New Gold Dream (81,82,83,84)
1. What is ‘Half-Speed Mastering’?
This is an elaborate process whereby the source is played back at half its normal speed
and the turntable on the disc cutting lathe is running at 16 2/3 R.P.M. Because both the
source and the cut were running at half their "normal" speeds everything plays back at the
right speed when the record is played at home.
2. What are the advantages of Half-Speed Mastering?
The vinyl L.P. is an analogue sound carrier. Therefore the size and shape of the groove
carrying the music is directly related to whatever the music is doing at any particular point.
By reducing the speed by a factor of two the recording stylus has twice as long to carve the
intricate groove into the master lacquer. Also, any difficult to cut high-frequency information
becomes fairly easy to cut mid-range. The result is a record that is capable of extremely clean
and un-forced high-frequency response as well as a detailed and solid stereo image.
3. Are there any disadvantages?
Only two, having to listen to music at half-speed for hour after hour can be a little
difficult at least until I get to hear back the resulting cut when it all becomes worthwhile.
The other dis-advantage is an inability to do any de-essing. De-essing is a form of processing
the signal whereby the “sss” and “t” sounds from the vocalist are controlled in order to avoid
sibilance and distortion on playback. None of the tools I would ordinarily employ on a real-time
cut work at half speed as the frequencies are wrong so the offending “sss” does not trigger the
limiter and everything is moving so slowly there is no acceleration as such for the de-esser to
look out for. This has always been the Achilles heel of half-speed cutting until now (see 6 below).
4. What was the source for this record?
This album was cut from a high-resolution digital transfer from the original ½" analogue
masters. The tapes were re-played on an Ampex ATR-102 fitted with custom extended bass response
playback heads. Only minimal sympathetic equalisation was applied to the transfer to keep everything
as pure as possible. Also, as this was an analogue, vinyl only high quality release, I did not apply
any digital limiting. This is added to almost all digital releases to make them appear to be loud
and is responsible for “the loudness war” and in almost every case is anything but natural and pure
5. Why could it not be cut ‘all analogue’?
The biggest variable when cutting from tape is the replay machine. Every individual roller in the
tape's path will have a direct effect on the quality of the audio emanating from the machine. In
addition to this, there is the issue of the sub 30Hz low-frequency roll off on an advance head
disc-cutting tape machine which in effect will come into play at 60 Hz when running at half speed.
In addition to this, there are also some unpredictable frequency anomalies in the 35-38 Hz region
with analogue tape that will double up at half speed. These are all problems if you want to hear
as originally intended the lowest register of the bass end on a recording. There is also the lesser
potential problem of tape weave that effectively increases at lower speeds and leads to less high
frequency stability and the possibility of minor azimuth errors. Even if these problems could be
overcome, this is quite a long album and the masters were recorded on ½" tape running at 30
inches per second. The master reels are 14" in diameter and are just too big to fit onto a Studer
A80 advance head replay machine. Neither Studer nor anyone else made a machine that could be used
to play 14" reels and have an advance head for all analogue disc cutting. Even when this album
was originally cut in 1982 it was played on an Ampex ATR-102 feeding into a digital delay. The
advantage I have now is that digital converters are greatly improved over what was available 34
years ago. Finally, analogue tape becomes degraded with each pass over the replay heads. These
tapes are getting old and it is no longer considered good practice to play and play and play
precious old original masters for fear of damage and general wear and tear. Far better, then,
to eliminate the variable of the reply machine and to minimise wear of the master by capturing
the music digitally at very high resolution using professional converters locked down with stable
external word-clocks. I can completely understand the reasons for the concerns that some people
have when cutting classic albums from digital sources. Historically, there have been some horrible
digital transfers used as a vinyl cutting source. This has absolutely not been the case with this
series. Micro-management of the audio and attention to detail has been the order of the day. Abbey
Road has striven to eliminate any digital weaknesses from the signal path in all the rooms in the
building. Therefore to capture to high resolution digital from a well maintained Ampex ATR-102 with
extended bass heads is a far superior working method in my opinion.
6. Are there any advantages to this working method?
Yes, any problems with the tape can be treated far more accurately digitally than they could be by
using traditional analogue techniques. For example de-essing. I can, by careful editing, target
just the offending “sss” and leave intact the rest of the audio. Therefore high-hats, bright guitars
and snare drums are not affected or reduced in impact. Using an analogue scatter-gun de-esser approach
would also trigger the limiter in many parts of the audio that do not need to be worked on. The
de-esser cannot tell a bright guitar from bright vocal and will smooth everything out leading to dull
guitars or soft snare drums and weak hi-hats. Targeting the “sss” sounds in the vocal as I have done
in this series is time consuming but is worthwhile in the pursuit of the very best possible sounding
record. Also if there was any damage to the analogue tape (drop-outs and clicks for example) this
can by and large be restored using modern digital methods in a way that is unobtrusive and this would
be impossible using analogue methods. For the record, none of the albums in this series have been
de-noised. Only clicks have been removed and drop-outs repaired where possible.
Miles Showell - Mastering Engineer