Mastering Vinyl
Electronic Musician
Mar 1, 2008 12:00 PM, By Gino Robair
Learn about the peculiarities of releasing music on vinyl.
BONUS MATERIAL
Web Clips: Click for audio clips and videos that accompany the March 2008 issue of EM.
Nearly a quarter century after the CD was introduced, and kept alive in large part by club-based music, vinyl records are experiencing a resurgence in popularity. (Time magazine reported in January that record sales were up 15.4 percent in 2007.)
Musicians in nearly every musical genre are pressing records again, not only because they believe the sound quality is superior to that of digital audio (and especially data-compressed formats), but because of the large graphics and collectibility, which help these products stand out in the crowd of new releases. The latest trend is to offer a free downloadable version of the record with the purchase of the LP; this makes the release more attractive to members of the iPod generation who want instant gratification as well as something collectible.
However, simply pressing an LP or a 7-inch from your CD master does not guarantee the best results that vinyl has to offer. Often a number of decisions, and even some compromises, have to be made to get a great-sounding record.
I asked four mastering engineers who specialize in cutting vinyl — John Golden (www.goldenmastering.com), George Ingram (www.nashvillerecordproductions.com), Pete Lyman (www.infrasonicsound.com), and Richard Simpson (www.richardsimpsonmastering.net) — to weigh in on the subject. Their insights will help you understand what to expect from your release and allow you to create masters that will translate well into the analog medium of the vinyl record.
Groovin'
To cut a record, the engineer plays your master recording in real time — whether on analog tape, DAT, CD-R, or as digital files — through a lathe (see Fig. 1) that mechanically translates the audio information into an etched groove on a 14-inch, lacquer-coated aluminum disc using a precision cutting stylus. EQ and limiting are added as needed.
The resulting disc is known as the master lacquer, and the engineer cuts one for each side of your LP or single (see Fig. 2). The master lacquers are sent to the manufacturing plant, where they are processed to create the metal stampers used in mass-producing records. (To watch a video of this process from start to finish, see Web Clips 1 and 2.)
Although the master disc's diameter is 14 inches, the engineer starts cutting where a 12-inch disc would begin. The extra surface area allows for ease of handling and ensures that the critical area for cutting is free from flaws that are typically at the edges of a disc.
During the mastering session, the engineer determines how loud the resulting playback levels can be, based on program length and overall volume; how much, if any, EQ or limiting is required; and how the grooves are laid out across the disc, among other things. It's a good idea to find an engineer who has cut records in your musical genre, because he or she will know from experience what kinds of demands it makes of vinyl.
Short but Sweet
With iPods that can hold a month's worth of nonstop music and CDs that offer 80 minutes, it comes as a surprise to some that LPs typically have less than 45 minutes of music on them. Whether or not you think the amount of storage space on a record is a limitation, the amount of good-sounding space on the disc is important to consider. The rule of thumb is that the greater the circular distance over which the music is cut into the record, the better the reproduced sound quality will be.
“Most people don't realize that the distance around the inside of a 12-inch record is about half the distance than around the outside,” Golden explains. “As the distance around each revolution decreases, the high frequencies become harder for a playback stylus to read.”
FIG. 1: The Neumann AM-32 lathe at Infrasonic Sound. The large dial on the control panel at the right can be used to manually regulate the number of lines etched into the master lacquer.
As a result, the inner tracks will sound duller than the outer tracks. The high frequencies “simply can't be reproduced the same as if they were cut on the outside of the disc,” Golden adds. “And no, it can't be fixed by adding extra high end. That would add more distortion to the inside cuts.” Consequently, song sequencing for a vinyl release is very important if you want to maximize sound quality, particularly in the upper frequency spectrum.
Lyman notes that you will begin experiencing a loss of high end about halfway through an LP. “A lot of classic records were sequenced so a softer song or a ballad was on the inside, and usually the louder cuts were on the outside. I always tell clients to consider sequencing the vinyl version differently than the CD. Maybe put a softer song with less high end on the inside. You'll have a better-sounding record, especially if you keep the length of each side under 20 minutes.”
Simpson notes that even if he puts only a few minutes of music on a 12-inch record, he tries to keep the grooves closer to the outside of the disc rather than spacing them out evenly across the entire platter. “It might look like you're not getting your money's worth, because the disc doesn't look full, but it'll sound better overall.”
