One of the most interesting approaches to the mechanical behaviour of cables was presented by Vertex AQ, who built cables with dispersive matrices in direct contact with the conductors. That’s right – right up against the metal, with no insulation in between. The Vertex cables were ugly, barely practical, far from cheap but undeniably effective. But the most interesting thing about them wasn’t the cables themselves but the thinking behind them. For the first time, a cable design was created not simply to deal with the impact of external vibrations on cable performance, but to deal with the issue of internally generated mechanical energy on system performance.
Looking inside out…
Vertex started by looking at the generation and transmission of mechanical energy within the system. They weren’t the first to do that, with Goldmund’s approach to the mechanical grounding of their components being an early example. But what made the Vertex solution so different was its emphasis on preventing or minimising the transfer of mechanical energy from one point to another. In many ways they were swimming upstream – and not just when it came to received wisdom. While the prevalent perspective ion system building (at least in the UK) was very definitely ‘front-end first’, they asked us to reverse our thinking (at least as far as mechanical energy was concerned) and start with the speakers – or more precisely, the drive units, those things that by definition, vibrate in order to function. Vast amounts of acoustic and mechanical energy aren’t so much a by-product as their raison d’etre. What Vertex pointed out was the unfortunate circumstances that joined those vibrating elements, directly to the output devices of your amplifier, firmly strapped together by metal strands that transmit mechanical energy very nearly as efficiently as they transmit electrical signals. Okay, so you might quibble at describing the path as ‘direct’. There are, after all, junctions along the way, at the crossover and the connecting terminals. But the problem is that a good electrical connection is also pretty much by definition a good mechanical one – and the negative leg on most crossovers offers a direct return path. So, what you end up with is a bunch of bits that are positively encouraged to vibrate, linked securely to the devices in your amplifier’s output stage – that don’t like vibrating at all!
Start to think about this and a whole lot of other stuff starts to make sense. Just like OTL amplifiers working so well with electrostatic speakers (‘cos the speakers have a transformer on their input!), how much of the mellifluous sound accorded to tube amps is down to the simple fact that there’s a big chunk of iron mechanically isolating the output tubes from the loudspeaker drivers? Does having more output devices make an amplifier more vulnerable to mechanical interference? Minimalist binding posts (like the Argento) sound better because they contain less metal – but is that for electrical or mechanical reasons? Or both?
