The short version: This section covers the first physical step in making a record. Every pressed record starts as a groove carved in real time by a heated stylus on a lathe, usually into a lacquer-coated aluminum disc, one side at a time.3334 The cut obeys physics a streaming master never meets: bass has to stay centered, harsh "s" sounds have to be tamed, and every extra minute on a side costs level, bass or both.3536 The machines are mostly decades old, with a couple of new ones arriving since 2023, and the playback curve that undoes the cutting EQ has been standard since 1954.373839
Do I need a separate master for vinyl?#
Usually, yes, and the reason is that a groove is a physical object with a stereo problem built in. The mid signal (what the left and right channels share) moves the groove side to side, and the side signal (the difference between them) moves it up and down.40 Big low-frequency differences between channels mean big vertical swings, and if the two channels are out of phase the groove can narrow until a stylus cannot track it, or the cutter head lifts off the lacquer altogether.4135
That is why one US plant's mastering guide puts it bluntly: "Always center your bass frequencies."35 Hard-panned bass, kick or toms can make a record skip or skate.35 Engineers typically keep the low end in mono below a certain frequency, and on long sides they often roll off bass as well, trading away low end and stereo width for time.36
There is no single number. Writing for iZotope in 2019, mastering engineer Jett Galindo noted that bass-to-mono tools typically offer crossover settings from 20 Hz to 700 Hz, and that many vinyl cutters already consider a 100 Hz setting excessive.42
The same plant lists the other usual suspects:35
| Problem | What happens at the lathe | Usual fix |
|---|---|---|
| Sibilance | Heavy "SSSS" can distort the master | De-ess every vocal |
| Bright cymbals, hi-hats, tambourine | High end can distort if sent unchecked | Tame the top end |
| Brickwall limiting | Distortion, no headroom | Leave headroom; the cutting engineer sets level |
| Track order | Loud, bright songs suffer near the label | Loud songs early in a side, quiet ones last |
Veteran cutting engineer Richard Simpson ranks sibilance as one of the two big cutting problems, causing distortion and tracking trouble on both the lacquer and playback.41 He also offers a useful dissent: he found that skipping the low-end roll-off or elliptical EQ (the filter that sums bass to mono) often sounded fuller, so "mono the bass" is a strong default rather than a law.41 He recalls that RCA Hollywood's "Motown filter" rolled off everything below 70 Hz and above 12 kHz.41
Why does the end of a side sound worse?#
A record spins at a constant speed, so the groove under the stylus moves fastest at the rim and slowest near the label. HiFi News puts a 12-inch LP at 33 1/3 rpm at "almost 21ips" at the outer edge and about 7.4 inches per second near the center.43 The same waveform has to squeeze into roughly a third of the groove length, so wavelengths shrink and get harder to cut and to track. This is inner groove distortion, worst on loud passages with lots of high-frequency energy, and a pivoting tonearm's tracking error also grows toward the center.44 Soundfly calls the same effect "diameter loss."40
The fixes are all about planning: quieter songs at the end of a side, shorter sides, or splitting an album across two discs.44 Soundfly's version is to put the ballad last.40
Is 45 rpm better than 33 1/3?#
On the numbers, a 12-inch at 45 rpm moves about 28.3 inches per second at the outer edge, which HiFi News notes is "close to the professional tape standard of 30ips."43 More groove per second means more room for each wavelength, and the article calls higher-speed formats "almost always sonically superior."43 The cost is time: a 45 rpm side holds far less music, as the next table shows. Whether a given listener hears the difference is a separate argument.
