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Purpose
and Function of the Turntable Mat
1. The mat has
to provide a firm grip to both the platter and the record, so that
the mat does not slip, nor does the record.
To improve
the contact between platter and mat a record weight (stabilizer) or
clamp can be used. The record can also firmly coupled to the mat/platter
by means of a vacuum pump as in the sophisticated vintage turntables
of Micro Seiki where this system is integrated. Audio-Technica produced
the special Disc Stabilizer (AT666EX) which could be used on a variety
of turntables and is a so called vacuum mat. Another very effective
accessory is a record
stabilizing ring.
The firm grip diminishes distortion of mechanical origin. That is
distortion caused by heavy modulations which make the mat/record move/vibrate.
A weight/stabilizer is best used with a rubber mat. An acrylic turntable
mat is best served with a clamp.
However a stabilizer weight can very well be used on an acrylic mat
if at the same time a stabilizer ring is used.
To improve the stability of any mat, gluing the mat at at least three
points with very thin two sided tape gives excellent results.

2. The mat should
support the entire (grooved) surface of the record.
In example
A only contact with the mat is made by the groove guard (edge of the
record) and by the label. This is because the mat's diameter exceeds
the actual diameter of the engraved surface of the record.

In B
the mat has the appropriate size and perfect contact is possible.
If the mat you use is too large it should be trimmed down to 28.7
cm. Support is improved when the mat is slightly concave (as is the
case with the Goldmund mat) or convex (as in the case of the Oracle),
but only in conjunction with a clamp!
Custom
mats should have a center area which is somewhat receding in order
to accommodate the label.
If the
mat does not support the record at the periphery, the easiest thing
to do is to cut a small circle from 200 gr. cardboard (the thickness
of the cover of an audio magazine) and about the diameter of the mat.
Put this circle at the rim of the platter under the mat.

3. The mat should
protect the record's surface in order to avoid damage.
In
order to comply with this criteria the mat has to be cleaned from
time to time. It should be kept clean and dust free in order to avoid
particles settling in the record groove. A rubber mat can be washed
with lukewarm water and a few drops of soap. An acrylic mat can be
cleaned by using a paper tissue wetted in blue
methylated spirit.
If
your turntable does not have a dust cover just use a carton disc (the
size of the record) that you put on the mat when the table is not
in use.
4. The mat's
material should have good sound characteristics.
Although
a mat does not generate sound by itself, it should have an even frequency
characteristic. No part of the audioband should be accentuated.
Here again the use of a record clamp, weight or stabilizing ring will
improve the sound. The lower frequencies will be tighter, the midband
firmer and the high frequencies will be neater and more precise because
the needle tip and cantilever of the cartridge will not transmit false
high frequencies caused by minute vibrations of mat (and record),
but will track the grooves in a more controlled and precise way since
the record itself cannot move.
Remember: we are talking about analog recordings which may have up
to 700 bits (so to speak, not 16), and maybe more. A vibration of
one or two micrometers that do not come from the groove itself will
distort the sound. The mat should not give cause to vibrations. That
is why it is not advised to use flimsy and light mats of felt.
5. The nature
of the mat's material should be close to that of the vinyl.
Another
important feature which adds to the sound characteristic of the mat
is that the mat is relatively hard. In that way it is as if the record
is heavier, only of course if a clamp is used and the fundamental
resonance of the mat (and record) is damped (attenuated) by several
dB.
As said: fixing the mat to the platter at least at three points, with
a very thin two sided adhesive, improves the signal reading.
If a clamp or a stabilizer
is being used the material which the devices are made of also plays
a significant role. Generally the characteristics of the mat itself
are better controlled by a clamp or weight and therefore somewhat
less interfering. Nevertheless mats made of light and soft materials
(rubber, felt, paper, cork) can easily cause a slight phase shift
in the lower-mid region which is translated in a slightly smeared
out attack.
Different
Materials
At first
hearing a rubber mat will allow more detail, but you may discover
after a while that these are make believe refinements. Peaks in the
frequency curve should be avoided at all times. A relatively hard
mat is the best option: acrylic (Goldmund type), hard rubber (the
Technics SP-10mk2 type). The choice of mat should always be made in
relation to the turntable itself and the arm and cartridge combination.
