Half-Speed Mastering: What, and Why?

I've searched the web and found no explanation as to what "half-speed mastering" is, or why it's desirable. I did find out, however, that ELO's Discovery was half-speed mastered at source.

I'm confused. Does it mean they play the tape at half-speed? If so, how does that help?

Thanks in advance.

Rob

 

Stan Ricker is the man most closely associated with half speed vinyl mastering. He still cuts records that way.

Here's the link to his website--it may answer some of your questions:
http://rickermaster.com

Mobile Fidelity has some info:
http://www.mofi.com/productcart/pc/viewcontent.asp?idpage=9

Basically, the analog or digital source is played back at half speed--the cutting lathe is also run at half speed while cutting the lacquer. When you play the resulting lacquer back at regular speed, everything sounds at the original speed and pitch.

 

Thank you!

 

A lot of the Mobile Fidelity "Original Master Recordings (OMR)" LP's, use to come with sheets that described the process in great depth and detail.

There are still many professionals who will still argue that "Half Speed Mastering", was/is nothing more than a marketing gimmick, much like the Gold as opposed to Aluminum CD theory. It still comes down to the mastering. A poorly mastered album is still going to sound bad, Half Speed, or no Half Speed.

 

Half-speed mastering is a two-edged sword. One one edge, for a response of 20-20,000, the cutterhead only has to go up to 10,000, so if there are any nonlinearities in the upper range, they will be greatly reduced. Plus, if you were going to, say, 30,000 Hz (and you can, with both analog masters and vinyl) you'll have that much more "breathing room" up there.

On the other edge of the sword, and this is a pretty sharp edge, you have to apply only half the RIAA curve when cutting the lacquer, and that's not always easy to do. Plus, now your response for 20-20K has to go down to 10 Hz. And to make things even more fun, the response of playback heads is slightly different at 15 IPS than at 30 IPS. That's why, generally, you'll find 15 IPS machines set to NAB, and 30 IPS machines running IEC.

Half-speed, when done well, is very good. It's just not easy, and my kudos to those that can pull it off.

 

Weren't the Beatles MFSL vinyls half speed masters?

 

JBStephens is 100% right. I would add that half-speed mastering was invented for RCA's CD4 Quadradisc LP pressings in the early 1970s, when they had to figure out a way to get the 30kHz subcarrier frequency into the grooves. By reducing the cutting speed in half, they could easily get 15kHz in there with no problem.

Somebody discovered that there were advantages to making regular stereo LPs this way, too, but as Mr. Stephens says above, this affected the RIAA curve, NAB tape playback EQ and a bunch of other stuff. I remember at the RCA cutting room I used a few times on Sunset Blvd. in the late 1970s (across from the Ceramic Dome), they had some black boxes that they would plug in-line when they needed to do half-speed mastering, plus some charts and notes on a bulletin board above the Studer A80s they used for playback. The stuff I was doing was always straight-across, no fuss, and we never went more than 20 minutes a side, so it was fairly straightforward.

 

Yes.

 

So, the two CD4 Lp's I own are half speed cut? That I wouldn't have known. Not that I ever played them on any quad equipment. I never purchased the stylus required. I do, however, have a Sansui Quad decoder unit.

I wonder if it would be a value-add to hook things up?

I am glad to have read the great responses on this topic.

 

I was a huge fan of 1/2 speed mastering back in the 70's. I even took a few projects into the JVC cutting center to be mastered with Stan Ricker.

IMO there were tremendous advantages to using the process, in that transient response and freedom from high frequency distress were greatly improved.

The problems with the process are the same ones mentioned in this thread. All the equalizion had to be done trial and error in that you couldn't monitor in real time. For records that didn't need much help I never thought this was a big deal.

Steve and others have noted that the tonality seems to change when using 1/2 speed mastering. This may be, but when I was involved it was not my prime concern. After all, slight differences in tonality seemed like a small price to pay for the other benefits. To me, this was much like making backwards tape copies, which generally yielded better copies than straight copies. The reasons for this are similar.

My goal was to make the best sounding record possible. That it didn't sound exactly like the master tape was not as important to me at the time as was making what I thought was a better transfer. After all, who really got to hear the master tapes?

 

I have a question. I have what must be one of the earliest digital recording commercially released on vinyl. It is Odyssey Y33200, Jean-Pierre Rampal, Telemann: Twelve Fantasies For Flute. On the cover and on the LP label itself is a little logo:

PCM Recording, MS Master Sonic, Non-Distortion Cutting, Half Speed Cutting. This was cut by Nippon Columbia according to the back of the album cover.

It looks like this was a 14-bit PCM digital recording (claims a 75dB dynamic range with flat response from zero to 20kHz), copyright 1973 Nippon Columbia (released in 1975 in the USA on the Odyssey budget classical music label -- i.e. Columbia Records)

Admittedly I haven't studied into this. Did Nippon Columbia do a lot of other stereo (i.e. not four channel) cutting on vinyl in the early 70s?

I had forgotten that this claimed to be half speed mastered until I pulled it out a few weeks ago. I could just buy the CD, but I'm experimenting with needledrops, and I just happened to pull this one out.

 

Interesting thread. My knowledge of half-speed mastering was just from what I've read on my MOFI inserts. It's cool to hear about it from industry insiders and people who are in the know. Cool beans, man.

 

What are some of the best or worst sounding Half-Speed mastered LP's?

Pat

 

Good - Mobile Fidelity, Frank Sinatra & Sextet, live in Paris, June 1962. That one can leave me in tears.

Not so good - CBS Master Sound, Charlie Daniels band, Million Mile Reflections. They didn't get the equalization quite right, and this thing has a high end that could circumsize a gnat.

 

I have MoFi vinyl half-speed masters of the White Album, Aja and Days of Future Past. I espically like DOFP. The roaring gong that starts the first song begins from dead silance and slowly builds up to huge sound. Great fun!

 

Interesting stuff Doug, the EQ part especially. If I undertand you correctly, one would have to "1/2" the EQ frequencies of interest, not really getting to hear the effects until playing back the lacquer after it was cut?

 

This is the response curve that actually gets cut into the groove. You can see that response is fairly even over only a short distance around 1,000 Hz. So for half-speed cutting, that entire curve has to be shifted down one octave, the "knee" at 500 Hz has to be lowered to 250 Hz, which when played back at normal speed would be shifted back up to 500 Hz. Which is just a matter of changing a couple of component values in the cutting amp. But, as was pointed out, you really can't hear what effect the changes will have on the finished product until you play it. Theory is one thing, listening is another.

 

All I know is that LP by LP, as my system improved and I A/B'd my old audiophile 1/2 speed cut LPs against a good original w/ the 'right' matrix - the 1/2 speeds didn't come off anywhere near as good as I ...uuhh...remembered them in the 70's & 80's.

Quiet surfaces yes - mastering and/or tone? Not so great. A real ear opening experience.

 

I'm still amazed they can put sound on a piece of plastic

 

Or as been said: 'whodda thunk that a rock being dragged through plastic could sound so good?'

 

I have a half-speed MFSL LP of 'Seven & the Ragged Tiger' by Duran Duran which is still sealed. I'm wondering if anybody has any opinions of this particular disc (content aside, ahem) and whether it would be worth needle-dropping.

 

I'm not a fan of either of the first two MFSLs you just mentioned. More for the EQ choices, however, rather than any bias I have against half-speed mastering. Ricker's job on Green Day's American Idiot yielded great results.

 

I think he cuts at 2/3 speed now to get benefits of slower cut without the drawbacks.