Doomlord_uk
Prominent Member
There have been a few threads and comments recently about this extraordinary loudspeaker cable. Extraordinary in price, extraordinary in design, extraordinary in application – but not extraordinary in audio performance. Townsend are marketing this cable as offering extraordinary audio performance as a result of its design and construction. This marketing is backed by uncritical reviews online, both from individuals who don’t know how cables or hifi work, and from journalists who should, and possibly do...
The goal of this post will be to examine Townsend’s cable and the marketing claims made about it to see what they mean if there is any substance to this very expensive product. First though, it would be worthwhile to revisit just what a speaker cable is and what it does.
From a practical point of view, a speaker cable has a very simple job to do – transmit a time-varying voltage signal from an amplifer to a loudspeaker, along with as much current as the speaker draws, whilst introducing as little distortion to that voltage signal as possible. The amplifier’s job is to supply as much current as the speaker needs. The ideal cable transmits that voltage and current without any distortion. Any change to the voltage signal, or any change to the current, would be distortion. Cables can’t improve a signal.
To accomplish this, we need a speaker cable that conducts electricity – obviously – but beyond that we need it to have as low an impedance as possible whilst remaining practicable and affordable. Obviously using thick copper bus bars might be ideal electrically, but that would be neither practicable nor affordable. In fact, the job can be done well using relatively little conductor material, and this is for two reasons. One, the distances typically run are short and little attenuation will occur. Two, the net impedance of the wire remains small compared to the load; this prevents the wires acting as a filter component to the speakers, and thus altering the sound in a way the speaker designer did not intend. This also minimises power loss, although that’s not a major consideration.
The essential elements of speaker cable design are the length of conductors, the cross-sectional area of the conductors, the resistivity of the conductor material, the insulation material (dielectric) absorption value (permittivity) and the spacing (or “geometry”) of the conductors. At audio frequencies, the electrical behaviour of the cables can be fully predicted and understood from these values, and no other factors need to be considered. IOWs, it can be shown that all of the distortions introduced by a cable between one end and the other can be explained by considering these factors alone. (RFI is not a direct cause of distortion, and would be filtered out naturally by both the speakers and the amplifier’s output circuitry. “skin effect” does not produce an audible difference at audio frequencies, resulting in something like a 0.1% rolloff at 20kHz – quite inaudible).
Since we want the least distortion, we must design our cable accordingly. Quite simply, we want a high cross-sectional area to minimise DC resistance to current flow. We also want the AC reactance – or complex impedance – of the cable to be minimal too. Reactance can be simply understood as a frequency-dependent resistance. That means we want minimal capacitance and minimal inductance. These are called reactances or reactive impedance because both phenomena ‘react’ against the current, by literally pushing back against the voltage that pushes the current. If DC resistance is like ‘drag’, AC reactance is like actively pushing back – obviously we don’t want this.
Essentially, we need to understand that capacitance is a function of cable geometry but inductance is a property of the conductor itself (and is thus hard to minimise). Capacitance is a function of three properties of a cable – the distance between the conductors, the area of overlap of the conductors and the quality (“permittivity”) of the insulating material between them. To minimise capacitance then we want a big gap, a narrow overlap and a good insulator. Capacitance works by storing energy in an electric field between conductors, and inductance by storing energy in a magnetic field around a conductor.
With all this in mind, let us now look at Townsend’s Isolde cable. Townsend make some interesting claims about their Isolde cable. The most prominent is that the conducting material is made from “EDCT” oxygen-free copper. EDCT stands for ‘enhanced deep cryogenically treated’. The DCT part refers to a process of cold-annealing the copper. The enhancement to this process is not specified, and is apparently a trade secret. DCT is used to minimise grain boundaries between adjacent crystals of copper in the wire. This is done in industry to improve the physical strength of the copper, to maximise its working life in a variety of industrial applications – eg welding. From a basic electrical point of view, DCT leads to a minor drop in copper’s resistivity – its resistance to electrical current. This reduction is tiny and given the expense of deep-cryogenic treatment, it would make far more sense to just use a little bit more copper in the cable to achieve the same result. Copper isn’t that expensive, after all... DCT is. By employing EDCT, Townshend have priced their product right out of contention for all but a few privileged audiophiles with budgets in inverse proportion to their knowledge of basic electrical theory. Changing the resistivity of copper makes no qualitative difference to how a cable distorts the voltage signal, other than a tiny proportionate drop in DC resistance. Level matched, and in reality, you will not hear this, much less attribute complex audible characteristics to the EDCT copper.
