Does an inverted signal matter, audibly noticeable?

[Deleted]

Given that all speakers are in phase but are wired inverted [negative], that is, so all speakers go inward rather than outward on first note will there be any apparent audible difference? Generally speaking, most people seemingly think that it doesn't matter as long as all speakers are in phase to one another. Was curious, percussion wise, does it matter if the woofer is firing into the box before reaching the listener's ears? 

What sparked my interest in this subject is learning that my DR3 amp's XLR inputs are inverted. The Onkyo unit has the pin 2 and 3 hot or cold in a different configuration than the Emotiva. Just installed inverters to properly align the signal and I zeroed out the phase from 180 degrees as this was how I was compensating up until now. That's when I realized that whenever a percussion hits in the music the woofers are firing inwards upon first note. Does it matter? Tonight I'll be listening to the system after having installed the inverters. 

Your thoughts?

[repeetavx]

No. The hardware crossovers in your speakers do more to change the sound than changing the music by one half cycle does. Just make sure all of your speakers have this phase change and you should be golden.

Actually this is easy to figure out. Play the same song twice. Once in the original phase, and once with the speaker wires reversed. Only you can determine if you can hear the change.

[millst]

There are some studies with signals in headphones or anechoic chambers where people could detect a difference. However, there was no clear preference. For real world content, it is inaudible.

[Deleted]

Night and day difference. No comparison the change is not only blatant but glaring [upset]. The imaging of the front sound stage is totally different as the center doesn't disappear in contrast to before. The separation isn't as wide or drastic. It's not just an improvement to the bass but well into the mid range. This is actually kinda upsetting to me. However, now that's it's corrected I'll enjoy the new found difference.

[KeithL]

This question has been widely debated for a very long time.

I would have to go with: "Most people I know don't notice any difference at all".

(Note that we're talking about absolute phase... and NOT about some speakers being out of phase with others.)

However I would also concede that it may have a lot to do with what you listen to and your speakers.

(It may be different with a carefully recorded "direct-to-disc" digital recording than with a heavily processed multi-track recording.)

As someone already mentioned, many speakers introduce a truly major amount of phase shift.

Some commercial speakers actually shift the phase between 20 Hz and 20 kHz by over 720 degrees - that's four complete reversals.

And dipole speakers like Magneplanars produce a veritable jumble of phase information at the listening position.

All of the sound radiated from the rear of a dipole panel is out of phase with the sound radiated from the front... even before they mix together.

Yet fans of Maggies often describe them as producing a very concise sound stage.

There is also the fact that most modern recordings are mixed from a large number of tracks.

In many cases, a single instrument may have been recorded with several different microphones, in different locations.

(Remember that, at 1 kHz, a microphone six inches further from the source will be 180 degrees out of phase with one that sits six inches closer.)

And, to be honest, often little care is taken to ensure that all of those tracks maintain absolute phase.

(And, if some of the individual tracks are not in correct absolute phase relative to each other, there's no way to correct that after the fact.)

Because of this variability it's quite possible that such a difference might be audible, with certain speakers, and with certain carefully produced recordings.

There's something else worth mentioning here....

As I mentioned above, many commercial speakers have a significant amount of phase shift over their frequency range.

Furthermore, the amount of shift, and where it takes place, will be different for each make, and even model of speakers.

Therefore, unless all of your speakers are the same, or at least very similar, and have very similar phase characteristics...

At best they can only be in phase with each other at certain frequencies.

If two speakers are in phase at 20 Hz, but one has 360 degrees of shift between 20 and 20k, while another has 480 degrees of shift over the same range...

Then there must be several frequencies at which they "drift" in and out of phase with each other... right? 

Most people I know agree that it's rather critical that SYMMETRICAL PAIRS of speakers be identical....

Id not, then the sound stage will be downright weird, and everything will sound quite odd.

But most people find no problem, for example, with surrounds that are quite different than their mains.

HOWEVER, of course, it's easy to test this for yourself, by simply reversing the Black and Red leads going to each of your speakers...
Which is the simplest way to reverse the absolute phase on all of them.

