Why records can sound worse at end of side...an explanation

MajorFubar

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Assertion: I have not started this thread to slag-off records. I love records and embrace them in my home audio system, although in a minor way compared to digital. I just became aware that I’ve mentioned several times in threads how a record’s linear velocity decreases as the stylus moves closer to the label, and cited that as a reason why records can often sound worse at the end of each side. But what I haven’t ever done is explained what I meant by all that, for those who haven’t a clue what I’m on about.

So here goes. Long thread alert.

This is your average LP, but with its label blanked so this thread doesn’t quickly degenerate into a conversation about my musical preferences:



An LP record is typically 30cm diameter with a 100mm label. We know from our high school maths that the circumference at any point is 2πr or πd. So at the very outer edge (where obviously there won’t be any music, but work with me here), that’s a circumference of (30cm x 3.142) = 94.3cm. The last track is commonly at around the 7cm or 8cm radius, as you can see from this stereotypical 7 track LP. The circumferences at those points are 50.3cm at 8cm radius and 44cm at 7cm radius, so potentially less than half the outer circumference.

Ok, so why is this important?

Unlike a CD / DVD / BluRay disc, a record has a constant rotational velocity. An LP rotates at 33.33rpm. So at the very outer edge of an LP, were there any music in that section, 3,143cm (94.3cm x 33.33) of vinyl passes under the stylus every minute. There’s 60 seconds in a minute, so that’s (3,143cm / 60sec) 52.38cm per sec (or 20.6 inches per sec, in old money). This is what’s called the linear velocity.

However, by the time the stylus reachers the 8cm radius (50.3cm circumference), the linear velocity has plummeted. 50.3cm x 33.33rpm = 1,676.5cm per minute, or (1,676.5cm / 60sec) 27.9cm per sec (11 inches per sec). At 7cm radius it’s 24.4cm per sec (9.6 inches per sec).

Ok so why is even *that* important?

With analogue recording, be it vinyl records or tape, one of the contributing factors to fidelity, especially with higher frequencies and complex waveforms, is the speed at which the medium passes the reading/writing device, be that the stylus or tape recorder head. There’s literally only so much content you can cram in the plastic or magnetic particles in short distances, and because high frequencies and complex music have tightly-packed waveforms, there comes a point where the medium is travelling too slowly past the stylus/head to store the waveforms without deterioration (distortion in other words).

Engineers can manage the effect of this deterioration in various ways. One way is to only cut short records which don’t surpass 16-17 minutes per side, reducing the need to cut into any plastic closer than 7.5cm from the centre. Another clever trick is careful track sequencing, so that quieter tracks are closer to the inside and the floor-filler head-banging stuff is further out. This can be challenging when recording e.g. classical pieces. 1812 Overture is a perfect example, where the 16 minute opus builds from near silence to a loud climax. Luckily, 16 minutes is not too difficult to cut without compromise, especially when much of the piece is quiet, so the grooves in those sections can be very close together giving more space for the end.

This sounds all doom and gloom, but over the years, much progress has been made to help. Better quality vinyl and better stylus profiles, which more accurately track the teeny tiny undulations at the end of a record, both contribute massively. But sadly, the best stylus profiles don’t come cheap.

A factor I haven’t mentioned is stylus alignment, which warrants a whole explanation in itself. But in a nutshell, because the arm follows an arc (except on linear tracking turntables), the arc impacts the angle the stylus tip sits in the groove, which inevitably changes slightly throughout the duration of a side.

As a consequence of all these things, LPs often sound their best two tracks in from the start. The outermost track, although with the fastest linear velocity, can often have louder vinyl roar, and also the stylus alignment is probably not at its best there. So it becomes a balancing act between the linear velocity and the stylus alignment. All things considered, records probably sound best at their 9cm -13cm mark, which by no coincidence is where the average pop LP’s best songs and singles are cut (compilations aside, obviously).

Happy to discuss and explain further, but let’s keep it civil. This is not a “let’s slag off records” thread.
 

nopiano

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Indeed, a very good explanation for the uninitiated! A bit like switching from 7.5ips to half that on a reel-to-reel tape, for those who remember them. I’ve always thought it was something of a miracle that LP ever sounded so good, and I grew up with them as ‘the’ source, where FM radio and Dolby cassette was very much secondary.