How much music fits on one side?#
Less than most labels would like, and it depends on the music. Groove width and depth decide how much signal fits. A shorter side allows deeper, wider grooves with more dynamic range, bass and level; a longer side means lower level, a higher noise floor and tighter spacing, which raises the risk of overcuts (grooves running into each other, causing skips) and, on lacquer, pre-echo and post-echo, faint ghosts of a loud passage heard right before or after it.36 A louder cut also hides surface noise better.36
Two plants publish guidance, and they disagree:
| Format | Gotta Groove (US, undated page) | RPM Records (Denmark, 2023) |
|---|---|---|
| 12-inch at 33 1/3 | 18 min ideal, 20 "still good", issues may start at 22, call first beyond 2235 | Definition drops above about 20 min36 |
| 12-inch at 45 | 12 min ideal, 14 "ok", call first beyond 1535 | Up to 15 min36 |
| 7-inch at 45 | 4.5 min35 | Up to 5 min36 |
| 7-inch at 33 1/3 | 6 min; 45 preferred when the side allows35 | Not recommended36 |
Soundfly lands in the same place for the LP: about 20 minutes a side "without audible compromise."40 The ceiling moves with the material. Mastering engineer Scott Hull, quoted by RPM, says 25 to 27 minutes is "almost no problem" for quiet, lightly compressed recordings such as chamber music or singer-songwriter albums.36 Gotta Groove's own example: a four-minute soul ballad and bright heavy-metal guitar have very different limits on the same 7-inch.35
Stereo itself costs space. Simpson recalls that the mono cut of the first Monkees album ran about 3 to 4 dB hotter than the stereo cut, because stereo needs more room on the disc.41
For the 10-inch, the US plant United Record Pressing tells clients not to exceed 13 minutes per side at 33 1/3 or 8 minutes per side at 45.45
Side-length check
Will it fit on one side?
Cutting engineers trade loudness and bass for time: the longer the side, the closer the grooves and the quieter the cut. These are the recommended limits cited in this guide, not hard rules - ask your cutting engineer.
What is a lacquer?#
The lacquer (or master disc) is an aluminum plate with a thick coat of lacquer, and the engineer cuts it in real time with a stylus that is usually sapphire.33 There is one lacquer per side.34 The gaps between songs are made by nudging the stylus slightly toward the center, and the engineer adds the lead-in, lead-out and the crossover grooves by hand before checking each lacquer under a microscope for overcuts.3334
The supply of blank lacquers is thinner than most buyers would guess. On February 6, 2020, a fire destroyed the Apollo Masters factory in Banning, California, which per Wikipedia made an estimated 70 to 85 percent of the world's lacquers and was one of only two such factories; MDC in Japan was left as the only producer.46 DJ Mag reported after the fire that MDC was said to be basically closed to new business, that at least three groups were working on new lacquer manufacturing, and, per one industry source, that only two companies were known to still make gem-tipped cutting styli.47 Some plants moved to DMM (below), and the Vinyl Record Manufacturers Association of North America formed in response.46
Making new blanks has proved hard. Gotta Groove Records says it worked with Sherwin-Williams from 2017 to 2022 on lacquer blanks of its own, a project abandoned mainly over the difficulty of curing the discs, and as of 2026 it still recommends MDC blanks from Japan.48
Why is the cutting stylus heated?#
Heat is the trick that made quiet, detailed lacquers possible. In 1948 William S. Bachman at Columbia wrapped a copper wire coil around the stylus and heated it with direct current; the warmth softened the lacquer, allowed much smaller burnishing facets (the tiny flats that polish the groove wall) and kept more high-frequency detail.37 The method was published in Audio Engineering in June 1950, and Fairchild later sold a "thermostylus" kit with a claimed noise reduction of about 20 dB (a manufacturer's claim).37 The hot stylus matters beyond the cutting room: the RIAA curve's 75 microsecond treble setting relied on it.37
What is a mastering lathe, and who made them?#
The lathe turns the blank and moves the cutter head, which controls the cutting stylus, across it.49 Two names dominate the history.
