Re: [9fans] audio standards -- too many to choose from

["Steve Simon" <steve@quintile.net>]

Ok, My memory from about 1982...

first there was phillips who used 2 high speed, high linearity 14bit DACs
in their CD players using 4 times oversampling - as they had no apropriate
16bit converters at the time; which gives near 16bit resolution.

sony however developed a laser trimmed 16bit converter but due to the high price
they time ivison multiplexed a single converter between left and right channels.
This required very steep, very high Q reconstruction filters which had
significantly non-linear phase shifts in the audio band.

people where surprised how much nicer the phillips sounded nicer than the
sony solution. The nasties caused by filters in the sony design have resulted
in much of the that "digital sounds nasty" folklaw.

as time went past people realised that riunning at 256 times oversampling
means you can have a 1 bit converter (i.e. PWM) and get near perfect linearity
without the need for laser trimming.

I beleive the push for very high sample rates at 16 or 24 bits is because it
further simplifies the reconstruction filters and they can be made cleaner
and even less likely to introduce audiable artifacts.

just my opinion and not that of my employer.

-Steve