Automatic Polarity Correction Change Anytime or New Measurement?

whoareyou

Member
Thread Starter
Joined
Dec 23, 2021
Messages
57
My AV System  
Main Amp
Benchmark AHB2
Additional Amp
ATI AT525NC
Computer Audio
JRiver
DAC
Exasound E38
Front Speakers
Psb synchrony one
Center Channel Speaker
PSB synchrony one C
Surround Speakers
Revel m105
Does this need to be configured before taking a measurement, or is the setting passed to the correction filter for generation purposes?
 

whoareyou

Member
Thread Starter
Joined
Dec 23, 2021
Messages
57
My AV System  
Main Amp
Benchmark AHB2
Additional Amp
ATI AT525NC
Computer Audio
JRiver
DAC
Exasound E38
Front Speakers
Psb synchrony one
Center Channel Speaker
PSB synchrony one C
Surround Speakers
Revel m105
Thanks. That's what it seemed like when looking at various simulations. I do have one speaker that is a bit perplexing with regards to polarity that I'm trying to figure out.
It's a center channel and it's on a shelf below the TV, so very bad location and probably causing some of the "weirdness". But what am I seeing with the polarity?
I've checked and double checked all wiring and that is not the issue at least for polarity. I've measured many times, and the results are consistent.

It's a decent speaker (PSB synchrony One Center) with pretty decent response - at least on paper.

All other speakers have "normal" impulse response with proper polarity, so this one is definitely the exception.




CenterlImpulse.jpg
 

juicehifi

Audiolense
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Joined
Feb 5, 2018
Messages
418
It is not uncommon with a tweeter with a negative polarity. For instance, on a flat baffle it is often easier to phase align the tweeter and midrange by running the tweeter in opposite polarity. The thing that puzzles me here is the very strong reflection around the 7 ms mark.
 

whoareyou

Member
Thread Starter
Joined
Dec 23, 2021
Messages
57
My AV System  
Main Amp
Benchmark AHB2
Additional Amp
ATI AT525NC
Computer Audio
JRiver
DAC
Exasound E38
Front Speakers
Psb synchrony one
Center Channel Speaker
PSB synchrony one C
Surround Speakers
Revel m105
It is not uncommon with a tweeter with a negative polarity. For instance, on a flat baffle it is often easier to phase align the tweeter and midrange by running the tweeter in opposite polarity. The thing that puzzles me here is the very strong reflection around the 7 ms mark.
At least there is a potential explanation for the polarity. Should the automatic polarity be disabled in this case?

As far as the "reflection". I was attributing that to the speaker position, but that reflection is very odd looking and I am hoping there is not something wrong with speaker.
It almost looks like the same impulse is somehow played twice by the speaker.

I've always seen something similar when measuring this speaker. Speaker has always been on the same stand in approximately the same position. I never tried moving it to determine if it's something weird related to it's position / stand.

I just remembered that this speaker has a rear port. I am going to try plugging it to see if that could be the reflection's source.
Thanks
 

whoareyou

Member
Thread Starter
Joined
Dec 23, 2021
Messages
57
My AV System  
Main Amp
Benchmark AHB2
Additional Amp
ATI AT525NC
Computer Audio
JRiver
DAC
Exasound E38
Front Speakers
Psb synchrony one
Center Channel Speaker
PSB synchrony one C
Surround Speakers
Revel m105
Took another look at all of my measurements and discovered that my LF and RF speakers also have similar, but (much) less pronounced reflections and actually look similar to center channel. I just never paid attention to it since it did not look that bad. I corrected those speakers by better positioning existing room treatment at one of the reflection points. The measurements for those two speakers now look much better.

Based on results with those two speakers, I'd say the center channel's measurements is some kind of more pronounced early reflection issue with my room. Hopefully a bit more room treatment will resolve the center channel issue as easily as LF and RF speakers.

Thanks!
 

whoareyou

Member
Thread Starter
Joined
Dec 23, 2021
Messages
57
My AV System  
Main Amp
Benchmark AHB2
Additional Amp
ATI AT525NC
Computer Audio
JRiver
DAC
Exasound E38
Front Speakers
Psb synchrony one
Center Channel Speaker
PSB synchrony one C
Surround Speakers
Revel m105
It is not uncommon with a tweeter with a negative polarity. For instance, on a flat baffle it is often easier to phase align the tweeter and midrange by running the tweeter in opposite polarity. The thing that puzzles me here is the very strong reflection around the 7 ms mark.
Maybe this should be obvious, but to me it is a bit confusing....

In my case wiring is correct, and the measurement seems to be accurate so is negative peak the correct timing reference?

Per help file:
"When the automatic polarity correction is disabled, Audiolense will work on the premises that all speakers and drivers are connected with correct polarity and will use the first positive spike for timing reference."

So, should I be disabling the automatic polarity correction and force it to use first positive spike?

BTW - The attached impulse for center speaker is new measurement after adding some treatment on ceiling.
The treatment seems to have eliminated that reflection at 7ms mark (that image is attached several posts up in the thread).

Thanks
 

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2234rew

Member
Joined
Nov 24, 2020
Messages
228
I've disabled it and been happy with results.

I had some strange results with it enabled.
 
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