GEOMETRY & MATERIAL

synergy of design & build

GEOMETRY

For a loudspeaker cable to deliver a signal to the speaker without adding distortion or losing information it must have very low electrical inductance. The two conductors must be as close as physically possible to one another. The only way to do this is with flat strips laid against each other. This is what Townshend audio does with Isolda and Fractal speaker cables, and it’s the main reason why they are more revealing, have wider bandwidth and better imaging and timing than any other cable. There is a problem with this dielectric between the conductors and in Isolda cable we give the high purity copper conductors an Enhanced Deep Cryogenic Treatment so that they deliver all the detail in the musical signal, right down to the smallest nuance.

Geometry

Topology

Two flat insulated strips will ensure the ultimate listening experience.

Typical Topography

Townshend Isolda & F1 use two flat copper strips

Impedence Matching

8 om

By matching the cable impedance to the speaker you prevent echoes and reflections within the cable that would distort the sound

Our Chosen Geometry

The majority of loudspeaker cables consist of two conductors side by side, insulated with either PVC or PTFE.

This form of construction typically gives a characteristic impedance of around 80ohm, which is a poor match to the average loudspeaker impedance of 8ohm and a very poor match to the average amplifier output impedance of around 0.2ohm.

Hence reflections can be expected, leading to audio problems. Such widely spaced cables are also susceptible to radio frequency interference and are noticeably sensitive to their surroundings, as the electromagnetic field associated with the signal passing through them is not confined in space.

By contrast, Townshend “Isolda” Impedance Matched cable has a characteristic impedance close to 8ohm for optimum loudspeaker matching and minimum reflections in the audio band.

The cable is also comprised of two flat strips, a construction which confines the signal’s EM field within the cable and minimises the effect of surrounding objects and interfering fields.

Why We Impedance Match

Transmission of an electrical signal from one end of a cable to another is fast but not instantaneous.Transmission velocity is finite, and unless certain strict conditions are met, signal reflections occur at the cable ends so that a delayed and attenuated version of the signal bounces back and forth within the cable until it is finally dissipated. At radio frequencies, where the transmission delay I~ comparable to the reciprocal of frequency (1/f), such reflections can completely disrupt the accurate transfer of information.

To prevent this, electrical connections are impedance matched. That is, the Characteristic Impedance of the cable is the same as the input impedance of the signal receiver. When this is the case, signal transmission is reflection-free. Examples of Impedance matched connections familiar to audiophiles are the aerial input to an FM tuner and the digital interfaces between equipment such as CD players and stand-alone digital-to-analogue converters.

According to conventional wisdom, impedance matching at audio frequencies is unnecessary because the transmission delay is very short for the lengths of cable used in a typical hi-fi system, and the signal frequencies are comparatively low. Some have taken this to mean that cables do not act as transmission lines at audio frequencies, but that is untrue. The Issue is not whether cables act as transmission lines – they do, whatever the frequency – but whether their transmission line behaviour is significant in an audio context.

At Townshend Audio, we are convinced that it is. Our design aim is simple: to ensure that the signal waveform undergoes the most minor possible change between one end of the cable and the other. Impedance matching helps achieve this.

As the longest cables in most hi-fi systems are the loudspeaker cables, these are most in need of impedance matching. However, typical loudspeaker cables have a much higher characteristic impedance than the loudspeakers to which they are connected. Whereas most hi-fi loudspeakers have a nominal input impedance of 8ohms or less, most loudspeaker cables have a characteristic impedance of 100ohms or greater. As a result, the audio signal is not faithfully conveyed.
Critics of impedance-matched loudspeaker cables point out that proper impedance matching is impossible between a conventional amplifier and loudspeakers. Loudspeakers usually have an input impedance that varies substantially with frequency, cable characteristic impedance also varies with frequency over the audible range, and the output impedance of a typical power amplifier is a fraction of an ohm.

As the longest cables in most hi-fi systems are the loudspeaker cables, these are most in need of impedance matching. However, typical loudspeaker cables have a much higher characteristic impedance than the loudspeakers to which they are connected. Whereas most hi-fi loudspeakers have a nominal input impedance of 8ohms or less, most loudspeaker cables have a characteristic impedance of 100ohms or greater. As a result, the audio signal is not faithfully conveyed.

Critics of impedance-matched loudspeaker cables point out that proper impedance matching is impossible between a conventional amplifier and loudspeakers. Loudspeakers usually have an input impedance that varies substantially with frequency, cable characteristic impedance also varies with frequency over the audible range, and the output impedance of a typical power amplifier is a fraction of an ohm.

All these factors make a genuine impedance matched connection unrealisable. It is quite true: the theoretical ideal cannot be achieved. But by lowering the cable’s characteristic impedance to 8ohms you still achieve more accurate signal transmission than with a conventional loudspeaker cable. To achieve such a low characteristic impedance in a loudspeaker cable requires a particular form of construction, with the ~o conduct~ placed as close together as possible to minimise the cable inductance and maximise its capacitance.

