Hi there, thought I would have a play with DSP. Why does roon up the bit depth then down the but depth (see pic)
Cheers
To help [improve] with the sample rate conversation.
Floating point is ideal for internal calculations – but gibberish for D/A conversion. That is why.
AJ
OK both of those explanations flew way over my head, but I gather from them that this is normal and correct. So I am happy.
Yep, all is as it should be. Enjoy.
Imagine if I told you you could do a bunch of math to solve some problem, but you only got 1 digit after the decimal point on your calculator.
Let’s say the problem is ((1/3)+7)*100, but at every step you had to round to 1 digit after the decimal point. What would the answer be?
1/3 = 0.33333, or 0.3 when rounded
0.3 + 7 = 7.3
7.3*100=730
Now what is the answer if I gave your calculator 2 digits after the decimal point?
1/3 = 0.33333, or 0.33 when rounded
0.33 + 7 = 7.33
7.33*100=733
The difference between 730 and 733 is a difference in the data that is sent to your DAC. 733 is closer to the right answer than 730 is. The difference is a loss of “sound quality”
If we were to do the sample rate conversion and put the output directly into 16 bits, there could be a loss in quality when the sample rate conversion algorithm produces an output that requires more precision then 16 bits. The conversion to 64 bit adds 48 bits of precision for that output. Eventually we need to go back to something your DAC can play. In this case, your audio output supports 24 bit samples, so Roon down converts to 24-bit, losing 40 bits of the precision from the 64-bit. However, because Roon is smart, it did not go all the way back down to 16 bits because it knew your endpoint didn’t need it to do that.
I know we are switching from integers to floating-point here, but that actually makes a lot less different than what one would think. The real meat of this is the fact that you have more bits of precision for those calculations along the way.
I hope that helped explain it.
20 Likes
I almost posted here this morning, but decided against.
On reflection I have decided I will…
I think that for a COO to take the time to respond to a forum member, (not a member of the press, not a media show, not a reviewer) about an aspect of Roon that was confusing that person, shows thoughtfulness, helpfulness and a love of his product that deserves a written well done from me.
Brian
3 Likes
I was too embarrassed to respond because I dont really understand it at all, however I have passed the maths to my son so he can help me!
But thank you for responding, and all I know is it sounds very good 
This is a perfect explanation thank you and by the COO.