I have a basic understanding of dither but my question is this. I'm using 24 bit 44.1k audio files on the tracks. This is what I have the Vegas project preferences set to, When I burn a mix to redbook cd does Vegas automatically dither to 16 bit or do I need to dither in my master FX chain. If so would I add it pre or post noise reduction when used.
I couldn't find any evidence that Vegas will dither when delivery bit depth is lower than source bit depth. When I render mastered files to 16 bit, such as for CD delivery (or even to MP3), I put a dither plugin on the master bus. In my case, that is Izotope Ozone. Vegas has a built-in dither audio FX for this purpose, too, as you probably know. Based on my limited understanding, I don't think audio would suffer from being dithered twice, in case my presumption about Vegas not auto-dithering is false.
Noise reduction is the very first processing at the mixing stage, i.e., pre-everything! I don't want to reduce processed noise. Get it out first. Hence, noise reduction is the very first FX, dithering is the very last when mastering.
I concur with vtxrocketeer and would place any noise reduction processing at the head of a chain, before compression, EQ, effects. However I don't recall ever using NR in the CD authoring stage and normally put any NR processing on individual tracks in the mixing stage.
The later versions of Sound Forge Pro (10 and 11 as I recall) has the 'iZotope MBIT + Dither' bit depth converter. You could experiment for quality difference if you have it. Otherwise I would just let Vegas handle the bit depth conversion, which does not require any user input. FWIW, I use CD Architect for any music CDs which has a superior work surface for CD authoring IMO. CD Arc comes with SF Pro (at least it did with SCS) which also can burn Redbook compliant CDs on it's own.
songsj, without knowing more about your workflow or experience, it occurred to me to suggest (the usual steps) of first mixing your tracks, including NR first followed by any further processing, and rendering a stereo mix. Second, master that mix, including dithering, to obtain finished masters. (I use the standalone version of Ozone for mastering, for instance, though I could achieve the same via the plugin in Vegas or even with Vegas-only tools.) Sorry if this was obvious to you; your mentioning NR and dithering in the same breath prompted me to think you're trying to mix and master all at once.
vxtrocketeer you are somewhat correct. the projects I do are just home studio projects. covers and some originals. I normally track on a Tascam 2488 24 bit 44.1k, Clean tracks unprocessed as much as possible. Then export/import them into Vegas for mixing. I normally do my final mixing at that stage and put a Waves C4 or C6, X Noise and a L1+ Ultramaximizer in the master channel of Vegas. I usually use a C4/C6 mastering preset and slightly adjust to my liking to kind of even everything out a bit and use the X noise to get as quiet of a 2 track mix as possible, then the L1+, maybe I have the FX chain order screwed up. Then I burn to redbook Cd. Nothing here goes to a professional CD mastering house or printing process. What I finish here is what friends and family get to listen to so I try to make my recordings sound "radio ready" at least to the average persons ears. I think I put the X noise in the middle thinking that if the C4/C6 added any noise it would end up on the recording. I am making a last attempt at sharpening my skills for an old guy. When I have recorded in professional studios several engineers have stated I have been blessed with exceptional ears when it comes to music and mixing so that has probably allowed me to get away with doing a lot of things wrong or in a less conventional way due to ignorance. If it sounds really good in the end I'm not sure it matters how you got there, often there is more than one means to a really good end. That being said I am making an effort to be sure I am not violating any steadfast rules that if corrected may make my recordings sound even better. Thanks for the help.
Well, you came here simply to ask where to dither and I think you have an answer. As to the order of other elements in your workflow, you also have consistent comments, though they do not support your order.
Certainly "If it sounds good, it is good" is not a maxim to ignore, as your post embodies. I record classical orchestral and choral subject matter, sometimes in less than ideal venues, so NR right at first, if used at all, is an immutable principle. Best wishes for your recordings!