How come the -Y switch is not used with the --alt-preset 128, 144 and similar settings by default?
I've noticed that it is used with the --alt-preset medium, which is supposed to give a little higher bitrates than 128 or 144.
How much degradation in quality would the --alt-preset 128 or 144 have if I used the -Y switch with it?
And, yes, I know that the alt-presets are tuned for optimal quality, but I'm just being curious, because I tried some samples, and they were easier to listen with the -Y switch... is it just me?

Many thanks.

What do you mean, "easier to listen"? That does not sound like a valid ABX test, does it?
Anyway, -Y does only make sense with VBR and not CBR/ABR. IIRC, these function as if they actually do use -Y (i.e. no noise shaping in sfb21), so adding it is pointless. Maybe someone else can provide more technical details...

Greetings, sTisTi

The adding -Y does not change the abr/cbr behavior.
Apart from technical explanations, this is a clear demonstration of placebo effect.

Does that mean that the output file should be the same, regardless of my usage of the -Y switch?

As for the "easier to listen" term... well, what I meant was that the sample did not have that much "squealing" artifacts within the treble range when I listened to it... I could have been wrong, though, I admit

Yes. Another victim of the placebo affect.

Ok... I am also another victim of an infinite ignorance (but trying to fix it):
what exactly is a placebo effect?

Thanks.

http://en.wikipedia.org/wiki/Placebo
http://en.wikipedia.org/wiki/Placebo_effect

In other words, the difference only exists in your mind.
(because: "The adding -Y does not change the abr/cbr behavior.")

OK... thanks to everyone.
More questions coming soon