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   Home » Playback Listening » The open project: a lateral cross-injection. (26 posts, 2 pages)
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  »  New  Preamplifiers: keys to mystery. (Lamm L1, L2)..  In analog domain...  Audio Discussions  Forum     2  60721  11-14-2004
10-20-2018 Post does not mapped to Knowledge Tree
rowuk


Germany
Posts 438
Joined on 07-05-2012

Post #: 21
Post ID: 25131
Reply to: 19195
Cross Phase or simply head correct?
When listening to stereo, we initially have 4 images to deal with. Th right speaker to the right ear, the right speaker to the left ear, the left speaker to the right ear and the left speaker to the left ear. Broader images can be made when we “cancel” the cross talk. Most of the attempts to do so had such serious problems elsewhere that the experiment could not be considered valid.
We can at least partly “cancel” cross talk. Polk Audio did this acoustically many years ago. Bob Carver made his contribution electrically with “sonic holography”.
I do not know of any real high quality experiments but rereading this thread gives me some ambition to try. The initial L-R and R-L will be created acoustically. The speakers will be located about an ears width from the main speakers and I will play with level. Perhaps there is something to learn here and it is certainly cheap enough.


Whenever I feel blue, I start breathing again.
10-20-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 22
Post ID: 25132
Reply to: 25131
Attempts to Correct Presentation
Robin, there have been many and varied attempts to present a "realistic", "3-D" version of recorded music.  The late Jame Bongiorno adamantly insisted that it could not be done with two channels, and he came up with his Trinaural Processor to "correct" the problems.  This device takes into account just what you mentioned about the R/L/L/R thing, with an algorithm that directs  a "scaled" combination of R & L to a center channel and "scaled" amounts of R to L & L to R.  There isn't much of worth out there about this device, but I cynically suppose anything gained is offset by electronic "issues".  Another "problem" is that original recordings might be... anything, so any given fixed "treatment" might have any sort of final outcome one could imagine, even without other variables.


Paul S
10-20-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 23
Post ID: 25133
Reply to: 25132
The Art of Memory
(with apologies to Giordano Bruno)

OK, had I re-read this entire thread from the top before posting again (above) I would likely not have repeated myself.  However, IMO, this subject is not thought about nearly enough going in, at the recording end, to make for a simple, one-size-fits-all fix.  I'm thinking as I sit here typing that "Sound" and "Presentation" are juxtaposed.


Paul S
10-20-2018 Post does not mapped to Knowledge Tree
rowuk


Germany
Posts 438
Joined on 07-05-2012

Post #: 24
Post ID: 25134
Reply to: 25132
The desired result?
Paul,at least from my moronic standpoint, using a couple of closed boxes with wide band drivers (I have some JBL LE-8T2 without the aluminum domes) in a L-R/R-L connection, should give me the power to widen the stereo basis. Adjustable level could make the amount of widening fine tunable based on the recording. I have pretty much an equilateral triangle between the listening spot and the speakers so I get somewhere around 60° now.

If it works as intended, this could be my injection channel...


Whenever I feel blue, I start breathing again.
10-20-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 25
Post ID: 25135
Reply to: 25134
If It "Works",
then it works!  Of course, nobody really wants a 12' piano keyboard, or 2' bells on the French horns, so (obviously) we want both more and less than rote "widening" of the event.  Likewise with solo performers; we want a "more accurate" recreation of the "venue", and some of this also has to do with "subtle" sound cues that can actually be blurred by combing, etc..


Best regards,
Paul
07-21-2019 Post does not mapped to Knowledge Tree
rowuk


Germany
Posts 438
Joined on 07-05-2012

Post #: 26
Post ID: 25521
Reply to: 19195
The phase trick is actually not that difficult
Hafler, Carver, polk and most professional mastering has a technique that actually came from MS recording techniques. A MS microphone array has a "mono" microphone and a figure 8 bipole microphone above it. The stereo spread is controlled by altering the balance of the "l+r" uniphase channel with the bipolar l-r signal. Changing the proportions in an acoustically well made recording does not "screw things up". It simply changes the balance of l+r to l-r and widens or narrows the soundstage accordingly. In many playbacks, this extends the image far to the left and right of the speakers - without losing the center image or losing bass response. As the hall ambience is random phase, it of course gets the "most" effect.
I Think that the original specification for the Hafler circuit used by Dynaco called for a 7dB lower lever for the l-r/r-l speakers. Dynacos idea of putting the "phasey" speakers behind the listener is pretty smart (if time alignment is adhered to).


Whenever I feel blue, I start breathing again.
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  »  New  Preamplifiers: keys to mystery. (Lamm L1, L2)..  In analog domain...  Audio Discussions  Forum     2  60721  11-14-2004
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