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.

 

 

A big education programme is required.

 

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.

 

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