Fun with vinyl measurements

[melloncolliecat]

Yes- the 'mat'.

OK, thanks! Do you have any measurements of different mats and how they behave?

 

[Balle Clorin]

I tried with and without mat , could not really see much difference in the sound floor it spectrum of a W&F track. Possibly not the correct/suitable test to too. I suspect a mat should isolate against bearing noise and rumble an drive noise.

Some change due to VTA change must be expected

 

[atmasphere]

OK, thanks! Do you have any measurements of different mats and how they behave?

Not a lot. Most of the mats I've encountered don't work so measurements were pretty pointless. The ones that do work I've been able to count on one hand.
Its easy to measure what they do if you put a microphone near the cartridge. A good mat will be measurably lower sound pressure on the mic. Of course you can hear this by simply having the volume all the way down.

 

[melloncolliecat]

Not a lot. Most of the mats I've encountered don't work so measurements were pretty pointless. The ones that do work I've been able to count on one hand.
Its easy to measure what they do if you put a microphone near the cartridge. A good mat will be measurably lower sound pressure on the mic. Of course you can hear this by simply having the volume all the way down.

Interesting. I haven't noticed a difference, but I don't have a lot of different mats, only a few. Are there any particular types of mats you think would perform better in a test like that?

EDIT: Would you care to mention those few that you think do work?

 

[atmasphere]

Interesting. I haven't noticed a difference, but I don't have a lot of different mats, only a few. Are there any particular types of mats you think would perform better in a test like that?

EDIT: Would you care to mention those few that you think do work?

The best one we've seen is sold as a separate by Oracle. Not sure what the get for them but probably around $400.00. Its acrylic, with similar hardness to that of vinyl, which in a platter pad is really important if the pad is going to be able to absorb vibration at all frequencies without reflections.

The only other pad I've seen was built about 30 years ago by a private party that spent about 7 years developing it. I think its better than the Oracle, but its nla and was a lot more expensive even back then. It employed an aluminum disk to give it stability. It weighed about 6 pounds- some turntables couldn't handle it on that account alone. He sold the formula to SOTA, who used it on the first 100 of their Cosmos turntables. As I understand it they changed the formula around the 100th unit; I can't speak for how the newer pad sounds.

 

[melloncolliecat]

Thanks for answering! @atmasphere

Personally, I'm skeptical about the mats making such a difference, apart from isolating noise in the lower freqs. I'd love to see good measurements, though. There are a lot of acrylic mats (and/or platters) out there, for Rega and Pro-Ject TT's for instance,,I can't imagine them being that much worse than Oracle's equivalent...

 

[Balle Clorin]

Ultimate analog test record VTA track 60Hz:4000Hz + harmonics. This track is useless for VTA adjustments by the way- the track must be vertical modulated=out of phase for that, and it is not!!

Green=no mat
Red= 2mm mat
Cannot really see any difference , the noise level deviation is as as for variation between different sectios of the track
This may not be the correct method, It seem reasonable to me to listen/record the sound emitted directly from the stylus/record under play.

Silicone Turntable Platter Mat, svart

Meget god platespillermatte i silikon - perfekt for de av dere som leter etter mer demping enn det en filtmatte kan tilby. Produsert i 2mm mørk grå sil...

bigdipper.no

TACET vinyll Check record
Green no mat. red=Mat

Not sure what is going on here?? Vertical modulation.

Lateral modulation is identical with and without mat

 

[atmasphere]

Thanks for answering! @atmasphere

Personally, I'm skeptical about the mats making such a difference, apart from isolating noise in the lower freqs. I'd love to see good measurements, though. There are a lot of acrylic mats (and/or platters) out there, for Rega and Pro-Ject TT's for instance,,I can't imagine them being that much worse than Oracle's equivalent...

I get the skepticism. If you've not been exposed to a good mat, its likely that you would think they have no effect because most mats (I've seen, so IMO) are so much junk.

But the method I described is an easy metric to tell if the mat is doing its job. FWIW, if I use the Technics stock mat on my SL1200G, the stylus tracking the groove is easily audible from several feet away. When I replace the mat with the Oracle (and adjust the VTA, which is easy on the Technics) it changes quite a lot. Since that difference is about the vinyl resonating, its not much of a stretch to see how that can affect how the recording sounds.

I'm very convinced that since this variable is so acute and so misunderstood that its one of the major reasons people prefer digital. But when you nail this one down, its a very different picture.

 

[melloncolliecat]

I get the skepticism. If you've not been exposed to a good mat, its likely that you would think they have no effect because most mats (I've seen, so IMO) are so much junk.

But the method I described is an easy metric to tell if the mat is doing its job. FWIW, if I use the Technics stock mat on my SL1200G, the stylus tracking the groove is easily audible from several feet away. When I replace the mat with the Oracle (and adjust the VTA, which is easy on the Technics) it changes quite a lot. Since that difference is about the vinyl resonating, its not much of a stretch to see how that can affect how the recording sounds.

I'm very convinced that since this variable is so acute and so misunderstood that its one of the major reasons people prefer digital. But when you nail this one down, its a very different picture.

Alright, interesting. Are you referring to the same Oracle mat as mentioned in this discussion (1st post on 4th page)? https://www.vinylengine.com/turntable_forum/viewtopic.php?t=94733&start=36

 

[atmasphere]

Alright, interesting. Are you referring to the same Oracle mat as mentioned in this discussion (1st post on 4th page)? https://www.vinylengine.com/turntable_forum/viewtopic.php?t=94733&start=36

No. The mat I have from them is not sticky at all.

 

[Balle Clorin]

Quite A lot adjustment was required here.
Azimuth adjustment with new headshell with Azimuth adjustment…

 

[Thomas_A]

View attachment 343377
View attachment 343378
Quite A lot adjustment was required here.
Azimuth adjustment with new headshell with Azimuth adjustment…

I am sorry to say, but that is a faulty stylus that need replacement.

 

[mfalcon]

Thomas A,
I don't doubt you but how can you tell from the pictures?

 

[Thomas_A]

Thomas A,
I don't doubt you but how can you tell from the pictures?

In general, you want to adjust for deviations of the cartridge coils to match the V-shaped groove to get an even cross-talk. The stylus itself should not deviate more than +/-2°; if more you risk getting uneven tracing of the groove walls.

 

[mfalcon]

I see, and you are eyeballing that it's well outside the acceptable deviation?
Thanks

 

[Thomas_A]

I see, and you are eyeballing that it's well outside the acceptable deviation?
Thanks

From what I can judge, ≈8° off.

 

[Balle Clorin]

I am sorry to say, but that is a faulty stylus that need replacement.

Yes and the seller accepted my returns...the SRA was less than 85 too.

 

[Thomas_A]

Yes and the seller accepted my returns...the SRA was less than 85 too.

That’s good. Would be interesting to compare with the JICO when it arrives.

 

[Balle Clorin]

I have the Jico SAS it looks OK. But the VTA is high as anyone can see, 30degrees VTA not 20. SRA is still correct. See post 887

 

[VinyLuke]

I have the Jico SAS it looks OK. But the VTA is high as anyone can see, 30degrees VTA not 20. SRA is still correct. See post 887

Well according to the article on Audio p.21 (https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1981-03.pdf),
SRA is much more important to be correct than VTA.