Hello all:

I've recently had success using a technique that occured to me while trying to troubleshoot a surround sound problem.

First, my setup:
- Square room, 13' x 14' x8'. Large opening to stairway and short hall on front wall right side. Large doorway in left wall to another room, as well as a large window to same room. Left side of theater room ceiling with a lower drop down section that hides the household mechanicals. Remainder of theater room with suspended ceiling. Mostly carpeted tile floor.
- 12' sectional couch along 13' back wall

- Polk R150s for mains, mounted near ceiling in front corners.
- Polk RM101s for satellites, again up near ceiling in back corners.
- Klipsch RC-52 for center
- Outlaw LFM-1 Compact for sub.
- Onkyo SR705 AV receiver.

I've used a couple of different Klipschs for the center. The specific reason is that my sectional sofa stretches about 12 feet along the back wall. I want the "sweet spot" for the center to be as wide as possible, and Klipsch uses a 2.5 crossover, eliminating "lobing" effects from the horizontally in-line drivers. I can verify from experience that this really works.

I can pretty much balance the timbre between the Klipsch and the Polks with the 7 band EQs on the Onkyo.

My real problem has been dialog clarity and "openness" of the center channel, regardless of what center channel I use. Music is not an issue, just some movies (DVD & cable) rendered through either 5 channel surround (Dolby) or 2 channel rendered through PLIIx matrix decoding. Also same problem with some general cable broadcasts, sporting events, etc. The overall surround experience just never sounded as good as I would expect it to sound.

I could make some improvement by biasing the channel EQs to favor the human voice. But even this didn't really solve it to my satisfaction. At least for not a wide enough range of source material.

I eventually noticed something else: if I were to sit forward on my couch, so that my head was not so close to the back wall, the center sound field seemed to "open up", and had a much clearer feel to it. Additionally, I experienced the same thing if I got up and walked around, or even if I went to the adjoining room to play pool. The center channel sounded good everywhere but when sitting on the couch up against the back wall.

This got me to thinking "maybe I have some phase cancellation between the front, surrounds and center speakers" occuring at specific frequencies. So I thought that it would be good to try "shifting the phase" of the center channel "just a little". Too much (such as inverting the speaker leads) might generate much more unwanted phase cancellation. So I just wanted to make a small phase shift.

The Onkyo doesn't have the ability to directly set delays for the various channels. But it occured to me that I could do this indirectly by adjusting the speaker distances. Since sound travels at roughly 1000 ft/sec, a shift of 3 feet would equal about a 3 millisecond shift. I theorized that in the mid vocal frequencies, this would be enough to accomplish a significant (and hopefully beneificial) phase shift of these frequencies relative to that coming from the front mains or surrounds.

If I thus wanted the sound from the center channel to arrive at the couch a few milliseconds before the sound from the front mains, I figured that I could do this by increasing the center channel distance setting by a few feet.

The measured distance from the center listening position in the middle of the couch to the front of the center speaker was about 10.5 feet. (Audyssey calibration had also come up with 10.5 feet, but I have not been using Audyssey for some time now due to not being allowed to change the Audyssey-determined channel EQ settings.)

Based on the above reasoning, I changed the center channel distance from 10.5 feet to 14.0 feet. The effect was immediately noticeable and pretty dramatic (at least to my ears). Suddenly everything was much more open, and dialog was really clear (even with a lot of other competing sounds in the source material). This was true for both true surround and matrix decoded surround. I could even listen at low volume levels and notice the difference.

It seemed that there maybe was even a small bit of "good" reverb produced, such that even the sounds coming from the surrounds were much more realistic and spatial. Again, a more "open" sound was the best description of what I was hearing.

An additional benefit was that I was then able to optimize the center channel EQs to produce the best quality sound and timbre matching for the center channel, instead of using EQ to maximize vocal intelligibility during movies.

Has anyone else had a similar experience?


Thanks

I have a similar problem with my surround speakers, even after correctly adjusting them to match the rest of speakers at 80db with avia (they only needed +1db). The sound simply seems to swallow the rear channel. I suspect phase/delay being the problem here.

So this weekend I am gonna try this (quoting Guy Kuo from another thread):

Using AVIA Phase Tests to Fine Tune Speaker Distance and Delay

AVIA's speaker phase testing signals are also useful for very accurate adjustment of speaker delays and distances. You'll need an analog RS SPL meter set to fast response in order to take advantage of this tidbit. This may seem a bizarre way to check delays and speaker distances but it is surprisingly accurate.