Scully. John J. Scully built a weight-driven lathe in 1921, and Western Electric bought one in 1924 to demonstrate its Westrex cutter.49 Per Wikipedia, Scully dominated the US professional market from the 1930s to the 1960s.49 It lost ground once Neumann lathes were imported, its new design did not arrive until the mid-1970s, and it was often fitted with Westrex cutter heads and electronics.50
Neumann. Per Wikipedia, Neumann's AM31 arrived in 1931, followed by the VMS66 in 1966, the VMS70 in 1970 and the VMS80 in 1980.49 Pspatial Audio calls the VMS 70 the world's most popular recording lathe and says Neumann was the only company selling lathe, cutter head and electronics as one system, at more than $100,000 in today's money (an estimate on an undated page).50 Neumann lathes from 1931 to 1980 used Lyrec synchronous AC motors whose speed followed the mains frequency; the VMS-80 dropped the traditional bed and used DC servo motors, and in 1989 the last remaining disk-lathe maker assembled a VMS-82 DMM lathe in Berlin.51 Pspatial dates Neumann's switch to crystal-locked Technics DC motors to after 1976.50
On heads, Ortofon made its first moving-coil cutter head in 1946, and per Wikipedia Western Electric/Westrex showed the first commercial 45/45 stereo cutter head in 1957.5049 Neumann's SX-74 is a stereo feedback head; the SX-84, developed with Teldec for DMM, fits only the VMS-82.51
Does anyone still build lathes?#
Sources disagree on when the old line ended. In 2019 Mix wrote that "no manufacturer in the world has made one since the early 1980s," in a profile of a Nashville rebuild of a 1940s Scully 501: about $3,000 in 2014 for the bathtub, sled and original platter, $25,000 to $30,000 in parts overall, and roughly four years of work, finished in summer 2018.52 Copper Magazine's 1989 date for a VMS-82 built in Berlin sits later than that.51
New machines have arrived since. Agnew Analog unveiled the Type 612 at the International Disk Recording and Mastering Convention in July 2023 and listed it for order by August; it cuts lacquers, dubplates or plastics, has a hydraulic carriage, takes a 12- or 14-inch vacuum platter and accepts any cutter head, including Agnew's own Type 602.38 In July 2026 MusicTech reported the Teenage Engineering APC-2, built with SUPERSENSE, a 104 kg made-to-order lathe that cuts playback discs in real time; price and availability were not stated.39
What is groove pitch, and what does variable pitch do?#
Pitch is groove spacing, measured in lines per inch.50 A fixed pitch wastes space on quiet passages and risks overcuts on loud ones. Variable pitch solves this by reading the music about a second early: on tape-era Neumann systems a preview head sat about 38 cm ahead of the playback head, so the lathe could widen the spacing before a loud or bass-heavy passage and tighten it during a quiet one.50 Neumann paired it with dynamic depth control driven by the side (L-R) signal, and an "ECHO" button widened the pitch to cut down pre-echo.50 Tight spacing on long sides is what raises the overcut and echo risk in the first place.36
The sources disagree on dates. Per Wikipedia, Scully introduced variable pitch in 1950 and automated it in 1955, and the VMS80 introduced it to Neumann's line.49 Pspatial Audio says the VMS 66 and VMS 70 already had a separate pitch-control console fed by the preview head.50 Both accounts put variable pitch in the 1950s at Scully; they differ on when Neumann got it.
What does DMM mean on a record?#
Direct Metal Mastering skips the lacquer. Per Teldec's own document, a diamond stylus, excited at an ultrasonic frequency so it cuts more easily, carves the groove straight into amorphous copper electroplated onto a 0.8 mm stainless steel disc, with no heated stylus needed.53 The cut disc becomes the "mother" for plating, which skips the silvering and nickel steps a lacquer needs.53 Teldec claims no lacquer springback, no pre- or post-echo, 10 to 15 percent more playing time per side, up to 6 dB less high-frequency noise and stampers in about two hours, and pitched it as economical for short runs (all manufacturer claims).53 With no springback, Teldec says, the grooves can also sit closer together.53
Per Wikipedia, DMM came from Teldec (Telefunken-Decca) and Neumann, about 30 DMM lathes were ever made, about 10 were later converted to lacquer, and as of 2009 seven public DMM facilities remained, in Germany, the Netherlands and the Czech Republic; the US lost its last in 2005.54 The DMM logo was tied to Teldec's specification while it enforced it; after the patents expired the name and logo were unrestricted.51
The sound is argued over. Some listeners hear DMM as bright or forward, which some attribute to the hard copper and a near-zero cutting angle that needs electronic correction.54 In 2020 DJ Mag noted doubts about DMM for dancefloor releases, and Richard Dron, founder of the pressing company Mobineko, said he did not love its sound while noting that big European plants such as GZ and Optimal relied mostly on it.47
A 1987 Audio magazine feature dates DMM's introduction to 1981, and notes that Teldec had used the underlying process for its TED videodisc, introduced in 1976.55 Teldec's US patent for DMM was filed on April 7, 1982, per Pspatial Audio.56
What is the RIAA curve?#
Left alone, bass would carve enormous swings and treble would barely scratch the surface. The RIAA curve fixes this: the cutting side cuts bass and boosts treble, and the playback side does the exact opposite, so the overall response comes out flat.57 It roughly approximates a constant-amplitude groove, so no part of the band hogs the disc, and it improves signal-to-noise.57 The playback half of that curve, plus a lot of gain, is the job of a phono preamp, covered in the playing section; the history section tells how the labels settled on one curve.
