As much as I like this speaker I am wary because:
- No XLR input. It's not future proof or present proof. Processors such as Lyngdorf, McIntosh and Trinnov no longer have RCA outputs and I'm sure other manufacturers will follow suit. This is a deal breaker for something I want to last 20 years at $6,999 a pair.
- How reliable are class D SMPS amplifiers? I know in the past longevity for SMPS has been a concern. Reliable enough to last 20 years?
- How is volume set if using RCA? With lets say a RCA capable AVP.
- Any measurements? Particularly of the ADC and DAC? Especially since AVR/AVP's will output analog
Is there a reason this speaker cannot be passive? The KEF Blade Two Meta spinorama and dispersion is about as good as it gets and that's passive. If the KEF LS60 was made passive for $5,000 a pair I would leap and buy three in a heartbeat and call it my endgame speakers. Would be the perfect KEF R series replacement too.
If not passive they should have at least included XLR input. I have the same issue with their KF92 subwoofer, it's useless with the higher end AVP's that only have XLR.
For some of these questions:
1. Unless you have an extremely noisy environment, or are running extremely long cables, you can probably use some XLR to RCA cables here and notice no actual difference in performance. XLR is a more secure connection, and has uses other places, but for home audio you aren't likely to hear an audible difference (but people think all high-end gear should have XLR connections, so they do it).
2. No idea
3. There's a volume level that is unity gain on the LS60, and if you search through this thread you will find it. If you set the speakers to that level and don't adjust it, then you can use them with a preamp of your choice and adjust the volume there. There's no way to force this (like a HT Bypass mode), and if you stream audio then you'll have to remember to set the volume back, but you could do this.
4. Measuring the ADC would require taking the speaker apart and being able to tap into the ADC output, so I wouldn't expect to see these measurements anytime soon. Even if the ADC isn't reference grade, it's still going to have lower distortion than the drivers themselves.
Finally, there have been multiple discussions in this thread, based on the KEF white paper, on why this speaker can only exist as an active system and cannot be passive. Without DSP it just can't happen, so I'd go read that white paper if you want to know.