RPM’s Vinyl Blog

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How To Decide On Vinyl Record Length?

7 min read
A musician's guide to playback time on a vinyl record. Learn how to decide on a vinyl record length and what effects it will have on the final album.
vinyl record lenght explained feature3 How To Decide On Vinyl Record Length?

Perhaps the most frequently asked question in the vinyl industry is “ How long can a vinyl record be? ” In fact, a more important question would be ” What is the right balance for a great sounding record?

Let’s look more closely into some of the technical aspects of the record production and the relationship between quality and vinyl record length.

vinyl record length explain. from the article on RPM Records blog.
A cutting lathe Westrex Scully at KDS. Copenhagen.

DISC RECORDING

The longer the playing time, the lower the volume of the record. More chance of audible noise (pressing noise floor). Also more chances of over cuts causing skips, because grooves need to be cut close together at a narrower groove depth.

Richard Simpson. A mastering engineer at Erika Records.

First and foremost, the playback time on vinyl records is strictly limited to the disc diameter. Since grooves inscribed on a vinyl record are analogous to audio wave-forms – the wider and deeper cuts means louder music, and vice versa.

It also means, that continuously loud and heavy bass music will eat the available space on a record in a shorter period of time. While dynamic audio material with loud and silent parts results in dynamic cut, with narrower grooves at quiet places and wide deep grooves at loud passages. Consequently, saving available space on a record and allowing longer sides to be cut in good quality.

Stereo information will always cut deeper, and hence wider – occupying more space than for example a monophonic recording.

vinyl record length explain.RPM Records Vinyl Blog. taken from the book Basic Disc Mastering.
Basic Disc Mastering. Larry Boden, 1981.

The cutting engineer will have to make a calculated decision about fitting your program material on a given diameter. Taking into consideration the amount of low frequency content, playback time, phase correlation, track sequencing, type of music and so forth.

There might occur a situation when program material in all its qualities can not fit on a disc and demands certain mastering adjustment. More often than not – lengthy playback will lead to filter roll-off and diminished low-end, stereo width and level output.

It is because treating the low end, narrowing stereo field and dropping the level will decrease horizontal and vertical groove modulation allowing narrower groove spacing and more program on the record side. It is clear that lengthy playback means less definition, especially in the area of above 20 minutes per record side.

RECORDING, MIXING & MASTERING

Sonic characteristics of a program material will have huge effects on how many minutes we may cut on the side in good quality. Insufficient microphone placement causing phase correlation issues will eat a lot of space on the disc. Excessive sibilance such as from vocals or muted trumpets will cause difficulties in cutting longer sides without distortion at a decent output level.

In a situation of intense high frequency recording, half speed mastering may allow louder sides without distortion. At half speed both frequency spectrum and groove velocity are lowered by two. Meaning that the cutting equipment will work under less pressure, being able to more accurately gouge complex groove geometry of the upper frequency spectrum.

Track sequencing that won’t take peripheral groove speed into consideration will become an obstacle for cutting longer sides in good quality as well. It is because severely reduced groove speed in the inner circles can’t accurately trace intense high-frequency modulations. As a consequence, causing distortion even at a moderate level output.

Sequencing high intensity tracks for the outer diameter and quieter compositions for the inner circles will allow longer sides in good quality. If a story telling is important and high intensity, excessive sibilance track must end the record side – cutting the disc inside-out may allow better results in some cases.

Heavily compressed, brick-wall limited master with little dynamics will cause difficulties in cutting a lengthy record and heavy compromises to be expected in most cases. Each decibel of peak limiting will force the cutting engineer to drop a decibel or more to spare space for a record that is above 20 minutes per side.

basic disc mastering 09 How To Decide On Vinyl Record Length?
Basic Disc Mastering. Larry Boden, 1981.

Although we can cut stereo bass on a record, it eats a lot of space. Reckless microphone placement for drums/piano, stereophonic effects for bass/guitars or master stereo widening effects may cause difficulties cutting LP in good quality. Experienced recording, mixing and mastering engineer will make sure nothing weird is happening in the low-end, and that everything below certain frequency is in mono.

LONG PLAYBACK QUALITY CONCERNS

Numerous issues may occur with extended playback. Firstly, the weak output signal will expose noise from various sources: electroplating, mechanical low frequency rumble from the turntable, dust and record wear.

