On Thursday night I was invited to Metropolis Studios in Chiswick where a masterclass in mastering was being given in conjunction with PMC, who were launching their new FACT hi-fi speakers. The event was aimed at journalists, many of them from the hi-fi mags rather than the recording mags, and I was invited along as a journalist - despite being an employee of Metropolis Group, and these days doing most of my work there for the mastering dept.

There were two sections to the masterclass; a look at 5.1 surround mastering with a focus on up-mixing by Mazen Murad, and a display of half-speed vinyl mastering by Miles Showell.

The 5.1 seminar took place in Metropolis’ newest mastering suite, named Dylan after the Magic Roundabout character I’m led to believe. Mazen showed us a variety of projects he’s been working on and the different techniques he has to use when presented with different surround mixes. This was interesting enough, but things got really fascinating when he showed us some up-mixing he’d done. A mono Dusty Springfield mix, that he’d cleaned up and given some spatial treatment to was impressive mostly for how clean he’d managed to get the master. A stereo Elbow track given some surround ambience. At first it all seemed fairly simple, but then he showed us a rock track he’d been working on. It wasn’t the best track in the world, but he’d taken a stereo mix and placed elements throughout the room. It was magic. Beats and noises were flying about, this wasn’t simple ambience in the rear channels, it was voodoo! I figured it must have taken hours to edit it all together, but Mazen assures me it didn’t take all that long and he said I can take a look at the files next time I see him in the studio so I can get a better idea of how he did it. But for now, in my eyes at least, Mazen is a wizard.

The half-speed mastering seminar was equally revealing. Miles and Crispin Murray (my boss and Metropolis’ Technology Development Manager) explained the inspiration behind the idea and the technical reasons why half-speed cutting improves the finished master. Apparently reducing the speed of the lathe and running the audio at half speed reduces the amount of current required and therefore reduces the amount of heat produced, improving the efficiency of the system. It also means that special tricks that the lathe does to audio below 300Hz can now be done to audio below 600Hz and the top end is brought under control because the wavelengths being carved into the acetate are twice as big. There was much discussion of inverse square laws and with the cutting room it all felt like a science lecture, but it wasn’t until I heard the normal speed cut A/B’d with the half-speed cut that I truly believed them. We did the cut using a new Magic Numbers track and I was amazed by how focussed the bass guitar became. The low-end acquires a considerable amount more clarity and definition and the top-end loses any sibilance problems it once had.

As a gift we were each given a 12-inch vinyl containing two tracks by Eleanor McEvoy, which were cut using this half-speed process. But to further ensure the quality of the vinyl, Metropolis had asked the pressing plant to use only a single step pressing process. Normally when a pressing plant receives an acetate they make a negative copy of that acetate, from which a positive “mother” is then created. Multiple stampers are then made from the mother, with each stamper being good for a few thousand copies. However, each of these steps introduces noise, so Metropolis asked that a single stamper be made from the original acetate. This destroys the acetate and creates a single stamper that is only good for 100-150 pressings. But because their are no further steps no further noises are introduced. We listened to this pressing, on the new FACT speakers in Studio A’s lounge, and compared it to the album vinyl pressing and the CD album. The difference was so big that one beardy hi-fi journo asked if the tracks were even from the same mix.

I don’t imagine it’s cheap, especially since Miles is the only mastering engineer in Europe with both the equipment and the know-how to perform a half-speed cut, but if you have the budget, I sincerely suggest getting a quote from Metropolis on half-speed cutting. And if you only need a 100 or so copies then inquire with your pressing plant about single step (often called half-step) pressing.

Mike