A second claim is that it is designed deliberately as a high-capacitance cable! Given that we want a cable with as low as capacitance as possible, why on earth would Townsend do this? It’s a good question. Now, typically, amplifier outputs include a capacitor in series with the output but one or two manufacturers - *cough*Naim*cough* - omit this, compensating with their own high-capacitance speaker cables to match. The rest of the industry just does things normally. Are Townsend targeting owners of Naim amps? Not according to their marketing materials. Instead, what they are doing is offering us pseudoscience – claiming that their high-capacitance cable enables it to be “impedance matched” with an “8 ohm” speaker. In short, they’re making the extraordinary claim that their speaker cables act as transmission lines, and that you’ll get better performance because of this.
To understand the pseudoscience being touted here, we first need to understand what a transmission line is. In short, it’s any wire or conductor carrying an AC (time-varying) voltage signal where the length of the cable is at least a quarter as long as the wavelength of the highest frequency of the signal. (lower frequencies have longer wavelengths – it’s only those wavelengths that approach ¼ or more of the length of the cable that are affected). In simple terms, it’s a really long wire! The classic example is of course the long-distance telephone circuit, and the most extreme of those were the old copper undersea phone cables, some of which ran for literally thousands of miles in length. Not really comparable to speaker wires at home, or in a studio! Indeed, at 20kHz – the highest frequency with the shortest wavelength in the audio passband – a speaker cable would have to be over 15 kms long, yet very few audio cables exceed one thousandth of that length! Clearly, speaker cables are not transmission lines.
What does it matter? Well, transmission lines (ie long cables) suffer from signal reflections that cause signal cancellation, and from significant power loss. Neither is a problem for speaker cables though, and here’s why. Firstly signal cancellations are microscopic at audio frequencies in short cables, the effect is essentially non-existant and would be hard to measure with scientific apparatus, much less hear as distortion. Power loss is also not an issue – the load impedance is far higher than the line impedance and the amplifier is more than capable of supplying the required power despite the attenuation of the line.
Now, these problems are solved in transmission lines by matching the load impedance (the speaker's impedance) to the “characteristic impedance” of the cable, to prevent reflections, and by matching load and source impedance (the amplifier's output impedance) – to maximise power transfer. But to do this, you need the right characteristic impedance, and you need a high source impedance – neither of which is desirable or needed in audio. In order to obtain a good damping factor, source impedances are typically kept very low compared to the load impedance. And an 8ohm characteristic impedance requires a very high capacitance cable... which as I explained above, we don’t want!
EVEN IF a speaker cable were to act as a transmission line, we also have to consider the final error in Townsend’s pseudoscientific marketing – that a speaker is an 8-ohm load. Few if any speakers are 8-ohm loads. In actual transmission lines, the loads are purely resistive (with good reason) yet in speakers the load is often highly reactive, which is bad for transmission lines! Whilst speakers are often described as ‘8 ohm nominal’ this is just an averaged value – impedance curves can vary wildly between minimum and maximum values across the desired frequency range. This is because drive units and crossover components have high reactances (by design, of course). So in fact even if you wanted to buy 15,000m of Isolde to run a pair of speakers in the next county... it STILL wouldn’t work as a transmission line! Incidentally, such a cable run would cost you £3.9m – before discount, of course! You can bet the telcos don't pay that much for their wiring...
