33 Vs 45 Vinyl Records: What’s the Difference?

What does RPM stand for?

RPM stands for Revolutions Per Minute and measures the number of times a record completes a full 360° rotation in a minute.

For example, a 33 ⅓ rpm record makes 33 whole rotations in 1 minute of playtime, taking slightly over 2 seconds per rotation. A 45 spins faster, 45 times per minute, roughly 0.75s per rotation.

Three speeds are commonly used (33⅓, 45, and 78) when making records. 33⅓ and 45 rpm records are the most popular choices today, and 78 is more of an old-fashioned format, which is no longer being produced.

(Note – not all record players can play at 78 rpm. In fact, most modern ones don’t support this format anymore).

Record companies pick a particular speed when pressing a vinyl based on the needs of the release. Each rotational speed has its own advantages and disadvantages.

A comparison of vinyl record sizes and common speeds.

Vinyl also comes in a range of record sizes, which tend to use specific speeds for each size.

The standard record sizes are 12”, 10”, and 7”.

12-Inch vinyl records usually come as 33⅓ for full albums and 45 for EPs and singles.

The 7-inch record size is generally cut at 45 rpm, although not always, and many vinyl collectors have 7s that run at 33. (Although 7” records are often called 45s.)

There’s always a strong reason to choose one speed over the other, but I’ll get into that in the comparative portion of this post.

10-inch records don’t have a standard speed, and you can find them pressed at 33, 45, or 78 RPM. (In the old days, they were usually 78, but these days it can be anything.)

You can calculate a record’s maximum playtime using the record’s diameter and rpm, as demonstrated in the table below.

33 Vs 45 – Playback Time Comparison Table

What are the differences – 33 vs 45 vinyl records?

The main point is – the faster a record spins, the less information it can hold.

So for 45s, get ready to be getting up and down a lot to change the record, but with 33s, you can sit down and relax.

So, what’s the benefit of increasing rpm? Theoretically, it creates higher sound quality by increasing the frequency resolution at the expense of less playback time.

Let’s take a closer look at the science.

Effects of rpm on audio quality

Under analysis, it’s clear why a higher rpm would lead to better audio quality. Vinyl moves quicker beneath the stylus as the rpm is increased. For every second the record is playing, the stylus reads additional sound information. You can see in the (simplified) table above more information fits into the same timeframe.

As a result, vinyl records at a higher speed have the ability to provide better sound quality, with more depth and detail in the frequencies, even with less distortion.

In general, 45 rpm vinyl records have superior high frequencies, particularly near the end of each side. At 33 1/3 rpm, the final inch before the label frequently sounds much worse. This is due to the record groove having a smaller radius as it gets closer to the center of the disc.

45rpm has more aesthetically pleasing sonic qualities. For example, if you spin the disc at 45 rpm, the groove velocity increases by 35%. This allows for a large increase in perceived sound quality.

As a parallel, the higher the kbps (kilobytes per second) in MP3s, the better they sound. This compares well to speeding up records. More vinyl passes beneath the stylus every second at higher rpm. The grooves of a record are analogous to a computer file’s kilobytes. We get a more accurate representation of the audio information by reading more grooves each second.

In records, a higher rpm yields the same results as a higher kbps. Faster data speeds are always preferable, and this is the same with many audio formats, even cassette tapes.

However, the recording time of a 45 is also cut by around 35 percent. The only problem here is that it results in a 45 vinyl having less room for music, which makes it unsuitable for larger recordings (although the other factors situationally outweigh this.)

Moreover, the expenses of mastering, plating, pressing, and labels also increase with 45s. But when you hear the sound, you know it’s worth it! This isn’t a marketing ploy; it’s a scientific fact.

45s Can sound louder than 33s

Because 45s offer more space for wider grooves, they allow mastering engineers a lot more flexibility in terms of volume, meaning 45s can sound louder than 33s.

Because the loudness of a record is based on the depth and width of its grooves, 45s can be louder, as their grooves are naturally wider and deeper, with more space between them.

45s can be pressed from a louder master tape, giving up to +3db increased headroom. Also, note that shorter pressings (with lower running times) can increase their volume compared to longer ones.

A brief history of record speeds

The history of these speeds helps you to understand why certain formats are used.

78 rpm

The first phonograph, created by Thomas Edison in 1877, inspired the first vinyl record speed. These were not powered electronically; instead, they used a hand crank mechanism (can you imagine…?) The final rpm fluctuated, but records were generally made to play around 80 rpm.

