[Vintageologist]

Hi,


as I'm in the process of upgrading my surround system, I am thinking about a couple of different possibilities.


Basically, my space is limited, but I still want to add front-wide channels to the system.


Thing is, this space is currently taken up by the sub and I'll even be upgrading to two subwoofers.


Therefore, I was thinking about taking the subs away from the frontal area where the TV is and instead placing them left and right of the viewers.


Would this be a bad idea? Basically they'll be x-overed @80Hz, so the location shouldn't make a difference (in terms of the hearer being able to locate the sub), right?


Thank you!

 

[mojomike]



Quote:
Originally Posted by Vintageologist /forum/post/19593583


Hi,


as I'm in the process of upgrading my surround system, I am thinking about a couple of different possibilities.


Basically, my space is limited, but I still want to add front-wide channels to the system.


Thing is, this space is currently taken up by the sub and I'll even be upgrading to two subwoofers.


Therefore, I was thinking about taking the subs away from the frontal area where the TV is and instead placing them left and right of the viewers.


Would this be a bad idea? Basically they'll be x-overed @80Hz, so the location shouldn't make a difference (in terms of the hearer being able to locate the sub), right?


Thank you!

You would most likely be fine with this especially since you would have a sub on both left and right. What does become more critical as you move the subs further from the front mains is getting the phase and the delays set as best as you can so that the subs integrate well with the mains.

 

[N8DOGG]

As long as they are set up properly, it would work fine. It's possible though you may find that placement area not to be ideal because we have no idea what you room looks like but just try out a few different placements, pick the best one and your off to the bass race lol!

 

[Vintageologist]



Quote:
Originally Posted by mojomike /forum/post/19593650


You would most likely be fine with this especially since you would have a sub on both left and right. What does become more critical as you move the subs further from the front mains is getting the phase and the delays set as best as you can so that the subs integrate well with the mains.

AFAIK Audyssey should take care of the phasing issues, right?

Quote:
Originally Posted by N8DOGG /forum/post/19593655


As long as they are set up properly, it would work fine. It's possible though you may find that placement area not to be ideal because we have no idea what you room looks like but just try out a few different placements, pick the best one and your off to the bass race lol!

Yes, but as a matter of fact, pushing 'em around a bit to find the sweet spot in the particular room is the way of doing it for us home-theatricidals anyway

 

[mojomike]



Quote:
Originally Posted by Vintageologist /forum/post/19595003


AFAIK Audyssey should take care of the phasing issues, right?

Audyssey will take care of setting the proper delay, but that may or may not make the phase correct.

 

[Vintageologist]



Quote:
Originally Posted by mojomike /forum/post/19595073


Audyssey will take care of setting the proper delay, but that may or may not make the phase correct.

Ah ok, thank you for the info, didn't know that... must have been lucky till now then.

Edit: Audyssey's website does say "Crossover, Polarity, Delays, Levels"...

 

[Roger Dressler]

Audyssey is s'posed to check for polarity, and IIRC that includes the sub, so ought not be an issue.

 

[mojomike]

In the case of the sub, setting the phase is not just a simple black or white issue. Many subs have a variable phase control rather than a 180 degree switch. The best setting might be something other than either 0 degrees or 180 degrees, but instead something in between. Odd phase shifts can happen in the crossover region. If not corrected, they may cause a bit of a dip in the area where the sound is shared between the sub and the mains.

 

[stang323]

Don't mean to hijack your thread but how do you manually figure the phase and also does ypao fix phase? My yamaha receiver only has reverse and normal

 

[Roger Dressler]



Quote:
Originally Posted by mojomike /forum/post/19597220


In the case of the sub, setting the phase is not just a simple black or white issue. Many subs have a variable phase control rather than a 180 degree switch. The best setting might be something other than either 0 degrees or 180 degrees, but instead something in between. Odd phase shifts can happen in the crossover region. If not corrected, they may cause a bit of a dip in the area where the sound is shared between the sub and the mains.

Most subs do not have true phase controls, but only polarity. Also, the internal sub's filters are normally defeated when the AVR's crossover are in use. If those crossovers are properly designed, as is usually the case, there will be no troublesome phase shifts introduced there. Time delay will solve remaining crossover splice problems, if polarity does not already do so.

 

[Roger Dressler]



Quote:
Originally Posted by stang323 /forum/post/19597510


Don't mean to hijack your thread but how do you manually figure the phase and also does ypao fix phase? My yamaha receiver only has reverse and normal

Are you saying your AVR has no time or distance adjustments for the various channels including the sub? If not, then just make sure the polarity is set correctly.

 

[mojomike]



Quote:
Originally Posted by stang323 /forum/post/19597510


Don't mean to hijack your thread but how do you manually figure the phase and also does ypao fix phase? My yamaha receiver only has reverse and normal

In not very familiar with the ypao system, so I can't answer that. As far as setting the phase manually, there are a couple of ways to go about it. The best way is to measure the frequency response and set the phase for the best response. Another simpler, but less precise way is to play a test tone that is close the the frequency of the crossover point and set the phase so that it give you the loudest playback of that tone.

