Phasing/soundtage anomaly

[Puffin]

I use two sets of speakers running in parallel. If I wire them all in phase the sound is fine and bass is solid and coherent. If I wire one pair out of phase with the other, I seem to get a much better insight into the recording and a lot more detail. However on some tracks the bass is ill defined and doesn't sound right, on others it appears to go much deeper and is perfectly ok?

[poldus]

When I invert the polarity on only one of the subwoofers I get the exact same result that you describe, and yes, only on some recordings (seems to sound better on some, not all, orchestral material)
I decided to install a switch to select correct/inverse polarity on one sub so I can enjoy the better sound on those recordings.
I would like to know what is causing this perceived improvement. As a subjective perception, though, even the experts will have a difficult task in pointing to a cause, I guess.

[DF96]

Out of phase speakers will reduce bass. This may be misinterpreted as an increase in treble, which may sound like more 'detail'. The effect on different tracks might arise from stereo bass phase effects, or how much true bass is really there (as opposed to synthetic bass generated from the presence of bass harmonics with the fundamental missing).

[Puffin]

I have always struggled to like the production on the Massive Attack - Protection CD. The title track has a repetitive bass line that has always (on any system I have had) sounded boomy. I listened to this CD today, and it was a revelation. I have never heard the bass sound so tuneful and "right". In the same way I listened to Teardrop - Massive Attack and heard a bass line (almost subliminal) that I had never heard before. The whole track sounded fantastic.

DF96, you say that out of phase speakers will reduce bass. Is this only where they are being used in conjunction with "in-phase" speakers or as a general rule?

I have not experienced a reduction in the amount of bass, but a refinement and greater depth. I am having a great time it's good to fiddle

[Face]

http://www.polkaudio.com/downloads/t...WhitePaper.pdf

You may find some of this interesting.

Sent from my DROID3 using Tapatalk 2

[DF96]

By 'out of phase' I mean out of phase with another speaker, either in parallel or the other stereo channel. This causes partial cancellation of bass. The cancellation is less effective at higher frequencies. It will normally destroy the stereo image, if the recording had a proper stereo image. If it is just pan-potted multichannel then it might do less harm.

[dewardh]

Originally Posted by Puffin

I use two sets of speakers running in parallel.

By two "sets" of speakers do you mean different 'kinds" of speakers "paired up"? Because if that's what you've got it is entirely likely that they have different box and port tuning, and thus phase shift . . . resulting in a different pattern of cancellation and re-enforcement depending on the relative phase of the connection of the two boxes (this would persist over the whole operating range, but be most obvious in the bass . . . at higher frequencies it would probably just sound "phasey").

[Puffin]

Originally Posted by dewardh

By two "sets" of speakers do you mean different 'kinds" of speakers "paired up"? Because if that's what you've got it is entirely likely that they have different box and port tuning, and thus phase shift . . . resulting in a different pattern of cancellation and re-enforcement depending on the relative phase of the connection of the two boxes (this would persist over the whole operating range, but be most obvious in the bass . . . at higher frequencies it would probably just sound "phasey").

Yes, two different kinds paired up (everyone tells you NOT to do this)
I get a much better image IMO, seems almost 3D, not 2D.

[Puffin]

Originally Posted by Face

http://www.polkaudio.com/downloads/t...WhitePaper.pdf

You may find some of this interesting.

Sent from my DROID3 using Tapatalk 2

Interesting read. Thanks

[dewardh]

Originally Posted by Puffin

Yes, two different kinds paired up (everyone tells you NOT to do this)
I get a much better image IMO, seems almost 3D, not 2D.

This may be one of those rare cases where "everyone" is right . . . and where what you are calling "a much better image" is likely what users of the old Shure test record came to know as "a diffuse and directionless quality" . . .