Emile Berliner designed the electric motorized record player in 1888. The records for this device used speeds between 70 and 80 rpm. This device popularized vinyl players in the consumer market, which prompted other companies to start manufacturing and selling them. At the time, 78 rpm was found to be a sweet spot for peak performance, and so it became the industry standard in 1925.

33 ⅓ rpm

Because of technological advancements, when 78 rpm became the norm, it became possible to cut records at a wider range of speeds. As a result, records could be made that could be played at 33 rpm. RCA Victor released the first 33 ⅓ vinyl in 1931, although it didn’t become a popular speed until later.

These had certain advantages, such as cheaper manufacturing costs and lower surface noise, although, at the time, radio was the preferred medium for listening to music. Until Columbia Records began selling a 33 rpm record player in 1948, which spurred its popularity.

45rpm

It didn’t take long for 45 rpm recordings, which were smaller records, to become popular, thanks to record companies like RCA Victor. These became popular in the ’50s, partially due to teenagers having more expendable income (also due to the quality and smaller size). Both singles but especially EPs (typically containing two songs on each side), gained popularity quickly.

Record player models were then constructed to play both 33 and 45 rpm records, as a result. Around this time, 78 rpm records were being phased out in favor of more modern formats. Generally, 78rpm isn’t found on modern turntables.

For a deeper dive, check out this article → History of vinyl and record players.

Which records are best – 33 or 45 rpm?

In truth, they both have their own strengths and weaknesses, so picking which is “best” depends on how you are measuring the competition.

In terms of space, a 33 wins, but for quality, a 45 is better. Audiophiles prefer the way 45 rpm sounds, but 33 is more practical due to the added storage space.

In a 45, more information is sent per second, resulting in a greater level of detail and, as a consequence, better audio quality. This is particularly noticeable in higher frequencies, giving the audio a more realistic feeling – a huge advantage. It also preserves further details of the original music, which are otherwise lost.

This makes 45s attractive to vinyl collectors and music lovers who obsess over audio quality and love the extra depth and resolution provided.

Then why aren’t all records 45 RPM?

Cost and space are the primary factors. Indeed, 45 rpm is much quicker than 33 rpm. Because of this, a 12′′ 45 rpm vinyl record has less music than a 12′′ 33 rpm record. As a result, if the songs are very lengthy, just one or maybe two tracks will fit on each side of a 45.

To hold everything, an LP or album would need more discs. This increases the overall production costs, including the pressing cost, mastering cost, labels, plating cost, and jackets. Because of this, 12″ 45 rpm records aren’t as prevalent as they once were, although they’re still used for promotional purposes.

Secondly, they store less audio, allowing fewer grooves on the disc. This makes them unsuitable for long-play records, which need the extra space to fit extra music. This is why 33 is still such a common format. It has the benefit of storage space, allowing for a massive increase in recording times.

How can you tell if a record is 33 or 45?

Learning to tell the difference between rpm speeds is important and helps you find records of the right style for your needs. It also helps so you can choose the right rpm speed on your record player when you spin the disc.

So, if a record is 33 or 45 rpm, how do you know?

Generally, if a record is 12”, it’s a 33. The only exception to this is when a single or EP (extended play) is pressed on a 12”, where sometimes they might be able to use 45, maximizing audio quality thanks to the shorter playing time.

7-inch tends to be cut at 45. Ultimately the best way to test it is to put it on and spin, and there’s no harm done playing it at the wrong speed. It will just sound weird, which is a clue to what the actual speed is. If it feels like a slower speed than normal and low-pitched, you’re probably playing a 45 at 33. If it sounds fast, with chipmunk-like vocals, then you probably have a 33 spinning at 45.

The speed is generally put on the central label (or jacket) if you’re not sure.

Another way to tell is based on the number of tracks per side. A 33 rpm 12′′ record is far more likely to include more than three songs on each side of the record, usually around 4-6 per side.

If there is only a single song per side of a 12”, chances are it’s a 45 unless it’s some kind of long 20-minute track or dubbed-out remix. The track count approach works nicely for 12”, although it doesn’t work so well for 7-inchers.

How do you play a 45 RPM record?

You might notice that some 7-inch records have a much larger hole than a 12”. In this case, you need to use an adaptor to play the record. Most turntables include one, although you can pick them up super cheaply.

To play it, simply pop the adapter over the center spindle, then slot the record onto the adaptor.

Then switch your turntable to 45, and get spinning. Note that not all 7-inch records come with larger holes, and you will find many that use the standard size.