Kees
Headphoneus Supremus
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- Feb 18, 2006
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Computers work not with single bits but with 8-bit words. Hence every increase would be an 8 bit increase.
Computers work not with single bits but with 8-bit words. Hence every increase would be an 8 bit increase.
Quote:
Good questions! You are correct in your assumption that you can't hear the noise and 16bit is already overkill, which was the whole point of my original post, to dispel the market hype about 24bit. Even in a listening environment equivalent to a top class recording studio, the dither noise of 16bit will be below the noise floor of the playback equipment and/or the noise floor in the listening environment. The only error in your reasoning is the consequence of not using dither. Dither is a mathematical process which randomises all the quantisation error, the result is a perfectly encoded (and reconstructed) waveform plus some noise (which is the result of the randomised quantisation error). If we don't apply dither the consequence is potentially correlated (non-randomised) error, which is much more noticeable and unpleasant.
The only thing I'd take issue with is that I personally would say that using a grenade to kill a fly is not "equally" but slightly more stupid than using a bat!Generally a quite good analogy and understanding of the situation though. I would not say that 12bit was quite enough, although you theoretically only need 10 bits to encode a 60dB dynamic range. The overkill of 16bit ensures that the dither noise is below the noise of your playback environment and therefore you can forget all about it. Dither noise using 12bit would probably add enough to the noise of a good sound system to be perceivable even at normal hearing levels.
Hope this helps,
G
I heard a 32 bit DAC will make 16 and 24 bit recordings sound better, does anyone have any deep technical insight on this? I'm talking about the latest (and long postponed/awaited) Fostex headphone amps in Japan, they use some Asahi Kasei DAC Chip.
Yes, I see, however I'm curious why does the 32 bit chip exist in that case, and why are Fostex using it?
Thanks for responding Gregorio, but the real question that I was trying to bring up is "sort of" answered by your last statement. Are you stating that people can perceive the difference between a 16bit recording with and without dither? If this is the case, then doesn't that imply that we do in fact perceive up to the full 16 bit dynamic range?
On a side note, I wonder if other folks have started to use their 24 bit audio systems for data recording. I've used audio amplifiers and simple diy DACs for my own measurements in my lab, and now I'm very curious to see what kind of results I get with a 24 bit audio dac versus a 24 bit data acquisition dac, perhaps there are additional signal processes in the 24 bit audio dac not found in a DAQ card.
I heard a 32 bit DAC will make 16 and 24 bit recordings sound better, does anyone have any deep technical insight on this? I'm talking about the latest (and long postponed/awaited) Fostex headphone amps in Japan, they use some Asahi Kasei DAC Chip.
There's a DAC somwhere which supports up to 384kHz sampling rate. Slap a bigger number on it and audiophiles will flip out, even if there's no recordings that would actually use those extra bits.
Sorry, I thought I explained this when I said "If we don't apply dither the consequence is potentially correlated (non-randomised) error, which is much more noticeable and unpleasant." In other words, correlated error results in unwanted frequencies or tones in the music but probably not related to the musical content. It's probable that these correlated errors are higher in amplitude (louder) than the dither. Chances are that even with a very high end system correlated errors will be near the limits of hearing at normal listening levels but we use dither just to play it safe. Another fact: When we record music there is usually a great deal more noise in the recording chain than is created by dither, so any dither noise in the finished product should be masked and unrecognisable. This may not be true of correlated errors.
I don't know what the difference is between a 24bit audio DAC and 24 bit data acquisition DAC, what is a 24bit data acquisition DAC?
G