Apart from these two major aspects of Isolde cable, the speaker wire is also offered with ‘biwiring’ links, and these are remarkable in themselves. Across the rest of the audio industry, bi-wiring means running two sets of wires from the amplifier to the speakers – with a separate crossover filter on the end of each wire. One driving the bass, the other the mid/treble. When – as is the case most of the time – speakers are not biwired, little shorting straps or cables are used to connect the bass and mid/treble crossover sections, allowing a single run of cable to be used (and saving money and mess for everyone concerned). These are typically provided by the speaker manufacturer (so that they fit properly and neatly). SOME speaker cable manufacturers make their own, and at a remarkable markup for what are rarely more than 6” of cable. Townsend though – apparently having no idea what bi-wiring is for – do something else entirely. They offer ‘bi-wiring terminals’!! What are those you wonder, and well you might! It turns out that these are speaker cable terminations that can stack on top of each other, just like the connectors on multimeters and oscilloscopes do! How extraordinary!!! So you can plug two Isolde cables into the SAME crossover terminal! Aside from the fact this is NOT biwiring, it’s just insane – you double the cost and double the reactance of your cabling. It also nullifies another putative benefit of the Isolde geometry – RFI resistance (which Townsend claim is minimal up to 60GHz due to the closenss of the gap between the cables). Like all cable manufacturers, Townsend stand to profit mightily (literally, doubling profits) from biwiring so its understandable they’d support biwiring, but to do it with these stackable terminating plugs is incredibly cynical.
It’s also worth remarking on the construction of these cables. Cables, once in place, rarely find themselves moved about or damaged from heavy contact, but it’s always possible and where such contact or impacts can damage the cable and (somehow...) affect its operation, it is important to anticipate this and design appropriately. Unfortunately, by their own admission, Townshend have not done this with their super-expensive cable. Instead, they warn against excessive bending or treading on the wire ‘end on’ unless they’re under the carpet... and in high-wear areas, even under carpet. They offer to supply ‘at cost’ a machined metal cover for the cable. The thing is, it would not have been hard to construct the cable in a more robust manner, with thick, strong insulation that would also protect the conductors and their geometry. This has not been done, leaving the customer to worry about protection instead. For such an expensive product, this is simply not acceptable, especially considering the cheapness of a tough cable shroud.
In fact, it pays to have a close look at the page-length ‘instructions’ for these cables. Speaker cables are just plug and play you’d think, sure, but... just have a look. Away from the website, and in the hands of the customer, we see even more claims made about these cables. They are well worth examining.
Addressing these points in turn:
1) The cable requires delicate handling to avoid kinks and bends. Oddly, at least one reviewer claimed the cables could be bent over at 45 degrees (to create a right-angled bend) when installing. He didn’t report any issues. Call me a cynic, but I suspect Townsend are creating a ritualistic manner of handling, to further imply the value of these cables (as if the sticker price was not enough of a clue!) and create a nice feeling of ‘value’ in the hands of the customer.
2) Don’t tread on the cable! Especially on edge. The site’s FAQ specifically mentions heels, and warns that damaging pressure on the cable, with its thin insulation, could cause an amplifier-destroying short. Really, what kind of cable can’t be stood on? Guess where almost all cables end up – on the floor!
3) Luckily, if you have carpets and run the cable under them (no explanation of how to get the cable round corners etc...) that’s OK though, as long as its not a high-traffic area. The customer is advised to consult with the manufacturer, and Max Townshend himself has said that a machined metal cover can be supplied ‘at cost’ which sounds very generous, at least. Better to make a tough cable, though, really... at the Isolde’s price, proper engineering is a reasonable expectation.
4) Yup – these cables are directional, AC theory notwithstanding... They come with a ‘terminating block’ and the end with the block is to be attached to the amplifier. Connect these cables the wrong way and, according to Max Townshend “unstable amplifiers may overheat”. Not sure why that might be, but it sounds like a huge flaw in a cable design if mis-use can cause unstable amplifiers (which ones are unstable???) to overheat! Most wires don’t do this, so it doesn’t really recommend these ones to have this design flaw. What’s in the ‘terminating block’? A filter network (crossover components – in a cable!) to “ensure optimum performance with all amplifiers”. It would be interesting to know what this filter network does, exactly, but for sure you don’t want to add filter networks to cables, because speakers already have filter networks and altering how those works will affect the sound balance of the speaker adversely. OTOH, it’s possible this filter network is there specifically to impart distortions to the voltage signal to fool customers into thinking the cable has an identifiable sound. Just in case you think this is a good thing, remember that the ideal cable does not distort the signal – and any filtering does distort the signal!
5) See above about Townsend’s unique take on biwiring! Note that the CSA for these cables is 4mm square – that’s quite high, but perfectly good, but it means there’s no point in going to 8mm square CSA, with double the reactance. Non at all. Even before we remember that biwiring is mean to be about... (and no, biwiring isn’t useful anyway).