[doc1963]

Mar 18, 2020 16:50:32 GMT -5 @shimei said:

Night and day difference. No comparison the change is not only blatant but glaring [upset]. The imaging of the front sound stage is totally different as the center doesn't disappear in contrast to before. The separation isn't as wide or apparent. It's not just an improvement to the bass but well into the mid range. This is actually kinda upsetting to me. If I were to do it again I might just well of went with Parasound. However, now that's it's corrected I'll enjoy the new found difference.

You’re not alone in your findings. It’s not so apparent with HT usage because you’re actually filling in the center with a physical speaker. But with 2-channel, it sticks out like a sore thumb.

My T2’s image much better with the phase corrected at the back of my DR-2. Just as you’ve found, it’s not just a subtle difference. Without correction, the center image between the L/R is almost non-existent and the pair become noticeably localized. Reverse the polarity and the imaging is beautiful.

I’m using the same type of polarity inverter as you, but distributed by Hosa rather than Neutrik. I’ve got them on all 11 channels since both of my (Gen 3) amps are affected. If you ever find that, due to the length and weight of the phase inverters, they sag at the back of your amp, you can do what I have done and use two shorter XLR cables using the inverter to join them together.

Glad you’ve found your sweet spot...

[KeithL]

I'm a little confused here....

If you "installed inverters to properly align the signal" then the absolute phase should now be correct.

(If you used passive inverters, at most you put them on the wrong channels, and it's easy enough to move them...)

You also shouldn't rule out the possibility that the inverters you used are introducing some form of audible coloration or distortion.

Flipping the speaker wires, or the wires in a balanced XLR cable, is a passive and lossless process... 

However, there is no way to invert the signal on an RCA cable without introducing the possibility of adding distortion and coloration.

(You have to use either an active inverter, or a transformer, neither of which is perfectly free of distortion and coloration.)

There is another possibility here.....

In real life the first hit on a bass drum moves the membrane of the drum outwards towards you...

But the first hit on a snare drum moves it inwards (depending on exactly where you're sitting)...

And, in fact, the drum head oscillates back and forth for quite some time...

The signal is also altered during recording and processing (the "DC component is removed").

So, if you look at actual oscilloscope traces of drum recordings, the signal often looks almost symmetrical.

However, with many bass reflex speakers, there is a tendency for the driver to drift inwards or outwards.

(This occurs because of "mechanical rectification" due to asymmetrical pressure paths in the port and cabinet.)

Because of this, with some speakers, you'll find that the woofer cone tends to drift on one direction or the other, regardless of the phase of the signal itself.

(It's easy enough to tell... if this is happening with yours the woofer will tend to move the same way regardless of whether you flip the wires or not.)

And sometimes it's just plain hard to see which way the cone is moving.....

(It does move back and forth, in both directions, really fast...)

I would also correct a sort of stated misperception.....

The shape of the sound wave is inverted.....

This does NOT mean that "the woofer is firing into the box before reaching the listener's ears".....

(Saying it that way makes it seem as if "the sound has to bounce around in the cabinet before we hear it".)

It simply means that the inverted part of the signal is the first part to reach the listener's ears.....

Mar 18, 2020 13:15:41 GMT -5 @shimei said:

Given that all speakers are in phase but are wired inverted, that is, so all speakers go inward rather than outward on first note will there be any apparent audible difference? Generally speaking, most people seemingly think that it doesn't matter as long as all speakers are in phase. Was curious, percussion wise, does it matter if the woofer is firing into the box before reaching the listener's ears? 

What sparked my interest in this subject is learning that my DR3 amp's XLR inputs are inverted. The Onkyo unit has the pin 2 and 3 hot or cold in a different configuration than the Emotiva. Just installed inverters to properly align the signal and I zeroed out the phase from 180 degrees as this was how I was compensating up until now. That's when I realized that whenever a percussion hits in the music the woofers are firing inwards upon first note. Does it matter? Tonight I'll be listening to the system after having installed the inverters. 

Your thoughts?

[Deleted]

Mar 18, 2020 18:01:26 GMT -5 KeithL said:

I'm a little confused here....

