DAC/Pre's Digital attenuation vs. analog

I'm having a hard time agreeing with "32bit offers only 16dB of attenuation before eating into the 16bit resolution of Redbook".
As far as I know, every bit accounts for 6dB, thus 16x6 would mean that a DAC chip working internally on 32 bit will offer 96dB of digital attenuation of a redbook stream before loss of information occurs. And that's pretty much the entire dynamic range of redbook.
Attenuation in the digital domain is no longer the bad thing it used to be, with the advent of these 24-32 bit DAC chips. The myth, though, will continue, I'm sure.

Using digital volume exclusively for volume control will result in a significant reduction in detail and imaging. It's okay to do about -9dB, but not more. This requires that the DAC have some kind of gain control or a good volume of its own.

There are five types of volume control:

1) Digital volume control - reduces resolution as the volume is decreased

2) resistive attenuation - delivers detail, but kills dynamics with most amps

3) active gain control - adds distortion, noise and compression, but has good drive, so dynamics are good.

4) Transformer scaling attenuation - with strong DAC outputs and good transformer linestages, like Music First TVC, this is more transparent and preserves the dynamics. Easy to match to amps

5) D/A reference voltage control - This volume adds no noise, distortion or compression, in fact it actually improves S/N ratio as the volume is decreased. No loss of resolution. The best of all possible options.

Steve N.
Empirical Audio

"5) D/A reference voltage control - This volume adds no noise, distortion or compression, in fact it actually improves S/N ratio as the volume is decreased. No loss of resolution. The best of all possible options."

Thanks Steve. How many companies make something like this and @ what price point?

Robertsong - there are two I believe, and Empirical Audio is one of them. $6K pricepoint for the DAC. Includes preamp, DAC and USB interface.

Steve N.
Empirical Audio

Isn't it fascinating how different well respected digital audio design engineers can express diametrically opposing views on something as basic as loss of resolution in digital volume controls or lack thereof. Engineering is supposed to be an exact science! In the absence of consensus I trust my ears, and ended up ditching a 10k preamp in favor of digital volume control.