Upsampling in Roon 1.3

[Confused]

I tried  Roon Upsampling yesterday afternoon in different combinations.
First I did try PCM  up to 192/24 through ethernet. First album I tried was Eric Clapton - Unplugged. The different was quite perceivable, the sound was more airy and spaced, definitively an improvement. Just to make sure I wasn't imagining things I asked both my wife and my daughter to do a blind test and both of them perceived the difference.
Then I tried the same thing on other records both CD and Tidal and the results were a lot less noticeable and in certain cases not noticeable at all.
One thing I noticed is that you can have clipping even with PCM upsampling. I enabled headroom with value of 0 to check and the clipping red light started to go off. A bit of headroom did the trick. As an hindsight Probably Roon should have implemented the clipping check outside the headroom DSP engine.

Bottom line, depending from the source the mileage of the PCM upsampling could vary.

Then I did try the DSD upsampling using a MacPro connected to USB (admittedly the cable was a cheap USB cable as this is not my usual set up so I had to do with what I found at home). I found it very difficult to compare due to the difference in volume, I had to raise quite substantially the volume to get to the same level as PCM so a straight A ->B comparison was not possible. Listening at the same material on DSD left me a underwhelmed, I felt the sound too soft, lacking of punch, kind of muffled up. Not sure if this was due to the cable and as I don't have original DSD recording I cannot compare them with upsampled ones.

Bottom line, considered my set up I am not sure I want to go into the fuss of having a permanent USB connection to my Devialet to allow the play of DSD. I will wait patiently that DSD is available for streaming for Devialet, at the present I don't think I am missing a lot.

For completness my set-up is pretty basic
iMac 2012 (i5 quad core 3.1 GHz 24GB RAM) connected to a Devialet 250 PRO through giga ethernet using AIR release candidate 3.0. Speakers are Sonus Faber Amati Futura, speaker cables are Oyaide Tunam II
The computer connected to the USB was a MacBook Pro i5 dual core 2.7GHz 8GB RAM
With both the computer I didn't have any computing issue in running the upsampling.

Cheers
Marco

Marco, I am surprised to see you were getting clipping issues with PCM upsampling.  I did not notice this myself.  (although maybe I wasn't looking that hard!)  To clarify, this was Roon PCM upsampling only, no Parametric EQ or anything else?

Does anyone understand why PCM upsampling can cause clipping?  I can understand how PEQ can cause clipping, but with PCM upsampling alone this puzzles me.