If you "installed inverters to properly align the signal" then the absolute phase should now be correct.

(Unless you put the inverters on the wrong amp.)

You also shouldn't rule out the possibility that the inverters you used are introducing some form of audible coloration or distortion.

(Flipping the speaker wires, or thw wires in a balanced XLR cable, is a passive process...  whereas an inverter is an active device.)

There is another possibility here.....

In real life the first hit on a bass drum moved the membrane of the drum outwards towards you...

But the first hit on a snare drum moves it inwards (depending on exactly where you're sitting)...

And, in fact, the drum head oscillates back and forth for quite some time...

The signal is also altered during recording and processing (the "DC component is removed").

So, if you look at actual oscilloscope traces of drum recordings, the signal often looks almost symmetrical.

However, with many bass reflex speakers, there is a tendency for the driver to drift inwards or outwards.

(This occurs because of "mechanical rectification" due to asymmetrical pressure paths in the port and cabinet.)

Because of this, with some speakers, you'll find that the woofer cone tends to drift on one direction or the other, regardless of the phase of the signal itself.

(It's easy enough to tell... if this is happening with yours the woofer will tend to move the same way regardless of whether you flip the wires or not.)

And sometimes it's just plain hard to see which way the cone is moving.....

(It does move back and forth, in both directions, really fast...)

I would also correct a sort of stated misperception.....

The shape of the sound wave is inverted.....

This does NOT mean that "the woofer is firing into the box before reaching the listener's ears".....

(Saying it that way makes it seem as if "the sound has to bounce around in the cabinet before we hear it".)

It simply means that the inverted part of the signal is the first part to reach the listener's ears.....

Mar 18, 2020 13:15:41 GMT -5 @shimei said:

Given that all speakers are in phase but are wired inverted, that is, so all speakers go inward rather than outward on first note will there be any apparent audible difference? Generally speaking, most people seemingly think that it doesn't matter as long as all speakers are in phase. Was curious, percussion wise, does it matter if the woofer is firing into the box before reaching the listener's ears? 

What sparked my interest in this subject is learning that my DR3 amp's XLR inputs are inverted. The Onkyo unit has the pin 2 and 3 hot or cold in a different configuration than the Emotiva. Just installed inverters to properly align the signal and I zeroed out the phase from 180 degrees as this was how I was compensating up until now. That's when I realized that whenever a percussion hits in the music the woofers are firing inwards upon first note. Does it matter? Tonight I'll be listening to the system after having installed the inverters. 

Your thoughts?

KeithL, thank you as I do respect you and your help. I also realize as you stated different speakers etc may have a factor. Can't imagine what was going on with an inverted signal. As I wrote what I had above I expressed it in full confidence because the change was that drastic. I've sat in front of the system now for over a hour shaking my head several times in disbelief over the difference. To say that things were "out of whack" is an understatement. The change was so drastic I mind as well have turned every speaker around in their enclosure. Granted my system has a wide range of different size speakers:





Thanks for your help Keith!

Enjoy,
William

[garbulky]

So what might have happened is that your speakers may have initially been connected out of phase with each other. Correcting the phase by swtiching the connections on just one speaker should result in the night and day differences you are hearing.
You can test if your speakers are connected in phase by using this handy tool.
www.richardfarrar.com/are-your-speakers-wired-correctly/
(Go to phase test to check it out)

[Deleted]

Mar 18, 2020 17:52:42 GMT -5 doc1963 said:

Mar 18, 2020 16:50:32 GMT -5 @shimei said:

Night and day difference. No comparison the change is not only blatant but glaring [upset]. The imaging of the front sound stage is totally different as the center doesn't disappear in contrast to before. The separation isn't as wide or apparent. It's not just an improvement to the bass but well into the mid range. This is actually kinda upsetting to me. If I were to do it again I might just well of went with Parasound. However, now that's it's corrected I'll enjoy the new found difference.

You’re not alone in your findings. It’s not so apparent with HT usage because you’re actually filling in the center with a physical speaker. But with 2-channel, it sticks out like a sore thumb.

