[Shiraz (Ray)]

thanks Glen.

I could have posted some measurements, but there was no meaningful difference, so put up the images for those who don't trust numbers.

As far as I know, there is no specific requirement for the number of subs needed at 12 bits, but I think that there was some discussion on CN to that effect. If you stack subs, you will increase the bits covered by the target and reduce the number of bits dominated by noise, but the process gives the same result regardless of how many bits in your original data - provided the original bit depth is enough to cover the dynamic range. Stacking 2x12 bit subs gives a 13 bit result, 4x12 bit subs gives 14 bits, 8x12 bits gives 15 bits etc, so quantisation noise decreases with stacking in the same way that normal noise does.