In audio, you'll have some critics saying that:
- "this class D amp has digital glare"
- "this ESS DAC chip has Sabre glare"
I wonder what is glare, what causes it and would this glare be related to harmonic distortion that causes the treble to lack control or else?
Thank you!
Don't know what they mean by "Sabre glare". In my experience, any contemporary DAC with a properly designed filter and output stage doesn't introduce anything I would call "glare". Perhaps they refer to some cheap Sabre-based DACs, with a rudimentary and/or overloaded output stage? Otherwise, quality DACs, Sabre-based or not, shall be subjectively virtually indistinguishable under controller listening tests, just like Amir says.
Class D glare is easier to encounter, especially in older designs, and in budget consumer electronics. The distortions of higher frequencies at highest and/or lowest output levels are usually caused by insufficiently high switching frequency, in combination with insufficiently sophisticated and/or non-linear low-pass filter, and excessive switching interference. See
https://en.wikipedia.org/wiki/Class-D_amplifier#Design_challenges for discussion of some of these issues.
The design challenge of a transparent AB amp was mostly met in the 1980s, all the relevant patents expired long ago, best schematics and components are widely known, and today one can buy an incredibly good AB for not much money. The D class is not there yet. The designs are actively revised and patented. You can buy a really nice D, yet it will still cost a pretty penny (e.g.
https://epc-co.com/epc/GaNTalk/Post...Sound-Quality-and-Efficiency-to-Class-D-Audio). Majority of D amps sold today can't touch the transparency of a classic AB at the higher audio frequencies.
I like using class D amps for subwoofers - that's the best match, as the major D issues diminish rapidly at lower audio frequencies, while the power efficiency advantage shines. None of my current home gear uses class D for tweeters, where the D issues are most noticeable. Class D driven tweeters are not often encountered in pro studio gear either. High-quality class D amps are OK for mid-range in my opinion - driving woofers in a center speaker of a home theater for instance.