Replying to both JJ and RBJ:
In addition to Lipschitz, no less of an authority than Robert Stuart made it clear years ago that noise shaped dither is not a problem when a noise shaped source is played through any digital monitor control or processor.
The amazing thing that Alex has proved is that noise shaped dither actually is BETTER for use if the monitor control is not dithered and truncated to 16 bits. Such a situation may not even exist anywhere in current products, but Alex has shown that what is likely the worst case scenario is a pretty decent scenario. Look at the spectrogram of -17 dB attenuation to see that the noise shaped dithered source is largely intact, which is quite miraculous for a non-dithered 16-bit DSP at 17 dB of attenuation!
Yes, for 24-bit volume controls and similar DSP, whether the source is 16-bit 44kHz made with noise shaping dither or TPDF is academic, and dithering the volume control is highly recommended but not the world’s worst tragedy. But what Alex has proved to my satisfaction is that not only is noise shaped 16-bit 44kHz dither acceptable and harmless for 24-bit monitor controls, it actually is a BETTER choice when you’re dealing with something as crazy as a 16-bit non-dithered monitor control. This refutes any claims by certain wayward mastering engineers who think that noise shaped dither is the devil incarnate.
In the near future, Alex and I will have a Powerpoint that demonstrates the measurements and discoveries that Alex has made.