Alternative platters ?

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Originally Posted by Mike_New

Paul,
It would seem that maybe you would have the abillity and equipment to persue an experiment I have been
considering for some time now. There is always discussion on the type of mat to use (and platters for that matter)
My idea is this: to actually try to measure the amount of reflected/transmitted energy through the record material.

This could be done using a second arm running on a perfectly smooth surface, I have used a CD (recorded side) on my single SME V
and the surface noise is very low. I guess a piece of thin plate glass would be better. I know this is what we used to check the surfaceometers (which used a MM cartridge) when I worked at AWRE in the metrology section for a while. Now the second arm could be connected to the required electronics and a speaker, whilst the first arm is actually reading the track but not being output to a speaker. What do you think?
With some extra effort an annulus (annuli?) could be made so that various positions on the record could be measured.
This way even the effectiveness of centre weights and maybe bearings could be measured.
Effective sonic connection of the plain medium to the record could be a problem.
The ultimate perhaps would be a laser sensor.


PS: If you think this is off topic Marco then move it to another thread.

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Mike, this has given me a few ideas, I'll PM you some thoughts

Cheers

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Originally Posted by Macca

You don't do mechanical engineering without measurements. As for the headphones would a truer statement be 'they measure poorly but sound coloured (which some people will prefer)' ?

I appreciate no-one has sent a bearing back. That implies to me it is at least as good as the exisiting bearing at doing the job it is intended to do, but that is all I glean from it. After going to the trouble of fitting it you would only return it if it actually made things worse. I'd be surprised if it did not improve wow, flutter and noise, or at least one of those parameters. It's the fact that we don't know if it does or not because no-one has measured this when it should have been the first thing done before offering it up for sale.

I'm being controversial and a pain I the arse I know but these points should be raised even if most people will dismiss them with 'well it sounds good to me.'

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Vantage audio claim a -2 DB improvement with a modified bearing , perhaps Noel Keywood could test it ? Any chance of this I wonder .

I think it it would be useful to know and put this to bed once and for all .

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Originally Posted by howlindawg

No offence, but at £445 I would expect most people to return it if it didn't make for a significant improvement in percieved sound quality.
It only takes a few minutes to swap bearings so why would someone part with that amount of cash if they find it offers no improvement?

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Martin - no offence taken - There will be a number of factors that will effect the percentage of returns of any product that is not actually faulty. In this specific case, and as I understand it, until recently that would mean returning the bearing to Australia. In fact I'm not sure returns were an option at that point ( although I stand corrected if they were). In any case tweaking a hi-fi system is rarely straightforward. I can imagine many people fitting the bearing, listening over time and thinking that it was making some positive contribution in some areas. These things are rarely night and day. The general consensus is that the item does make an improvement so even if you can't hear it you may decide that it is due to issues elsewhere in your system, that, once sorted, will let the improvement show through. The price is at the level where the likely purchaser is going to have a fair amount of disposable income and quite possibly leads a very busy life - enough to add to the lethargy factor in terms of returns. 'I can't hear an improvement so I could send it back and get a refund but what the hell, it works fine and it's just too much bother.'

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Originally Posted by Macca

I can imagine many people fitting the bearing, listening over time and thinking that it was making some positive contribution in some areas. These things are rarely night and day.

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In the case of the MNB against the stock,i would argue that there is a night and day difference,which is immediate and doesn't require lots of listening time! I was dubious about all the claims at first but having taken the plunge i can see it was wholly justified! :)

Whether the platters offer the same level of upgrade i don't know,so will be interesting hearing people's thoughts on that!

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Originally Posted by synsei

An honest to goodness question Martin, if via a demonstration you heard for yourself the improvement the MN bearing can bring to a Techie would you still require a spec sheet?

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The problem is that's so hard to do. It is this issue of route to market and the decline of the hifi retailers I bought my gear from 30 years ago. I want to go into a shop and listen to the shortlist I'm Interested in. A few on here are priviliged to be able to borrow kit extensively. That is a tiny percentage of normal users. They need shops.

And measurements are both valuable in product development and "screening" for auditioning. I'll post those headphone measurements soon. Whilst measurements don't tell all they give some useful clues about whether that sound we like and choose is hi fidelity or hi likeability (coloured). The headphone tests made that point really well

Martin Colloms once did some turntable/platter/ mat tests once for 'Choice at the very least and the confirmation was definitely that what was right for one turntable (Dumpa style squidgey mat on a Thorens 160 for example) could be a disaster if the same mat was plonked on a different deck, such as an LP12 in this case, whereas a Linn felt mat to me sounded horrid on a GL75, which sounded far better with its own heavy ribbed one.

