[patrick-turner]

Andre asked me a question......

Andre Jute Jul 13 (18 hours ago)

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On Saturday, July 13, 2013 6:51:14 AM UTC+1, patrick-turner wrote:
But I had a customer with 3 stacked pairs of ESL57 and I sold him an 8585 tube amp to drive them.
Three pairs stacked two, two and two, or two pairs stacked three and three?
Andre Jute

Allow me to explain exactly. The customer had a total of six (6) ESL57 speakers.

For each L and R channel, three were placed vertically on top of each other to make a virtual single panel with height = 3 x height of one speaker, and aligned on the one vertical axis. The guy had timber stands made to do this very easily. The two channels meant two stands maybe 3M apart. He sent me a picture of his system.

One could say that he had a virtual line array of drivers for each channel. Because of the height of the stacked speakers, and most probable large differences in speaker to ear path length then there must have been serious
variations in level for MF and HF due to phase of signals arriving at the ear.

This raises a question about the "rightness" of line arrays regardless of the drivers used, because of timing issues. But where I have been at outside public concerts with line array public address, the music has always been far better to listen to than where old fashioned bins were piled up around the stage and played loud to deafen front rowers, but yet be devoid of HF content, presumably for acoustic FB to mic problems. So, one can reproduce music with amps and speakers and commit huge engineering sins and have ppl find they like it.
Being an old phart, I avoid "gigs" with loud amplified sound - like the plague.

For hi-fi, line arrays and stacked ESLs present special problems, IMHO. The best ESL I heard belonged to a guy Chris Feliefe, a gentleman of Roseville in Sydney, and he built his own ESL after many years of research. He was able to make a very fine sounding system with only 16 Watt SET amps using well designed OPTs and 6C33c tubes. Music was natural, fresh, lively, balanced and warm. Panels were not huge. I could have listened forever. Once I heard Martin Logans, 1.2M high, with subs, and I thought they gave superb sound, even with an SS amp. But two other Quad ESL systems I found to be kind of harsh, and so I've found it impossible to agree Quads are the best. But whatever I think about sound of ESL doesn't matter, I am just a retired amp worker, but I suggest all readers keep an open mind, and be prepared to try things based on applied science rather than applied snake oil.
Patrick Turner.