My T2’s image much better with the phase corrected at the back of my DR-2. Just as you’ve found, it’s not just a subtle difference. Without correction, the center image between the L/R is almost non-existent and the pair become noticeably localized. Reverse the polarity and the imaging is beautiful.

I’m using the same type of polarity inverter as you, but distributed by Hosa rather than Neutrik. I’ve got them on all 11 channels since both of my (Gen 3) amps are affected. If you ever find that, due to the length and weight of the phase inverters, they sag at the back of your amp, you can do what I have done and use two shorter XLR cables using the inverter to join them together.

Glad you’ve found your sweet spot...

Thanks for the tip Doc. The inverters do add extra length but seemingly it isn't too bad. If I needed to subtract an inch or two of clearance behind the entertainment stand to the wall to get them closer I'll definitely use your tip in putting the inverter in the middle of two short length cables. 

I actually was at a lost because what I was hearing at times made no sense. I actually don't understand the MTM array completely or the crossovers. Haven't any idea whether an inverted signal in the 4 ways could be more pronounced than with other setups. 

This is the extra length in case anyone is interested. Picture was taken with inverters at the Onkyo but have since been moved down to bottom at the amp. 

I'm stoked at the moment. 

[Deleted]

Mar 18, 2020 19:46:30 GMT -5 garbulky said:

So what might have happened is that your speakers may have initially been connected out of phase with each other. Correcting the phase by swtiching the connections on just one speaker should result in the night and day differences you are hearing.
You can test if your speakers are connected in phase by using this handy tool.
www.richardfarrar.com/are-your-speakers-wired-correctly/
(Go to phase test to check it out)

Thank you garbulky. 

Quite sure the speakers were all in phase to one another beforehand. I did not try reversing the polarity from the amp to the towers before installing the inverters. Once I got wind that the XLR pins were of different configuration between the Onkyo and Emotiva I 2nd day aired the inverters. The subwoofer has an amp with a 180 degree phase dial. The thing about that dial and trying to change the phase is that it wasn't as dramatic as expected. Though I could tell a difference if the phase was left at zero [out of phase with the towers powered by the Emotiva] and 180 degrees to align with the towers before the inverters were installed. Of course after I installed the inverters I immediately turned the phase dial to the subwoofer back to zero. Something was always off, I mean I'm crawling around the floor listening to bass etc trying to figure out what's going on and whether I need to move the subwoofer or change the distance between the towers and toe etc.Phew, just couldn't figure it out before. 

Expecting room treatment acoustic panels to arrive within a week. I hope for lots improvements soon. 

To note the Onkyo's room correction or ACCUEQ doesn't have phase adjustments but only distance, levels, and standing wave room correction. Even if it did I'd prefer to fix the physical issue rather than relying on processing to make the changes. 

[audiosyndrome]

If you’re hearing a night and day difference something other than the Emotiva XLRs were the problem. I’m supposing this because your first post is totally not understandable. When this “issue” first came to light some time ago I reversed the red and black leads at the terminals of my NHTs. Could not hear any difference. 😎. I think your Tektons are great speakers but with all those drivers the chance of an internal miswiring goes up dramatically. Whatever you did (?) may have fixed such an issue.

Also, David Reich, who is a terrific amplifier designer and technical reviewer, did a fabulous article on fully balanced amps for Secrets of Home Theater. He compares two amps in the article; the ATI 6002 and the Emotiva XPA-1. He classifies the ATI amp as non-inverting, and the Emotiva amp as INVERTING! Hmmm, inverting amp with XLR pins 2 and 3 reversed equates to the amp output IN PHASE! So maybe much ado about nothing???

I read the article several years ago. I have to go back and read it again to ascertain if the Emotiva output is inverted prior to the XLR output. Or I’m confused. 🙄 Likely. 😉

Russ

hometheaterhifi.com/technical/technical-reviews/the-fully-balanced-power-amplifier-advantages-and-design-challenges/

[audiosyndrome]

Mar 18, 2020 20:23:10 GMT -5 @shimei said:

Mar 18, 2020 19:46:30 GMT -5 garbulky said:

So what might have happened is that your speakers may have initially been connected out of phase with each other. Correcting the phase by swtiching the connections on just one speaker should result in the night and day differences you are hearing.
You can test if your speakers are connected in phase by using this handy tool.
www.richardfarrar.com/are-your-speakers-wired-correctly/
(Go to phase test to check it out)

Thank you garbulky. 

