[quote author="Rossi"]Yes, it was 16 bit. S/N was somewhere in the 70s or low 80s if I remember correctly, so 24 bit wouldn't have made sense anyway. It's not a chip for "serious" audio. It's a handy chip for "okay" audio.[/quote]
I am i pretty out in the modern digital system, but
what difference in dynamic range is between 16 an 24 bit
codecs?
I read the catalogue and dynamic range is between 70 and 80 dB in
16 bit codecs and between 90 and 100 dB in 24 bit codecs.
If I compute bits, I get: 24 - 16 = 8. and 6*8 = 48.
Why 24 bit codecs have not 130 dB dynamic range ?
And is that 90 dB some barier in dynamic range, which can be
handled by (standard) semiconductor equipment ?
And if we can headroom 15 dB, useful dynamic range is only 75 dB ?
and what about dynamic range of mic signals ?
If some mic have 15 dB self noise, and signal in fortissimo is 100 dB,
dynamic range of all signal without compression is 85 dB.
For that dynamic 18 bit ADC is enough.
And I mean, that good 18 bit ADC is touching the analog signal
limitation and difference in the dynamic range can be 10 dB between
16 and 18 bits, and is nothing between 18 and 24 bits.
It is maybe reason, why best analog-devices SAR converters are 18 bits.
The only usefullnes of low significant 6 bits in 24 bit AD converter is
for random generator.
There are only two ways to improve dynamic ratios of chips.
1) to made chip with 100 V input signal range (it is impossible because
of parasitic thyristor in semiconductor structure)
2) to made chip with 500 mA range current input. It may be possible,
but every designer want device with voltage input and digital output.
(If it is the only reason why nobody made it, I will manufacturing it.)
Then we will still buy on paper 24 bit chips with 18 bits effective.
What is real on 24 bit "proffesional" mania. For nearly all recording
16 bits is enough, 18 bits are top.
xvlk