Soft rubber, fluffy felt and very soft sorbothane are all just fantasy.
It is like eating cake with too much cream. After a while you get
sick of it. And if the sound is not detailed enough you should check
if your phono cable is the restricting factor or the preamplifier
does not deliver or maybe it is the cartridge or even the relation
between amplifier and loudspeaker system.
Not long ago I bought a mat which was relatively thin (only 3 mm)
and made of a rather brittle material. Though it looked somewhat like
acrylic on first inspection, it emphasized the mid-high frequency
band and did not provide good mids. The difference between this quasi
audiophile mat (it was advertized as being audiophile) and the mat
of the Technics SP-10 Mk2 for example, could be heard when there were
a few ticks. These lacked the mid frequencies when the brittle mat
covered the platter. The audiophile mat weighed only 242 gr. while
the Technics mat was 4 mm thick, weighed 414 gr. The acrylic mat I
use is 4 mm thick at the edge and weighs 174 gr. The 4 mm corian mat
was 426 gr. There is abviously a relation of weight, thicknes, and
good sound.
History
In the
early days of the record era the gramophones which played the 78 RPM
shellac discs generally had their platters covered with a velvet fabric
in nice green, black, red, brown or blue.
After the LP had arrived the rubber mat was introduced. At first it
was just a very thin rubber sheet with a circular pattern to cover
the platter. Rubber was used because it was a practical material.
It kept the grooves relatively free of dust, could be removed and
easily cleaned whereas velvet could contain dust and leave this behind
in the micro grooves of the vinyl.
In time
thicker rubber mats were used and audiophiles and manufacturers discovered
the differences in sound depending on the sort of rubber and the difference
related to a good contact between record and mat.
Technics,
Thorens, Nakamichi
In the
nineteen seventies designers of turntables started to listen even
more carefully to their products and many not only came up with a
heavier platter but also with specific turntable mats.
In Japan Technics used a not too thick mat on their SL-series direct
drive machines.
On the SP-10Mk2 a thicker mat
made of hard rubber was used which contributed to the straightforward
and uncolored sound quality
From
Japan were also the specifically shaped mats from Nakamichi. One made
from extremely hard and heavy rubber (it contained a relatively high
percentage of metal). And there was also a thin mat from red copper,
specifically shaped for maximum support and close contact with the
record. But such a mat was easily bent. Initially the mats on Thorens
turntables were not too good. The later versions of TD-160 and TD-126,
at the end of the nineteen seventies, had mats which supported the
record in a better way and on top of it they were made of a harder
rubber which contributed to a far more dynamic and precise performance.
Spectra,
Audioref, Dumpa
In France
the Spectra turntable mat was introduced. It consisted of 3 layers
of different
kinds of polymer, each with specific properties. The surface provided
a firm grip on the record because it was sort of 'sticky'. A record
was not easily lifted up. This mat provided a remarkable transient
response which was more situated in the upper regions as with a felt
mat than in the fundamental frequencies as in harder rubber mats or
the acrylic mats. The diameter of the Spectra was too large, 300 mm
instead of about 280 mm. Records with a thick groove guard were not
always optimally supported.
The Spectra
was superseded by the Audioref (marketed by Jean-Claude Fourrière
in the 1970's in France) and a later edition which he devised was
the Dumpa mat. It was made of harder rubber and made it less tricky
to remove the record.
It also had more neutral properties which translated in less coloration.
Measurements showed that rumble was less prominent as in conventional
mats.

Not
only the rumble spectrum was many dB lower but now the curve also
had a regular pattern in the lower register which is the fundament
for a faithful reproduction of the many harmonics.
(Note: One could say that Jean Claude Fourrière knew what he
was doing. He was the designer of the incredible loudspeaker systems
named Audio Reference 800 which could boast on four 38 cm Audax woofers
(from the PR 38 series) per channel and yet the sound was as light
and fast that the most refined details and subtleties in the recording
were heard. Later he designed the Toltèque cold plasma loudspeakers
which would promise an even more transparent sound devoid of matter.)
Mission,
Ariston, Linn, Hiraoka, Oracle
In the
UK Farad Azima of Mission Electronics proposed a mat made of sorbothane
which was said to have excellent damping properties. (Mission used
sorbothane also in the 3 feet of their turntable. But there it was
apparent that the isolation from rack or other support was not sufficient.)