 

[yadfgp]



Quote:
Originally Posted by mojomike /forum/post/19597847


In not very familiar with the ypao system, so I can't answer that. As far as setting the phase manually, there are a couple of ways to go about it. The best way is to measure the frequency response and set the phase for the best response. Another simpler, but less precise way is to play a test tone that is close the the frequency of the crossover point and set the phase so that it give you the loudest playback of that tone.

The loudest playback of that tone from the main seating location right? Let's just say that if you have the sub the exact same distance from all seating locations, the noise level everyone will hear will differ slightly due to room nulls and room layout right?

 

[mojomike]



Quote:
Originally Posted by yadfgp /forum/post/19597926


The loudest playback of that tone from the main seating location right? Let's just say that if you have the sub the exact same distance from all seating locations, the noise level everyone will hear will differ slightly due to room nulls and room layout right?

The bass and the sound in general is always going to vary form one location to another. I'd suggest setting the phase for the best result at whatever you consider the primary seating location (presumably your chair

).

 

[xianthax]



Quote:
Originally Posted by Roger Dressler /forum/post/19597832


Most subs do not have true phase controls, but only polarity. Also, the internal sub's filters are normally defeated when the AVR's crossover are in use. If those crossovers are properly designed, as is usually the case, there will be no troublesome phase shifts introduced there. Time delay will solve remaining crossover splice problems, if polarity does not already do so.

In my experience Audyssey, not sure of YPAO, does not correct for phase issues between the mains and the sub correctly. It will attempt to time align the passband of each speaker, that is it will calculate the acoustical distance to each speaker, but it does not account for effects in the cross-over region. I've always had to adjust the subwoofer distance after setup is complete to flatten response in the cross-over region.


Depending on the nature of your mains and chosen cross-over point the phase shift at/near the cross over point may or may not be zero without the cross-over engaged. To put it another way, speakers are not flat in their phase response. If your cross over point is in a region where the phase response of the speaker is non-zero you will have alignment issues that need to be corrected. There are many factors that can impact the phase shift of the speaker in this region. Vented vs sealed, woofer size and -3dB point being most important.


Some manufacturers provide phase response plots for their speakers, many do not, so in most cases the best course of action is using a meter and adjusting the phase either with a phase knob on the sub or with the distance setting on the AVR until you get flat response in the cross-over region.

 

[Roger Dressler]



Quote:
Originally Posted by xianthax /forum/post/19597973


In my experience Audyssey, not sure of YPAO, does not correct for phase issues between the mains and the sub correctly. It will attempt to time align the passband of each speaker, that is it will calculate the acoustical distance to each speaker, but it does not account for effects in the cross-over region. I've always had to adjust the subwoofer distance after setup is complete to flatten response in the cross-over region.

Other folks use things like REW to measure the effect of MultEQ, and are sometime dissatisfied as the responses don't look optimal. Part of that may be that each method looks at the sound differently. Since we cannot know the actual result that MultEQ thinks it is achieving, we can only guess or give it the benefit of the doubt that its time delay adjustments are applied with the goal of creating a proper splice between the mains and the subs. If that's not the intent, what other goal would be more important? On top of that, we all know that it is not entirely possible to blend one sub to several (3-7) mains as they are all spaced differently. In the end we can only speculate whose compromise is the better.

Quote:
Some manufacturers provide phase response plots for their speakers, many do not, so in most cases the best course of action is using a meter and adjusting the phase either with a phase knob on the sub or with the distance setting on the AVR until you get flat response in the cross-over region.

A manufacturer's subwoofer phase plot is meaningless once the speaker is moved into a different room, but nevertheless, the advice is sound.

 

[LTD02]

i'm going unconventional here...put the subs in the direction of the source/sound...EVEN if it measures worse. my hypothesis is that the brain is sensitive to directional cues in a way that does not show up in frequency response measurements. if you can experiment and provide some data, that would be cool.

 

[stang323]

Is it normal for the phase in a sub woofer not to change much in my frequency response or loudness?


Just did a lil test and not much changed?

 

[yadfgp]



Quote:
Originally Posted by stang323 /forum/post/19599215


Is it normal for the phase in a sub woofer not to change much in my frequency response or loudness?


Just did a lil test and not much changed?

That can be very normal. Especially when only using 1 sub.

 

[Roger Dressler]



Quote:
Originally Posted by stang323 /forum/post/19599215


Is it normal for the phase in a sub woofer not to change much in my frequency response or loudness?


Just did a lil test and not much changed?

Try the test when playing a sine wave signal at the same frequency as the crossover. One setting will be louder than the other. The loud one is the correct one.