From my tests of versions I have on hand, Toast Titanium 10, 11 and 12 HORRIBLY distorts the audio when converting from higher quality down to RedBook CD (16/44.1).
Here is a screenshot of a file I converted from 16/48 to 16/44.1, using HOFA (top), TT10 (middle), and TT11 (bottom), you can plainly hear and see the distortion, and it isn't subtle. (sorry, I do not have TT12 available on this computer)
I've done other tests using a variety of files at 24/88.2, 24/94 and multiple other bit depths/sample rates and the distortion is evident.
This happens in both the "Convert" windows, as well as the "Audio" CD burning windows.
Toast use to be my go-to, but after numerous complaints from customers, I no longer use Toast to convert files; I only use to burn masters.
(I've also tested using XLD, dbpoweramp, Audacity and a few others and they DO NOT distort the audio. However VLC does distort)