The properties gave an airy sound with a clear upper midband but the
attack still could be improved, specifically in the mid band. Sorbothane
is also used today by Audioquest.
Mission's mat prompted Ariston of England to produce a mat with a
more amorphous structure and different damping properties.
When Linn originally started the production of the Linn Sondek LP12
a rubber mat was used for several years. It was a mat with a striped
profile. Later Linn discovered that the LP12 would project a more
tasteful image with a felt mat, first relatively thin and soft and
later somewhat thicker and "harder" if that is the word
to describe the feel.
From Japan came the Hiraoka mat which was a very heavy and thick mat
consisting of rubber with a high content of metal. This mat promised
to give a better stereo image, a cleaner sound, and improve speed
constancy. The mat is not supple but stiff and very hard. This resulted
also in a much better transient.
Another interesting design was the mat which adorned the Oracle turntable.
It was used in conjunction with a clamp that had to be screwed on
the threaded spindle. The shape of the mat was slightly convex and
the record was clamped down in order to make a firm contact between
the surface of the record and the mat. This led to a more precise
signal and an improved transient response.
Mikro
Seiki Copper Mat
Micro
Seiki proposed a mat turned from copper, the CU-180, which could be
used on different turntables.
This mat could be covered with an additional mat of felt and this
would result in more or less the same sound pattern as was given by
the Linn LP12 turntable: detailed high frequencies, smooth and fast
mid section and transparent bass.
The CU-180
could also be used with no additional mat and in that case it would
not only add weight to the existing platter, but also would give a
clear, no nonsense transient without any phase shift. In that case
more attention would have to be paid to the choice of cartridge and
arm combination and choice of phono cable.
The CU-180 was marketed for several years and was a gadget which was
appreciated by many a high end audio adept.
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A
DIY acrylic mat 28.8 cm in diameter. The center hole is larger
than the spindle to keep the spindle free. The rings in the middle
give room to the label of the record. For practical purposes the
diameters of 10" and 7" records have been marked. There
is also a marking at the periphery of the label.
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Goldmund,
Acrylic, Marantz, Nagaoka
Glass Mat, Corian
When
the Goldmund engineers designed their turntables (Studio, Studietto,
Reference) an acrylic platter was used in conjunction with a specially
designed clamp which consisted of different materials. They also made
a separate mat plus clamp available for audiophiles who wanted to
imitate more or less the 'Goldmund sound quality' with their existing
turntables. Also imitation Goldmund mats with clamps where made by
hobbyists and a few other manufacturers. They did not succeed in obtaining
the same effect for 100% because the materials used by Goldmund (specifically
in the clamp) could not be imitated entirely. Nevertheless these imitations
were not too bad. Important is that an acrylic mat is glued to the
turntable's platter using a very thin double sided adhesive sheet
in order to obtain the clean sound. The drawback of course is that
a glued mat can not be removed in case a new turntable is bought,
hence many audiophiles glue the mat only at three points with the
extremely thin double sided tape.
Best
Dimensions
Here
I give the measurements for having a simple and a more sophisticated
acrylic mat turned by a machinist in a workshop. The maximum diameter
should not exceed 290 mm and should be preferably less: 285 mm.

Marantz
Glas Mat
Marantz
proposed a mat of glass on their TT 4000 top of the line turntable.
Nagaoka marketed a separate glass mat, the Crystal. Rega gave their
turntables a glass platter to be covered with felt in order to counteract
'the sound of glass' (which also can be heard in designer audio racks
with glass shelves). With the revival of the long playing record other
mats have been proposed in the last decade: cork and suede leather,
a.o. It seems however that many people are trying to reinvent the
wheel as if all these years from 1950 on of designing, of research
and development (and of marketing) were useless. Especially the praises
for carton, a thin sheet of foam or bituminous sheet should not be
believed.
Firmness of the material, good damping characteristics (not collecting
the energy but transmitting the energy so it can gradually die out)
and the optimum diameter for support of the entire LP (and not just
the groove guard and the center) make a good mat.