The phasing tests work by playing noise in the two channels being tested in phase and 180 degree out of phase intermittently. If the speaker distances and delays are both set correctly, then the in phase sounds from both speakers reinforce each other at the prime listening positioning. During the out of phase (diffuse) portion of the test, the sounds cancel. An SPL meter set to fast response can readily show the magnitude of the cancellation/reinforcement.

Start by playing the Phase left front/right front signal. Move your SPL meter slowly left and right at your listening position. If you have set distance and delays correctly the maximal SPL delta will occur in the middle of your sitting position. I get about a 6 dB needle bounce on my system. If it happens right of center, then your right speaker is either too farther away than the left speaker or delayed more than the left speaker. Conversely, if the peak SPL delta occurs left of your prime listening spot, the left speaker is too far or excessively delayed.

Once you have the front left and right speaker distanced and delayed exactly right, the SPL meter position at peak delta will be in the middle of your prime listening position. Note that position carefully. You'll need to be able to refer to that point within half an inch during the next step.

Now comes the trickery that gets the center speaker also precisely phased and delayed. The AVIA disc also has a Phase Left Front/Center test. We can take advantage of it to bring all three front speakers into very tight phase alignment. From the previous step we already know where the two front main speakers are in phase. Leave the left and right delays and speaker positions alone now. We'll next adjust the center speaker to be in phase with the left front. This places all three into phase.

Play the Phase Left Front/Center test and once more move the SPL meter left and right to find the maximal SPL delta point. Compare this new position to the one for the front mains. If all is perfect, they exactly coincide. If the left/center maximal SPL delta point is left of the left/right point, then the center speaker is either too close or insufficiently delayed. If the left/center max delta point is right of the left/right max delta, then the center speaker is too far. Move or adjust CENTER channel delay as needed to get the left/center max SPL delta to occur at the exact same place as for the left/right channels.

Your left, center, right speakers are now in phase. You'll probably note that a 1 msec adjustment in channel delay makes for a considerable shift in max SPL delta position. After all, that is about a 1 foot speaker distance equivalent. Use very small speaker movements to fine tune the center speaker into phase alignment.

Put your head at the center of the max SPL delta position and listen to some stereo and 5 channel material. You will be pleased with what has happened to sound imaging in your system.

Moving your speakers to achieve exact phase match isn't the entire story. One must also position the speakers with relation to room acoustics to smooth frequency response. Sometimes, moving speakers into exact phase also moves one or more of them into positions that yield uneven frequency response. In such cases, some compromise is needed to address both imaging and frequency response concerns. Happily, the home theater sound processor does have delays and these can sometimes help bring speakers into phase, while still keeping them closer to best tonal balance position.

The Onkyo doesn't have the ability to directly set delays for the various channels. But it occured to me that I could do this indirectly by adjusting the speaker distances.Why do you think the ONKYO has speaker distance settings if it is not to "directly set delays for the various channels"?


Based on the above reasoning................Sorry, but your logic is FAULTY.




The distance setting is useful for adjusting the phasing of the lower frequencies that the subwoofer shares with the main speakers. It is not so useful for adjusting the phasing between your speakers. Audyssey has the ability to set your speaker distances very accurately based upon the actual acoustic distance; the time it takes the signal to reach the microphone. If there is one thing that Audyssey does correctly, it is this. And because of the way that Audyssey's EQ works, the speakers' phases are also very accurately adjusted across a range of frequencies.

Where and how are you positioning the calibration mic when you calibrate with Audyssey? Do you have a picture of your setup that shows the front and center speaker? If so, please post it.

Why do you think the ONKYO has speaker distance settings if it is not to "directly set delays for the various channels"?




Sivadselim:

When I say direct, I mean just that, "direct", as in being able to "directly" input a 5 ms delay, or whatever I desire.

In my mind, although setting the speaker distance may do the same thing, it's indirect inasmuch as I change the distance to change the delay. That's what I meant by "indirect".

I work on scientific instruments that utilize nanosecond timings. Sometimes we effect the timings by changing the "distance" of a given element that is registered with the system software. We don't physically change the distance. We just make the software think that it has changed, which changes the timing, effecting an "indirect" change of the timing. A similar concept.

I hope my meaning is now clear to you.

:(

My phase spot between LF and LS is missing, I found it once, about a feet from the floor like 3 feet to the left of the LF/C/RF phase spot, I changed distances and it vanished for good.


