How Records Are Made: Part 1
In this two-part series, we’re going to peer into the complicated, mysterious, and fascinating world of vinyl record manufacturing. There are several stages and terms involved, as well as alternate methods which change or bypass certain steps, so we've split this into multiple posts. Hopefully by the end, we can dispel some myths and give a glimpse into the science and artistry involved in the making of our favorite musical medium.
To start the process of creating a vinyl record, you need a master recording, which is the finalized audio of the album (or whatever you’re pressing to vinyl). This used to be in the form of 1/4” tape, but nowadays they are typically high quality digital audio files.
From here, we dive into old-school technology that, despite having been around for decades, is still the best way to make records. The master recording is sent to the cutting head of a lathe, or a record cutting machine, which transfers the electrical signals from the master recording onto a lacquer, also known as a test acetate or dubplate. The lacquer is a playable record, but it will suffer from wear much more quickly than a standard vinyl record. Unlike the finished product, a lacquer can only be played a few times before it will degrade noticeably. Lacquers are used to evaluate the quality of the disc transfer early in the vinyl production process to see if there needs to be any adjustments in the vinyl mastering* before production continues.
Photo: Anton Spice / The Vinyl Factory
* Vinyl mastering can be a different beast than mastering for CD or digital. Because audio information is stored in grooves on a record, there are physical limitations on the type and amount of audio per side. Low frequencies in audio use more space than high frequencies, so to make sure recordings with a lot of bass content can still be pressed to vinyl, the engineer operating the lathe lowers the bass information when transferring to a disc and boosts the high frequency information. Then, when you actually play the record back, the phono pre-amp does the opposite, reducing the high frequency content and boosting the bass so the record sounds the way it was intended by the artist and mixing engineers. This is called the RIAA curve, named after the Recording Industry Association of America, which standardized the process. But because the high-boost/low-cut happens during the lathe cutting process, you do not always need a separate masters for CD/digital and vinyl. Other aspects of recording (limiting, the placement of the bass content in the stereo field, overall loudness) might necessitate two separate masters, but that is a complex and contentious topic best saved for a different blog post.
After the lacquer has been created and approved, the lacquer undergoes a process called electroforming. In electroforming, the record plant applies a nitrate to the lacquer which attracts metal (usually nickel) to fill in all the grooves of the record and create a perfect negative copy of the lacquer. This negative copy has ridges instead of grooves and is called a metal master, or “father”. The father is separated from the lacquer, which is then discarded. Because the father is too malleable to create records directly, it needs to be duplicated again - and this is where we’ll go over our first two divergent methods of record pressing.
Electroforming baths. Photo: GZ Vinyl
In the three-step process, the father is used to create another negative copy, called the mother. The mother is typically made of copper, which means it is much more resilient than the father, and has grooves instead of ridges, which means it is playable. The mother is then used to make ANOTHER negative copy, which is called the stamper (ridges, not grooves). The stamper is the plate used to actually make the vinyl records.
In the two-step process, the father is converted directly into the stamper, and the mother is either bypassed entirely or created and then shelved for future use.
So why use the three-step process over the two-step process, and vice versa? It’s all to do with balancing quality and manufacturing quantity. Each additional step gives another chance for noise to be introduced into the production chain, but it also means that more records can be made from the same master. A stamper will wear out after creating about 1000 records. A mother can produce around 10 stampers, and a father can produce about 10 mothers. This means that with the two-step process, about 11,000 records can be created before you need to start the entire process over with a new lacquer (remastering). The three-step process can produce about 100,000 records before remastering.*
Separating the stamper from the mother. Photo: GZ Vinyl
* There's also a process called Direct Metal Mastering, or DMM, which can be thought of as a one-step process. Here, the original master recording is sent through a specialized DMM cutting machine that can carve directly into a copper disc using a diamond stylus vibrating at over 40kHz. This method is thought to give better transient and high frequency response, reducing the introduction of noise during the multiple plating steps, as well as preventing a phenomenon called “groove echo” where adjacent grooves could bleed over into the quiet parts before them. However, DMM requires specialized pressing plants to process their masters. When CDs were introduced and sales of records declined, most DMM lathes were converted into standard lacquer-cutting machines. As of 2009, only six or seven DMM facilities remain in the world, all located in Europe. The last DMM facility in the US closed in 2005, and their DMM lathe was bought by the Church of Scientology at an auction for $72,500.
That's the end of Part 1. To recap, we've covered LACQUERING, where we transfer the master audio into the first step of the physical record manufacturing process. Next comes PLATING, which uses the fragile lacquer to create resilient stampers (in either a two-step or three-step process). In the next installment of this series, we'll cover how stampers are used in the pressing process - and we'll actually get to the "vinyl" part of vinyl records!