reverse polarity use.

rmurray · « **on:** 28 Jun 2015, 11:03 pm »

I was wondering how much use does the reverse polarity feature get by users of BP25 /26 preamps. I like the feature and have occasionally heard an improved soundstage on some records. This is rare but I feel the feature is a good thing to have . It is something I wish was on the BP17 as well. Thanks for any opinions....

rmurray · « **Reply #1 on:** 29 Jun 2015, 01:30 am »

Ok , I guess no one has an idea or understanding of this feature . Perhaps James can better comment on it's purpose . I think Elizabeth once mentioned she plays most things in reverse polarity mode....

Tympani · « **Reply #2 on:** 29 Jun 2015, 02:58 pm »

Quote from: rmurray on 28 Jun 2015, 11:03 pm

I like the feature and have occasionally heard an improved soundstage on some records.

You have hereby stated the purpose. Some folks, some recordings, some systems, allow music to sound better in a "reversed" polarity. There is massive discussion and debate on this subject, including die-hard believers and nay-sayers. Regardless of one's position, the inclusion of a (well-executed) switch allows the listener to see for themselves the impact.

Personally, I feel it is critical to my enjoyment of my tunes, and almost always I find a reproducible "correct" position for a given album (or sometimes a specific track). You have declared yourself as someone who can hear the difference, at least in some tracks. A bit more testing and listening may allow you to hear the "better" polarity more consistently. Or not.

Certainly don't want to re-start a debate here, only to respond the question. A quick search on any audio forum regarding "Absolute Polarity" will introduce you to the concept, phenomenon, and certainly the often contentious tone of the debate.

rmurray · « **Reply #3 on:** 30 Jun 2015, 02:27 am »

The fact that Bryston has offered this on at least the bp25 and 26 must have some merit. I certainly like having the option to experiment with. Yes, what you said about even individual tracks on the same album vary in their polarities . My perception of any difference seems to be a sense of a slightly greater presence in overall sound stage, perhaps a bit more forward . Thanks for your opinion

James Tanner · « **Reply #4 on:** 30 Jun 2015, 03:46 pm »

Hi Folks,

Depending on whether the totality of your components 'invert phase' or not will determine if your in or out of absolute phase.

Typically you will hear it on transients. It is subtle at best.

If you want to maintain 'absolute phase' throughout your system then you have to know which components retain 'positive signal in' and 'positive signal out'. All Bryston components maintain absolute phase from input to output. The problem is that some components are designed with absolute phase in mind and some are not. So the chances are about 50-50 that one of your components or your software (CD DVD) etc. is not maintaining positive phase throughout the signal chain. With multi-mic recordings this is a tough thing to predict because specific instruments depending on the mic used and the signal chain can be different from another instrument in the same mix.

But hey here is another issue - the speakers themselves may not have all the drivers in phase with each other. It is very common to see the woofer moving forward when fed a positive signal and the tweeter or mid moving back.

james

Marius · « **Reply #5 on:** 30 Jun 2015, 04:32 pm »

Hi James,

Thank you for this.
I must say I've never used it, because after trying and failing to hear a substantial change in sound, I've never remembered it as an option.
Whenever the sound of a recording is below par, and we all know there are far to many of those, I've just accepted it as a 'bad' recording. Being represented as good as it gets, in my 'neutral' Bryston/Quad setup.

I will give the polarity switch a push with the next, and see if it helps.

Would you say that with all those variables in the system, flipping the switch is just as effective as not flipping it...: What im trying to ask is: flipping the polarity also flips the correct ones? Or is that not the way it works

Sorry if this sound stupid, just trying to understand

Marius

I.Greyhound Fan · « **Reply #6 on:** 30 Jun 2015, 04:47 pm »

A phase invert switch is very important for gear with XLR. European and Japanese gear have a different pin layout than U.S.gear. This puts the music out of phase and dynamics suffer. For example, I have a BAT preamp and a Luxman DAC. The Luxman has its polarity reversed and bass is noticeably flat. Both the Luxman and BAT has a phase invert button. When I invert the Luxman to the U.S. standard, bass is noticeably deeper and more powerful and the music is more dynamic. It is not subtle.

James Tanner · « **Reply #7 on:** 30 Jun 2015, 04:59 pm »

Quote from: Marius on 30 Jun 2015, 04:32 pm

Hi James,

Thank you for this.
I must say I've never used it, because after trying and failing to hear a substantial change in sound, I've never remembered it as an option.
Whenever the sound of a recording is below par, and we all know there are far to many of those, I've just accepted it as a 'bad' recording. Being represented as good as it gets, in my 'neutral' Bryston/Quad setup.