My wife thinks I'm crazy btw, walking around like I'm sniffing the empty space all over the room...


-.-

It's worth noting that

1) multi-way speakers with higher order cross-overs are not minimum phase devices. If you have a different driver configuration and/or cross-over points in the center channel, you're going to have phase differences.

2) even minimum phase devices of finite bandwidth have phase shifts which extend into the pass-band, with high-pass responses (like a speaker's roll off as frequencies drop) having phase lead. Speakers with different f3 points and the same enclosure type (sealed, ported) are going to have different phase shift because of this.

It's worth noting that

1) multi-way speakers with higher order cross-overs are not minimum phase devices. If you have a different driver configuration and/or cross-over points in the center channel, you're going to have phase differences.

2) even minimum phase devices of finite bandwidth have phase shifts which extend into the pass-band, with high-pass responses (like a speaker's roll off as frequencies drop) having phase lead. Speakers with different f3 points and the same enclosure type (sealed, ported) are going to have different phase shift because of this.
:confused:
Man, that made me feel like a real audio n00b (which I am)...


Well, I found the spot again, it was like 2 inches above the floor this time... ) I was able to bring it up to the front speakers sweetspot by moving LF and RF up a bout 20 inches.

I don't think all of your problems are all phase related. Distance controls should not be used for personal preference. Meaning that if you wanna hear clearer vocals, you should not adjust the center to be a half a foot farther from you. While this will make the speaker stand out more, that is not what you want to do. Distance adjustments are almost absolute as they stitch the sound from all your speakers together. Audessey and the like do do pretty much a flawless job setting these. If the adjustments on the receiver are too course, you can fine tune by physically moving the speakers closer or farther away. If you are having clarity problems, there are some things that can be checked and adjusted. For one most center and surround speakers are placed in less than ideal spots in the room as far as acoustics are concerned. Acoustics can tear a speaker up to where it gives their sound bad characteristics. The Audessey EQ should help clear a lot of that up. Second Audessey is not good at speaker level setting. If your surrounds seem to get eaten up be the front, that does not mean that they need to be set farther from you. If the distance is set correctly check your speaker levels. Third check your subwoofer settings. Too much bass will muddy up the sound really quick. While a little too much bass may go almost unnoticed or even may be desired in music, too much bass quickly drowns out details in vocals. Lastly what you should realize is not all movies and tv programs are equal. There are some movies where the dialog is just muddy and unintelligible, and some that are as clear as crystal.

It's worth noting that

1) multi-way speakers with higher order cross-overs are not minimum phase devices. If you have a different driver configuration and/or cross-over points in the center channel, you're going to have phase differences.

2) even minimum phase devices of finite bandwidth have phase shifts which extend into the pass-band, with high-pass responses (like a speaker's roll off as frequencies drop) having phase lead. Speakers with different f3 points and the same enclosure type (sealed, ported) are going to have different phase shift because of this.

Hello Drew, Mr. Audio, and everyone:

Thanks for the responses. Drews' response especially makes sense (at least part 1....part 2 is beyond the scope of my knowledge).

I know that changing the center channel delay (via the distance setting) really has helped on many fronts, not just clearer vocals: there is a distinctly more open sound, music and sound effects are much tighter, bass response is improved for both music and effects.

Also, scenes that were recorded with echo and/or reverb are now very distinct, like I am right in the middle of the so-called "audio bubble". (My current center distance setting is 13.5', up from a measured value of around 10.5 to 11.0'.) When I go back to the measured distance setting, the drop off in quality for all of the above mentioned improvements is quite dramatic. This is true at both low and high volume levels. After playing with different settings, 13.5' seems to be the best selection.

I think that one thing that hurts my setup is that the long sectional couch where we sit is right up against the back wall. The surrounds are mounted in the upper rear corners, right at each end of the couch. I believe that this has something to do with what I previously reported: with the original center distance setting, getting up from the couch (or even leaning forward a couple of feet) would significantly improve the sound of the center channel. As previously mentioned, when standing or sitting anywhere else the center would sound good for just about any type or quality of source.

I previously noticed that due to the time domain functions that Audyssey employs, my system would sound pretty good when I used Audyssey for the setup. But for my theater and setup, I didn't like what Audyssey did to the low frequencies. And the Onkyo SR705 AVR that I currently use doesn't allow any modification to the Audyssey EQ settings. So I was forced to not use Audyssey, and instead set up my system manually, if I wanted more control over the lower bass frequencies.

