PSG was used better

Yes, late-80s/even early 90s (SMS) PSG music generally sounds better than early to mid 80s (MSX). I don't understand your point.
I love 8-bit Sonic 1 music btw, done by Yuzo Koshiro.

I think it is the same chip as PSG. I never read about an AY clone mentioning an additional register. The bass is envelope abused as waveform, and then bleeping and apreggio and all that.

But, there is some nice softness to it. "recorded with AV cable". At 7:00 in the video an emulator is shown. I remember when doing PSG tests on real MSX, I too felt like there is something more soft.

I wonder, do the PSG pins go straight in the plug or are there some capacitors around?

Of course they do not go directly. But i guess hit9918 mean:'Are there some capacitors, or a simple resistor-based mixer?'

@hap, to the software man it is not clear why the cartridge sound pin should not just as well be directly connected with the plug

So, are there capacitors on the PSG pins?
Maybe on real MSX higher frequencies come out a bit less strong than on emulator?
Under the youtube video, people talk how different segas do FILTER things different.
That can't be about the PSG itself, because there is nothing but the purely digital square wave.
Well except that DAC at the very end. But I feel that one doesn't go filtering.

"less possible pitch" would mean the sega can go down deeper, but not really additional effects.
Likely the Sega too is on nothing but the square wave. Plus messing with the envelope to make triangle wave.
The nice flair of the sound, I don't hear anything new in terms of PSG register feature.

Oh, so there is an extension to AY.

And when I think of "periodic noise", I really start to wonder.
"11011010", that is like making a waveform whose samples come from the random number generator!
How does the feature work, is there a "reset random numbers after n cycles" register?

Has one been lucky, are some usable samples in the random sequence?
Any example videos about it getting used?