Quite sure the speakers were all in phase to one another beforehand. I did not try reversing the polarity from the amp to the towers before installing the inverters. Once I got wind that the XLR pins were of different configuration between the Onkyo and Emotiva I 2nd day aired the inverters. The subwoofer has an amp with a 180 degree phase dial. The thing about that dial and trying to change the phase is that it wasn't as dramatic as expected. Though I could tell a difference if the phase was left at zero [out of phase with the towers powered by the Emotiva] and 180 degrees to align with the towers before the inverters were installed. Of course after I installed the inverters I immediately turned the phase dial to the subwoofer back to zero. Something was always off, I mean I'm crawling around the floor listening to bass etc trying to figure out what's going on and whether I need to move the subwoofer or change the distance between the towers and toe etc.Phew, just couldn't figure it out before. 

Expecting room treatment acoustic panels to arrive within a week. I hope for lots improvements soon. 

To note the Onkyo's room correction or ACCUEQ doesn't have phase adjustments but only distance, levels, and standing wave room correction. Even if it did I'd prefer to fix the physical issue rather than relying on processing to make the changes. 

Are the outputs of the Onkyo in phase, or out of phase? Lots of equipment tested by JA are out of phase.

Russ

[audiosyndrome]

Mar 18, 2020 17:52:42 GMT -5 doc1963 said:

Mar 18, 2020 16:50:32 GMT -5 @shimei said:

Night and day difference. No comparison the change is not only blatant but glaring [upset]. The imaging of the front sound stage is totally different as the center doesn't disappear in contrast to before. The separation isn't as wide or apparent. It's not just an improvement to the bass but well into the mid range. This is actually kinda upsetting to me. If I were to do it again I might just well of went with Parasound. However, now that's it's corrected I'll enjoy the new found difference.

You’re not alone in your findings. It’s not so apparent with HT usage because you’re actually filling in the center with a physical speaker. But with 2-channel, it sticks out like a sore thumb.

My T2’s image much better with the phase corrected at the back of my DR-2. Just as you’ve found, it’s not just a subtle difference. Without correction, the center image between the L/R is almost non-existent and the pair become noticeably localized. Reverse the polarity and the imaging is beautiful.

I’m using the same type of polarity inverter as you, but distributed by Hosa rather than Neutrik. I’ve got them on all 11 channels since both of my (Gen 3) amps are affected. If you ever find that, due to the length and weight of the phase inverters, they sag at the back of your amp, you can do what I have done and use two shorter XLR cables using the inverter to join them together.

Glad you’ve found your sweet spot...

Would it not have been much simpler, less obtrusive, less expensive and more reliable to (just) reverse the connections at the terminals of the 11 speakers? Easy Peasy.

[doc1963]

Mar 18, 2020 20:52:05 GMT -5 audiosyndrome said:

Mar 18, 2020 17:52:42 GMT -5 doc1963 said:

You’re not alone in your findings. It’s not so apparent with HT usage because you’re actually filling in the center with a physical speaker. But with 2-channel, it sticks out like a sore thumb.

My T2’s image much better with the phase corrected at the back of my DR-2. Just as you’ve found, it’s not just a subtle difference. Without correction, the center image between the L/R is almost non-existent and the pair become noticeably localized. Reverse the polarity and the imaging is beautiful.

I’m using the same type of polarity inverter as you, but distributed by Hosa rather than Neutrik. I’ve got them on all 11 channels since both of my (Gen 3) amps are affected. If you ever find that, due to the length and weight of the phase inverters, they sag at the back of your amp, you can do what I have done and use two shorter XLR cables using the inverter to join them together.

Glad you’ve found your sweet spot...

Would it not have been much simpler, less obtrusive, less expensive and more reliable to (just) reverse the connections at the terminals of the 11 speakers? Easy Peasy.

