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Mastering Vinyl

Mar 1, 2008 12:00 PM, By Gino Robair

Learn about the peculiarities of releasing music on vinyl.

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Center the Lows

At the other end of the spectrum, there are things to consider when working with bass and low-midrange content destined for vinyl. “Low frequencies use up the most space, especially if they're heavy and constant,” Golden remarks. “Care must be taken to control excessive low end. The lathe can cut it just fine, but if the volume exceeds a certain level, the record could skip when played back.”

Two things that can cause problems are bass instruments that are hard-panned, and phase issues in the low end. To compensate, the lowest frequencies going to vinyl are often moved to the center of the stereo field during the mastering stage. The engineer chooses a crossover frequency at which the centering begins based on orchestration, volume, program length, and other variables in the music. Because every project is different, there are no hard-and-fast rules, so if you are concerned about this happening to your master, consult with the engineer who will cut your lacquer (see the sidebar “The RIAA EQ Curve”).

“I always tell clients, especially dance artists, ‘Mono your bass,’” Lyman says. “Staging is a big problem for vinyl cutting. I've run into situations where producers try to do stereo kick drums, and they think they're fattening them up by moving one a couple of milliseconds, which only knocks it out of phase and results in less bass. And it's almost impossible to cut. We can do things to try to mono the low end, but usually it requires a remix.

“When something's out of phase, it tries to pull the cutting head two different ways, and then the cut just collapses,” Lyman adds. “Phasing causes the cancellation of frequencies, and the cutting head can't process that, so you lose your groove, which causes a skip.”

“Our Neumann cutting system has the ability to record a bass in one channel only, and when I play that disc back, the bass is still in the same channel,” notes Golden (see Fig. 3). “It is true that the more low frequency you mix on the sides, the more vertical up-and-down movement will be required of the cutter to make that sound. And with more vertical movement, the groove will use more space on the disc. Significant amounts of low end panned hard left and/or right can also cause a record to skip during playback. For the record to have fewer problems, you should try to keep most of the low end near, or in, the center of the mix, especially percussive sounds like the kick drum and bass guitar.”

Golden uses a crossover that centers frequencies of 70 Hz and below. “I use that frequency because it's nondirectional,” he adds. “You can't tell where the sound is coming from when it gets down that low.”

He also points out that if the crossover frequency is too high, it can have an adverse effect on the mix. “Depending on the frequency, it can make the low end become cloudy, because the bass, bass drum, and low guitars go to the middle.” He says that you'll hear the artifacts when you compare the vinyl pressing to the CD result of the same project.

“Before CDs became available,” Golden explains, “when a vinyl record was cut, the only source to compare it to was the master tape, in a studio that had a machine that could play it. After the CD was introduced, people started saying, ‘The vinyl record doesn't sound like my CD.’ And to some degree, that still happens today. The fact is, it will never sound like the CD — it's the ‘vinyl version’ of your music.”

Simpson usually uses a crossover point at 150 Hz. “But if we don't need one, we don't use it. It's only needed if there are too many vertical or out-of-phase components.”

Ingram uses a variable crossover with a range from 0 to 750 Hz. “Normally I set it to 70 Hz. If I see problems with vertical modulation on the disc, I will select 150 or 250 Hz. If I have to exceed 250 Hz, I'm in dangerous territory and it's going to affect the sound quality. At this point I conference with the clients and suggest a reference lacquer. If it's okay, we move forward; if not, it's remix time.”

Check Your Reference

To get a sense of how their project will sound on vinyl, the pros get a reference disc cut before creating a master lacquer. Similar in composition to the master lacquer, the reference disc is a 12-inch, lacquer-coated aluminum record that the artist or producer can listen to at home to see whether or not they want to make any EQ or level adjustments. “The actual purity of the coating on a reference disc is not quite as high as what's on a master disc,” Simpson says.

“We always made a reference disc first, with every record we did at RCA,” comments Simpson, who spent more than a decade at the label. “We'd write down the levels and any EQ we used. They'd go listen to it, and if they approved it, we would cut the master. Or they would come back and say they want to make minor changes. There might be two or three reference discs before we got the final okay.”

Although it's tempting to skip this step to save money, it's better in the long run to have a reference disc made. Otherwise, the first time you'll hear how your mix translated to disc is from a test pressing, which is more expensive to produce than a reference disc because of the steps involved (cutting the master lacquer, plating, producing metal stampers, and pressing), all of which you'll pay for. And if you want to make changes at this point, you'll have to pay for the entire process again.

Lyman notes that the reference will wear out over time. “But you can get upwards of a hundred plays out of it if you're really careful.”

Know Thy Master

Much of the vinyl mastering work is done without the artist or producer in attendance. Clients will either mail in the master or deliver files over the Internet via FTP. Though it may seem obvious, be sure that the master sounds the way you want it to, and that the songs are in the proper order. I heard several stories of artists who hadn't auditioned their master tapes or test pressings and wound up pressing records they didn't intend to.

“We have to assume that the customer has listened to the master tape,” explains Ingram. “They like what they hear, and this is what they want their record to sound like. We'll do 2 to 3 dB of EQ in any of three frequencies. If we have to go beyond that, we talk with the customer before proceeding forward.”

In addition, the master should include printed documentation showing song titles in the proper order, with correct timings. This information, among other things, will allow the engineer to accurately gauge the distance between grooves.

If your master is on linear media, such as tape or CD, indicate where side one of your record ends and side two begins by inserting a long area of silence. A minute or two will be sufficient, but check with your mastering engineer about the length of the gap required, as well as other technical information they may want, such as test tones on analog media, a minute or two of silence at the beginning of a DAT master before your music begins, and IDs for each track on DATs and CDs.

Although some mastering houses charge extra when clients attend a disc-cutting session, Lyman prefers to have them present in case he has any questions. “Sometimes local artists come down and watch the record being cut: it's not really something you get to see every day. I like having people in the studio. It takes longer with the client here, but it makes my job more fun. And it's well worth it for the artist to be involved.”

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Gino Robair is the editor of EM.

The RIAA EQ Curve

The RIAA equalization curve, a standard adopted in the mid-'50s, allows engineers to overcome certain limitations and maximize the amount of full-frequency music they can get onto a record. The EQ curve is applied as the music is cut into the master lacquer. When a record is played back, the inverse of this EQ curve is applied by the phono preamp so that the listener hears the music as it was intended. (Try playing an LP without a phono preamp if you want to hear how drastic the curve is.)

Because low frequencies require larger grooves and more space on a disc than high frequencies, the EQ curve gradually rolls off the bass by 6 dB per octave starting at 1 kHz so that by 20 Hz, the level has been reduced 20 dB. Without the RIAA bass cut, only about 5 minutes of low-frequency information could be stored per 12-inch side.

In addition, the RIAA curve boosts the frequencies above 1 kHz to increase the signal-to-noise ratio in the high end. The maximum increase is about 20 dB around 20 kHz. “Unfortunately, all the high end we're now used to is aggravated by the RIAA curve,” Lyman says. “When they came up with this system, there wasn't much going on above 8 and 10 kHz.”

Additional Resources

Richard Simpson's overview of vinyl in Remix

Producing Great-Sounding Phonograph Records

How records are made, part 1

How records are made, part 2

How records are mastered

Vinyl Gets Its Groove Back

BONUS MATERIAL
Web Clips: Click for audio clips and videos that accompany the March 2008 issue of EM.