Although I have some reservations about a mat turned out of a sheet
of Corian, the performance of that material not only depends on the
aluminum content which may vary, but also on the turntable, the phono
cable. Corian opens the mid band somewhat, but than only if compared
to a relatively cheap rubber mat which emphasized the lower mids and
the extreme top. Corian rounds the extreme top of the audio band somewhat
and is good in suppressing some distortion in that region. That is
our experience. While with a Goldmund or imitation Goldmund mat you
can be assured of a neat performance on many a turntable, their outcome
with Corian varies. The properties of Corian are not always as desired
because the percentages of aluminum varies (large or small flakes,
more or less flakes).
Well
Tempered, Fulton, Sota, Townshend
There
are more mats (according to Greg Stewart from Minneapolis) which were
maybe not so prominent because they were not available separately
or did not get a vast proliferation. Well-Tempered Labs used for a
time on their Well-Tempered Table a moderately-soft damping mat like
the Audioquest/Mission and the Oracle, but much thinner. The idea
was to damp while but increase the firmness of bass and impact which
was lost in the thicker sorbothane mats. The Well-Tempered mat was
fairly effective, but didn't catch on and could not establish itself
due to the introduction of acrylic platters and acrylic mats. So Well-Tempered
started to use a better-damped acrylic-like platter.
Another
thick flexible mat that appeared about the time of the Dumpa/Spectra
was the one by Robert Fulton. Then there are the acrylic varieties.
Sota had an acrylic mat on top of a flexible Sorbothane-like material
to try and get the best of both. Nowadays, you see a lot of turntables
with an acrylic or similar plastic platter, but no mat at all. These
can work pretty well, but unless they are damped like the Goldmund
platter in the 1980's, they can be lively and procure a less balanced
sound. There was also the Townshend Elite Rock with the plaster-filled
aluminum-shelled platter with a flexible, but rigid plastic mat on
top of it which was quite effective, but the plaster had a tendency
to separate from the aluminum. The Warren Gehl mat is a favorite of
certain audiophiles. It is a multi-layer, heavy plastic composite
that does a great job of damping the record on the topside and damping
the platter on the bottom side while providing a rigid surface for
good impact, slam, and bass. The mat was extremely expensive and rarely
seen, but is by far the most detailed, accurate, neutral, and revealing
mat.
What
is the Right Combination?
Of course
there is a relation between your turntable and the mat, and also between
the nature of the arm and the mat. And there is a relation between
your loudspeaker system and the turntable. Because of the very fine
structure of acrylic, the sound and its characteristic is accordingly.
The sound is somewhat rounded in the midband and the result can give
the impression of a slightly retracted midband (if compared to most
ordinary rubber mats) and providing more space but less straightforwardness
depending on the clamp or turntable weight which is used. In the top
the frequencies are refined. Because of the well controlled lower
register and the lower-mids, transients are less exuberant and do
not get the distortion as with rubber mats. So that is a good thing
too. Acrylic mats are precise and sound natural because of the correct
phase (the harmonics are established at the same time as the fundamentals),
especially when using a screw-on clamp.
Glass accentuates the top frequencies but lacks in transparency and
structure of the low and mid-low registers. I would never advise the
use of glass because of its amorphous nature. Yes, go for a hard mat.
But than preferably an acrylic mat.
There
are various kinds of rubber which all sound differently. Rubber is
in general more blatant, but has speed and can add to realism, and
often sounds also more 'ordinary', less sophisticated.
The Spectra mat has a more airy sound but seems to shift everything
one octave higher in the spectrum.
The Mission sorbothane sounds also a bit lighter with less firmness
and weight in the lower-mid band, but is also speedier (which is good
for transients) than acrylic mats and most rubber mats.
The Ariston mat was in my view not in accordance with the harmonics
of the music and sounds a bit amorphous.
The
Best Turntable Mat
The best
mat delivers sound with good transients, an even characteristic, deep
bass which is well controlled, and gives a good reproduction of the
mid band frequencies inconjunction with clear and detailed high frequencies.
All of course with the least distortion. The best mat provides the
best signal reading in order to give a sound reproduction as if the
music is performed live. Do not forget that. By all means do dare
to change an acrylic mat for a rubber one if it gives more realism
in your system. Or leave the felt mat on the shelf and change it for
a rubber one. In other words: do not follow trends but find the best
solution for your sound system. But above all: follow your own ears
and not your eyes! And if you do that you probably will opt for the
acrylic mat. A commercial one or the poor man's home made acrylic
mat.
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