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THE STORY OF
RINGMAT
JOHN ROGERS REVEALS
HOW HE AND DENIS MORECROFT CONCEIVED
AND DEVELOPED THE WORLD'S PREMIER TURNTABLE MAT
 Some
years ago I had a call from a gentleman in Holland; he was
interested in hearing a pair of Max Townshend's Glastonbury speakers
and as he was due to visit relatives in England in a day or so,
could he call in and have an audition? I was naturally delighted to
offer our hospitality and next morning I started to set up a system
for him to listen to when he arrived.
At that time we
had not had the speakers for very long as they were then still quite
new to the market. We were very impressed with their performance,
although up till then we had used only modest equipment to drive
them. So with the forthcoming audition I decided to go overboard to
impress the customer, wheeling out our Marantz CD12, Musical
Fidelity pre-amp and P270 power amp, and wired up with our most
expensive Van Den Hul cables.
I switched on in
anticipation of hearing what I imagined would be heavenly bliss. It
sounded simply awful!!! I frantically checked all I could think of,
made this adjustment and that, all to little avail. So that
afternoon I changed round all the components, one at a time, except
the speakers. In the event, they all had to go if the sound was to
come right, which eventually it did in all its glory.
Over the months
and years that followed, I have been fascinated by the problems of
incompatibility between products and the need to obtain the correct
"loading" in the system, so that an optimum match is
achieved between amplifier and loudspeaker. I shall cover these
matters and the work I have done in connection with them in another
article at a later date.
Some months after
the Dutch visit, having already worked out not only how best to
demonstrate the Glastonbury speakers (successfully selling many
pairs) but to assess whether they were best suited to a customer's
system, I prepared to demonstrate them to someone who seemed to have
a very suitable system. I was pleased with the sound, but as the
customer had already expressed a particular interest in precise
imaging, I spent some time listening carefully in the "hot
seat", and could clearly discern what I thought might trouble
him. After a concentrated period of experimentation, I found the
answer to the problem, which related to the absolute phase of the
recordings used, phase changes in the signal chain and the
"orientation" of the drive units in the speaker cabinets.
I will also deal with these subjects in a future article, as they
are endemic, in some degree, to all hi-fi systems.
The reason I
mention all these earlier experiences is that they prepared me for
the beginning of a long journey on which I am still traveling -
namely, to determine the means by which it is possible to recreate
on playback a quality of reproduction which, as nearly as possible,
reproduces in the listening room the original performance that was
recorded (given the sometimes limited quality of the recording
itself). I hope that this and subsequent articles will provoke
interest in what I regard as fundamental problems in the hi-fi
industry and why it has been failing its customers - the public.
 The
issues raised above, which I shall be discussing more fully in later
articles, have had an enormous impact on our business. Not only did
they govern the way we looked after our customers when our business
was largely retail, they also provided the impetus we needed to
devote more time and resources to research work and to the design,
manufacture and marketing of our own products. This impetus stemmed
primarily from our frustration in retail when we found that not all
the components needed for the standard of reproduction we were
seeking for our customers were available.
In designing each
product, we have inevitably drawn on our experience in retail and
the special insights that have been gained in recent years by myself
and my colleagues in the way components work and in the way the
signal is handled by those components. In particular, we have
concentrated on how electrical and mechanical vibrations at the
front-end of the system, where the signal on playback is first
generated, affect the phase of the signal which is heard as sound
from the speakers. As a result, each product is somewhat unique in
the way it tackles problems of reproduction. RINGMAT was the first
of these products to be widely marketed and is the standard to which
all our products will, in future, adhere. Because of this, I shall
explain the function of RINGMAT, its importance in helping to
reproduce a clear signal and how it was developed.
 RINGMAT
was a joint development between Denis Morecroft of DNM Design and
myself, representing QR Design, the design arm of our business. The
basic idea was initially Denis Morecroft's, and I became involved at
a stage when I had already done much of the research work mentioned
earlier in this article, some of which I had discussed with Denis.
The collaboration was also brought about by the fact that, when in
retail, we stocked the DNM amplifiers and solid core cable, and had
jointly held some "musical evenings" for our customers;
and we both lived and worked in the Brentwood area. Denis was
developing a DNM turntable to be called the "Rota", which
was to be marketed with the amps, cabling and the French made
Rehdeko speakers that were distributed alongside the DNM products,
making a complete vinyl system. For the new turntable to be an
advance on what was already on the market, it had to deal more
effectively with all those adverse influences which usually
inhibited the reproduction of a clear signal.
As readers will
be aware, there are many approaches to turntable design, but in
general they fall into two schools of thought. Each endeavours to
overcome the vibration problems caused by unwanted energy from both
the tracing stylus and the sound pressure waves in the room, as well
as any inbuilt vibrations from the working of the turntable itself.