Interestingly, using the center channel delay change that I selected really makes my AV in "manual" mode sound much more like "Audyssey" mode, but with improved low frequency response.

I can confidently say that changing the center channel delay has really transformed my listening experience in a very positive way. This most likely will not be true for others' systems.

Thanks for the feedback.

Hello all:

I've recently had success using a technique that occured to me while trying to troubleshoot a surround sound problem.

First, my setup:
- Square room, 13' x 14' x8'. Large opening to stairway and short hall on front wall right side. Large doorway in left wall to another room, as well as a large window to same room. Left side of theater room ceiling with a lower drop down section that hides the household mechanicals. Remainder of theater room with suspended ceiling. Mostly carpeted tile floor.
- 12' sectional couch along 13' back wall

- Polk R150s for mains, mounted near ceiling in front corners.
- Polk RM101s for satellites, again up near ceiling in back corners.
- Klipsch RC-52 for center
- Outlaw LFM-1 Compact for sub.
- Onkyo SR705 AV receiver.

I've used a couple of different Klipschs for the center. The specific reason is that my sectional sofa stretches about 12 feet along the back wall. I want the "sweet spot" for the center to be as wide as possible, and Klipsch uses a 2.5 crossover, eliminating "lobing" effects from the horizontally in-line drivers. I can verify from experience that this really works.

I can pretty much balance the timbre between the Klipsch and the Polks with the 7 band EQs on the Onkyo.

My real problem has been dialog clarity and "openness" of the center channel, regardless of what center channel I use. Music is not an issue, just some movies (DVD & cable) rendered through either 5 channel surround (Dolby) or 2 channel rendered through PLIIx matrix decoding. Also same problem with some general cable broadcasts, sporting events, etc. The overall surround experience just never sounded as good as I would expect it to sound.

I could make some improvement by biasing the channel EQs to favor the human voice. But even this didn't really solve it to my satisfaction. At least for not a wide enough range of source material.

I eventually noticed something else: if I were to sit forward on my couch, so that my head was not so close to the back wall, the center sound field seemed to "open up", and had a much clearer feel to it. Additionally, I experienced the same thing if I got up and walked around, or even if I went to the adjoining room to play pool. The center channel sounded good everywhere but when sitting on the couch up against the back wall.

This got me to thinking "maybe I have some phase cancellation between the front, surrounds and center speakers" occuring at specific frequencies. So I thought that it would be good to try "shifting the phase" of the center channel "just a little". Too much (such as inverting the speaker leads) might generate much more unwanted phase cancellation. So I just wanted to make a small phase shift.

The Onkyo doesn't have the ability to directly set delays for the various channels. But it occured to me that I could do this indirectly by adjusting the speaker distances. Since sound travels at roughly 1000 ft/sec, a shift of 3 feet would equal about a 3 millisecond shift. I theorized that in the mid vocal frequencies, this would be enough to accomplish a significant (and hopefully beneificial) phase shift of these frequencies relative to that coming from the front mains or surrounds.

If I thus wanted the sound from the center channel to arrive at the couch a few milliseconds before the sound from the front mains, I figured that I could do this by increasing the center channel distance setting by a few feet.

The measured distance from the center listening position in the middle of the couch to the front of the center speaker was about 10.5 feet. (Audyssey calibration had also come up with 10.5 feet, but I have not been using Audyssey for some time now due to not being allowed to change the Audyssey-determined channel EQ settings.)

Based on the above reasoning, I changed the center channel distance from 10.5 feet to 14.0 feet. The effect was immediately noticeable and pretty dramatic (at least to my ears). Suddenly everything was much more open, and dialog was really clear (even with a lot of other competing sounds in the source material). This was true for both true surround and matrix decoded surround. I could even listen at low volume levels and notice the difference.

It seemed that there maybe was even a small bit of "good" reverb produced, such that even the sounds coming from the surrounds were much more realistic and spatial. Again, a more "open" sound was the best description of what I was hearing.

An additional benefit was that I was then able to optimize the center channel EQs to produce the best quality sound and timbre matching for the center channel, instead of using EQ to maximize vocal intelligibility during movies.

Has anyone else had a similar experience?

Thanks



Yes I had a similar problem except that I have the same brand / series speaker up front. My R & L mains are large 3 way, and my center is identical except it is a 2 way (AKA dropped subwoofer part of large mains). It turns out that a lot of large speakers reverse polarity of the drivers at some crossover point in 3 and 4 way speakers. So do a lot of 2 way speakers.

