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Test result - Edison test record is A440 when played at 80rpm - Mickey




----- Original Message ----- 
From: "Richard L. Hess" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, May 06, 2015 11:08 AM
Subject: Re: [ARSCLIST] Playing Edison Diamond discs


> Hi, Pete,
> 
> You are not confused. The audio world has misused the word "phase" when 
> we mean "polarity." I TRY to use the word "polarity" when I mean that,
> as in "flip the polarity of the left channel."
> 
> (a) I don't always succeed and sometimes succumb to the widespread 
> practice of "inverting phase." I apologize for this.
> 
> (b) Not everyone knows the difference and many people use "phase" to 
> mean "polarity."
> 
> I fear we have to live with this confusion for a long time.
> 
> Cheers,
> 
> Richard
> 
> On 2015-05-06 11:51 AM, Pete Tinker wrote:
>> Please forgive this uneducated question.  Much of the discussion on this
>> topic has focused on the "phase" of different transfers.  I'm not a
>> signal processing guy, but to me "phase" involves the frequency of the
>> signal, so changing the phase is a temporal shift in the signal (a
>> lateral shift along the time axis) by a fraction of some wavelength.  At
>> times in this discussion, it seems that the intention of changing the
>> phase is a reversal of the amplitude of the digital signal (mirroring it
>> across the time axis), for which frequency is irrelevant.
>>
>> If I have a stereo signal from a hill 'n' dale source, it seems the
>> preferred next step is to invert the phase of one channel and then
>> combine (add) the two channels prior to any digital noise reduction.
>> What is the meaning of "phase" in this context?
>>
> -- 
> Richard L. Hess                   email: [log in to unmask]
> Aurora, Ontario, Canada                             647 479 2800
> http://www.richardhess.com/tape/contact.htm
> Quality tape transfers -- even from hard-to-play tapes.
>

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