They were so ubiquitous we never really gave it much thought. But when you see the amazing engineering and results from top turntables today it is quite extraordinary.
 

chebby

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This is why 12” singles were so good. Bags of ‘real-estate’ for big groove excursions. They - typically - didn’t go anywhere near the centre like LPs either.

Anyway it’s all bollox now because we have digital thank goodness. (Unless you are a hopeless nostalgic or a ******* hipster!)

Edit: I always favoured Stevenson geometry (which slightly ‘favoured’ inner grooves compared to Baerwald).
 

MajorFubar

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nopiano said:
Indeed, a very good explanation for the uninitiated! A bit like switching from 7.5ips to half that on a reel-to-reel tape, for those who remember them. I’ve always thought it was something of a miracle that LP ever sounded so good, and I grew up with them as ‘the’ source, where FM radio and Dolby cassette was very much secondary.

They were so ubiquitous we never really gave it much thought. But when you see the amazing engineering and results from top turntables today it is quite extraordinary.
Indeed. Great-sounding records are an absolute triumph of clever engineering over physical limitations. Long may they live.
 

newlash09

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Was a very interesting read indeed. I guess some kind of new HD vinyl is in the offing. With supposedly greater headroom. Don't know if they can mitigate this limitation. I've never tried a vinyl setup myself, but I heard a not so great one and came away unimpressed. Still open to hearing a well setup system, as not everyone can get it right. But really need to hear one, to know why people even bother to put in all that effort and tweaking to get playing, when digital is so easy and straight forward. Is it nostalgia or sound quality or a sense of dedication to a critical listening session :)
 

insider9

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I knew of this but not really ever stopped to think why this is. This makes it very clear.

So here's a thought why not have vinyl in a shape of a ring? Somewhat looking like a car tyre. With grooves on the outside this would take care of linear velocity issue.
 

newlash09

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insider9 said:
I knew of this but not really ever stopped to think why this is. This makes it very clear.

So here's a thought why not have vinyl in a shape of a ring? Somewhat looking like a car tyre. With grooves on the outside this would take care of linear velocity issue.
+1 :)
 

insider9

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newlash09 said:
insider9 said:
I knew of this but not really ever stopped to think why this is. This makes it very clear.

So here's a thought why not have vinyl in a shape of a ring? Somewhat looking like a car tyre. With grooves on the outside this would take care of linear velocity issue.
+1 :)
I'll be expecting a cut if you decide to progress with this idea ;)
 

chebby

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insider9 said:
newlash09 said:
insider9 said:
I knew of this but not really ever stopped to think why this is. This makes it very clear.

So here's a thought why not have vinyl in a shape of a ring? Somewhat looking like a car tyre. With grooves on the outside this would take care of linear velocity issue.
+1 :)
I'll be expecting a cut if you decide to progress with this idea ;)
Too late.
 

Infiniteloop

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This is precisely why ‘audiophile’ pressings are 180gram and 45rpm. A simple but highly effective work around.

There’s tons of life left in Vinyl yet and that’s why it continues to increase in popularity.
 

nopiano

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Half speed mastering was designed to get around the challenges, at least from a cutting perspective. Of course it presents other problems but that’s life!

And, as above, 45rpm is a solution of sorts (though I’m not personally a fan as itreminds me of scratchy Beatles singles on a record player wired through the radio!)
 

MajorFubar

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insider9 said:
I knew of this but not really ever stopped to think why this is. This makes it very clear.

So here's a thought why not have vinyl in a shape of a ring? Somewhat looking like a car tyre. With grooves on the outside this would take care of linear velocity issue.
Mass duplication is the problem, and is one of the reasons why the cylinder was not as successful as Berliner's phonograph. That and the fact you need a pretty long cylinder to get more than 3-4 minutes. Or have it as wide as a sewer.
 

Al ears

Moderator
nopiano said:
Indeed, a very good explanation for the uninitiated! A bit like switching from 7.5ips to half that on a reel-to-reel tape, for those who remember them. I’ve always thought it was something of a miracle that LP ever sounded so good, and I grew up with them as ‘the’ source, where FM radio and Dolby cassette was very much secondary.

