Stylus speed inside the groove

[KlausR.]

What is Diameter Loss?

Eargle, "Performance characteristics of the commercial stereo disc", J. of the Audio Engineering Society 1969, p.416

Diameter losses are of three types: cutting losses, tracing losses, and deformation losses.

Cutting losses are the result of the finite width of the burnishing facets of the cutting stylus. At the short wavelenghts which occur when high frequencies are recorded at reduced diameters, there is a certain amount of self-erasure of the signal due to the burnishing facet.

Tracing losses are fundamental to the disc playback process. They would be present even if cutting and deformation losses were non-existent. They are due simply to the fact that tracing distortion, as wavelenghts grow short, gives rise to a reduction of signal fundamentals as more of the signal is converted into harmonics.

Deformation losses far outweigh tracing and cutting losses. They result from yielding of the vinyl or lacquer material under the force of the playback stylus.

Eargle then shows curves for diameter losses on vinyl with 18 micron stylus, which result in a reduction in level of 5 dB (7 kHz), 8 dB (10 kHz), more than 10 dB (14 kHz).

Klaus

 

[Groucho]

Eargle then shows curves for diameter losses on vinyl with 18 micron stylus, which result in a reduction in level of 5 dB (7 kHz), 8 dB (10 kHz), more than 10 dB (14 kHz).

Ouch!

You're into CD/SACDs now? ...The speed of a CD/SACD also varies according to the outer and inner circles (rotations).
- Spins faster at the beginning.
* More jitter at the beginning, or at the end of a "digital" CD?

Yes, unlike a vinyl record, the CD spin rate varies to maintain Constant Linear Velocity. It is slaved to the crystal-clocked DAC via a buffer, and merely has to keep up with the required data rate on average. As long as this requirement is met, the transport makes not one iota of difference to the playback quality.

Later optical formats such as the audio CD also employ CLV to maintain both a constant data rate and a constant bit density. Their rotation gradually decreases from 495 to 212 rpm to keep the disc moving past the read laser at 1.2 m/s (3 ft. 11 in. per second).

http://en.wikipedia.org/wiki/Constant_linear_velocity

 

[KlausR.]

Originally Posted by KlausR.
Eargle then shows curves for diameter losses on vinyl with 18 micron stylus, which result in a reduction in level of 5 dB (7 kHz), 8 dB (10 kHz), more than 10 dB (14 kHz).

Ouch!

Tracing distortion is generated because of the difference of the geometries of cutter and playback stylus: the sharper the latter, the lower that distortion.

Deformation loss is easy to decrease: use styli with large contact area and low tracking force.

That's two of the reasons why I use the Shure V15 with microridge stylus.

Klaus

 

[Soundproof]

So many myths, so little time.
I love vinyl, have thousands of records and several turntables - but I also have a very straightforward relationship to their claimed fidelity to the original recording ...

Whenever I demonstrate the consequences of the "speed over terrain" outer-to-inner-groove variation of vinyl, and relate that to the eq-curves used to compensate for bass/treble deficiencies relative to those terrain domains, we agree to just sit back and enjoy the music, while listening past the many imperfections.

Somehow, a lot of people don't hear them ... but there is no 1:1 relationship between source and output on vinyl.

 

[NorthStar]

Stylus, LP's grooves, travelling between the walls, cartridges (MM & MC), ...

MC cartridges have more frequency extension than the MM ones. ...Why?
Also, their different output voltage matched with the proper phono preamp; what beneficial contribution does one provide from the other one in reading accurately the original music contained in the grooves?

Last, what is truly the very best shape and material stylus to get everything right that is contained between the walls of the groove?
...And without any damage to the walls for a long-lasting pleasurable listening experience.

 

[Soundproof]

Stylus, LP's grooves, travelling between the walls, cartridges (MM & MC), ...

MC cartridges have more frequency extension than the MM ones. ...Why?
Also, their different output voltage matched with the proper phono preamp; what beneficial contribution does one provide from the other one in reading accurately the original music contained in the grooves?

Last, what is truly the very best shape and material stylus to get everything right that is contained between the walls of the groove?
...And without any damage to the walls for a long-lasting pleasurable listening experience.

MC-styli are (adding: usually) lighter and finer beasts, and therefore able to resolve better. There is less suspended on the cantilever's opposite end, compared to MM, and therefore the cantilever assembly is more responsive to the groove variations.

However, while able to resolve a greater range, it's probably worthwhile to investigate how much is actually in the groove, in the form of a music signal. (A lot of people are confused by the carrier tone for half-speed mastered quadraphonic LPs, thinking the higher frequency carrier tone contained music, it carried instructions for the routing of the musical signal to the four channels).

While more sensitive, MC-cartridges do not generate as much of a signal current as MM cartridges. B&O developed a moving iron micro-cross system which is today preferred by Soundsmith, where one sought to reduce the moving mass even further, while actually getting more of an output signal than that achieved with the finer MC-cartridges.

As to best shape and material stylus - that's a long discussion. Some shapes are preferred today, because they get deeper into the groove on pre-owned records, past where other styli have worn the walls, to virgin territory. As you point out.

This is a good link: http://www.vinylengine.com/turntable_forum/viewtopic.php?t=22894

 

[KlausR.]

MC-styli are lighter and finer beasts, and therefore able to resolve better.

Wrong, as the below list of effective tip masses shows.

0.270mg Denon DL-301 (MC)
0.250mg Denon DL-207 (MC)
0.240mg Van den Hul Colibri (MC)
0.220mg Ortofon Jubilee (MC)
0.180mg Denon DL-303 (MC)
0.170mg Shure V15VxMR (MM)
0.168mg Denon DL-305 (MC)
0.098mg Technics EPC-100CMK3 (MM)
0.077mg Denon DL1000 (MC)
0.055mg Technics EPC-P100CMK4 (MM)



Klaus

 

[Soundproof]

Wrong, as the below list of effective tip masses shows.

0.270mg Denon DL-301 (MC)
0.250mg Denon DL-207 (MC)
0.240mg Van den Hul Colibri (MC)
0.220mg Ortofon Jubilee (MC)
0.180mg Denon DL-303 (MC)
0.170mg Shure V15VxMR (MM)
0.168mg Denon DL-305 (MC)
0.098mg Technics EPC-100CMK3 (MM)
0.077mg Denon DL1000 (MC)
0.055mg Technics EPC-P100CMK4 (MM)



Klaus

Yes, there are exceptions, and lots of different applications of the approaches - my answer was as a general rule, when it comes to how they resolve.

I use MM, MC and Moving Iron on different turntables, and like what I hear.

 

[MylesBAstor]

http://www.vinylengine.com/turntable_forum/viewtopic.php?t=30049

 

[jcarr]

Eargle then shows curves for diameter losses on vinyl with 18 micron stylus, which result in a reduction in level of 5 dB (7 kHz), 8 dB (10 kHz), more than 10 dB (14 kHz).

Klaus

The effects of groove diameter on LP frequency response have likewise been noted in the Japanese audio engineering press, and specifically pointed out by Denon and other cartridge manufacturers. In practice, it makes phono cartridge frequency response a bit meaningless, as the measured frequency response will change depending on the groove diameter of the frequency response track.

Last week I spoke to a German audio magazine editor who plans to make a test LP. One of the requests that I made was for frequency response tracks placed at both the innermost and outermost grooves, to make it easier to see how groove diameter and stylus shape interact to affect the measured frequency response.

kind regards, jonathan carr