The Townshend lsolda speaker cables achieve this by using two thin strip conductors laid face-to-face, with only a very thin layer of insulation material separating them. Because some power amplifiers rely on cable inductance to ensure their feedback stability, a low inductance loudspeaker cable can cause certain amplifiers to oscillate and eventually self-destruct. To prevent this from occurring with lsolda Loud-speaker cables, series inductors incorporated within the elongated terminating cylinder at the source end of the cable. The value of these inductors (1.5µH per conductor) has been carefully calculated to ensure that amplifier instability will not occur. Because the strip conductors in lsolda loudspeaker cable are so closely spaced, any radio frequency interference (RFI) pickup -from mobile phones or the myriad other VHF and UHF transmitters in use today is substantially common-mode (i.e. equal in both conductors). The series inductors at the ‘send’ end of the cable perform a crucial secondary function in preventing RFI from entering the amplifier via its output terminals.

Max Townshend 2001

This topic is further explored in analysis.

Non-Impedance matched will show ringing on oscilligraph

Impedance matched cable (Isolda) will show a retained square wave on oscilliscope

Isolda Cable

Square wave in square wave out

By matching the cable impedance to the speaker impedance you preserve the square wave reading ISALDA CABLE

Oscilliscope and Oscillograph

measure using square wave

Measure the voltage difference between one end of the cable and the other to see if there is any loss or ringing

Most other cables

Square wave shows ringing

When cable impedance is mismatched with the impedance of the speaker impedance you will get this 'ringing' readout

I solder, I solder and Isolda

It worked, so why fix it? the original Isolda design required 900 ends to terminate in a pair hence the name Isolda from the verb to solder! – yet fitting in well with our Arthurian legend theme after Tristan and Isolda and manufactured as far back as 1978 and giving a nod to the pioneering Japanese cable designer who was getting fantastic sonic results with this technique.

Isolda cables are made from six parallel sets of 50-ohm coax, with a composite 8.3 ohms impedance mismatch. With such cables and amps of the signal hitting the load is reflected back MF to the amp. Some of this signal will be reflected back to the speaker where it will eventually reappear with a phase delay, a pattern which is repeated at progressively lower levels until it dissipates (this is measurable) and some is reapplied to the amplifier input by the feedback loop. Isolda cable is a close impedance match to the Glastonbury speaker, and sharply reduces these reflections to give controlled bass.

Alvin Gold July 1990 – AUDIOPHILE HIFI ANSWERS

“The original users of this process [CRYO] with respect to high-end hi-fi cabling was Townshend with their Isolda DCT cables highly regarded by many in the trade.” Hifi Brillance

MATERIAL
Cryogenically treating copper removes residual stresses and improves wear resistance
THE LATTICE STRUCTURE
The lattice structure of copper changes when it has undergone cryogenic treatment.
CRYO IN INDUSTRY
The cryogenic treatment of metals and plastics has been developed, with much being owed to NASA who used the process to achieve performance enhancements in materials for the space race.
PHEW! CHILLY!
Temperatures as low as 180 are reached in the cryogenic process
THE FINISHED RESULT
The Award Winning Townshend Isolda
Previous slide
Next slide

Why we process our copper with Deep Cryogenic Treatment

When we first discovered Deep Cryogenic Treatment (DCT), the technology was in its infancy for use in audio. Nevertheless, we developed the technology for our use and, after sharing the listening experience with experts, decided that the encouraging test results deserved the investment of time and money for further experimentation and development. Eventually, we pushed the performance envelope so far that it became a no-brainer to use this extraordinary cable in all our products.

DCT & FRACTAL treatments

Treating copper with DCT and Fractal prosesses changes the the lattice structure creating the finest sounding cables

Then Came Fractal

The F1 Fractal has a ‘dark’ quality that lets you hear into the soundstage, walk around the musicians and oh-so-easily tease apart the threads of their mix. Bass sounds robust and extended, treble pin-sharp and sparkling but never too hot or fierce…

This is a cracking set of cables…the cable sounded deliciously smooth and detailed and promoting, the kind of easy listening, inky black backgrounds typically associated with the best HiFi systems. Go on treat your self!”

PAUL MILLER – HiFi News

Why we use a Fractal Treatment on our premium F1 Fractal cable

How does this work?

The DCT and FT processes change the copper crystals’ lattice structure, allowing for superior conductivity.
As far as we know, we are the only audio company exploring Fractal technology. Its use is guaranteed to extract every last ounce of performance from your system and deliver a sublime listening experience. 

Visionaries

We owe a debt of gratitude to the cable visionaries that have pushed the performance envelope of audio playback through cable design whose ideas have shaped the products we market today. It’s our mission to continue to extract every last onze of sonic truth from music. 