They were so ubiquitous we never really gave it much thought. But when you see the amazing engineering and results from top turntables today it is quite extraordinary.
+1
 

MajorFubar

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Apologies, I missed responding to this:

newlash09 said:
But really need to hear one, to know why people even bother to put in all that effort and tweaking to get playing, when digital is so easy and straight forward. Is it nostalgia or sound quality or a sense of dedication to a critical listening session :)
For all its foibles, there's nothing quite like owning and listening to your favourite album on a record. 'Tactile' is a word that sums it all up nicely for me. You feel part of the process, not just a witness to it. Infinitely more tactile than streaming, even way more tactile than watching a CD get swallowed into a box and hitting play on the remote. In fact you don't listen to your favourite albums on LP, you experience them. Sorry that sounds vague and just a touch sanctimonious. But it's the best way I can explain it. I guess it's something you either get or you don't, and it's totally fine either way.
 

insider9

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MajorFubar said:
Apologies, I missed responding to this:

newlash09 said:
But really need to hear one, to know why people even bother to put in all that effort and tweaking to get playing, when digital is so easy and straight forward. Is it nostalgia or sound quality or a sense of dedication to a critical listening session :)
For all its foibles, there's nothing quite like owning and listening to your favourite album on a record. 'Tactile' is a word that sums it all up nicely for me. You feel part of the process, not just a witness to it. Infinitely more tactile than streaming, even way more tactile than watching a CD get swallowed into a box and hitting play on the remote. In fact you don't listen to your favourite albums on LP, you experience them. Sorry that sounds vague and just a touch sanctimonious. But it's the best way I can explain it. I guess it's something you either get or you don't, and it's totally fine either way.
Major, absolute know what you're talking about. This is what Roon gives me for digital. Would you be interested trying it? You can usually get a 60 day trial somewhere on the web. There is no credit card necessary. Just register with email. I could find a code for you if you'd be prepared to try. All you do is download Roon tell it where your files are located and that's it. Then you get an app for mobile or tablet to control it.
 

MajorFubar

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I'll take a raincheck on that at the moment insider, but allow me to take you up on it at a later stage if I may.
 

newlash09

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MajorFubar said:
Apologies, I missed responding to this:

newlash09 said:
But really need to hear one, to know why people even bother to put in all that effort and tweaking to get playing, when digital is so easy and straight forward. Is it nostalgia or sound quality or a sense of dedication to a critical listening session :)
For all its foibles, there's nothing quite like owning and listening to your favourite album on a record. 'Tactile' is a word that sums it all up nicely for me. You feel part of the process, not just a witness to it. Infinitely more tactile than streaming, even way more tactile than watching a CD get swallowed into a box and hitting play on the remote. In fact you don't listen to your favourite albums on LP, you experience them. Sorry that sounds vague and just a touch sanctimonious. But it's the best way I can explain it. I guess it's something you either get or you don't, and it's totally fine either way.
I get the spirit of what you were trying to convey. Being a part of the experience has summed it up nicely. Thanks
 
Infiniteloop said:
This is precisely why ‘audiophile’ pressings are 180gram and 45rpm. A simple but highly effective work around.

There’s tons of life left in Vinyl yet and that’s why it continues to increase in popularity.
And also spreading an album over four sides rather than two - keeps the stylus away from the centre of the record.
 

iMark

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davidf said:
And also spreading an album over four sides rather than two - keeps the stylus away from the centre of the record.
It's remarkable that after all the faff in most cases you end up with a copy that sounds worse than the original digital file from which the record was cut. The records also wear out when you play them and as a bonus you get free added noise!

I still like playing records. We even bought a couple yesterday on Record Store Day. But I tend to digitise them as quickly as I can to ALAC files to go into the iTunes library. We bought a direct to vinyl recording by Rag'n'Bone man yesterday. Yellow vinyl, 12 inch single. Nice sound!
 

MajorFubar

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iMark said:
davidf said:
And also spreading an album over four sides rather than two - keeps the stylus away from the centre of the record.
It's remarkable that after all the faff in most cases you end up with a copy that sounds worse than the original digital file from which the record was cut. The records also wear out when you play them and as a bonus you get free added noise!
Conversely, I have various inherrited records in my collection dating from the late 50s which have been played hundreds of times. Contemporary opinion suggests they should at the very least have lost all their HF content by now, yet a spectrum analysis shows they still have HF content to beyond 15kHz, which was probably the limit of the three-track Ampex tape recorder and the cutting head. They all still play significantly quiter with less pops and bangs and surface noise than a modern LP after half a dozen plays. We were better at making records then, for some reason.
 

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