Trust me... it was much easier for me to do it the way I did. The time involved and/or the resulting backache wasn’t worth the $77 investment in additional parts.

For those who have easy access to all eleven speakers (including those in the ceiling and walls) or the back of their amp(s), then the answer is yes, of course it is.

[KeithL]

The wavelengths of sound at various frequencies are VERY different.... which accounts for the different effect you get by changing or reversing them.

(Note that we're talking about phase between speakers in a pair here...and not absolute phase.)

For example, at 1 kHz, the wavelength of sound, in air, is approximately one foot.

So, at that frequency, reversing the phase is equivalent to changing the distance by six inches.

If two speakers are the same distance from you and in phase - moving one six inches further away will make it 180 degrees out of phase with the other speaker.

The reason it's important to get the distances, and distance settings, right is that those are the frequencies that are most important when it comes to imaging and sound stage.

Now, at 10 kHz, the wavelength of a sound wave is about one INCH.

So, if the distance on one of a pair of speakers is off by a mere 1/2", it will be out of phase with its mate.

However, because high frequencies in this range tend to reflect and diffuse so significantly, we tend not to notice when this happens.

(Because of all the diffusion in a typical room the phase of sounds we hear at those frequencies is pretty much a random jumble anyway.)

Now, at 20 Hz, the wavelength of sound is about FIFTY FEET.

So, if the distance setting is off by a few feet, the difference really isn't that much (in degrees).

Also, because what we hear in a room depends so heavily on nodes, nulls, and room boundary effects, interactions between sources often don't play a major role.

A sub should be in phase with your main speakers at the crossover point...

But the locations of each in the room, and how they interact with the room boundaries, probably have a much larger effect on their overall performance.

(So, for example, moving the subwoofer a few feet closer to or further away from a corner will often have far more effect than adjusting the phase by 180 degrees.)

Mar 18, 2020 20:42:36 GMT -5 audiosyndrome said:

Mar 18, 2020 20:23:10 GMT -5 @shimei said:

Thank you garbulky. 

Quite sure the speakers were all in phase to one another beforehand. I did not try reversing the polarity from the amp to the towers before installing the inverters. Once I got wind that the XLR pins were of different configuration between the Onkyo and Emotiva I 2nd day aired the inverters. The subwoofer has an amp with a 180 degree phase dial. The thing about that dial and trying to change the phase is that it wasn't as dramatic as expected. Though I could tell a difference if the phase was left at zero [out of phase with the towers powered by the Emotiva] and 180 degrees to align with the towers before the inverters were installed. Of course after I installed the inverters I immediately turned the phase dial to the subwoofer back to zero. Something was always off, I mean I'm crawling around the floor listening to bass etc trying to figure out what's going on and whether I need to move the subwoofer or change the distance between the towers and toe etc.Phew, just couldn't figure it out before. 

Expecting room treatment acoustic panels to arrive within a week. I hope for lots improvements soon. 

To note the Onkyo's room correction or ACCUEQ doesn't have phase adjustments but only distance, levels, and standing wave room correction. Even if it did I'd prefer to fix the physical issue rather than relying on processing to make the changes. 

Are the outputs of the Onkyo in phase, or out of phase? Lots of equipment tested by JA are out of phase.

Russ

[KeithL]

I suspect that the extreme difference that you noticed may be related to a specific characteristic of the Tekton Ulfberhts.

From what I've read the Ulfberhts are not simply a four way speaker.

As I recall, according to their description, they actually drive different tweeters in their array with different-phased signals to control dispersion and directionality.

(They're using a complicated crossover, which alters the phase between the individual drivers, in order to create a "steered array" of sorts.)

It's quite possible that this makes them especially sensitive to phase relationships that might not be significant with other speakers.

I should point something out however...

Even if the speakers do in fact sound different depending on the phase of the signal they're playing...

It's still difficult to know whether many modern recordings are in fact recorded in correct absolute phase to begin with...

Some labels claim to be especially careful to preserve absolute phase in their recordings... while many seem quite oblivious to it...

