This is where most of you go off the rails, and fail to understand the very, very tight coupling between amp and speaker on ESL technologies.
Let me share some insights gleaned over the past 20 years of following ESL tech and reading really great books, like Rogers own “the Electrostatic Loudspeaker Design Cookbook”. So far, the definitive tome on the subject available to the public, and with entire chapters focused on electronics.
Unlike pretty much any other speaker, ESL speakers present many challenges to an amplifier:
- High Capacitance (several thousand pF)
- High capacitance reactance
- Amp is driving a step-up transformer
- Incredibly varying resistance (dropping with increasing freq.)
- High demand for voltage AND current
- Large back-EMF currents
Since the power amp design is a critical component in the ESL circuit (in any topology, an amp is part of the electro-mechanical circuit, but in ESL’s many more interdependent variables exist), designers like Roger have been studying their effects since day one. Roger has indeed been designing amps since 1974, including a pretty massive direct-drive amp. The current Sanders ESL monoblocks can match or outperform those DD beasts.
Also, one can’t seriously design ESL’s without some regard to the electronics that will drive them or of the interactions of the ESL electronics. Both Innersound and Sanders speakers have been used with all kinds of amps.
So calling Roger just a ‘Speaker designer’ is a serious injustice, and ignores his long (and well documented) history with electronics design.
The knocks against other electronics design houses that try and produce speakers is likely accurate, as good speaker design is indeed a challenge to get right. I’ve yet to hear an amp house that then produced a great speaker (that I've personaly heard), Carvers 'Amazing' came close though.
Now, companies that specialize in vertical integration, exemplified by the best of the breed (IMHO) Meridian, do succeed. But I believe their success is largely driven by the HUGE benefit of controlling all parameters of the SYSTEM. So when the designer can control cabinet, drivers, crossover (actives in this case) and amps as well as sources (the 800 and G-series), they can indeed produce knock-out results.
It’s not that their amp topologies are so innovative or overbuilt, or that their speakers are designed with the care, say KEF expends, it’s that the ability to coordinate at an R&D level yields such huge payoffs, the rest is secondary.
Having highly customized speakers, crossover and such in my own rig, I certainly understand the value of systematic design.
Finally, Roger Sanders does do systemic design and sells holistic solutions, such as the 10b, which includes a sophisticated active crossover and bass amp as part of the package. Layer on his ESL (or larger monoblocks) amps and you have a cohesive, integrated solution.
Read some of the reviews of his recent appearance at the AudiogoN THE show
