Townshend Audio Isolda EDCT speaker cable

Hardware Review

Townshend Audio Isolda EDCT speaker cable
Monday, March 4, 2013
Speaker cable
Jason Kennedy

I have been using Townshend Isolda EDCT for a number of years now and regard it to be one of if not the best speaker cable money can buy. So I was surprised when its maker told me that the current version, the enhanced deep cryogenic treated variant had never been reviewed, an oversight by me and for all other reviewers for that matter. This is the cable that makes all the other speaker cables that people send me to review seem insubstantial and lacking in stereo solidity, it pretty well stops me from wanting to review speaker cable to be honest which is not such a good idea from the point of view of making a living. But as no-one else makes or distributes a cable of this type in the UK it’s hard to find anything to beat it.

Isolda EDCT consists of two flat copper ribbons that sit one atop the other in very close proximity with only a polyester dielectric between them. It is a solid copper cable with extremely low inductance and unusually high capacitance. The low inductance means that it is relatively easy for the amplifier to control the loudspeaker compared to regular stranded cables, but the high capacitance means that certain types of amplifiers – primarily Naims – would literally die if used with this cable alone. This is because these amps need to see a fairly high inductance to remain stable, hence the spaced nature of Naim speaker cable. In order to avoid problems Townshend Audio fits a very simple network to the cable at the amplifier end which stops any problems arising. It works, I have used Isolda EDCT with Naim amps very successfully.

There is another advantage of this construction and that’s almost total immunity to RFI, radio frequency interference, this is because the strips are so close together, 0.07mm to be precise. This limits the frequencies that can get into this gap to 60GHz and up, not an area where you get radio transmissions. Max Townshend has made a series of videos called Geometry Matters that are on YouTube if you’d like to know more about the science.

The EDCT part of the name indicates that the copper has undergone Townshend’s variation on deep cryogenic treatment, the company was the first to use this with audio cables and somewhat regrets telling the rest of the world how to do it. Hence the Enhanced element is a secret process that is claimed to give their cables the edge.



I choose to review equipment and listen to music with them because they are consistently more revealing of space within a recording and produce extraordinarily good stereo imaging, Take my word for it, you have not heard truly 3D holographic imaging if you are not using a cable with this geometry. But that’s not all, this is also the best cable for bass that I have ever encountered, it can produce genuinely bone crunching lows when connected to amps and speakers that are up to the job. It won’t make your compact stand mount shake the furniture but it will let you hear just how low any speaker will go in a superbly controlled and highly entertaining fashion. This applies whether it’s a kick drum, an organ or a synthesiser, often it’s the latter that deliver the lowest notes. If you enjoy electronic, orchestral or rock music the bottom end is crucial to the full visceral experience. I’d say it is crucial whatever the music, even chamber orchestras or folk bands need to have headroom in the bass if they are to sound real, if the acoustic character of the venue is to be reproduced.

This cable is not only about bass however, I wouldn’t have been using it to review amps and speakers for over ten years if that was the case. It is also extremely revealing in an even handed way, there does not appear to be an emphasis on a particular part of the audio band, which is what a lot of supposedly detailed cables do to give the impression of transparency. There are plenty of cables that emphasize leading edges to give a strong sense of pace and many others that have a prominent midband which brings out fine detail, but it’s always at the expense of other aspects of the sound. This is fine if you want to use cables as a tone control but less so if you want to hear all of the music. The character will eventually become audible and result in a preference for particular recordings or music types because others don’t sound so good. Then the tail is wagging the dog and you lose sight of what this pursuit should be all about.

Isolda EDCT is very revealing of detail, tone colour, timing and soundstaging, you can clearly hear what a change in hardware or software is doing to the sound whether it be lowering the noise floor, improving the dynamics or making you jump about with excitement. In many ways its surprising that so few cable companies opt for this geometry, one reason is that it’s not available off the reel from an industrial cable company, Townshend has to build Isolda from the ground up and that’s very rare. It’s also not as robust as conventional stranded cables, if you bend it too much or tread on folds it will eventually die. I did abuse one cable enough to do this once, the constant equipment change of reviewing and the fact that the cables crossed a walkway was the problem, I’ve since figured out how to protect them

If you find yourself going round in circles trying to find a speaker cable that’s perfect for your system this should knock that habit on the head. If you want a filter/tone control in the form of a cable this however is not for you. Townshend Audio Isolda EDCT will show you what your system is capable of doing to an extent that might well come as a surprise. The first thing that hits you is the sense of calm that is presumably brought about by the reduction in RFI, then when the music gets going bass extension and power make themselves known, eventually however it will become apparent that you are getting more music from the system and that is easily worth the asking price. Isolda EDCT is sold in terminated pairs, below are the current prices for common lengths but pretty well any length can be supplied. Controversially Townshend also claims that uneven pairs work as well as those of equal length which will represent a saving in most systems.


Inductance    20nH/m

Capacitance    3.1nF/m

Resistance    8.5mOhms/m

Leakage    25MOhms/m

Impedance     8ohms

Width 20mm

Thickness 0.2mm


Up to 2m £500
2-3m £900
3-4m £1,100
Manufacturer Details: 

Townshend Audio
T 020 8979 2155