I have been experimenting with Audirvana PCM->DSD128 conversion for my SGCD over the weekend and I’d like to report my findings. Notice I was not told to do this and just tried it on a whim. I have tried PCM upconversion in Audirvana in the past and was underwhelmed so I wasn’t expecting much. Well I am shocked at the SQ improvement here.
Audirvana uses Izotope 64bit SRC to do upsampling/conversion to the DSD sample rate and then uses a modulator to go 1-bit DSD.
Here are my Izotope settings :
- Slope 10db
- Max filter length 1,250,000
- xNyquist 1.00
- Anti-aliasing 200
- Pre-ring 1.0 (this results in a pure linear phase filter)
- DSD filter is set at C(7th order)
I have experimented with the Pre-ring which lets you change the balance of minimum vs. linear phase filtering. I have messed with this a lot and I find anything other than pure linear to have too many negative trade-offs. For example, sibilance goes up significantly and reduces the lifelike quality, depth decreases, and there is too much of an edgy quality.
Signal path is Audirvana to Ultrarendu (powered by Sbooster Linear Power supply) via DLNA (router and FMC’s/powered by linear power supply) to SGCD via WW silver starlight USB. For those unaware, the Ultrarendu uses similar USB hub circuitry as the new Uptone Iso Regen which produces excellent signal integrity/very clean signal.