The unwanted energy causes the stylus to move in a way which is
unrelated to the original signal and the accuracy of reproduction is
reduced accordingly. One approach towards overcoming this problem is
to try to simulate the conditions under which the record was
originally cut by clamping the record to a solid, heavy surface
which will hold it still, prevent any movement and therefore allow
so-called "perfect" reproduction of the information in the
record grooves. Another method is to allow movement to occur but to
arrange it so that it is as inaudible as possible.
The first of
these two methods is not ideal because it is virtually impossible to
exclude all vibrational energy in any material; in practice, the
energy will always be changed in form or reflected back into the
system from which it originated. The second method is more practical
but hitherto it had not been properly designed in a "total
system" approach. Denis wanted to make a turntable that was
quite different, as is always the case with him, by incorporating
many innovative ideas, the most outstanding and recurring feature
being the decoupling of certain elements in a way that enabled the
stylus to track the record as free from inbuilt and room resonance's
as possible.
Picture: Ringmat MkII XLR
As the interface
between the vinyl record and the platter would naturally play a
crucial part in this overall concept, one of the first design
initiatives was to find a new way to support the record on the
platter. Denis believed that none of the previous approaches to this
problem had satisfactorily resolved the matter and was looking at
new ways of solving the puzzle. He conceived that the record must be
supported in a manner which allowed movement but, as far as
possible, it must be outside the audio band. The movement that
occurs should be as free as possible from structural resonance's
within the record itself or anything attached to it, including the
surface on which the record lay e.g. its support mat. The record
support mat must generate the minimum noise whilst absorbing the
movement and dissipating the unwanted energy. Essentially, there was
to be minimal contact with the underside of the record and as much
air as possible between the playing surface of the underside of the
record and any structure designed to support the record on the
platter.
Using his then
resident Linn LP12, Denis showed me what happened if, for example,
the record was supported only at the centre (under the area of the
label) by a thick mat of soft felt. I was immediately struck by the
increased clarity, openness and fullness of the sound. However, I
was concerned with the way the record "flapped" a bit
because of the softness of the felt, and in any case, I was not a
lover of felt mats because of the noise they generated through
friction under the record. I said I had a few ideas we could try and
would experiment back at our own premises.
My first decision
was to find a replacement for the felt. I knew Mike Knowles at
Alphason had taken a great deal of care in developing the surface
they used for the platter of the Sonata turntable, where the record
rested directly on the platter. As it was not practicable to use his
materials, I went for what I considered was the nearest equivalent -
cork. I also liked this material because of its properties in
relation to aspects such as static.
Many types of
cork were tried and all were found to be far superior to the felt.
It was also found that significant variations arose according to the
size and shape of the cork used and its placement under the record,
and that, by restricting the contact area, considerable improvements
in sound quality were obtained. This led to the development of the
cork rings. However, we were achieving different results from the
various types of cork and found that one type was best for contact
with the record itself whereas another was better on contact with
the platter underneath.
 I
then decided it was time to experiment by building into the
structure a degree of movement such as we had with felt, only more
controlled. This eventually led to the development of rings on a
substrate but we were having difficulty in finding something
suitable for the substrate that provided the right speed of movement
and control. Eventually we found a paper that incorporated cotton
and cotton flock which provided just the right degree of movement,
as well as minimising resonance. The structure also had plenty of
air between the underside of the LP and the substrate and between
the substrate and the platter. The significance of this was that the
enormous energy generated by the stylus as it tracked the groove of
the record could readily be dumped into the air above and below the
substrate. With hard mats like rubber, and with bare platters such
as acrylic and glass, and even with the special textured surfaces
like the Alphason, this energy is reflected up the cantilever and
comes out of the speakers as distortion. The effect is similar with
felt mats, though to a lesser extent because there is some
"give", but there is the added problem, to which I have
already referred, of noise caused by friction between the mat and
the record.
At each stage
both Denis and I were carefully evaluating the progress made by
means of listening tests. Also, Denis was meanwhile obtaining
computer printouts of resonances of a standard 12" record and
from this data we placed cork rings at the various significant
points during the listening tests. It soon became obvious where the
main support ring should be placed for the primary support of the
record - in the middle of its mass.
