high-efficiency loudspeakers

@kqvkq with regard to Quad ESL 57s the recomended maximum amp size was 45 wpc as I had them and when Quad brought out their 405 current dumping amplifier they stipulated that you had to put current limiting resistors in it to limit the amp to 45wpc when using the 57s. I'm afraid I know this to my cost as twice I had to replace bass panels as I thought I would be smart and not use the resistors.

Ken Shindo gets the hammer green color that he uses in some of his amps from the Altec Lansing 604C. 

He actually once used a pair of 604Cs in a pair of floor standing cabinets that were being sold for $33,000 in a Manhattan audio salon, maybe two summers ago. 

The pair I have are in an identically sized pair of cabinets. I added the Mastering Lab crossovers, the whole package costing me $3,300, a mere tenth of what the “Shindo” pair eventually sold for, to some unsuspecting Wall Street sucker no doubt. 

I’ve had my pair for 35 years. Every 7 or 8 years or so I figure there must be something better, I go shopping for a month or so and decide well, yes, this or that may be better but is it $50K better, and the answer is always decidedly no. 

The speakers are 103DB. I run them with a pair of Julius Futterman OTL3s, converted to triode. The depth and detail are outstanding. 

I’m basically a happy camper. 

I own Spatial Audio M2 Turbos - 94dB?  They're wonderful.

I have a pair of the new Spatial X2s on order.  92dB? Clayton Shaw and the world tell me they'll be wonderfuller.  Impatient?  Me?

I run the M2s with a PS Audio Sprout.  It's wonderful, too, and what? 33w/channel?  And a good 'nuff DAC, and Bluetooth.  Lively and fun with the M2s.

I also play my music very loud. I have a pair of  Source Loudspeaker Technologies 7211's with 2 H/VS 10 Subwoofers and I'm very happy. I have a DB meter on my ipad and I play in the 92 DB up to 98 range with ease. Don't hear much about these speakers but at $2400 and $1800 each for the sub's there a very good deal. Built in  South Windsor, CT by
John Sollecito. You can give him a call he's very happy to talk to you about your music needs. 

PWK Khorns for decades. They have a deep sound stage, when properly voiced with good quality amps. Quality is key. And most of my listening is done slightly below 90dB.

In the last 60 years of this hobby I've heard systems that sound as good or only different, but none better. And none that delivered a "live in the next room" sound.

I have Martin Logan ESL's in another room, which are extremely transparent but sterile. I like the MLs, but they are not very involving. They provide a good reason to talk about and discuss amplifiers with other audiophile. Good material for helping selling amps in audio rags. Had Maggie's, Quads . . . same issue despite throwing tons of watts at them at any level. Odd, that I still like the MLs.