I don't think very many LPs contained "super-sonic" frequencies, because everyone rolled off at some 
point to avoid blowing out the cutterhead. You are very correct, though, that it's easier to cut 
10kHz than 20kHz at a high level, but what music has high levels of 20kHz in the first place? I just 
don't see any big advantage to half-speed cutting, but I should call up my friend Stan Ricker and 
discuss this in-depth before saying more.

For what it's worth, among the major classical LP labels cutting records in NY in the first decade 
of stereophony, it was typical to low-pass around 15K, meaning there was a decrease in level down to 
about 10K. No one tended to complain that there's not enough treble on Mercury, RCA and Columbia 
albums of the time. If you didn't low-pass, you used something like a Fairchild Conax, which was a 
relatively fast limiter for high-frequency (above 10K) signals. The reason was, it was expensive to 
blow out Westrex cutterheads and they were easily blown out with intense high-frequency information. 
One thing that mystifies me about half-speed cutting is that it came into vogue later on, when most 
people were using Neumann lathes and cutterheads. I thought one of the big advantages of Neumann 
cutterheads was that they pretty much solved the problem of blowing up with intense high-frequency 
information. I know that George Piros, who could cut a LOT of HF into an LP using a Scully/Westrex 
system in the early 60's, said he could cut even more HF and level "if I turn off the computer" 
using his Neumann lathe at Atlantic Records.

A major test of how much HF you could cut with a circa 1958 Westrex cutterhead came with "Persuasive 
Percussion" by Terry Snyder and Enoch Light, the all-time best seller among "Stereo Spectacular" pop 
records. My father told Enoch Light's biographer that he and George blew out "about a dozen" 
cutterheads trying to get acceptable fidelity with the Chinese bells. They finally arrived on a 
compromise that kept the cutterhead from blowing up and ended up with a close approximation of 
Chinese Bells when played back with a good cartridge on a light-tracking turntable of the era (2g 
was very light tracking in those days). It was during that time that my father got Westrex to 
customize his cutterheads, making them mechanically stiffer (less compliant), so he could use much 
less electrical feedback and more net power from his 200W McIntosh amplifiers. George perfected 
cutting right on the edge of coming out with a trackable record and not blowing up too many cutters.

Ironically, now that I wrote that, I think half-speed cutting would have been really beneficial in 
the early stereo days. But not when it was en vogue.

-- Tom Fine

----- Original Message ----- 
From: "Dave Burnham" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, March 12, 2015 2:46 PM
Subject: Re: [ARSCLIST] Decca FFRR "backwards" disk-cutting -- likely a MYTH

>I always thought the advantages of half-speed mastering were in the high frequencies, not the lows; 
>super-sonic frequencies were brought down to sonic frequencies and recorded more easily, but very 
>low frequencies were pushed down into a subsonic range and frequencies in the low teens can be 
>troublesome for tape heads. Also consider that direct to disc recordings are better sounding than 
>any half speed mastered disc and, of course, they can only be recorded at normal speed.
> db
> Sent from my iPhone
>> On Mar 12, 2015, at 8:49 AM, Tom Fine <[log in to unmask]> 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 Decca's
>>> advanced cutting techniques developed during WWII, many of which were ported
>>> over to microgrooves.
>>> For 78's, they said again there was no reason to cut a disk backwards since
>>> they could easily accomodate FFRR cutting forward like everyone else. Unless
>>> someone can come up with some documentation saying otherwise, I would say
>>> this is a MYTH and should be nipped in the bud here.
>>> -- Tom Fine