6) Don’t touch the cable, and after a while – presumably after being installed – it will sound even better. Just leave it and do nothing – and it improves all by itself! Extraordinary!! Further, unlike other cables that do need ‘burning in’ (another example of pseudoscience) these cables don’t. Supposedly the (E)DCT has already had the same effect. OTOH, constant bending would lead to ‘work hardening’ (um, that’s what annealing – DCT – does) which apparently makes the sound worse...
7) Stating the obvious for once, the cable can be safely installed next to masonry and metal (phew...) so no need for cable elevators (yet another audio pseudoscience concept!) etc. Also claims the cables are immune to RFI inherently due to the close gap (not true... a gap is a gap, and you need a twist to prevent RFI) whilst the network blocks also have RF filtering (ie inductors) anyway. Maybe that’s what ensures ‘optimum’ amplifier operation???
8) Much like point (1) above, more feelgood ritual to appreciate the delicacy and value of your new investment. Actually, an interesting point, is that the two flat ribbons of copper in the wire are free to move across each other, which implies the dielectric between them is not bonded, and there must also be air in there. This would imply that these cables are actually microphonic! Whilst in practise a minor concern if it is one at all, it doesn’t sound like a good idea!
Altogether, Townsend Isolde represent a remarkably difficult, fragile, inappropriate and expensive way of accomplishing a very very simple engineering task – getting an audio-frequency signal voltage from amplifier to speaker with minimal distortion. Isolde deliberately adds distortions through faulty understanding of electrical theory, bad design, filter networks, potential microphony and advice on how to double reactances, in a high-reactance cable that is fragile and easily damaged. All at an eye-watering, wallet-reaming price...
Even if you wanted what Isolde does in a cable, there’s simply no need to do what Townsend did. You can add your own (high-power) capacitors and inductors on the end(s) of your normal, cheap, robust, low-reactance speaker cable and – electrically – the result would be no different to Isolde. Except the price and practicality – which would be vastly superior to the Townsend product. What Townsend are selling in effect is a product that comes with an aura of belief, but no substance to justify it. Like the emporer’s new clothes, the benefits are all in your mind, they just don't exist in reality. If you like the aesthetics, can accept the impracticalities and don’t care about money (or sound, or physics...), then these expensive audio baubles may well be for you. There is nothing wrong with decorating your hifi, after all
The goal of this post will be to examine Townsend’s cable and the marketing claims made about it to see what they mean if there is any substance to this very expensive product. First though, it would be worthwhile to revisit just what a speaker cable is and what it does.
From a practical point of view, a speaker cable has a very simple job to do – transmit a time-varying voltage signal from an amplifer to a loudspeaker, along with as much current as the speaker draws, whilst introducing as little distortion to that voltage signal as possible. The amplifier’s job is to supply as much current as the speaker needs. The ideal cable transmits that voltage and current without any distortion. Any change to the voltage signal, or any change to the current, would be distortion. Cables can’t improve a signal.
To accomplish this, we need a speaker cable that conducts electricity – obviously – but beyond that we need it to have as low an impedance as possible whilst remaining practicable and affordable. Obviously using thick copper bus bars might be ideal electrically, but that would be neither practicable nor affordable. In fact, the job can be done well using relatively little conductor material, and this is for two reasons. One, the distances typically run are short and little attenuation will occur. Two, the net impedance of the wire remains small compared to the load; this prevents the wires acting as a filter component to the speakers, and thus altering the sound in a way the speaker designer did not intend. This also minimises power loss, although that’s not a major consideration.
The essential elements of speaker cable design are the length of conductors, the cross-sectional area of the conductors, the resistivity of the conductor material, the insulation material (dielectric) absorption value (permittivity) and the spacing (or “geometry”) of the conductors. At audio frequencies, the electrical behaviour of the cables can be fully predicted and understood from these values, and no other factors need to be considered. IOWs, it can be shown that all of the distortions introduced by a cable between one end and the other can be explained by considering these factors alone. (RFI is not a direct cause of distortion, and would be filtered out naturally by both the speakers and the amplifier’s output circuitry. “skin effect” does not produce an audible difference at audio frequencies, resulting in something like a 0.1% rolloff at 20kHz – quite inaudible).
