Direct Metal Mastering - aka “DMM” - was the final refinement in vinyl mastering technology issued by Neumann in cooperation with Teldec and Toolex in 1982. In DMM a specially made record lathe (the Neumann VMS-82, using the SX-82/84 cutter head and SAL-82/84 cutting amplifiers) uses a diamond stylus to cut into a layer of copper electro-plated over a steel substrate (instead of the more usual heated sapphire stylus cutting into a layer of lacquer coated on an aluminium substrate). The “metal mothers” can then be directly electro- plated with nickel in order to create a stamper in a single step - meaning there is less potential for resulting surface noise to be introduced during the plating process simply because there are less plating stages. DMM relative to more traditional lacquer mastering also generally results in better high frequency definition and much less pre-echo. Because DMM lathes use the excellent VMS-80 pitch/depth computer, and also due to the greater resistance of copper relative to lacquer, you can generally get higher levels for longer side with DMM. More info on DMM can be read at: https://www.gammaelectronics.xyz/audio_04- 1987_dmm.html https://www.pspatialaudio.com/DMM.htm New developments in 2023: Swiss based engineer and craftsman Florian “Flo” Kaufmann, operating as FloKaSon, is now creating new DMM-spec compatible cutting systems, using FloKaSon’s “Ultracut” amplifiers and their new version of the SX-84 cutter head, mounted either on modified vintage Neumann lathes, custom lathes by Thorsten Scheffner of Organic Music, or FloKaSon AM44 lathes. TZO in Leipzig, Germany is also now offering copper blanks for cutting DMM spec masters for public purchase. The following studios can still do Direct Metal Mastering for your music (list updated October 30, 2023):

Czech Republic

GZ

Germany

Celebrate Records Einstein Cutting Emil Berliner Studios Fonotec MY45 Optimal Media / Sector 5 Pauler Acoustics Railroad Tracks The Entire Sound Spectrum Studio

The Netherlands

24Mastering Record Industry

Poland

Optical Disc Mastering

USA

The Church of Scientology (aka, the Scientologists) have at least two DMM lathes in their mastering studio (which is most likely located in their Golden Era Productions facility in Gilman Hot Springs / San Jacinto, California) - but they do not work on projects other than their own (they transcribe L. Ron Hubbard’s speeches onto disc and place them into time capsules along with hand-cranked turntables. Sometimes truth is stranger than fiction). Europadisk in New York City (based first in Manhattan, and then moving in 2000 to Long Island City) was the last mastering studio in the USA to offer Direct Metal Mastering on a commercial basis - but it ceased operation in 2005, and its lathe and other DMM mastering equipment were sold to the Scientologists at auction.