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Re: [ARSCLIST] Absolute Polarity

At 01:41 PM 2008-10-19, Clark Johnsen wrote:
On Sat, Oct 18, 2008 at 6:02 PM, Richard L. Hess

> Clark, are the higher peaks usually the positive peaks?

Hmmm... Well they are if you think of "high" as being above the X-axis. But
sometimes the peak occurs beneath, but greater in amplitude that the top

Please allow me to restate for clarity and so we don't get lost in discussing questions I did not ask. I am well aware of the limitations in studio and distribution practice, but most studios that I was familiar with (mostly in the broadcasting environment) took studio electrical polarity quite seriously. Since at least some of the tapes that I transfer are good-quality 2-mic recordings, the multitrack issues are a non-issue.

The question that I have is if we see a waveform signature where the absolute values of the positive and negative peaks relative to the X-axis are substantially different, which instruments, when properly recorded should have that greater (and usually narrower) peak be positive-going and which should have that peak be negative going. Usually the first attack of the note is what I would look at, not the decay. In other words, dare I say, which instruments "suck" and which don't, in a technical sense (i.e. compression and rarefaction)?

Here is a start of what the useful list might look like with some of my guesses

Piano - compression attack (i.e. positive-going peak)
Saxophone - compression attack
Snare - compression attack
Tympani - rarefaction attack

Are these correct in your experience and what others would you care to share?

As an aside, the lack of a standard for laying down and retrieving an absolute polarity from magnetic tape was something that I personally attempted to address in at least one large project in the 1980s, where I tried to include Dr. Lipschitz's proposed standard in the tape machine procurement spec, but the client rejected it. With the switch to digital, this has become somewhat moot at the system level. I have not checked at the consumer level what is happening with various devices.

Thanks for the interesting discussion.



Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.

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