Since we want the least distortion, we must design our cable accordingly. Quite simply, we want a high cross-sectional area to minimise DC resistance to current flow. We also want the AC reactance – or complex impedance – of the cable to be minimal too. Reactance can be simply understood as a frequency-dependent resistance. That means we want minimal capacitance and minimal inductance. These are called reactances or reactive impedance because both phenomena ‘react’ against the current, by literally pushing back against the voltage that pushes the current. If DC resistance is like ‘drag’, AC reactance is like actively pushing back – obviously we don’t want this.
Essentially, we need to understand that capacitance is a function of cable geometry but inductance is a property of the conductor itself (and is thus hard to minimise). Capacitance is a function of three properties of a cable – the distance between the conductors, the area of overlap of the conductors and the quality (“permittivity”) of the insulating material between them. To minimise capacitance then we want a big gap, a narrow overlap and a good insulator. Capacitance works by storing energy in an electric field between conductors, and inductance by storing energy in a magnetic field around a conductor.
With all this in mind, let us now look at Townsend’s Isolde cable. Townsend make some interesting claims about their Isolde cable. The most prominent is that the conducting material is made from “EDCT” oxygen-free copper. EDCT stands for ‘enhanced deep cryogenically treated’. The DCT part refers to a process of cold-annealing the copper. The enhancement to this process is not specified, and is apparently a trade secret. DCT is used to minimise grain boundaries between adjacent crystals of copper in the wire. This is done in industry to improve the physical strength of the copper, to maximise its working life in a variety of industrial applications – eg welding. From a basic electrical point of view, DCT leads to a minor drop in copper’s resistivity – its resistance to electrical current. This reduction is tiny and given the expense of deep-cryogenic treatment, it would make far more sense to just use a little bit more copper in the cable to achieve the same result. Copper isn’t that expensive, after all... DCT is. By employing EDCT, Townshend have priced their product right out of contention for all but a few privileged audiophiles with budgets in inverse proportion to their knowledge of basic electrical theory. Changing the resistivity of copper makes no qualitative difference to how a cable distorts the voltage signal, other than a tiny proportionate drop in DC resistance. Level matched, and in reality, you will not hear this, much less attribute complex audible characteristics to the EDCT copper.
A second claim is that it is designed deliberately as a high-capacitance cable! Given that we want a cable with as low as capacitance as possible, why on earth would Townsend do this? It’s a good question. Now, typically, amplifier outputs include a capacitor in series with the output but one or two manufacturers - *cough*Naim*cough* - omit this, compensating with their own high-capacitance speaker cables to match. The rest of the industry just does things normally. Are Townsend targeting owners of Naim amps? Not according to their marketing materials. Instead, what they are doing is offering us pseudoscience – claiming that their high-capacitance cable enables it to be “impedance matched” with an “8 ohm” speaker. In short, they’re making the extraordinary claim that their speaker cables act as transmission lines, and that you’ll get better performance because of this.
To understand the pseudoscience being touted here, we first need to understand what a transmission line is. In short, it’s any wire or conductor carrying an AC (time-varying) voltage signal where the length of the cable is at least a quarter as long as the wavelength of the highest frequency of the signal. (lower frequencies have longer wavelengths – it’s only those wavelengths that approach ¼ or more of the length of the cable that are affected). In simple terms, it’s a really long wire! The classic example is of course the long-distance telephone circuit, and the most extreme of those were the old copper undersea phone cables, some of which ran for literally thousands of miles in length. Not really comparable to speaker wires at home, or in a studio! Indeed, at 20kHz – the highest frequency with the shortest wavelength in the audio passband – a speaker cable would have to be over 15 kms long, yet very few audio cables exceed one thousandth of that length! Clearly, speaker cables are not transmission lines.
What does it matter? Well, transmission lines (ie long cables) suffer from signal reflections that cause signal cancellation, and from significant power loss. Neither is a problem for speaker cables though, and here’s why. Firstly signal cancellations are microscopic at audio frequencies in short cables, the effect is essentially non-existant and would be hard to measure with scientific apparatus, much less hear as distortion. Power loss is also not an issue – the load impedance is far higher than the line impedance and the amplifier is more than capable of supplying the required power despite the attenuation of the line.