The numbers are three time constants, 3180, 318 and 75 microseconds, which put the corners at 50.05 Hz, 500.5 Hz and 2122 Hz.57 A true constant-amplitude cut would need about 60 dB more gain at 20 kHz than at 20 Hz; RIAA asks for about 40 dB.57 The curve dates from 1954, after the 1953 NARTB standard, replacing what Stereophile calls "an anarchy of different EQs."3757 It became part of IEC 98, first published in 1964; in September 1976 the IEC added a fourth time constant (7950 microseconds, 20.02 Hz) to roll off infrasonic rumble, and critics say that adds audible errors of -3.0 dB at 20 Hz, -1.0 dB at 40 Hz and -0.5 dB at 60 Hz.57
What is half-speed mastering?#
Run the source and the lathe at half speed, so an LP is cut at about 16 2/3 rpm, and the stylus gets twice the time for every wiggle, which makes high frequencies easier to cut.58 The lathe's EQ has to be modified or the curve lands in the wrong frequency range, and each album needs an acetate check, so a cut takes about four times as long.58 Stan Ricker cut half-speed LPs for Mobile Fidelity Sound Lab, which licensed classic albums and had them pressed in Japan.58 At Abbey Road in London, Miles Showell, who joined in 2013, cuts half-speed masters from high-resolution digital transfers on a modified Neumann and calls the method the "holy grail of vinyl cutting."5859
What do one-step and three-step mean?#
After cutting, a lacquer is silvered and electroplated with nickel. The nickel peeled off is a negative called the father; plating the father makes a positive mother, and the mother makes stampers, the plates that press the records.3334 Disc Makers describes three routes:34
| Process | Chain | Used for |
|---|---|---|
| One-step | First plate off the lacquer is the stamper | Very small orders |
| Two-step | Stamper is plated again to keep a mother | Future stampers |
| Three-step | Father to several mothers to several stampers each | Runs of tens of thousands or more |
Yamaha puts it at one stamper per thousand records, though real stamper life varies.33 DMM needs only one electroforming stage, since the copper disc is already the mother.5453
On audiophile reissues, "One-Step" is also a selling point. Mobile Fidelity's UltraDisc One-Step pressings use stampers made straight from the lacquers, skipping the father and mother, which the label says avoids the generational losses of three-step plating.60 Since each lacquer yields one stamper, more lacquers have to be cut.60 The sonic benefit is the label's claim.
What is a lathe-cut record?#
A lathe cut is cut one at a time in real time, the groove engraved straight into a blank by a diamond or sapphire stylus, with no plating and no press.61 Per a seller of them, lathe cuts make economic sense from one copy up to "a few dozen," while pressing pays off from hundreds up; blanks include vinyl, polycarbonate and acrylic.61 The same seller says lathe cuts may sound more raw or lo-fi than pressed records, with quality varying by equipment, material and mastering, and that vinyl lathe cuts may last longer than polycarbonate or acrylic ones, without giving a play count.62 New professional lathes cover this ground too: Agnew lists "plastics" among what the Type 612 can cut.38
Where are records cut today?#
The cutting trade is small and scattered: the last public DMM rooms (as of 2009) were in central and northern Europe, and after February 2020 the only lacquer maker left standing was in Japan.5446 RPM Records in Denmark publishes the side-length advice quoted above, and Abbey Road in London is the best-known home of half-speed cutting.3659 Mobile Fidelity's early half-speed LPs were pressed in Japan.58