Craig Sawyers

T2 image - Damn, everyone beat me to it - I really really really like it, a winner!

I can't think why not - they will take over at around 100Hz, so peak accelerations aren't so great, at least in loudspeaker terms (5g or thereabouts). The ESL itself has a fundamental bass diaphragm resonance at 40Hz or so (which is the 35 ohm peak in their impedance), so it isn't behaving ideally itself down there. The key thing is a good strong motor and a grunty amp that will put the cone where it ought to be. All the substantial 14.5kg is in magnet and support structures - the moving mass is only 200 grammes (7oz). Gradient do a dipole sub for the ESL63 (called the SW63). That apparently uses custom 12" Peerless drivers (or Tymphany as it is now). No idea of the driver spec. Anyway, I'm a real mug for well engineered product - and the ShivaX2 certainly is that. Exodus do even stoopider drivers, like an 21" animal called the Maelstrom at $647 a pop, with an Xmax of 32mm, a resonant frequency of 16Hz, and weighing 53lbs. But I really don't want to blow the windows out Craig

Wow - that really is hot off the press! The first collisions were only an hour or so ago - thanks for pointing that out. At that energy, the proton mass is 7000 times its rest mass. Truly outrageous.

Include a washed bottle

I've got interested in putting dipole subs on the ESL57's. Gradient in Finland used to do one (with 8" drivers), but no longer do. Since 1995. The guy who has published most on dipole speakers is Siegfried Linkwitz. I've followed his thinking off and on since the late '70s. His day job before he retired was designing microwave test equipment at HP. Anyway, his website sets out design rules. The main issue seems to be aerodynamic noise from the voicecoil cooling vents on the magnet side of the speaker. You don't hear that in a sealed box, but you do on a dipole. He kept finding speakers that were good in this respect, and then they were discontinued by whatever manufacturer. The really superb one was called the Shiva by Adire Audio. Of course Adire is defunct. Figures. So I bought a JL Audio 12" sub for trials, and I could get no more than 6mm excursion at 35Hz before it started chuffing from the magnet side. That driver is due for the dreaded e-Bay, unless anyone in the UK wants one for a car system, or a sealed box sub for the listening room. It would be great in a sealed (or vented) box. Brand new. It turns out though that the Shiva still exists, made by Exodus Audio and called the ShivaX2. By the time it gets from the US to the distributor in Holland, and then to me in the UK, being punished by dollar and Euro rates all the way, this beast comes in at a hefty

That figures. Perhaps that results in the film losing mechanical tension, because most of the dead ones I was looking at at One Thing had torn films - some spectaculaly so.

Awesome! I read somewhere that owning a Quad ESL is a bit like owning a classic MG car - great to own and a pleasure to drive, but you are always tinkering under the bonnet. Certainly the case for the '57s. The really good news is that yours have been re-panelled. I was a bit surprised on my visit to One Thing Audio how many of the '63's suffer panel damage. They rebuild the panels for 400 '63's a year, and can't keep up with demand. And that is just the UK and mainland Europe mostly.

Go easy on the recovery, and do whatever god awful exercises the physio tells you. I had a knee op three years ago, and it was scary how the leg that was op'd on lost muscle tone in spite of lots of single leg strengthening. I've got back to running, but it has been a long journey. Folks I know who have had knee ops (and there are quite a few) either had to stop running and take up biking or swimming, or got away with it and still run. Do whatever works and have a really speedy recovery.

I gave up bike riding - I got fed up with how much it hurt falling off. Now I stick to running - you go slower and can't fall off

The raw feed in the road here is actually three phase (ie each phase being 120 degrees from the other two) plus neutral. Every third property is connected to the same phase, so approximately balancing the phase currents over many properties. The voltage between any two live phases is 415V (240 x root 3). So the 240V that comes into each property is fundamentally unbalanced. And yeah - if you have a piece of gear that uses three phase, or even wierder two out of three phases, there is nothing much you can do except use a transformer. Craig

We've exactly the same system on UK 240V. Neutral is grounded (ie connected physically to the soil) at the electricity substation, and at regular intervals underground. Only two wires come out of the ground to the electricity meter (live and neutral), with the domestic ground wire attached to neutral at that point. Since the neutral wire inside the house takes the return current, it floats an unspecified and usually horribly distorted ac voltage above house ground as a result of wiring resistance and ac impedance. I've been thinking about a balanced isolation transformer for the audio system for some time, so interesting to see that you have gone a similar route. Craig

Rare commodity. Fill up stations and supermarkets no longer take cheques (in the UK anyway). It is only a matter of time that cash goes the same way. Craig

A mix of doing some circuit board layout and running. For my sins (they must have been bad) I'm in the London marathon this year. Done it many times before, 8-ish but I've lost count, but I'm way behind with training. So 13 miles yesterday and 5 today - and still lots to do in the next four weeks. Plan for another 10 or so tomorrow. Permanently knackered. You'd think I'd know better in my mid fifties, but hey, what the hell. At least I'm fit and well. Craig