[sdiy] dsPICs with DACs: linearizing the 12 bit ADCs, external RAM?

[cheater cheater]

Oh yes, that's perfectly possible, if:

1. the lower-bitrate recordings aren't being done at a 'hot' level
2. the recordings are not attenuated at all in the mix
3. the recordings are supposed to be very-high-dynamic-range
(accoustic, solos, etc)
4. the recordings don't undergo any processing
5. the 20 bits are recorded with the same or better word clock as the 16 bits

I don't suppose any of those points is valid when you're using a
normalized output of a guitar or synthesizer for something as
mutilating to the sound as a delay or a filter.

Especially point 5 is moot as the ADC has the same word clock as the
DAC and thus, everything being in its own common timebase, does not
create phase distortion (correct me if I'm very wrong?)

>  nevertheless the difference
>  between tracks recorded in 16 bits and tracks recorded in 20 bits was
>  clearly audible...

And how are you sure that the one is better than the other? Difference
is easy to spot. 'Better' and 'worse' are matters of not only taste,
but even then very difficult technical considerations.

And even if one of them was indeed better - how do you know it wasn't
the microphone? Cables? Amplifiers? Jacks? Solder joints? Temperature?
Word clock?
the list can go on.
it's difficult to compare like that - unless you have a very good,
dedicated lab.
As far as I'm concerned, 12-13 bits are loads for a single instrument,
especially if you remember that most DACs will have a *usable* amount
of 14 bits.

But of course, you have your opinion, and your critique is highly appreciated :)

Cheers,
Damian

On 7/7/08, jbv <jbv.silences at club-internet.fr> wrote:
>
>
>  cheater cheater a *crit :
>
>
>  >
>  > For single instrument inputs, if the instrument is going to undergo
>  > heavy processing, this doesn't matter that much, really. Each of those
>  > instruments would probably be at -12 to -20 dB in the mix which lowers
>  > their effective output to those 13-14 bits (and most possibly 10-12
>  > bits effectively because of the DAC crappiness). The effects obscure
>  > the sound even more, so shave a bit or a couple off that as well.
>
>
> Mmmh... I'm not sure... My doubts are based on a personal experience :
>  in the mid 90's I did participate to a remix of a few songs that had been
>  recorded a few years ago on an 16-but ADAT. Additional tracks were
>  recorded on a 20-bit ADAT and then we went to a professional studio
>  for the final mix and did transfer all ADAT tracks to a Sony 48-trk tape
>  machine. I agree that we were in a high-end environment, very different
>  from the daily situation of hobbyists, but nevertheless the difference
>  between tracks recorded in 16 bits and tracks recorded in 20 bits was
>  clearly audible...
>  And AFAIR the difference was even more obvious when we sent a
>  track to some  FX processor...
>
>
>  JB
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>