Originally Posted by DS-21
I'd like to see evidence of that. The big sonic shortcoming of Class D is the output impedance. I don't know of any IR, Zetech, Intersil, or Crown amps that have published results into a simulated speaker load, but I would not call the performance of the TI chip in the Peachtree Decco "high-fidelity":
That's about 1dB of swing in the midrange! (And a speaker with more impedance variance than Stereophile's "Kantor load" will have cause more response deviations from the amp.) The same review shows basically flat FR from the preamp outputs, so one can reasonably surmise the variation to come from the amp chips.
I agree that Hypex and current Icepower (ASX2) designs are solid and the sonic equivalent of good AB amps. Stereophile "Kantor load" measurements of devices using those modules (Channel Islands for Hypex UcD180, Bel Canto for Icepower 125ASX2) show very little FR variation into the simulated speaker load. I would like to see data for the IR2092, Harman (Crown/Lexicon) DriveCore, and other current Class D amp designs, but cannot presume they are on the same level absent those data.
When evaluating an amplifier's sonic charaterisics by just comparing 2-D AP graphs...
There are many, many amplifiers that measure/display well on a graph but sound terrible
The Kantor Load
though adequate for a limited bandwidth
small 2-way loudspeaker does little for illustrating the performance of a high resolution, full-range loudspeaker capable of delivering a frequency response of 20Hz-20kHz..
The mentioned Class D solutions, have been highly refined and deliver superb sonics....
You will not find these used very much in price point AVRs as these leader products sold by Amazon,Target, Best Buy and Walmart are sold by some stretched
100W/ch spec, 4 K video and how many HDMI inputs there are...
And 90% of the products are never even demoed...
The implementation of Class D amplifiers are already established strongly in Pro audio, estoteric hi-fi components, multi-media and OE 12V infotainment applications.. Besides quality sonics, they simply offer better cost/performance specs, significantly better power efficiency(>90%) and while being capable of smaller form factors. There are some excellent examples of products with good-sounding Class D amplifiers including the latest Pioneer/Elite utlizing the IR solution plus the excellent Harman/Crown DriveCore technology done by a TI processor.
Regarding Harman International, over the next future product generations one will find their DriveCore technology being implemented in brands from Crown > JBL Pro > Lexicon > JBL Synthesis > Revel > Harman/Kardon..
Just my $0.05... 👍😉