Length vs. Volume
In addition, there's a direct correlation between program length and loudness: the shorter a record is, the louder it can be. “There is only so much room to cut the groove,” Golden explains. “The longer the time per side, the smaller the groove needs to be, and the lower the volume must be to make it fit and to prevent skipping.”
“A lot of DJs don't want to deal with big volume discrepancies when they're changing records,” says Lyman. “So if you're doing a club track and you want strong levels, definitely keep it under 10 minutes on a 12-inch disc at 45 rpm.”
Lyman notes that records produced during the LP's heyday rarely held more than 40 minutes of music — total. “And they sounded great! Because of the CD format, albums are definitely getting longer. These days, LPs are almost always over 45 minutes, as people try to cram more and more onto records. If you have anything over 40 minutes, spread it out; make the investment and do a double-LP release.”
The engineers I spoke with recommended putting no more than 16 to 18 minutes of music on a 12-inch record at 33⅓ rpm. “Anything over 18, and you begin to sacrifice sound quality,” Lyman warns. “The longer the disc, the lower the overall volume. When you're cutting a record at a lower volume, the noise floor increases.” (Disc manufacturers often post the recommended playing times for different-sized records at various speeds on their Web sites.)
Tame the Highs
Many of the engineers I spoke with noted that a wider frequency and dynamic range can be cut into a vinyl master than can be reproduced in playback. For example, extreme transients and high frequencies will distort because the stylus cannot properly track them in the disc's grooves.
Sibilance, the high-frequency noise burst that you get when the letters s, f, and t are emphasized, is a major issue that mastering engineers encounter. “Problematic sibilants typically fall in the 6 to 12 kHz range,” Golden observes. “Because a CD can reproduce it without trouble, it isn't recognized as a problem area until you decide to make a vinyl record.”
FIG. 2: The master lacquer is a 14-inch aluminum disc evenly coated with a nail-polish-like substance. The mastering engineer etches a single, long groove into the disc.
Photo: Lucas Phelan
“I hear a lot of tracks, especially from indie musicians, that have extremely sibilant vocals,” says Lyman. “It's something I'm always aware of when I'm mastering a CD, because I often cut a vinyl master of the same project. But when I get something that's already been mastered, and we're doing a straight cut from that master, I'll watch the high end. I try to cut it as flat as possible, without causing any distortion. If I have to do any high-frequency limiting, I let the artist know and see how much we can get away with on this end before we ask someone to change their mix or remaster it. Unfortunately, a lot of the rock stuff is coming through with more high end than is going to work properly on vinyl.”
“In general, if you even think it sounds a little sibilant, chances are you should be de-essing the vocal,” Golden recommends. “My rule of thumb is de-ess the vocal when you record it, then de-ess it again when you mix. It works much better if a little is done at both stages rather than trying to de-ess it all at once. A good de-esser can actually make the vocal sound brighter because the only time it affects the voice is during the s sound.
“Some vocalists learn to underpronounce the sibilant sound — that makes all of our jobs much easier,” he adds. “But if you double a vocal that's already sibilant, you get twice the problem. Heavy compression and limiting can also make a nonproblematic vocal very sibilant: the limiter will tend to pull up the s sound because most compressor/limiters don't work at the same threshold for high frequencies as they do for mid vocal frequencies. Consequently, the limiter doesn't see the s sound and opens up the level, adding even more sibilance.”
As you'd expect, the current trend of heavy-handed compression and limiting in the recording industry does not lend itself to releases destined for vinyl. It's not uncommon for engineers to be given overcompressed masters with exaggerated highs that sound terrible on a record. Lyman recommends that artists prepare a separate master for a vinyl version of a project, one that has “a greater dynamic range and is not overlimited.”
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.”
FIG. 3: Mastering engineers J.J. Golden (left) and John Golden with their Neumann VMS-70 cutting lathe.
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
A close-up of the Neumann AM-32 recording assembly that houses the cutterhead (lower right): the internal drive coil can reach temperatures of 392 degrees Fahrenheit, so the system is helium-cooled.
Photo: Lucas Phelan
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.”
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.”
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