At the time (80's), the material as used in PT (and Void?) platters was judged to be the closest to properly optimising/terminating the vinyl when played as any material could get. I'm surprised that composite platters are now 'the thing,' unless it's for cost/machining reasons?

The thing is, any proper objective suggestions or methodology on such stuff has gone out of the window I reckon, so now, one man's huge improvement may actually be taking the sonics away from what is strictly the higher fidelity (to the source material) approach. Selling mail order and bake-offs is a fun thing for the hobbyist, but hardly takes the industry forward in my current opinion - and no, decent dealers like happy customers who DON'T keep coming back every few months for numerous dubious 'upgrades,' swinging with the tides. Rather, a good few clients who stay in touch occasionally over a twenty five or more year period for occasional major and thoughtful changes.

Recalling Pink Triangle introduced the world to the impedance match concept in the guise of the acrylic platter (obvious).
Martin Colloms then went forth, measured and produced results that showed a nicely damped response to a pulse.
What was not obvious was the actual effect that this transformation achieved. But it did sound "good".

If we look at FXR, measurements show a similar, order of magnitude improvement in the measurements.
Again, we extrapolate to a highly beneficial sonic experience.
But again, can we put our finger on just what we are going to experience? Not in the least. We only know we ought to be in for a treat.

Now, what about dynamic wow? The hypothesis seemed reasonable.
(Briefly: with 2g the minimum force required to keep the stylus in the groove at all times, track a 3kHz reference tone, apply a 2g load (a dustbug set to 2g!) and measure any drift)
Look! The results indeed showed problems and on that basis, deleterious conclusions were drawn on the outcome. (In the hysteria surrounding the LP12, the damage to Pink’s credibility cannot be overstated).
Only this time, there was no justification whatsoever. Although the full analysis is too long to provide here, try this gem:

In the publication, all turntables slowed (as they ought); all that is except DDs, which measured zero! Nil. Nix. Nada. I.e. Perfect. (Go dig out your original HiFi Choices)
What happened? Given the settling time, the servos had kicked in and pulled the platters up to speed. Moral: Measure at your peril!

Back to the thread: Having agreed that the original platter is indeed a weak link, we want to develop an improved one. But designers have their individual approaches.
One can indeed attempt to measure reflected energy but is that all there is to it? What about (as mentioned) the effect the servo has on the individual inertias?
Then we have the support quotient (for want of a label) to consider.
Here’s the problem: Regrettably, the ear, engineering solutions and measurements all travel along disparate paths, crossing fleetingly here and there.

Just look to cars and their setups when it comes to the driving experience. I like this car but you prefer that (and so just where does that leave the measurements?)
Similarly in our individual listening environments and systems, some will enhance and some will detract.

When developing a product, for what it’s worth, I bring to bear my 30 years experience into the design phase (creativity), develop interesting measurement methods - which I don’t always disclose (rigour) - and listen. Much tinkering and if I’m happy, the cake is baked. (The blend).

Ultimately you are left with cutting a slice, trying it when I hope you like it.
That’s subjectivism.

Voyd actually made two different 'plastic' platters. The cheaper was acrylic but they also made them from Lexan (polycarbonate).

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Originally Posted by kininigin

In the case of the MNB against the stock,i would argue that there is a night and day difference,which is immediate and doesn't require lots of listening time!

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Indeed - again this is the reality. Subtle is not the level of sonic improvement noticed when one upgrades from the stock Technics bearing to an MN one. It is immediate and fundamental. For 'subtle', see the likes of upgrading the headshell on the stock tonearm for a Sumiko.

Marco.

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Originally Posted by Macca

Martin - no offence taken - There will be a number of factors that will effect the percentage of returns of any product that is not actually faulty. In this specific case, and as I understand it, until recently that would mean returning the bearing to Australia. In fact I'm not sure returns were an option at that point ( although I stand corrected if they were). In any case tweaking a hi-fi system is rarely straightforward. I can imagine many people fitting the bearing, listening over time and thinking that it was making some positive contribution in some areas. These things are rarely night and day. The general consensus is that the item does make an improvement so even if you can't hear it you may decide that it is due to issues elsewhere in your system, that, once sorted, will let the improvement show through. The price is at the level where the likely purchaser is going to have a fair amount of disposable income and quite possibly leads a very busy life - enough to add to the lethargy factor in terms of returns. 'I can't hear an improvement so I could send it back and get a refund but what the hell, it works fine and it's just too much bother.'

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+1.