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> 16 bit audio ("CD quality") only has a 90 dB dynamic range. That's a persistent myth. The channel noise floor at the frequencies of interest of 4x kHz / 16 B

> 16 bit audio ("CD quality") only has a 90 dB dynamic range. That's a persistent myth. The channel noise floor at the frequencies of interest of 4x kHz / 16 Bit audio is below -100 dB due to combined noise shaping and dithering. While this means for music 16 bit audio is generally sufficient, it has leaves little room for error; mastering has to be excellent. That's why everyone is recording in 24 bit; it allows you to patch up errors later.

TheOtherHobbes 7y ago
It's not a "persistent myth" - it's absolutely correct. The "persistent myth" is that signal-to-noise ratio and dynamic range are somehow identical. They aren't. It's also a persistent myth that the unaltered quantisation noise spectrum is basically white noise. It isn't, except as a poor approximation. In fact it's very spiky - mathematically it's literally a function related to related to the sample rate. Some frequencies produce more audible quantisation artefacts than others. This is audible on very good hardware, and it contributes to both harmonic and intermodulation distortion on cheaper hardware. Dither and noise shaping distract from the effect in a subjectively pleasing way, but technically they're a cheap fix - like blurring a jpeg and pretending this somehow magically removes all of the compression artefacts. The result may be fine for Instagram, but not for commercial photography. The bottom line is that 24-bit sampling fixes these issues because they simply become irrelevant. The SNR limits are defined by the analog limitations of the converters, and all of the quantisation artefacts remain below audibility.
- blattimwind 7y ago
  > The "persistent myth" is that signal-to-noise ratio and dynamic range are somehow identical. They aren't. Obviously :) The SNR will stay at around ~96 dB for 16 bit audio. If that noise were white, then that would naturally limit the dynamic range to essentially the same number. But no one said that the quantization noise of the channel has to be white, indeed, the whole point of dithering and noise shaping is to de-correlate the quantization error from the signal and make the noise spectrum anything but white. Hence the dynamic range can be increased. > It's not a "persistent myth" - it's absolutely correct. No. The SNR is 96 dB; the dynamic range for the relevant frequency band is greater.

TheOtherHobbes 7y ago

It's not a "persistent myth" - it's absolutely correct. The "persistent myth" is that signal-to-noise ratio and dynamic range are somehow identical. They aren't. It's also a persistent myth that the unaltered quantisation noise spectrum is basically white noise. It isn't, except as a poor approximation. In fact it's very spiky - mathematically it's literally a function related to related to the sample rate. Some frequencies produce more audible quantisation artefacts than others. This is audible on very good hardware, and it contributes to both harmonic and intermodulation distortion on cheaper hardware. Dither and noise shaping distract from the effect in a subjectively pleasing way, but technically they're a cheap fix - like blurring a jpeg and pretending this somehow magically removes all of the compression artefacts. The result may be fine for Instagram, but not for commercial photography. The bottom line is that 24-bit sampling fixes these issues because they simply become irrelevant. The SNR limits are defined by the analog limitations of the converters, and all of the quantisation artefacts remain below audibility.

blattimwind 7y ago
> The "persistent myth" is that signal-to-noise ratio and dynamic range are somehow identical. They aren't. Obviously :) The SNR will stay at around ~96 dB for 16 bit audio. If that noise were white, then that would naturally limit the dynamic range to essentially the same number. But no one said that the quantization noise of the channel has to be white, indeed, the whole point of dithering and noise shaping is to de-correlate the quantization error from the signal and make the noise spectrum anything but white. Hence the dynamic range can be increased. > It's not a "persistent myth" - it's absolutely correct. No. The SNR is 96 dB; the dynamic range for the relevant frequency band is greater.