Dr. AIX's POSTS Vinyl — 20 September 2013

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In a direct to disc recording, the signals from the microphones bypass the analog tape recording stage as we discussed yesterday. The problems with analog tape recording are well known. I’ve outlined them a number of times in articles on this site and others.

According to Robert Harley’s TAS editorial “The Ultimate Format?”, direct-to-disc contends for the top slot in audio fidelity by, “eliminating the tape machines from the signal path, they avoid[ed] the tape format’s sonic degradation as well a tape machine’s electronics. Tape’s shortcomings include speed instability (particularly audible on piano, self-erasure of high-frequencies, a non-linear hysteresis curve, print-through, and myriad other problems.” I know there are a lot of analog tape fans among audiophiles but if you believe Robert Harley, the format has serious flaws.

But the fundamental question is this. Do the imperfections of analog tape degrade the accuracy of an audio recording more than the imperfections of vinyl LPs? By reading the editorial by Mr. Harley, you might think that vinyl comes out ahead. You’d be wrong.

The concept behind direct-to-disc recording is to produce a live session with all members of the ensemble present. There are no overdubs or “fix it in the mix” opportunities with this style of production. In fact, all of the microphones are sent through a mixing console and balanced in real time and output to the disc-cutting lathe. Things like compression, equalization, reverberation and leakage between instruments need to be sorted out before every take. And not only that but an entire side (20-23 minutes of music) must be performed perfectly and captured successfully on the lacquer master or the band has to start over again. If there’s one mistake at the very last moment, the whole thing is toast.

The folks at Sheffield Labs, the label that specialized in this type of recording, took great pains to avoid the problems that can occur during any disc cutting session. This includes knowing that dynamic contour of the tunes to be captured. The “pitch” (the distance between the grooves of a vinyl LP) of a record at any given moment is dependent on how much low frequency content is present. In a traditional disc mastering session, there is a “look ahead” playback head that gives the disc cutting system instructions to move the grooves more closely together or further apart. In a direct-to-disc session, you don’t have this ability…the music is happening in realtime.

The entire process is a very delicate balancing act for all involved. But if it’s done successfully, it can deliver very good results. At a time when PCM digital equipment didn’t exist or was unavailable to recording engineers, removing the analog tape machine and cutting directly to the lacquer master was a brilliant idea. Remember this was a time when ALL (or virtually all) music was being sold on 45s or LPs. This did elevate the sound of vinyl. But it’s still vinyl.

And as we know, vinyl is a seriously flawed way of capturing and delivering music. The low end is attenuated and the high boosted during the recording stage according to the RIAA equalization curve. This is done to maximize the duration of a single side of a vinyl record AND to prevent groove distortion caused by large swings of the stylus. Likewise, the high end is boosted during recording because the ability of turntables and cartridges to reproduce high frequencies is limited as you get above 15 kHz. It is almost impossible to get accurate HF response on a piece of vinyl LP as you approach the end of the audio band. Think about it…the physical mass of the stylus has to move back and forth 20,000 times a second!

We’ve already talked about the folding of all signals below a certain frequency to mono that is required for vinyl and not for analog tape. If “fidelity” is meant to reflect the intentions of the artists and producer, the act of mastering for vinyl distribution is one of the last you want to do to a mix.

So yes, if you enter your “way back” machine and limit your field of view to the time prior to digital recording and reproduction, the ultimate format just might be a direct-to-disc album produced by Sheffield Labs. It would be more accurate to say that direct-to-disc albums represent the very best that a piece of spinning vinyl can deliver.

Is analog tape equal or better than direct-to-disc…probably. If you prefer full stereo at all frequencies and accurate high-end response (although just like the RIAA curve…analog tape machines have an equalization curve all of their own), tape takes it hands down. When someone says that you’re going to get “Master Tape Quality” with your high-resolution downloads, it might just be the best representation of an album. But not likely as we saw the other day… it depends on the tape that’s used. And most of the time the master is the not the master you want.

I like the concept of recording “direct-to” whatever is the best recording format available at the time the session is held. My own AIX Records productions are made by recording all of the musicians at the same time, in the same room, with real acoustics and no overdubs. It works. But these recordings contain a lot more fidelity than the direct-to-disc albums from 40 years ago. The ultimate format is high-definition PCM with the right sensibility during the production of an album. Getting everyone to play and sing at the same time can deliver uniquely better fidelity. Certainly better than any piece of vinyl or analog tape.

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About Author

Dr. AIX

Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

(1) Reader Comment

  1. I have heard opposing reports on the treble EQ that is applied to make a vinyl master. Some say that a cut is applied, because of the limited ability of most turntable cartridges to handle high treble levels that may be present on the original master. Others say that it is boosted, because the turntable cartridges have a rolled off treble. Can you please help and clarify this?

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