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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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