On Friday afternoon of last week, I got the opportunity to watch the process of mastering a 12″ vinyl record. And what a fascinating thing it is…
I must start off though with a huge thanks to Danny Ryan of Freestyle Records and Kudos Records who organised the whole thing and also to Pete Norman, Mastering Engineer extraordinaire at Finyl Tweek for taking the time out to share with us his obvious love and huge knowledge of the dying art of vinyl mastering.
The undoubted star of the show is this wonderful piece of kit which is a Georg Neumann Cutting lathe from the 1980′s, and it’s sole function is to transfer the digital music files into something tangible and physical.
The track we were cutting today was an excellent new tune on Freestyle Records by Randa and the Soul Kingdon called The Things, and once Pete had listened to it all the way through to make sure the sound file was OK, that levels were correctly adjusted, and to make any minor tweaks to enhance the sound for vinyl, he placed a 14″ aluminium disc coated in cellulose nitrate (nail polish basically) onto the vacuum suctioned central plate of the lathe.
This disc is called the Master Lacquer and is 2″ wider than required to allow a short test run of the track on the outside inch of the coating. This is then removed at the processing plant to create the familiar 12″ we all know and love.
The cutting element of the lathe has a tip made of corundum, an artificial sapphire which is phenomenally hard (harder than diamonds apparently). Pete told us that the cutting mechanism is heated via an electric charge, and then cooled down with Helium. I didn’t quite catch why both processes were required, but I think the heating helps the cut strand of lacquer form into a single thread (making it easier to collect and remove) and the helium cools the disc once it has been cut, helping to avoid any distortion.
Once the test run had finished, the groove was inspected under the microscope to ensure it looked like it should, and magnified it is an amazing thing to see. It almost seems to wander all over the place, without the consistency it has with the naked eye. (Trivia: the flat bit between the grooves is called land). I have to admit though, despite Pete’s patient explanations, I am still in the dark as to how this trench actually makes music… (its all down to vibrations somehow I think)
The lathe also has its own built in stylus, and Pete showed us how different the same tune can sound by playing the test run on both the lathe and a nearby Technics 1210. Via the lathe (which is a technically “better” piece of kit) the record sounded too clean and bright, whilst on the Technics it had a lovely, warm analogue sound. Once Pete was happy, the lathe was reset, the file restarted and off it went, all in real time, all nice and loud, and all sounding pretty good….
Once finished, the disc was removed from the lathe, put into a box and sent off to the manufacturing plant in France, where it would be be matched up with the master lacquer of the flip side track, and then combined to become a single vinyl 12″ record.
After the mastering process, there are belive it or not, 3 further processes to go through.. a mould is made from the master lacquer, then another mould from that before the final metal stamper is produced from that (the final stamper is effectively a negative of the track of course with ridges rather than grooves). I’m pretty sure coatings of silver nitrate and tin were involved somewhere along the line, but I can’t remember all the details… It occurred to us however, that with all these physical transfer processes, there was potential for a serious loss of sound quality, but Pete reassured us that as long as the groove itself didn’t get damaged, loss of sound quality was negligible.
We also asked Pete about how the old cutting lathes managed to keep going, and he told us that it wasn’t reliability that was the problem (these German made machines are famously durable apparently) it was getting them mended when they did break that was getting difficult. Hardly anyone can fix these wonderful things anymore, and spare parts are also getting more and more expensive to source. (Finyl Tweek’s preferred engineer is actually based in Italy!)
So a really fascinating couple of hours especially for an old school vinyl junkie like me… Interestingly, one of our party was the 17 year old son of a friend of mine and although as a musician himself, he was undoubtably interested in the process as a whole, we could tell that it obviously all seemed rather laboured and arcane; Vinyl records to him were like something out of the Victorian Age, all steam powered and horse drawn…