Wavelab has a Bit Meter built into the software. You can also buy a "bit meter" from http://www.digido.com. There are other meters and other test equipment that can read the bit stream and give you a readout of the bit depth. Why do you think you are not getting the full 24 bits?

-TOM-

Thank you Tom for your reply.
I will try to expain what I have done so far that made me wondering

This is my setup:HEDD 192>SPDIF>Motu 2408mk1>DP.

I 've send 1khz tone into the HEDD at 0dbu.
setting spectrafoo's bitscope at a track and watching the code meter I see the lights from 1-24 blinking.
If I set HEDD at 16bit there is not a change at the meter. :?
Now if I set Dp recording at 16 bits I see the same thing happening,1-24 blinking

Is anyone familiar with spectrafoo's bitscope?Why there are two rows of 24 numbers?

PS:I have done the same test using pink noise.