[ Home | Staff & Contacts | HiFi Playground | Listening tests | DIY & Tweakings | Music & Books ]

Turntable tests - Methodology

[Italian version]

Reviewer: Geoff Husband

I've already explained what prompted me to start this series of tests, now I hope to explain how the tests will be undertaken and why...

Generally turntable test are undertaken by simply removing the existing turntable and substituting the one under test. Then over a series of days an impression is gained of the turntable - this is wholly subjective and relies on comparing notes and longer term memory...

I wanted to do something that removed as much of the subjective element as possible. I also wanted a method whereby I could directly refer to a review done 12 months previously. There was only one way to do this and that was to have a fixed reference and a complete duplicate set of identical ancillaries for the 'reference' and the turntable on test. As in a scientific experiment I had to remove as many variables as possible. This formed the Stage 1 of each test and in many ways was the most important and revealing part of the review.

Here a quick note on my decision to ask for turntable/arm/cartridge combinations. Yes you're right, doing it this way means that a superior turntable might be marked below another simply because it uses an inferior arm. However the alternative was to ask everyone to supply the turntables with an SMEIV, the result of which would merely rank the turntables in order of how well they worked with this arm. I told the manufacturers how the test was going to be done and asked them to provide the arm they thought was most appropriate - this way they lost a hiding place if their table failed to please. I also advised them to provide appropriate cartridges though with the three I had lined up this was less critical.

Stage 1

The Reference - my own Michell Orbe and SME IV tonearm. It's a well-known, well respected and widely available deck, ditto the arm. Having used it for over 18 months I know it intimately and know how to get the best from it, allowing me to concentrate on the review turntable.

By re-arranging my hi-fi I have made space on the turntable shelf for a second table.

Now the tricky bit... I needed complete duplicates of everything.

So underneath each turntable goes the Clearlight turntable support. Why this support? - It's a sturdy base, the Cetech tested earlier wouldn't cope with 40kg+ turntables and at least one that heavy was booked in. It's also a medium mass affair and incorporates damping rather than springs or bladders, which can upset suspended turntables. After a lot of thought I chose it mainly because I didn't expect it to wildly favour one design over another. It works very well under the Orbe, leaving its tonal balance essentially unchanged while sounding more open than when just on a slab of MDF - perfect and thanks go to Clearlight...

Then the biggest problem, two high-end cartridges good enough to reveal the differences between megabuck turntables. I owe a huge debt of thanks to Len Gregory for the loan of two of his "Music Maker" cartridges, already well reviewed by Lucio... Make no mistake these are real high-end devices as the first test is now confirming to me. However here there is an inevitable snag. Whatever cartridge I chose would immediately favour one arm over another. In the case of the 'Music Maker' it is a high compliance moving-iron (high-output) device. This needs bearings with the lowest friction possible, unipivots being ideal, and dislikes arms with a high effective mass. During the tests I will bear this in mind, but sadly it's an inevitable compromise. Len also supplied his stylus guage and level, without them the test would once again be worthless, a 0.1grm difference in tracking force being capable of producing 'differences' not down to the turntables, ditto if one of the turntables was out of level. Final adjustment is then carried out with the help of the HFNRR test disc.

My Audion Silver Knight pre has a superb valve phono stage, but only one, I needed two. Enter a 'White Knight' in the form of Graham Slee. He happily supplied two of his GramAmp2 phono stages. These are wonderful devices for beer money and my experience with them made me consider them capable of showing up front-end differences even at the high-end. I was right... Graham even included the optional bigger power supplies, which managed to lift the performance, particularly the sense of scale and openness, to a point where at times they were a match for the Audion stage...

Cables? AudioNote supplied two runs of their silver interconnects and using them the signals from the Gram2's were fed into two vacant line inputs of the Audion.

And lastly records... I managed to obtain a few duplicate discs.

So now I can run two turntables back to back, and at the flick of a switch hear one, then another. Usually switched A/B comparisons are worthless because of the variables involved, here any differences are down to the turntable and arm - nothing else... My doubts about the effectiveness of this were banished the first time I did it - the results were quite stunning.

Stage 2

But as I said before, the cartridge interaction with the arm is critical, inevitably biased to one design more than another. So the next stage is to remove the 'Music Makers' and begin the time consuming swapping and testing between different cartridges. Here I use whatever the turntable is supplied with (I asked for complete turntable/arm/cartridge combinations whenever possible), along with my Dynavector XV-1 and XX-2 and of course the Music Maker. This means I have two high-end moving coils, the first a highly demanding exotic because of its weight and ultimate resolution, the second more 'typical' of the breed, plus one of the finest high-compliance cartridges on the planet. An arm that fails with all three is in big trouble... In the case of the Orbe I know that the best possible sound is with the DRT-1, the Dynavector step-up and the Audion phono stage. The whole point of Stage 2 is to match or beat it with whatever I had to hand. Though now there are times when switched A/B comparisons are impossible, it is the work of 2 minutes to swap leads to change set-ups so my memory of any differences is sharp. If both preferred the DRT-1 the 'swap time' is 20 minutes, about the maximum for really detailed differences.

