ok, so let's review the seemingly impossible situation that i have myself in.

i have a number of project files that have not been modified in weeks, along with a number of renders of those files. the renders do not always sound good, but i believe this is because i was mixing on malfunctioning hardware. i am convinced that i have resolved the issues with the hardware, because things consistently sound the same.

when i paste source material into these projects, it does not null with itself. that is, if the project has x.wav in it and i paste x.wav into it and phase reverse it, it does not null on playback. if i then save the file and re-open it, it nulls.

if i render these files, they do not null with the renders i have saved from weeks ago. that in itself does not determine which render is "clean" and which is distorted by malfunctioning hardware.

if i export each individual file from these projects and then recreate them in new projects, the renders will initially null with original renders from weeks ago. however, if i then save the projects and render again, they now null with the renders from the original saved projects. all subsequent renders null with each other.

this exposes a more fundamental problem: projects are refusing to null with themselves after i save them.

i am certain that the renders from weeks ago were at least partially rendered from saved files.

what that means is that i am consistently rendering precisely two versions of each of these tracks - one before i save and one after.

testing up to now has indicated that the built-in equalizer in cubase may be malfunctioning when it interacts with the vst architecture. it is doing this in predictable but unfathomable ways - it seems to alter certain equalization decisions that it seems to not like.

i'm going to eat. then i'm going to do some mild testing. i think i should run a ram test. but i expect to go through another reinstall by the end of the night, but only install the precise, specific software that i need to run these projects.

while i've repeatedly seemed to isolate the problem, what i've actually done is systemically rule virtually everything out. i'm seemingly left with an error in the program. but, it is very strange that it worked for many years and stopped working all of a sudden, even on multiple reinstalls.