Does Fast Bounce effect the Quality of the audio ??

No

Nebula3 is one such plugin

BFD2 doesn't like to be fast bounced/exported, at least on my system

It's pretty simple. If your plug-ins work with fast bounce enabled, use it if you wish, there will be no difference in quality. If you have plug-ins that cannot handle fast bounce, don't use it. It is pretty obvious when fast bounce does not work, the output, if any, will be distorted.

In my experience most are, that is why it is the default option. I have not cataloged the exceptions.

I have found on the odd occasion especially when there are few reverbs involved that fast bouncing produced slightly erratic results (in the reverbs that is) compared to the music playing in real time. I use real time bouncing and the problems went away. It does not happen often either.

I think it is just the odd plugin behaves different under these two scenarios. If you suspect it then do a real time bounce to be sure.  

Waves Trans-X likes a slow bounce. Many Omnisphere patches prefer it. Sometimes very large Kontakt libraries need it. If you're using an external hard drive for samples the probability goes up that you'll need a slow bounce. Exhausting RAM may prevent a fast bounce. 

As a general rule, you'll avoid problems with the slow bounce. I have only encountered one instance where a plugin required a fast bounce: using MIDI automation with SampleTank. In one project, I had both MIDI in ST2.5 and Trans-X. To work around the conflicting requirements, I first froze SampleTank with a fast bounce and then exported the project using slow bounce.

But these are all cases where particular plugins just don't work right with a fast bounce, and have nothing to do with audio quality. 1 + 1 = 2 whether you do it as fast as possible or wait 22.7 microseconds at the equals sign.

This is strange...because I've used Melodyne quite a lot and my finished mixes sound just fine when I use fast bounce when exporting the audio mix.  Melodyne is not affected at all by using fast bounce on my system...it works perfectly....and I don't bounce any individual tracks first before mixing.

flyingvivaldi


Melodyne plugin is ignored when Fast Bounce is used - that needs real time bouncing to work. Oh, and that applies to the final mix too - so to save time you will probably want to track bounce all your Melodyne stuff once you're happy with it rather than having to run off real-time mixes.