Direct Metal Mastering (DMM) differs from the traditional lacquer-cutting process by cutting the audio signal directly into a copper master disc, which is then electroplated to produce the necessary metal parts for pressing. By reducing the number of plating stages normally associated with lacquer masters, DMM was promoted as offering lower distortion, improved high-frequency response, longer playing times and quieter surfaces. Admirers of DMM pressings often describe them as bright, clean and detailed; detractors tend to find them harsh, grainy or overly clinical.
In 1985, EMI (Australia) built a new three room mastering complex at its Homebush factory, incorporating a DMM suite. At that point, senior mastering engineer Allan Parsons transferred across from Studios 301 to the new complex, along with Clive Lipman (mastering manager) and Bill Ramsay (working towards retirement mastering cassettes). From then until Homebush closed in November 1990, DMM became the main vehicle by which most EMI releases—along with RCA, Polygram and other smaller labels—mastered at Homebush were produced. It became the preference for many local artists, including James Reyne, The Black Sorrows, Tim Finn/Nick Launay, Crowded House and Pseudo Echo.
Installed was a Neumann VMS-82/SAL84 DMM lathe (fitted with Maxicut II) fed from an EMI TG transfer console. Connected to the desk were all the sources, including Studer A80 1/2" and 1/4" tape machines, Sony PCM-1630, Sony DAT, Sony PCM-501, and CD. It was also possible to connect a (Technics SP10) turntable.
The Sony PCM-1630 was connected digitally (SDIF-2) to a Sony digital delay unit, which output two pairs of analogue signals - preview and signal. So, the lathe was always fed an analogue input, via an analogue desk. The Studer A80s were "preview" machines - ie they had two replay heads and a system of rollers to create the necessary delayed signal for cutting. The other sources would have to be fed through the Sony digital delay.
Some mastering engineers preferred the use of analogue sources for cutting due to the belief that DMM sounded best from an analogue source, however, digital sources were used where either analogue didn't exist or when a new production master was required, such as a different track sequence or a compilation.
Lacquer cuts (through patching in a VMS-70/VG66) were only made when there were difficulties getting supplies of copper blanks. Copper blanks were manufactured in house by an employee named Carlos from a supply of mirror finish stainless steel blanks, machined to size and copper plated in the Homebush matrix department. This particular form of amorphous copper hardened at room temperature and had to be stored in a freezer prior to use. Even so, they had to be used within a few days. Once cut, they had to be chemically treated within an hour to prevent tarnishing. The blanks could be stripped of copper and reused many times, similar to the glass master used for CDs and DVDs. This was the principal reason for splitting 301's mastering department - the DMM lathe had to be adjacent to matrix.
For EMI (Australia)'s DMM masters, there were several departures from the DMM specifications. Most notably, a basic groove width of 50 microns was used—the same as for lacquer cuts—rather than the 40 microns specified for DMM. This was done to minimise groove-jumping on the relatively modest consumer playback equipment then common in Australia. That variation, together with uncertainty as to whether the discs would consistently meet full DMM specifications, contributed to EMI (Australia) not purchasing a (Teldec) DMM licence. As a result, the Australian releases do not carry the DMM trademark on their packaging.
In 1986, EMI UK digitally remastered The Beatles' UK catalogue for release on CD and, subsequently, vinyl. In the process, the catalogue was standardised worldwide, establishing the now-familiar canon: the twelve original UK studio LPs, together with the US album version of Magical Mystery Tour. The remaining Beatles recordings not included on those original studio albums were gathered together on the two-volume Past Masters compilation.
For the local vinyl editions, EMI (Australia) mastered the albums from commercial CDs supplied by EMI UK. The Australian masters were cut at Homebush by Paul Bryant (up to and including Rubber Soul, plus Magical Mystery Tour and Past Masters) and Allan Parsons (Revolver to Let It Be). The work was undertaken over the weekend of 12/13 November 1988. Paul recalls: "The reason for the 'out of hours' cutting was that we had a deadline and were not allowed overtime. We both felt that something this significant had to be done properly and respectfully and not crammed into our busy schedule to meet a release date - many of which were often ridiculously unrealistic."
Australian-cut Beatles vinyl remained in production until late 1990. From that point, the canon albums were imported from the UK, and all locally manufactured Beatles records were deleted. The DMM lathe was sent to South Africa in 1992 before ending up back at Abbey Road Studios in 2015, where it was restored (to lacquer cutting) and, perhaps fittingly, used in February 2017 to master the Sgt. Pepper's Loney Hearts Club Band 50th Anniversary Edition - see image below (source article here).