Stage 3

After all the hard work I need a break and now the pleasure begins. I take the turntable down from its lofty perch and set it down on the Clearlight equipment table, chosen for the same reason as their turntable support. Here the turntable remains with its preferred cartridge and I just play music:-) Other components might change in order to drag out the last ounce of fidelity but mostly I will just listen. Two weeks of living with the table can often change an impression. An incredibly detailed table may begin to sound harsh and wearing, a lush warm one 'slugged' At the end of the review period was I enchanted or disappointed? Did it push me to certain types of music? And perhaps most important of all - did I miss it when it went...

Scoring

I hate this... 'Five Star Review' nonsense and 9/10 are in my eyes totally discredited.

In a former life I was a school teacher and part of my training was the assessment of children's work. It was drilled into me that if a marking scheme was say A, B, C, D, E. then to use only A+, A, A-, A/B and B+ made a mockery of the system, and of course we've all seen this sort of thing. A well known French Hi-Fi magazine marks components out of 10 in five categories. In a recent group test 10 speakers were tested and none got less than 8/10 in any category, this is of course worthless...

However I really wanted a system whereby readers could refer back to previous tests and have some idea of the absolute performance of a turntable relative to another tested twelve months previously. A 'marks out of ten' scale was obviously useless as if a turntable gained 9/10 and the next month I found a better one, then the next month one came along that was better still what would I do ?- 11/10? Rubbish!

So in the end I did the obvious. With a fixed reference, all I needed to do was to mark everything relative to that. So I chose a system whereby in a series of categories the Orbe/SME would be marked as 0. The test turntables would then be marked relative to that, therefore a turntable that gave the same soundstage width as the Orbe would get a 0 for that category. One that gave slightly better soundstage width would gain a +1, slightly worse would gain a -1.

The smallest difference i.e. + or -1 would be a difference that was only just apparent but of no real importance, a 2 would be a difference easily spotted in an A/B and the sort of thing that might, over a long term, become significant. A 3 would be noticeable enough to identify which turntable was playing blind. Higher numbers are less specific but allow further and further improvements to the scale. With each mark comes a comment to explain why if necessary. Obviously the categories that don't deal with aspects of sound will not be marked in exactly the same way but I try to keep them equally balanced.

Having sorted out the 'perfect' marking scheme, now to choose the categories... This I did with some trepidation, but you'll have to put up with them - it is my review after all. So the list is - Beauty, Fit and Finish, Engineering, Compatibility, Speed stability, Timing, Dynamics, Stage width, Stage depth, Bass depth, Bass control/speed, Midrange clarity, Detail retrieval, Treble extension, Treble quality, Overall Colouration, Realism and last and by far the most important - 'Miss you!' factor. As this category is the 'crunch' one, the differences in scores will often be greater than the others, though who knows, I may get a turntable with lot's of 'negatives' and yet which just pleases.... You'll note no 'Value for money' category. This is because these tests are all absolute, only you can decide whether a superior performance justifies a given higher price.

So with reference to the Orbe/SME how do I rate it the various categories?

Looking at this I hope you'll see that a really good alrounder will not automatically get 0's all through, rather it'll be better than the Orbe in some areas and worse in others.

OK to give a final idea of how this all works I'm going to do a 'dry' run. As you no doubt know (hey! - you read all my stuff!) my Orbe replaced a MK111 Gyrodec with SMEIV. So here is a 'rough' marking done from memory, it is NOT definitive as there is no back to back work and so is intended solely to give an idea of how the marking scheme works in practice.

So - Marking for Michell Gyrodec/SMEIV

So you get the idea? In this case the much cheaper Gyro scored quite a few negatives as you would expect. Whether the price difference justifies this is up to the person with the cheque book:-)

Then the review gets written... 2000+ words to describe as best I can exactly what turntable x is all about, and hopefully you read it:-)

Thanks

After reading this methodology I hope it is evident that without the following companies this series of reviews would have been impossible - thanks from me to them:-)

'The Cartridge Man' - http://www.thecartridgeman.com

Graham Slee - http://www.gspaudio.co.uk/

Clearlight - http://www.clearlight-audio.de

AudioNote UK - http://www.audionote.co.uk

© Copyright 2001 Geoff Husband - http://www.tnt-audio.com

[ Home | Staff & Contacts | HiFi Playground | Listening tests | DIY & Tweakings | Music & Books ]