Thus we arrived
at a construction whereby the record had minimal contact with its
support mat. It rested on a main ring under the centre of its mass
and, via the special paper substrate, this main ring moved between
two rings on the underside. The mat also provided a good impedance
match for transferring unwanted vibration energy into its own
structure and effectively dissipating it into the air underneath the
record and its support mat. The minimal contact with both record and
platter surface also meant that very little noise was created
underneath the record by reason of contact movement. To improve the
resonant properties of the mat and its impedance matching, the mat
also benefited from a second ring placed nearer the centre, which we
found had to go on top of the substrate, though we would have
preferred some support below it; this aspect featured as a further
development of the mat in a later model. We affixed the logo, and
RINGMAT 330 was born in the late Autumn of 1992 after some 18 months
of joint development work.
The
attractiveness of the product was that it could also be used on
almost any turntable with equally beneficial results, irrespective
as to whether the turntable was inexpensive or in the super league,
or whether it was of high or low mass, or whether or not it had a
suspended sub-chassis. For obvious reasons, it could not be used on
those platters using suction devices, or those that had a
significant "dishing" effect. Those that had felt or some
other substance stuck to the surface of the platter generally needed
to have it removed in order to obtain the best results.
I was, however,
concerned that some of the less expensive turntables that had fixed
height arms may have difficulty in coping with the thickness of the
mat at around 3mm, so RINGMAT models 200 and 250 were created with
thinner paper and, in the case of the 200, with the top rings having
a lower profile to reduce the overall thickness of those mats; model
250 lifts the record about 2.4mm off the platter and model 200 about
1.8mm. However, the thinner paper was not quite as ideal as that
used for the 330, so although the difference in performance was
small, the 330 definitely had an edge.
How would one
describe RINGMAT? Well, it is a unique (patented) design which
enables 12" records to be supported so that the main
vibrational modes of record movement - caused by input of stylus
energy - give the minimum possible error signal. It can also be used
with vinyl records of other diameters with some success and works
extremely well with 78s.
I believe it is
the first time that such a component has been properly designed. Its
use has also eliminated or reduced many of the problems associated
with record reproduction, many of which have, in the past, often
been wrongly blamed on other parts of the hi-fi system, especially
the speakers.
With RINGMAT,
there is a reduction in background noise, with a cleaner, crisper
and yet more delicate sound. It brings greater resolution and
separation to the sound, together with a wider and deeper
soundstage; there is an enhanced sense of power, with greater weight
and authority in the bass. Some of these attributes may be difficult
to realise in practice. There are numerous reasons for this, which
are related to problems elsewhere in the hi-fi system; some of these
will be discussed in future articles.
 In
the Autumn of 1994, a MlII version of the 330 was launched which
contained that inner ring under the substrate that we had previously
found so difficult to place. The newer version also used a slightly
different mix of the paper constituents and contained a small
plastic sticker near the spindle hole; how we came by this is an
interesting tale. I accidentally tore the paper of one of the
RINGMAT 330s I was using for development work, but rather than throw
it away I put a piece of Sellotape over the tear and put the 330 to
one side. Some weeks later, after significant improvements towards
the new MkII version, I went back to the torn 330 to use as a
benchmark - I was both astounded and puzzled that in certain aspects
it was better than anything I had developed thus far and could not
at that time work out why. I checked this and that, and was nearly
tearing my hair out when it occurred to me that the piece of
Sellotape was having a significant effect. Indeed it was, as
simulated stickers of various shapes and sizes placed in various
positions testified. It became clear that whilst the logo was having
a beneficial effect on the resonance of the mat itself and its
impedance matching, it needed to be "balanced" and the
sticker, as now used, does just that.
For some time I
had been concerned that with most records the area around the label
was of a greater thickness than over the record as a whole and I
felt this may not have been taken sufficiently into account in the
computer analysis we did. I was also interested in the effect that
very small variations in the width and spacing of the rings had on
the sound and after long periods of experimentation and evaluation I
finally settled on a formula that gave a significant and worthwhile
improvement in the sound, mainly in the way the stylus was now able
to track the groove with even greater security, enabling not only
the bass but all frequencies to drop lower and much nearer to their
natural level, thus enabling the system to obtain a much greater
degree of drive and power to the sound. Another benefit of the
slightly wider top ring we adopted was that the inner top ring could
now be reduced in profile. All these improvements were incorporated
in the new RINGMAT 330 MkII XLR launched in the Spring of 1996.
Some people have
asked whether RINGMAT can be used with a clamp. Whilst this may
physically be possible, it is undesirable for the way it often
"shuts in" the sound and changes all the parameters that
are so beneficial in the RINGMAT as it stands. The benefit of
RINGMAT is that it works with the natural resonance's that are being
created and largely dumps them into the air, whereas clamping
stresses the record, changes the nature of the resonance's and
reflects them on through the signal chain; as the record itself
comes under stress, it acts like a bell - and what happens when a
bell is struck?!!
©J D M ROGERS
1996 Revised, December 1998
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