what? The Behringer amp doesn't have a phase setting, just gain settings. Are you using it in bridged mode?

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Old 02-20-2013, 08:36 PM - Thread Starter
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The DCX2496 has a phase setting, and a delay setting, and a parametric equalizer, and just about any type of processing feature you will ever need.. The signal comes out of my HK 3490 to the dcx 2496, and then goes into my behringer amp. So how would I set the phase accurately?
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Old 02-21-2013, 06:25 AM
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If you are using the delays, don't use the phase control. Just set it to 0.

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Old 02-21-2013, 07:14 AM
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Originally Posted by craig john View Post

If you are using the delays, don't use the phase control. Just set it to 0.
+1. The phase control is a delay. You don't need to use two delays.

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Old 02-21-2013, 11:11 AM
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Quote:
Originally Posted by w00b3r View Post

The DCX2496 has a phase setting, and a delay setting, and a parametric equalizer, and just about any type of processing feature you will ever need.. The signal comes out of my HK 3490 to the dcx 2496, and then goes into my behringer amp. So how would I set the phase accurately?
If you want to use the full capabilities of your DCX 2496, you will *NEED* measurement gear. There is simply no way you can set the parametric EQ or optimize the delays without some way to see the effects of the changes you're making.

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Old 02-21-2013, 02:14 PM
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Quote:
Originally Posted by w00b3r View Post

The DCX2496 has a phase setting, and a delay setting, and a parametric equalizer, and just about any type of processing feature you will ever need.. The signal comes out of my HK 3490 to the dcx 2496, and then goes into my behringer amp. So how would I set the phase accurately?
First, understand what it does. If all you're running is the one sub, it doesn't do anything. But when you add a more sound sources in the same passband they must be phase/time aligned where their outputs overlap, otherwise those outputs not only won't sum correctly, they may even cancel each other out. The easiest way to adjust it is to run a sine wave through the system, its frequency that of the crossover frequency. Adjust the phase/delay until the volume at the LP is at a maximum. Anything more precise than that will require measurement gear.

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Old 02-21-2013, 02:38 PM
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Hey Bill - I've got 3 subs, 2 matching with adjustable phase, 1 mismatched without phase adjustment and REW. How can I best go about adjusting phase in my situation? Sine wave from REW at the xover and RTA?

Would adjusting phase even help when I don't have any issues right at the crossover point but problems both below and above that point?

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Old 02-21-2013, 02:52 PM
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Originally Posted by Alan P View Post

Hey Bill - I've got 3 subs, 2 matching with adjustable phase, 1 mismatched without phase adjustment and REW. How can I best go about adjusting phase in my situation? Sine wave from REW at the xover and RTA?

Would adjusting phase even help when I don't have any issues right at the crossover point but problems both below and above that point?
That's where it gets really complicated, because you're dealing with the variables of at least four sources in the crossover region, plus three sources below the crossover frequency, and all the jumbling of time and phase from all the room boundary, sub position and LP position relationships. I'd be inclined to set one sub at a time for maximum output at the LP when played with the mains. The issues right above the crossover region may not be related as much to the time align between the subs and mains as with boundary reflections. Fiddling with the delay on the subs could help, at least with an RTA you can instantly see the effect of any adjustments you make. You'd do that bit of adjustment running pink noise.

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Old 02-21-2013, 02:55 PM
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OK, thanks Bill. I'll give it a shot the next time I set up REW.

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Old 02-21-2013, 05:13 PM - Thread Starter
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Quote:
Originally Posted by Bill Fitzmaurice View Post

First, understand what it does. If all you're running is the one sub, it doesn't do anything. But when you add a more sound sources in the same passband they must be phase/time aligned where their outputs overlap, otherwise those outputs not only won't sum correctly, they may even cancel each other out. The easiest way to adjust it is to run a sine wave through the system, its frequency that of the crossover frequency. Adjust the phase/delay until the volume at the LP is at a maximum. Anything more precise than that will require measurement gear.

Thanks for the reply Bill,

I would have to disagree with you when you say that setting the phase control does nothing, because I definitely notice a difference when I'm laying in my bed and I have my girlfriend adjust it in 10 degree increments while playing an 80Hz test tone. I'm feeding the DCX2496 a balanced stereo source from my HK3490, converted from rca to balanced with the Samson S-Convert.

Now that you have confirmed the general method of setting phase with me, I just want to ask a few specific questions.

If my HK3490 were a HT Receiver, it would have a LFE crossover setting.. let's say I set that to 80Hz, it would roll off anything under 80Hz from the mains, and send it to the sub. To adjust phase in this scenario, the article I read recommends that I play a test tone of [whatever the crossover setting] is set to.

My HK3490 does NOT have a crossover setting, BUT my Bronze BX2 speakers are a ported design, and are said to start rolling off at around 42Hz. Given this information, could I set the crossover on the DCX2496 to 42Hz LR-12, Play a 42Hz test tone, and adjust the phase to the setting that sounds the loudest? Would that be the same ideology as described in the article? or would ANY test tone work?

And above all, would setting delay be an easier task than setting phase?
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Old 02-21-2013, 08:49 PM
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Originally Posted by w00b3r View Post

I would have to disagree with you when you say that setting the phase control does nothing, because I definitely notice a difference when I'm laying in my bed and I have my girlfriend adjust it in 10 degree increments while playing an 80Hz test tone.
With only the sub playing you can't hear a change. Phase is only audible when there are two or more sources playing at the same frequency.
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My HK3490 does NOT have a crossover setting, BUT my Bronze BX2 speakers are a ported design, and are said to start rolling off at around 42Hz. Given this information, could I set the crossover on the DCX2496 to 42Hz LR-12, Play a 42Hz test tone, and adjust the phase to the setting that sounds the loudest? Would that be the same ideology as described in the article? or would ANY test tone work?
Set the crossover where it sounds the best. You must set the delay/phase at the crossover frequency, that's the only region where the sub and mains must be phase/time aligned to each other.
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And above all, would setting delay be an easier task than setting phase?
Delay is phase. When you delay the signal you shift the phase. How much you're shifting it depends on the wavelength.

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Old 02-22-2013, 10:23 AM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

With only the sub playing you can't hear a change. Phase is only audible when there are two or more sources playing at the same frequency.
.
True of course, but perhaps one can hear the effect of actively changing phase as during the adjustment it will change the waveform, but once the movement of the phase knob stops it should sound just like it did before it was turned. Perhaps that is what is being heard. I don't know if that is audible or not, never tried it.
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Old 02-22-2013, 10:28 AM
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True of course, but perhaps one can hear the effect of actively changing phase as during the adjustment it will change the waveform,.
Sure, you'd hear that as modulation. That's what a sleep sound machine does. Doppler Effect, to be exact.

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