The bottom line is my center speaker has to be wired in reverse polarity from my main speakers in order to be "in phase". I tested for phase with the THX Optimizer phase test with the correct distance, and it passed the test only when when the center was wired in reverse polarity. Fiddling with the distance setting leaving the center wired in standard polarity acted the same way that you described.

You are mixing brands of speakers, and that is why you are having a problem. You can even have this problem if you mix different series of speakers of the same brand. I would reverse the polarity on the non Polk center speaker and give that a try. Set the center up with the correct center distance. If that does not work, you have to buy a center speaker that is phase compatible with the rest of your speakers.

Funny how you properly identified the problem as a "phase" problem (which is a valid observation). You just did not try what is perhaps the simple and correct solution of reversing the polarity of the center speaker. Polarity is not the same as phase, and the distance setting only changes relative phase.

Hello all:

I've recently had success using a technique that occured to me while trying to troubleshoot a surround sound problem.

First, my setup:
- Square room, 13' x 14' x8'. Large opening to stairway and short hall on front wall right side. Large doorway in left wall to another room, as well as a large window to same room. Left side of theater room ceiling with a lower drop down section that hides the household mechanicals. Remainder of theater room with suspended ceiling. Mostly carpeted tile floor.
- 12' sectional couch along 13' back wall

- Polk R150s for mains, mounted near ceiling in front corners.
- Polk RM101s for satellites, again up near ceiling in back corners.
- Klipsch RC-52 for center
- Outlaw LFM-1 Compact for sub.
- Onkyo SR705 AV receiver.

I've used a couple of different Klipschs for the center. The specific reason is that my sectional sofa stretches about 12 feet along the back wall. I want the "sweet spot" for the center to be as wide as possible, and Klipsch uses a 2.5 crossover, eliminating "lobing" effects from the horizontally in-line drivers. I can verify from experience that this really works.

I can pretty much balance the timbre between the Klipsch and the Polks with the 7 band EQs on the Onkyo.

My real problem has been dialog clarity and "openness" of the center channel, regardless of what center channel I use. Music is not an issue, just some movies (DVD & cable) rendered through either 5 channel surround (Dolby) or 2 channel rendered through PLIIx matrix decoding. Also same problem with some general cable broadcasts, sporting events, etc. The overall surround experience just never sounded as good as I would expect it to sound.

I could make some improvement by biasing the channel EQs to favor the human voice. But even this didn't really solve it to my satisfaction. At least for not a wide enough range of source material.

I eventually noticed something else: if I were to sit forward on my couch, so that my head was not so close to the back wall, the center sound field seemed to "open up", and had a much clearer feel to it. Additionally, I experienced the same thing if I got up and walked around, or even if I went to the adjoining room to play pool. The center channel sounded good everywhere but when sitting on the couch up against the back wall.

This got me to thinking "maybe I have some phase cancellation between the front, surrounds and center speakers" occuring at specific frequencies. So I thought that it would be good to try "shifting the phase" of the center channel "just a little". Too much (such as inverting the speaker leads) might generate much more unwanted phase cancellation. So I just wanted to make a small phase shift.

The Onkyo doesn't have the ability to directly set delays for the various channels. But it occured to me that I could do this indirectly by adjusting the speaker distances. Since sound travels at roughly 1000 ft/sec, a shift of 3 feet would equal about a 3 millisecond shift. I theorized that in the mid vocal frequencies, this would be enough to accomplish a significant (and hopefully beneificial) phase shift of these frequencies relative to that coming from the front mains or surrounds.

If I thus wanted the sound from the center channel to arrive at the couch a few milliseconds before the sound from the front mains, I figured that I could do this by increasing the center channel distance setting by a few feet.

The measured distance from the center listening position in the middle of the couch to the front of the center speaker was about 10.5 feet. (Audyssey calibration had also come up with 10.5 feet, but I have not been using Audyssey for some time now due to not being allowed to change the Audyssey-determined channel EQ settings.)

Based on the above reasoning, I changed the center channel distance from 10.5 feet to 14.0 feet. The effect was immediately noticeable and pretty dramatic (at least to my ears). Suddenly everything was much more open, and dialog was really clear (even with a lot of other competing sounds in the source material). This was true for both true surround and matrix decoded surround. I could even listen at low volume levels and notice the difference.

