True enough, Tom, running at half speed does throw the Dolby off, but
there were half speed Dolby modules available for this purpose.
On 12/03/2015 12:49, Tom Fine wrote:
> I do think they pioneered this, going back to SONAR training equipment
> in WWII.
> Speaking of half-speed cutting, I have never understood how this is
> pulled off in a modern context, especially with Dolby-encoded master
> tapes. I guess it's possible to make the NAB or CCIR tape EQ
> de-emphasis work at half-speed, and the RIAA emphasis at the lathe,
> but doesn't Dolby get screwed up when frequency bands are lowered?
> Today, I think one can listen to recent LP cuts by Bernie Grundman or
> Ryan Smith or Sean Magee and hear that there's no need for half-speed
> if the cutting engineer and his cutting chain are top-notch. I've
> heard arguments about fitting more bass energy on a disk at
> half-speed, but again I can't understand how that's true since the
> disk will be played back at full-speed and hence won't track on
> normal-priced systems if the grooves are too wide and deep.
> -- Tom Fine
> ----- Original Message ----- From: "Carl Pultz" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, March 12, 2015 8:18 AM
> Subject: Re: [ARSCLIST] Decca FFRR "backwards" disk-cutting -- likely
> a MYTH
>> Decca did do some half-speed cutting - am I remembering that right?
>> -----Original Message-----
>> From: Association for Recorded Sound Discussion List
>> [mailto:[log in to unmask]] On Behalf Of Tom Fine
>> Sent: Thursday, March 12, 2015 7:57 AM
>> To: [log in to unmask]
>> Subject: [ARSCLIST] Decca FFRR "backwards" disk-cutting -- likely a MYTH
>> I asked the folks at Decca Classics, including the guys who just put
>> together the excellent new "Mono Years 1944-1956" box set. All of
>> them said,
>> in essence, no way. The technical guys said it's not possible to cut
>> 20-minute LP sides this way and there was no reason to do it, given
>> advanced cutting techniques developed during WWII, many of which were
>> over to microgrooves.
>> For 78's, they said again there was no reason to cut a disk backwards
>> they could easily accomodate FFRR cutting forward like everyone else.
>> someone can come up with some documentation saying otherwise, I would
>> this is a MYTH and should be nipped in the bud here.
>> -- Tom Fine