Thanks, I’ve been reading a bit on phase shift or angle, same thing ?? Still trying to digest it
"phase shift or angle"
Two TOTALLY different things. Phase Shift can be caused by a few things, in Class-D case it’s caused the by the output filter that needs to get rid of the 600khz switching frequency noise, without that filter your speakers and ears would fry up.
This filter HAS to be low order because it needs to absorb a lot of wattage And because of it’s low order roll off trying to get rid of the switching frequency, it continues to create it’s effect in (degrees) down into the audio band as 70!! degrees of phase shift (red trace https://ibb.co/jfd6tqy
) and it’s sensitive to the human ear because it in the upper/mids and highs, which too many complain about in Class-D to be just a coincidence.
All this is related to the one smart thing atmasphere said about phase shift down into the audio band, but it was on another thread and the direct opposite to what he's trying to sell you here.
"If you really want to get the soundstage right, the amp needs to have minimal phase shift in the audio regions so it will need bandwidth past 80KHz.
The FIX= As Technics did in the SE-R1 because of the use of GaN technology, is to raise the switching frequency nearly 3 x higher to 1.5mhz, and you can then raise the filter up with it, and then the phase shift effects are also raised along with it out of the audio band. to above 20khz Simple isn’t it. This comes at a cost of having to use small heat sinks, nothing major.
Phase Angle also expressed in -degrees, common in bass measurements of speakers, it combines with the speakers impedance to create an amplifier loading measurement call EPDR (equivalent peak dissipation) resistance. It’s a long read but all explained here. 3 pages of it here, this is the 2nd page. https://www.stereophile.com/content/heavy-load-how-loudspeakers-torture-amplifiers-page-2