Now, these problems are solved in transmission lines by matching the load impedance (the speaker's impedance) to the “characteristic impedance” of the cable, to prevent reflections, and by matching load and source impedance (the amplifier's output impedance) – to maximise power transfer. But to do this, you need the right characteristic impedance, and you need a high source impedance – neither of which is desirable or needed in audio. In order to obtain a good damping factor, source impedances are typically kept very low compared to the load impedance. And an 8ohm characteristic impedance requires a very high capacitance cable... which as I explained above, we don’t want!
EVEN IF a speaker cable were to act as a transmission line, we also have to consider the final error in Townsend’s pseudoscientific marketing – that a speaker is an 8-ohm load. Few if any speakers are 8-ohm loads. In actual transmission lines, the loads are purely resistive (with good reason) yet in speakers the load is often highly reactive, which is bad for transmission lines! Whilst speakers are often described as ‘8 ohm nominal’ this is just an averaged value – impedance curves can vary wildly between minimum and maximum values across the desired frequency range. This is because drive units and crossover components have high reactances (by design, of course). So in fact even if you wanted to buy 15,000m of Isolde to run a pair of speakers in the next county... it STILL wouldn’t work as a transmission line! Incidentally, such a cable run would cost you £3.9m – before discount, of course! You can bet the telcos don't pay that much for their wiring...
Apart from these two major aspects of Isolde cable, the speaker wire is also offered with ‘biwiring’ links, and these are remarkable in themselves. Across the rest of the audio industry, bi-wiring means running two sets of wires from the amplifier to the speakers – with a separate crossover filter on the end of each wire. One driving the bass, the other the mid/treble. When – as is the case most of the time – speakers are not biwired, little shorting straps or cables are used to connect the bass and mid/treble crossover sections, allowing a single run of cable to be used (and saving money and mess for everyone concerned). These are typically provided by the speaker manufacturer (so that they fit properly and neatly). SOME speaker cable manufacturers make their own, and at a remarkable markup for what are rarely more than 6” of cable. Townsend though – apparently having no idea what bi-wiring is for – do something else entirely. They offer ‘bi-wiring terminals’!! What are those you wonder, and well you might! It turns out that these are speaker cable terminations that can stack on top of each other, just like the connectors on multimeters and oscilloscopes do! How extraordinary!!! So you can plug two Isolde cables into the SAME crossover terminal! Aside from the fact this is NOT biwiring, it’s just insane – you double the cost and double the reactance of your cabling. It also nullifies another putative benefit of the Isolde geometry – RFI resistance (which Townsend claim is minimal up to 60GHz due to the closenss of the gap between the cables). Like all cable manufacturers, Townsend stand to profit mightily (literally, doubling profits) from biwiring so its understandable they’d support biwiring, but to do it with these stackable terminating plugs is incredibly cynical.
It’s also worth remarking on the construction of these cables. Cables, once in place, rarely find themselves moved about or damaged from heavy contact, but it’s always possible and where such contact or impacts can damage the cable and (somehow...) affect its operation, it is important to anticipate this and design appropriately. Unfortunately, by their own admission, Townshend have not done this with their super-expensive cable. Instead, they warn against excessive bending or treading on the wire ‘end on’ unless they’re under the carpet... and in high-wear areas, even under carpet. They offer to supply ‘at cost’ a machined metal cover for the cable. The thing is, it would not have been hard to construct the cable in a more robust manner, with thick, strong insulation that would also protect the conductors and their geometry. This has not been done, leaving the customer to worry about protection instead. For such an expensive product, this is simply not acceptable, especially considering the cheapness of a tough cable shroud.
In fact, it pays to have a close look at the page-length ‘instructions’ for these cables. Speaker cables are just plug and play you’d think, sure, but... just have a look. Away from the website, and in the hands of the customer, we see even more claims made about these cables. They are well worth examining.
Addressing these points in turn:
1) The cable requires delicate handling to avoid kinks and bends. Oddly, at least one reviewer claimed the cables could be bent over at 45 degrees (to create a right-angled bend) when installing. He didn’t report any issues. Call me a cynic, but I suspect Townsend are creating a ritualistic manner of handling, to further imply the value of these cables (as if the sticker price was not enough of a clue!) and create a nice feeling of ‘value’ in the hands of the customer.