There is more chance for overcuts causing skipping on a record with long playback and narrow groove spacing.

When grooves are condensed very close on a lacquer disc, pre-echo and post-echo may easily occur during cutting or electroplating. Meaning that at a certain output level, one groove behind or ahead of the playback point will be audible.

Echo issues are less common with DMM (Direct Metal Mastering) since copper is a more rigid material than lacquer. For this particular reason, DMM is known to accommodate longer sides.

“Physically there is no difference in playback length for lacquer or DMM. But longer sides means lower level, higher noise floor and narrower groove spacing. On lacquer that imposes more chances for overcuts and pre/post echo problems since it’s a flexible material. DMM noise floor is 10-15 decibels lower than lacquer and it is a rigid material, producing no echo so grooves can be as close as possible. And that allows longer sides in good quality.”

Misjah. Mastering engineer at 24 Mastering.

Some definition is inevitably eluded during the manufacturing steps. Therefore, our primary objective is to have the strongest signal possible on a master disc and grooves that are rigid and deep. If the signal is weak from the very beginning – losing a decibel or two of the high-end during plating and pressing will just exaggerate the problem.

Finally, keeping the record within reasonable length helps to preserve genuine qualities of the recording. It allows big open sound and will leave an album competitive for the generations to follow. We aim for your record to stand out and be competitive, so fans won’t think twice before purchasing it.

RECOMMENDATIONS FOR VINYL RECORD LENGTH

“In order to get your records played on the radio in the 60s and 70s, the music had to get the attention of a program director. So a good record, louder then the others being previewed for an airplay had a better chance of getting on the playlist rotation. Most singles were under 3 minutes, allowing a loud level to be cut. All of us cutters pushed the limitations trying to get the loudest records.”

Richard Simpson. A mastering engineer at Erika Records.

Records come in a variety of shapes and sizes. The most widely used are 7”, 10” and 12” formats. Obviously, a wider diameter disc can accommodate more music, but that is not the whole story.

In theory, the short playback time allows deep and wide groove geometry, as a result broader dynamic range, more bass and more loudness. Simultaneously,reducing the available playback time by 35 percent.

The playback speed, would that be 33 or 45 RPM, will impact the maximum available length on the vinyl record. The loudest and arguably the most powerful records are those of short playback time, revolving at 45 RPM known as maxi-singles.

vinyl record length explain.RPM Records Vinyl Blog. taken from the book Basic Disc Mastering.
Basic Disc Mastering. Larry Boden, 1981..

45 RPM cut can fit up to 15 minutes per side on 12″ and up to 5 minutes on 7″ diameter. 45 RPM speed promotes more definition in high frequency spectrum, while 33 RPM allows longer cuts and deeper low-end within certain limits. Following industry’s best practices 7″ releases revolving at 33RPM are not recommended due to insufficient sound quality.

With all of these things there is some level of truth to them, but they’re not absolutes. You have to have more understanding to know whether that rule applies to your music or not.If you’re doing chamber music, or if you’re doing acoustic blues, or if you’re doing maybe a piano record that’s not heavily compressed, or a singer-songwriter thing that’s not heavily compressed, 25, 26, 27 minutes worth of music are almost no problem for the right cutting equipment—and this is an important distinction”

Scott Hull. A mastering engineer at Master Disk.

It is clear, that there is no standard formula for maximum vinyl playback time. All aforementioned variables will impact how many minutes and at what quality can fit on the record side. The tonal balance, album sequencing, type of music, recording mixing and mastering attributes will define how good your album may sound in given length on a given diameter.

I believe, that a principle of relatively loud and tonally rich record is important in a number of ways. Firstly, an impressive sounding record is obviously easier to sell. Secondly, loud records are more resistant to wear & tear as various noise coming from scratches and dust will get masked with the louder playback output. On the contrary, the records that are tiring long and weak level output will inevitably result in a much greater level of noise from the very start, and that will only increase during the years.

Thus, carefully considering the vinyl limitations, creative vision and recorded material will promote clever and informed decisions for an awesome sounding record release.

Microscope stock images used from our dear partner Stamper Discs. One of the most reliable electroplating laboratories in Europe.

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