[sdiy] Consider this DAC

[Simon Brouwer]

cheater cheater schreef:
> (...)
> The key word above is *later*. The test subjects are played back a
> tone at some pitch, and then *later*, after that note is *finished*,
> they are played a second tone. It is a huge difference from the way we
> are defining the required accuracy of a musical instrument; to see
> why, consider this:
>
> at 5000 Hz, the difference of 1 cent is almost 3 Hz:
>
> 5 000 * 0.000577789 ~= 2.888945
>
> Even consider something as small as 0.3 cents:
>
>  	
> 5 000 * (1.000577789^0.3) = 5 000.86651
>
> This gives us a difference of ~0.8 Hz. This means that if I play two
> notes *at the same time* and they have this difference in pitch, I
> will be able to hear them pulsate in
>
> 1 / (0.86651 Hz) ~= 1.15405477s
>
> so about 1.2-second intervals. I don't know about you, but I can hear
> this sort of thing very clearly.
You have an excellent point, although I wonder if a 1.2 second beating 
in 5000 Hz tones would be perceived by listeners as out-of-tuneness or 
even noticed at all if occuring in an actual piece of music rather than 
in a perceptual experiment.

I had been thinking a 12-bit-accurate DAC would be quite adequate 
controlling a 5-octave range, but maybe I should consider e.g. 
LTC2641-14 (14 bit, 1LSB max INL, EUR 7,64) or LTC2641-16 (16 bit, 2LSB 
max INL, EUR 14,34)

Those components are not cheap :(

-- 
Vriendelijke groet, 
Simon Brouwer.