RINGMAT
CONCEPT LOUDSPEAKERS
For many years Ringmat and QR Design
have been using for their research a
‘Ringmat modified’ version of Max
Townshend’s ‘Sir Tristian’ Loudspeakers,
which were made when Max was
manufacturing in Malta. They were the
only pair to be brought to the UK and
have proved to be an excellent tool for
our design work.
Since those early days, our
understanding of the ingredients for
accurate sound reproduction has
increased immeasurably and it is now
desirable for a wider audience to be
acquainted with the fruits of our
research work. This will entail
demonstrations of the advances we have
made and will show the direction in
which the industry needs to move in
order to achieve a decisively more
accurate sound reproduction in the
future. Not only of the audio equipment
itself that is required for accurate
sound reproduction but also, and perhaps
more importantly, of the standards
required in future for the software –
the records, CDs and DVDs. At the
moment, the systems of reproduction used
everywhere and the software available
for sale to the public all contain a
tremendous amount of avoidable
corruption.
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Recommended further
reading...
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A big
education programme is required.
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As a first stage in our plan, we have
taken delivery (August 2007) of a pair
of loudspeakers built for us by
Auracoustic to our specification
[http://www.auracoustic.co.uk]. These
Ringmat speakers are unusual in that
they embody many features not found in
other loudspeakers - they are speakers
of the future in terms of concepts, as
opposed to any defined article. We
therefore refer to them as our ’Concept’
loudspeakers, in much the same way as
car manufacturers design ‘concept’ cars.
This does not mean they cannot be made
available as custom-built orders, and we
are already receiving enquiries about
them from people who have been aware of
our plans.
The significant features are as follows:
-
There is no crossover, there are no
capacitors or inductors, so no
corruption of the absolute phase of
the signal
-
The drive units are orientated in a
particular way to obtain maximum
accuracy in imaging to our own
formula, with the right hand speaker
being a mirror image of the left
hand speaker rather than identical;
ideally, they need to be driven by
mono block power amplifiers fed
separately from the mains (i.e. each
has its own mains lead); not for
reasons of ‘power’, but so that the
mains delivery to each power
amplifier can be separate, as the
mains power to one power amplifier
needs to be inverted to that of the
other; the ‘mirror image’ aspect is
purely to get imaging accurately
reproduced because of the way the
signal is fed to the drive units in
the particular configuration we will
specify for the amplifier and mains
lead connections in order to
overcome a major aspect of
corruption in commercial software
-
The drive units are accurately
time-aligned and in line
perpendicularly down the centre of
the cabinets
-
The cabinets are made of
substantially braced plywood
We have opted for a special textured
paint finish (wood veneer is
impractical for custom built
cabinets anyway); there is therefore
a wide choice of colours available
-
The cabinets have been specially
lined with cork to our own
specification, including internal
use of our cork domes – no foam, no
wool, no carpet or any of the usual
stuff that damages sound
reproduction obtained through other
loudspeakers
-
Our own Pure Power speaker cable has
been used for internal wiring, the
number of strands selected as
specified and connections crimped
and bolted, not soldered
-
The baskets of all the drive units
have been substantially earthed
-
Ports are flared at each end
-
There are no horn effects for the
drive units
-
Although the cabinets are
substantial and very heavy, they can
breathe
They are, of course, designed to rest on
large Ringmat Domes, each placed upon a
set of 3 Ringmat Mammoth Feet. On top of
each speaker is a Ringmat Cabinet
Damper.
DRIVE UNIT SPECIFICATIONS
Each loudspeaker has:
1 pair of Visaton 8ohm Ribbon Tweeters
MHT12 (made in Germany) working in
parallel
Efficiency/Sensitivity 91dB
Nominal Frequency Range 2.5K – 40K
1 pair of 10” Volt Studio 8ohm mid-bass
drivers (made in UK) working in parallel
Efficiency/Sensitivity 92dB
Nominal Frequency Range 32K – 2.5K |
In
view of the drive unit arrangement, the speakers
present a 2ohm load
16ohm drive units in this arrangement would give
a 4ohm load, but the Visaton Ribbons are only
available at the moment as 8ohm.
We initially arranged the drive units in series
rather than in parallel. This gave us an overall
8ohm speaker instead of a 2ohm speaker, but we
have not had the opportunity to try them in this
arrangement since the final modifications were
made to the internal lining and tuning of the
speakers. This was all done using the 2ohm load,
with which our modest 70w amplification has no
problem at all.
One question in the minds of some people might
be the danger of using the ribbon tweeters free
range, as the conventional wisdom is that they
would overheat and thereby be damaged. The way
to protect the tweeters is to use a small PTC
(Positive Temperature Co-efficient) resistor
connected in series to the tweeters called a
polyswitch. If the current exceeds a certain
level, the resistance rises and at the
appropriate point the current is switched to
protect the drive units. It is important to use
the correct value of the polyswitch, which value
has been provided to us by Visaton.
Another concern might be the presence of bass
response in the speakers, or lack of it, due to
the absence of a crossover. There is no lack of
bass in the concept speakers; indeed, the
challenge is to position the speakers within the
listening room so that the listener is not
overwhelmed with bass, and that the clarity of
the recording is still retained despite the
massive, deep bass response.
It hardly behoves us to talk about the
performance of these ‘concept’ speakers, other
than perhaps to say that in all his years of
experience John Rogers has never heard such an
awesome and, at the same time, such a musical
and accurate reproduction from a pair of
loudspeakers. It is this combination of power
and detailed, even delicate, accuracy that is so
special, that feeling that one is actually
sitting there at the time of the recording
facing artists playing and singing, talking
even, which can be particularly difficult to
reproduce realistically. |