I will give the polarity switch a push with the next, and see if it helps.

Would you say that with all those variables in the system, flipping the switch is just as effective as not flipping it...: What im trying to ask is: flipping the polarity also flips the correct ones? Or is that not the way it works

Sorry if this sound stupid, just trying to understand
Marius

Hi Marius,

Its is sometimes a 50/50 option because absolute phase assumes that the recorded instrument is recorded in a specific manner.

So lets say we have a drummer in the studio and he hits the bass drum - that sends out a positive wave front (pressure wave) to the microphone - then the mic diaphragm moves inwards and based on its amplifier section outputs hopefully a positive pressure wave. This happens all the way back to the drivers in the speaker which then move OUTWARDS and create that same pressure wave in the listening area.

Now if any of the electronics in the chain in the studio or at home invert that phase you do not have an exact replica of that pressure wave. To further complicate things in multi-channel stereo recordings the number and types of mics used may in fact not allow all the instruments being recorded to be in absolute phase relative to one another.

So you can be listening to a recording where the drum is in absolute phase and the horn is not.

james

Marius · « **Reply #8 on:** 30 Jun 2015, 05:56 pm »

HI James,

Somehow I had a premonition it would boil down to us drummers being the bad guys:-)

Check why: https://www.facebook.com/DrumTalkTV/videos/862374147174584/

Seriously, is it a question of the final step between the amp and the speakers to flip, or are all actors, from Drummer-to-Tweeter-chain possible spoils. And is flipping the polarity switch more of a gamble than anything else. A gamble worth trying of course, but still.

Thanks for your clear explanation, much appreciated.

Cheers,

Marius

firing up Deeper Well for some Kickdrum in Phase

Quote from: James Tanner on 30 Jun 2015, 04:59 pm

Hi Marius,

Its is sometimes a 50/50 option because absolute phase assumes that the recorded instrument is recorded in a specific manner.

So lets say we have a drummer in the studio and he hits the bass drum - that sends out a positive wave front (pressure wave) to the microphone - then the mic diaphragm moves inwards and based on its amplifier section outputs hopefully a positive pressure wave. This happens all the way back to the drivers in the speaker which then move OUTWARDS and create that same pressure wave in the listening area.

Now if any of the electronics in the chain in the studio or at home invert that phase you do not have an exact replica of that pressure wave. To further complicate things in multi-channel stereo recordings the number and types of mics used may in fact not allow all the instruments being recorded to be in absolute phase relative to one another.

So you can be listening to a recording where the drum is in absolute phase and the horn is not.

james

rmurray · « **Reply #9 on:** 30 Jun 2015, 06:45 pm »

Now that's the discussion I hoped for. I run all XLR connections so perhaps that's the reason I seem to get fuller sound (on some recordings of course) Mostly there's no difference but their is something happening on those rare occasions. Thanks again for your thoughts on this....

spinner · « **Reply #10 on:** 3 Jul 2015, 02:11 am »

For me , the phase reverse has been a handy option on several albums. I am glad that it is there and hope that Bryston will keep it on any future top end preamps.

Tympani · « **Reply #11 on:** 3 Jul 2015, 01:58 pm »

I agree it is critical to getting best sound in a polarity-sensitive system.

And I am hoping it's available on the BDA-3, for those of us who don't have it on our preamps. I've heard from Bryston that it will be, but no details on how it will be implemented (by remote control?)

Marius · « **Reply #12 on:** 3 Jul 2015, 02:09 pm »

Hi,

Would it be a useful idea whenever one finds a recording with alleged reversed polarity, we'd post about it here? So fellow-AC's can take advantage and users can discuss/dispute the polarity-issues involved?

Cheers,
Marius

rmurray · « **Reply #13 on:** 3 Jul 2015, 11:26 pm »

Yes, a great ides IMO..........

Tympani · « **Reply #14 on:** 4 Jul 2015, 07:58 pm »

"Reversed Polarity" occurs in about 50% of recordings. It's not an error thing. If you can't hear it, I envy you (not really, but life is easier). If you can, its usually important and critical to music enjowment.

For a bit of reading (and a list) check this out.

http://ultrabitplatinum.com/how-to-play-most-if-not-all-digital-media-in-absolute-polarity/

I've found that music labels are not always consistent. Your ears are the best tool (aided by a phase-coherent setup, a well-implemented easy way to switch polarity, and an open mind.)

Hopefully we can keep it all civil, without a flame-out

spinner · « **Reply #15 on:** 4 Jul 2015, 10:07 pm »

Thanks that's an terrific article and list......no need for flames there.