Over the years the esl proto really took my heart, but it´s considerable height took away the light and appeared a bit dominant in the long run. As the esl MK2 prooved is a reduction in buid height and number of bass drivers from 8 to 6 of no acoustic disadvantage. The complete amplifier and crossover electronics needs to be done externally.

Acoustically the class-D amps with their associated little DSP-filter were only convincing with Rock and Pop material. With Classsic they never convinced.

My ex-boss meanwhile worked and tested on his ESLs and realized step by step a concept that originated already from the beginning of our work. This concept describes a DSP filter core, driving into a multi-channel DAC and following up amplifiers, possibly even a direct-drive ESL-amplifier.

Already when measuring the ESLs at the RWTH Aachen the advantages of the concept came clear, though neither the used amplifiers nor the DSP-controller matched with the ESL´s niveau.

We had the strong feeling, that mainly the design of the analog output circuitry of the DSP-controller formed the bottleneck, and not the DSP-core as such. In not too critical rooms mostly the analog crossover was still the preferred choice.

That changed the moment when we found in Accourate a Software-DSP solution and utilized our own DACs. Already as a overall- and room-correction under retention of the analog crossover, the ESLs progressed considerably. The new laboratory sample of the multi-chanel DAC doubtlessly and finally surpasses the analog crossover.

Since I was asked to put the DAC into praxis it´d be a opportunity to develop my ESEL further too.

One sticking point exists though. It is a fully digital concept and this mean either no Phono or to A-D convert and streaming into the music server.

A good quality USB audio interface from RME or ESI would allow to connect and digitize analog sources this due to their built-in ADCs, but doesn´t play in the same class of our DACs. But the costs would be alot more affordable.

Presumably I´ll use the L12-2 amplifier modules as drive, at least for the bass towers.

For the panel I´m still fancying a direct drive amplifier featuring HV-MOSFETs.

Its a lucky and random coincidence that my ex-boss also asked me about ESL-amp.

Well, let´s see how things develop.