2) Don’t tread on the cable! Especially on edge. The site’s FAQ specifically mentions heels, and warns that damaging pressure on the cable, with its thin insulation, could cause an amplifier-destroying short. Really, what kind of cable can’t be stood on? Guess where almost all cables end up – on the floor!
3) Luckily, if you have carpets and run the cable under them (no explanation of how to get the cable round corners etc...) that’s OK though, as long as its not a high-traffic area. The customer is advised to consult with the manufacturer, and Max Townshend himself has said that a machined metal cover can be supplied ‘at cost’ which sounds very generous, at least. Better to make a tough cable, though, really... at the Isolde’s price, proper engineering is a reasonable expectation.
4) Yup – these cables are directional, AC theory notwithstanding... They come with a ‘terminating block’ and the end with the block is to be attached to the amplifier. Connect these cables the wrong way and, according to Max Townshend “unstable amplifiers may overheat”. Not sure why that might be, but it sounds like a huge flaw in a cable design if mis-use can cause unstable amplifiers (which ones are unstable???) to overheat! Most wires don’t do this, so it doesn’t really recommend these ones to have this design flaw. What’s in the ‘terminating block’? A filter network (crossover components – in a cable!) to “ensure optimum performance with all amplifiers”. It would be interesting to know what this filter network does, exactly, but for sure you don’t want to add filter networks to cables, because speakers already have filter networks and altering how those works will affect the sound balance of the speaker adversely. OTOH, it’s possible this filter network is there specifically to impart distortions to the voltage signal to fool customers into thinking the cable has an identifiable sound. Just in case you think this is a good thing, remember that the ideal cable does not distort the signal – and any filtering does distort the signal!
5) See above about Townsend’s unique take on biwiring! Note that the CSA for these cables is 4mm square – that’s quite high, but perfectly good, but it means there’s no point in going to 8mm square CSA, with double the reactance. Non at all. Even before we remember that biwiring is mean to be about... (and no, biwiring isn’t useful anyway).
6) Don’t touch the cable, and after a while – presumably after being installed – it will sound even better. Just leave it and do nothing – and it improves all by itself! Extraordinary!! Further, unlike other cables that do need ‘burning in’ (another example of pseudoscience) these cables don’t. Supposedly the (E)DCT has already had the same effect. OTOH, constant bending would lead to ‘work hardening’ (um, that’s what annealing – DCT – does) which apparently makes the sound worse...
7) Stating the obvious for once, the cable can be safely installed next to masonry and metal (phew...) so no need for cable elevators (yet another audio pseudoscience concept!) etc. Also claims the cables are immune to RFI inherently due to the close gap (not true... a gap is a gap, and you need a twist to prevent RFI) whilst the network blocks also have RF filtering (ie inductors) anyway. Maybe that’s what ensures ‘optimum’ amplifier operation???
8) Much like point (1) above, more feelgood ritual to appreciate the delicacy and value of your new investment. Actually, an interesting point, is that the two flat ribbons of copper in the wire are free to move across each other, which implies the dielectric between them is not bonded, and there must also be air in there. This would imply that these cables are actually microphonic! Whilst in practise a minor concern if it is one at all, it doesn’t sound like a good idea!
Altogether, Townsend Isolde represent a remarkably difficult, fragile, inappropriate and expensive way of accomplishing a very very simple engineering task – getting an audio-frequency signal voltage from amplifier to speaker with minimal distortion. Isolde deliberately adds distortions through faulty understanding of electrical theory, bad design, filter networks, potential microphony and advice on how to double reactances, in a high-reactance cable that is fragile and easily damaged. All at an eye-watering, wallet-reaming price...
Even if you wanted what Isolde does in a cable, there’s simply no need to do what Townsend did. You can add your own (high-power) capacitors and inductors on the end(s) of your normal, cheap, robust, low-reactance speaker cable and – electrically – the result would be no different to Isolde. Except the price and practicality – which would be vastly superior to the Townsend product. What Townsend are selling in effect is a product that comes with an aura of belief, but no substance to justify it. Like the emporer’s new clothes, the benefits are all in your mind, they just don't exist in reality. If you like the aesthetics, can accept the impracticalities and don’t care about money (or sound, or physics...), then these expensive audio baubles may well be for you. There is nothing wrong with decorating your hifi, after all