Mar 18, 2020 20:23:10 GMT -5 @shimei said:

Mar 18, 2020 19:46:30 GMT -5 garbulky said:

So what might have happened is that your speakers may have initially been connected out of phase with each other. Correcting the phase by swtiching the connections on just one speaker should result in the night and day differences you are hearing.
You can test if your speakers are connected in phase by using this handy tool.
www.richardfarrar.com/are-your-speakers-wired-correctly/
(Go to phase test to check it out)

Thank you garbulky. 

Quite sure the speakers were all in phase to one another beforehand. I did not try reversing the polarity from the amp to the towers before installing the inverters. Once I got wind that the XLR pins were of different configuration between the Onkyo and Emotiva I 2nd day aired the inverters. The subwoofer has an amp with a 180 degree phase dial. The thing about that dial and trying to change the phase is that it wasn't as dramatic as expected. Though I could tell a difference if the phase was left at zero [out of phase with the towers powered by the Emotiva] and 180 degrees to align with the towers before the inverters were installed. Of course after I installed the inverters I immediately turned the phase dial to the subwoofer back to zero. Something was always off, I mean I'm crawling around the floor listening to bass etc trying to figure out what's going on and whether I need to move the subwoofer or change the distance between the towers and toe etc.Phew, just couldn't figure it out before. 

Expecting room treatment acoustic panels to arrive within a week. I hope for lots improvements soon. 

To note the Onkyo's room correction or ACCUEQ doesn't have phase adjustments but only distance, levels, and standing wave room correction. Even if it did I'd prefer to fix the physical issue rather than relying on processing to make the changes. 

[KeithL]

Good choice there...

Rom correction can match the relative phase between speakers...

(It does this by adjusting the delay between channels... which is related to both "distance" and "relative phase"...)

However room correction rarely if ever will ever actually reverse the phase of individual channels...

Mar 18, 2020 20:23:10 GMT -5 @shimei said:

Mar 18, 2020 19:46:30 GMT -5 garbulky said:

So what might have happened is that your speakers may have initially been connected out of phase with each other. Correcting the phase by swtiching the connections on just one speaker should result in the night and day differences you are hearing.
You can test if your speakers are connected in phase by using this handy tool.
www.richardfarrar.com/are-your-speakers-wired-correctly/
(Go to phase test to check it out)

Thank you garbulky. 

Quite sure the speakers were all in phase to one another beforehand. I did not try reversing the polarity from the amp to the towers before installing the inverters. Once I got wind that the XLR pins were of different configuration between the Onkyo and Emotiva I 2nd day aired the inverters. The subwoofer has an amp with a 180 degree phase dial. The thing about that dial and trying to change the phase is that it wasn't as dramatic as expected. Though I could tell a difference if the phase was left at zero [out of phase with the towers powered by the Emotiva] and 180 degrees to align with the towers before the inverters were installed. Of course after I installed the inverters I immediately turned the phase dial to the subwoofer back to zero. Something was always off, I mean I'm crawling around the floor listening to bass etc trying to figure out what's going on and whether I need to move the subwoofer or change the distance between the towers and toe etc.Phew, just couldn't figure it out before. 

Expecting room treatment acoustic panels to arrive within a week. I hope for lots improvements soon. 

To note the Onkyo's room correction or ACCUEQ doesn't have phase adjustments but only distance, levels, and standing wave room correction. Even if it did I'd prefer to fix the physical issue rather than relying on processing to make the changes. 

[Deleted]

Mar 18, 2020 20:33:25 GMT -5 audiosyndrome said:

If you’re hearing a night and day difference something other than the Emotiva XLRs were the problem. I’m supposing this because your first post is totally not understandable. When this “issue” first came to light some time ago I reversed the red and black leads at the terminals of my NHTs. Could not hear any difference. 😎. I think your Tektons are great speakers but with all those drivers the chance of an internal miswiring goes up dramatically. Whatever you did (?) may have fixed such an issue.