Development

Max Townshend’s pioneering approach to geometry, metualgy and  its enhancing treatments has meant massive inroads towards sonic truth and a true legacy for generations to come.

ISOLDA v's FRACTAL

“Oh man, I only had to listen for a few minutes and I bought them. They had all the clarity and detail of the HFC but added the most amazing richness to it, a real holographic 3D deep texture to the sound, and incredible controlled and extended bass. And I had never understood the meaning of the Hifi term ‘black background’ before hearing the F1 speaker cable.I can’t recommend the F1 highly enough.”
Peter Duckworth
UK
“Firstly, can I say a big thank you for giving me the opportunity to try your new F1 speaker cable in my system. As you know, your Isolda has been my cable of choice for a few years now, so I approached the F1 cable from an already high plateau.It took only minutes to hear that the F1 raises the standard still further. The gains are in terms of overall clarity. I think this is because the cable is remarkably well damped -- no resonance or ringing within the cable (?) This improves the quality overall, but particularly in the high and midrange frequencies, and therefore this creates an improvement in image stability and depth. In my system the bass is about the same as the Isolda, or maybe a shade rounder, but firm and deep in tone, as one would expect. The higher quality lockable banana plugs are a further improvement on the Isolda. It would not break my heart to return the Isolda to my system, but I'd rather keep the F1, so maybe that says it all. Cable is between: Concert Fidelity ZL 200 mono block amps & Avalon Eidolon Diamond Speakers (all on seismic stands) Well done Max, and thank you again.”
T.E
UK
Yesterday I swapped back to the standard Isolda speaker cables for the first time since the Fractal versions arrived 12 days ago, what a difference, the Isolda Fractal is so much better. I'm not great at describing these things but I think the music is much more enjoyable with better soundstage, increased detail, clearer deeper bass with better attack/slam. Altogether a major step up on standard Isolda which is already a great speaker cable. It also seems to be a robust and generally well made cable. But overall it's the musicality that's so impressive.” Peter“Firstly, can I say a big thank you for giving me the opportunity to try your new F1 speaker cable in my system. As you know, your Isolda has been my cable of choice for a few years now, so I approached the F1 cable from an already high plato. It took only minutes to hear that the F1 raises the standard still further. The gains are in terms of overall clarity. I think this is because the cable is remarkably well damped -- no resonance or ringing within the cable (?) This improves the quality overall, but particularly in the high and midrange frequencies, and therefore this creates an improvement in image stability and depth. In my system the bass is about the same as the Isolda, or maybe a shade rounder, but firm and deep in tone, as one would expect. The higher quality lockable banana plugs are a further improvement on the Isolda. It would not break my heart to return the Isolda to my system, but I'd rather keep the F1, so maybe that says it all. Cable is between: Concert Fidelity ZL 200 mono block amps & Avalon Eidolon Diamond Speakers (all on seismic stands) Well done Max, and thank you again.” Terry
Terry E
UK
"I’m not a great believer in cables. They are not the sort of thing I enjoy reviewing. Differences are fairly small, and you have to listen long and hard for differences that may not be obvious in a blind test. Using the Townshend F1 Fractal speaker cable was a different ball-game. I have various sets of expensive cable in the house, which shall remain nameless, and having swapped in and out the various cables, it rapidly became apparent that what the F1 Fractal were doing was blindingly obvious, and highly significant. Listening to a Hi-Res recording of the 2nd Brahms Serenade, the F1 was removing a level of smudge and dirt from the music, the bass was tighter and cleaner, much easier to understand musically, but perhaps the largest difference was the 3-d chiselled soundscape they were creating. I could suddenly hear the layering of the orchestra, where the instruments were located precisely in space, and with such clarity. Changing back to the previous cables, the sound stage became completely two-dimensional, collapsed and it was as if my review system was no longer of a “high-end” persuasion. Changing to the F1 was removing the greatest block in the system, and was making the greatest difference."Rafael Todes -
Rafael Todes
Allegri String Quartet

Oscilloscope Measurements

If you can see it on an Oscilloscope, you can hear it! Our ears, the most sensitive of all measuring devices, can perceive when music sounds more natural. Our listeners tell us that adding Isolda cable immediately renders music more relaxing, but how do we measure what is happening? The oscilloscope offers the best way of demonstrating the ‘ringing’ that we hear in music as subtle smearing and offers a new way to evaluate the accuracy of a cable.
In its simplest terms, we are trying to retain the integrity of the square wave (music input) throughout its journey between the speakers and the amplifier, any distortion will appear as a distorted square wave, and the ear should be able to pick this up too!
Once we compare a few different cables, we can discern which cables are preserving the signal most faithfully.

Now you have found us, let's keep in touch!

+44 (0)208 979 2155

UK
Email mail@townshendaudio.com
Translate »
Home
Geometry and Material
isolda
Interconnect
Fractal F1 Speaker Cable
Analysis
Shop
Cart