the binaural 3D sound bullshit was an additional tiny square chip on the PnP sound blasters, it's not part of the mixer chip and has nothing to do with poorly implemented QSound running off the CT1748A CSP/ASP chip
why do I think the mixer chip has a lot to do with the noise?
First, lets consider this:
the original SB16s and AWE32s had a CT1745A chip... everybody here knows and talks about how noisy the CT1730s are
everyone here talks about how great the CT3600 SB32s are in terms of SnR, it's due to the Vibra chip, which is much more integrated of course
BUT wait, I'm not finished yet!
the later non-vibra cards used the CT1745A-TBQ and CT1745A-S... later AWE32s and early AWE64 Golds had the latter, while some AWE32s and all regular AWE64s had the former... then the later AWE64 Golds got the CT1745A-SCP, which was the quietest non-vibra chip they made
all of these cards, with the newer chips had a discernible difference in noise levels compared to the ones with the older chips... they were much quieter than the early cards that had the CT1745A chips... I also happen to own one of the last CT1770s made, a 1st generation SB16 card, but it is rare in the fact that it has the CT1745A-S chip and 4.13 DSP on it... I tried it before, with the volume dial set halfway only... the audio was pretty clean compared to the noisy CT2230 I have... my CT1770 is on par with my CT3900.... but I don't use it because it's brand new and I don't need its SCSI functionality as I'm using a AHA-2940U card already 😀 I thought about finding an actual used CT1770 to use along side my goldfinch card just for grins, but every single one I came across on ebay were the early builds with the CT1745A chips... I don't want them... this shows to me how rare my card is, so I don't want to use it and risk frying it due to circumstances beyond my control (other vintage hardware is easier to replace)
the fact that I own a 1st generation design SB16 with a newer/improved mixer chip makes me feel qualified to argue that the mixer chip makes a big difference in SnR quality... I got pics of this card taken, I'll post it later for you all to see if you want to compare the other chips on it with any CT1770 examples any of you may personally have