🚀 go-pugleaf

Pentium 4 @ 2.6 gHz
512 DDR
RME HDSP 9632
Windows XP
Adobe Audition 1.5 (AA1.5)

I have a few questions about Adobe�s dithering function and what happens when AA1.5 opens, converts and processes files. I am working with some 30- year old piano performances that were originally recorded on reel to reel tape and then converted to .aiff format, 16-bit digital at 44.1 kHz, using Peak LE on MAC OS9. I have �Auto-convert all data to 32-bit upon opening� checked in AA1.5 as I need to do some noise reduction and equalization. I was initially not pleased with the sound quality and after trying several things I unchecked �Dither Transform Results� and �Use Symmetric Dithering� and the file sounded MUCH better.

1) Is Adobe is applying dithering when files are opened and when it converts from 16-bit to 32-bit? If so, what type of p.d.f. is being employed here? What type of noise shaping? Why is dithering being applied at all? I noticed that in the Convert Sample Type window that dithering can only be enabled when converting down to a lower bit amount, so what is going on?

2) Why does it take AA1.5 four times longer to open a file when �Dither Transform Results� and �Use Symmetric Dithering� are unchecked then when they are checked?

I had a similar experience when I applied parametric equalization, that is when �Dither Transform Results� and �Use Symmetric Dithering� are unchecked the sound is less veiled.

1) What p.d.f. and noise shaping is being used when adding effects? Can these settings be adjusted?

2) When �Dither Transform Results� and �Use Symmetric Dithering� are checked is dithering applied to all effects including noise reduction? Page 52 of the AA1.5 User Guide is vague about this.

Any thoughts?