It seemed that there maybe was even a small bit of "good" reverb produced, such that even the sounds coming from the surrounds were much more realistic and spatial. Again, a more "open" sound was the best description of what I was hearing.

An additional benefit was that I was then able to optimize the center channel EQs to produce the best quality sound and timbre matching for the center channel, instead of using EQ to maximize vocal intelligibility during movies.

Has anyone else had a similar experience?

Thanks



Yes, but I had a similar problem except that I have the same brand / series speaker up front. My R & L mains are large 3 way, and my center is identical except it is a 2 way (AKA dropped subwoofer part of large mains). It turns out that a lot of large speakers reverse polarity of the drivers at some crossover point in 3 and 4 way speakers. So do a lot of 2 way speakers.

The bottom line is my center speaker has to be wired in reverse polarity from my main speakers in order to be "in phase". I tested for phase with the THX Optimizer phase test with the correct distance, and it passed the test only when when the center was wired in reverse polarity. Fiddling with the distance setting leaving the center wired in standard polarity acted the same way that you described.

You are mixing brands of speakers, and that is why you are having a problem. You can even have this problem if you mix different series of speakers of the same brand. I would reverse the polarity on the non Polk center speaker and give that a try. Set the center up with the correct center distance. If that does not work, you have to buy a center speaker that is phase compatible with the rest of your speakers.

Funny how you properly identified the problem as a "phase" problem (which is a valid observation). You just did not try what is perhaps the simple and correct solution of reversing the polarity of the center speaker. Polarity is not the same as phase, and the distance setting only changes relative phase.

Funny how you properly identified the problem as a "phase" problem (which is a valid observation). You just did not try what is perhaps the simple and correct solution of reversing the polarity of the center speaker. Polarity is not the same as phase, and the distance setting only changes relative phase.


Hello J_Palmer:

Thanks for your reply. I actually had thought about reversing the polarity. But as this would cause the phase of all of center channel frequencies to be reversed (waveforms 180 degrees out of phase with what they are in normal wiring).

I was concerned that if I reversed the leads, then the "good" frequencies coming from the center (those that had been properly reinforcing those from the mains) would then begin cancelling. And I didn't want this to happen.

I actually only wanted to affect the relative phase of certain frequencies.
Hence the change in delay rather than reversing the leads.

As you suggested, maybe I should go back and try the experiment of reversing the leads.

The 2.5 crossover in my Klipsch center may be doing just what you mentioned (causing phase shifts due to the inherently diffferent design from my mains). It may even be doing it for only certain frequencies, but not all. The way that its particular crossover works is that all the high frequencies go to the tweeter, the mid-range frequencies to one of the two drivers, and low frequencies go to both drivers. This prevents the "lobing" effects common with most center channels that have horizontally aligned drivers. And compared to other center channels that I've tried (which only have 2x crossovers), it really works well, in terms of broadening the "sweet spot" to include the entire 12' sectional couch.

Could you elaborate on what you meant by "polarity is not the same as phase"? I know that they are not synonymous, but am I correct in saying that if the speaker leads are reversed then all frequencies will have their phase shifted by 180 degrees?

Thanks

Hello J_Palmer:

Thanks for your reply. I actually had thought about reversing the polarity. But as this would cause the phase of all of center channel frequencies to be reversed (waveforms 180 degrees out of phase with what they are in normal wiring).

I was concerned that if I reversed the leads, then the "good" frequencies coming from the center (those that had been properly reinforcing those from the mains) would then begin cancelling. And I didn't want this to happen.

I actually only wanted to affect the relative phase of certain frequencies.
Hence the change in delay rather than reversing the leads.





If there is a polarity problem with due to the mix and match of different brand speakers, you are going to have cancellations no matter what you do. The lowest frequencies cancel easiest, so that is what you work on.

Reverse the polarity, and you will find that the distance setting does not change the sound very much anymore (which is good - phase is good). If neither polarity works well, the speakers will never have a good phase match.

Note that it took me a while to get my speakers polarity set up right (including the subwoofer's polarity).






Could you elaborate on what you meant by "polarity is not the same as phase"? I know that they are not synonymous, but am I correct in saying that if the speaker leads are reversed then all frequencies will have their phase shifted by 180 degrees?

Thanks


Yes, reversing the polarity shifts each and every frequency by 180 degrees. There is no time shift.

A relative phase shift (or relative time shift with use of the distance setting) shifts the phase by a different number of degrees for different frequencies.

If you only have one speaker, you will never notice anything being different with changes in polarity or phase.