Re: [ARSCLIST] Absolute Polarity

[Jerry Hartke <jhartke@xxxxxxxxxxxx>]

Harmonic content, phase shifts, and distortion can cause this. If the area
under the positive excursions is equal to that under the negative
excursions, then there is no d.c. component, as you point out.

Jerry
Media Sciences, Inc.

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:ARSCLIST@xxxxxxx] On Behalf Of Richard L. Hess
> Sent: Saturday, October 18, 2008 6:02 PM
> To: ARSCLIST@xxxxxxxxxxxxxxxx
> Subject: [ARSCLIST] Absolute Polarity
> 
> While we have Clark Johnsen's attention here, I do have a question.
> 
> When we look at audio waveforms, we often see that the peak
> amplitudes are assymetrical while, obviously the total power on each
> side of "0" is the same (or there would be a DC offset).
> 
> In order to visualize the waveform, think of clock or watch hands
> that are balanced, but one side is longer while the other side is
> wider, but shorter. Same mass on each side.
> 
> Clark, are the higher peaks usually the positive peaks?
> 
> Let's say for brass and wind instruments?
> Voice?
> Drums--assuming distant mic placement, not something inside the kick?
> 
> What oddities have you found in this?
> 
> Thanks--that would be helpful in re-setting the absolute polarity in
> transfers of tapes that did not pay any attention to this.
> 
> I do have a copy of "The Wood Effect" and don't think that was
> mentioned in there, but maybe I missed it.
> 
> Cheers,
> 
> Richard
> 
> 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.