Originally Posted by nick_charles
CD theoretically anyway has a SNR of about 96db the Apple onboard device at 90db is around 15 bits, probably not noticeable but certainly not state of the art, in truth you are unlikely to notice the difference between 14 bits and 16 bits except at absurd volume levels like the Meyer and Moran study
Yes, but no 16 bit device ever does the theoretical 96dB without quite a bit of trickery like oversampling DACs and noise shaping. But it doesn't matter because if you hit it with 16 bit audio data you'll never get 96dB anyway, and you wouldn't want to because you do want that data dithered, and that alone will kick you down to 93 or less. If the audio was digitized at 16 bits there'll be 3dB at least of least significant bit jitter. And if digitized at 24 bits, the conversion to 16 should never just be truncation, sort of defeats the purpose. So 90dB, real world, is about right for anything. The stuff that measures better isn't measured with a digitized analog signal, and yes the measurements are real, but you have to consider the noise floor of real audio material too, and noise-shaping, over-sampling DACs can't help that. There are better measuring DACS, but that doesn't mean they'll sound better. And, 96dB or even 90dB is pretty much more that we need.
quote: "Interesting, then why do so many engineers seem to insist on hitting the end-stops if it just leads to distortion "
It's the loudness war, and the end stops they are actually hitting aren't in the DAC, they're in the data processed by some sort of DSP that may involve clipping or hard limiting. Yes, it's nasty, but until people stop buying, and start returning music that's so loud its distorted for their money back, engineers (technically, producers) will keep making it.
quote: "Hmmm, I've seen far more "optimistic" specs on some mainstream gear (add another couple of zeros) and some like the Benchmark stuff seems to have measurements to back it up, the one positive thing about Stereophile being that they do actually measure stuff, not turntables of course.... wonder why
But yeah the general lack of actual measurements is highly annoying !"
Yup, sure is. And yes, there are lots of things that measure better. Like I said, it's not all real once you start playing audio though. It might be me being cranky and old, but I tend to ignore DACs that measure better than theoretical because once you shove real digital audio into it instead of computer generated test data you're back to 16 bits again. Sort of pointless, but since so-called 24 bit ADCs behave like 18-20 bit ADCs, and when audio gets shoved up to the top end and squashed there, the discussion is really academic. Yes, it's fun to bash Apple, but frankly, they put pretty decent audio into their devices, on average way better than the integrated PC sound junk. And there are some VERY smart people in the audio department there. It's likely to get even better.