Also, David Reich, who is a terrific amplifier designer and technical reviewer, did a fabulous article on fully balanced amps for Secrets of Home Theater. He compares two amps in the article; the ATI 6002 and the Emotiva XPA-1. He classifies the ATI amp as non-inverting, and the Emotiva amp as INVERTING! Hmmm, inverting amp with XLR pins 2 and 3 reversed equates to the amp output IN PHASE! So maybe much ado about nothing???

I read the article several years ago. I have to go back and read it again to ascertain if the Emotiva output is inverted prior to the XLR output. Or I’m confused. 🙄 Likely. 😉

Russ

hometheaterhifi.com/technical/technical-reviews/the-fully-balanced-power-amplifier-advantages-and-design-challenges/

From information gathered only on this board about XLR [and correct if wrong] there are American [1 Ground, 2 Cold, 3 Hot], European [1 Ground, 2 Hot, 3 Cold], and EIA Standard RS-297-A [ pin 2 "hot" and pin 3 "cold"]. 

I imagined if the Emotiva "was" the only amplifier in my system a difference may of been unnoticeable even if I switched the polarity. However, from my Onkyo Pre-Pro I use an RCA out to the subwoofer which is active or self-amplifed. And I use 3 XLR to the Emotiva. The "inversion" I refer is simply the difference in pin configuration between the Onkyo and Emotiva as the actual parts I purchased to place in between the XLR signal outputs and inputs as it is called an "inverter". Obviously, there was a phase issue having the RCA and XLR simultaneously used in the system. Having used the subwoofer phase dial I attempted to "dove tail" the subwoofer to the main towers. There was always a phase alignment issue this way, I say that because I kept losing the front soundstage imaging and at times the lower end would just disappear. The major problem presented was that this was "inconsistent or intermittent" as though at times things were "going out of phase and coming back in".   

The inverters are installed in the LCR XLR cables going to the now powered by Emotiva amp. And I can with utmost confidence say that "whatever issue" existed before does not now exists. Even while viewing a movie last night for near two hours and listening to the dialogue of the center channel was day and night as it is more clear and dialogue isn't "lost" all of a sudden to the point where my wife is asking me every other sentence "what did they say"? I have the center channel crossed over from 150hz and above and I can actually hear the lower frequency of around 150hz now. The dialogue is now "fuller" rather than emptier or tingier as though a phase alignment issue was occuring. What complicates this matter is that that particular issue not only existed in the relationship between the center channel and the LR towers as well as to the sub in the rest of the system as much as it was intermittent. 

I don't believe that I am on par with snake oil sales here [for one I'm not selling the inverters]. There is a clear, obvious, physical alteration by inverting or changing the pin configuration of the XLR which has everything to do with phase alignment. As Keith was kind enough to point out going to great length to explain the Tekton's use a complicated crossover in the MTM array [there are two MTMs between the Towers and Center channel and the Center I'm using is a custom made sonically matched Ulfberht center but one with a 5 tweeter array rather than 15 tweeter array in each tower] and I can't imagine what exactly is going on by either 1) an absolute phase being negative or 2) a mixed phase from either the Fronts, Center, and Subwoofer, that is, in consideration of the phase shifts that may very well exists in the LCR and subwoofer crossover networks. 

Perhaps a lot of time and frustration may of been saved if [and they may already and I missed it] Emotiva were to inform that the amps do not adhere to the EIA standard? I hope for Emotiva's sake that amp reviewers know of this possible issue given the wide range of experience etc between one reviewer to another. I did retract in my OP a tiny fragment which I expressed my frustration in saying I'd go with a competitor's amp. I retracted that because I thought it was tasteless to post on the Emotiva board after having not contacted directly Emotiva support to verify any of the above or work out my problem directly. The problem is now resolved. 

Enjoy,
William 

[repeetavx]

Ok, now we hear the rest of the story.

Crossing over your center channel at 150hz is unusually high compared to most of us.

Yes, everything you described makes sense now. The signal from the center channel had (for practical purposes) nearly half of it's information 180 degrees out of phase from it self.

And the "suck out" of "richness" makes perfect sense because, whatever part of the center sound, below 150 hz, that was also presented by the left and right mains, were 180 degrees out of phase from the center. Which would have a cancelling effect on that part of the signal.