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Hi John,

This article by Ethan Winer might shed some more light on EQ and phase 
shift.

http://ethanwiner.com/EQPhase.html


Rgds
Tim.


----- Original Message ----- 
From: "John Haley" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 16, 2018 10:46 AM
Subject: Re: [ARSCLIST] Variable Reluctance Stereo Cartridges was "High Def 
vinyl?"


> Doing the phone EQ with digital de-emphasis does cause phase shifts.  To
> get it right with certainty, you need to do the phono EQ de-emphasis in 
> the
> analog domain, which is generally done upon playback of the record, before
> digitizing.  Gary Galo gave a detailed lecture about this topic a couple 
> of
> years ago at the ARSC convention in Pittsburgh.  Doing it analog exactly
> matches what was done when it was "encoded" (when the emphasis was added 
> to
> the recording).
>
> How much audible difference it makes, I think, depends somewhat on the
> source itself.  But if you do it analog, you know you have it right.
>
> Best,
> John
>
>
>
>
> On Sun, Apr 15, 2018 at 10:39 PM, Tim Gillett 
> <[log in to unmask]>
> wrote:
>
>> Hi John,
>>
>> Doesnt analog EQ, by definition,  shift phase? Or are you saying digital
>> EQ doesnt shift phase?
>>
>> Rgds
>> Tim Gillett
>>
>>
>> ----- Original Message ----- From: "John Haley" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Monday, April 16, 2018 10:28 AM
>> Subject: Re: [ARSCLIST] Variable Reluctance Stereo Cartridges was "High
>> Def vinyl?"
>>
>>
>> Yes, Paul, but after resampling it to get it to the correct speed, you 
>> have
>>> abandoned the analog world which is the best place to apply the 
>>> phono-EQ's
>>> de-emphasis without phase shifting--i.e., it is best to apply the right
>>> curve during analog playback, before digitizing.
>>>
>>> Best,
>>> John
>>>
>>>
>>> On Sun, Apr 15, 2018 at 9:51 PM, Paul Stamler <[log in to unmask]> wrote:
>>>
>>> On 4/15/2018 4:02 PM, John Haley wrote:
>>>>
>>>> Mickey,
>>>>>
>>>>> There is a real issue with dubbing 78's (or any other recording) at a
>>>>> speed
>>>>> other than what it was intended to be played back at.  You are
>>>>> drastically
>>>>> changing the frequencies of the recording when you play it at the 
>>>>> wrong
>>>>> speed, which will totally screw up the intended phono-EQ decoding, 
>>>>> which
>>>>> is
>>>>> keyed into the original frequencies.
>>>>>
>>>>>
>>>> [much more good stuff snipped]
>>>>
>>>> If you dub the disc using a flat preamp with no EQ at 33.33 rpm, you 
>>>> can
>>>> then resample it to an equivalent speed of 78.26, 76.6 or 80 rpm as
>>>> needed.
>>>> (Audition does his well.) Once it's at the right equivalent speed, you
>>>> can
>>>> add de-emphasis at the appropriate frequencies. This offers, for
>>>> example, a
>>>> way to get the good tracking of a Grado 78 cartridge, while minimizing
>>>> the
>>>> infamous "Grado wobble" -- there will be fewer things to excite it at
>>>> 33.33
>>>> rpm than at 78 rpm (or a similarly high speed).
>>>>
>>>> Peace,
>>>> Paul
>>>>
>>>> ---
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>>>>
>>>>