I have recorded stuff on a digital multi track at 16 bits (yamaha aw16g) and transferred stereo mix wav from it into acid 4 where i run it thru some mastering gear-psp tape warmer and izotope ozone and then burn it straight to cd thru acid. anyway ozone gives me the option of using several types of dithering. should i take this offer up and dither away or is it all still at 16 bits anyway and a bit pointless. can anyone answer ..thanks

If you're recording in 16 bit in the first place, unless you're planning to take the bit depth down further (e.g. 8 bit for really old sound cards or something),dithering is pointless.

Although, come to think of it, since ozone does 64bit internal processing, dither MIGHT affect the final output, letting your mastered version sound with the "best" 16 bits... Anyone more in-the-know than I want to comment?

It mainly depends on the auto-dithering settings of the host app you are editing in. Some host apps, like Cool Edit, when editing (or running plug-ins) on a 16-bit file, add the dither automatically after each operation (it's usually specified in host options). Some other hosts don't do so, and then it's advantageous to do dithering in Ozone. Almost any plug-in expands word length when editing, and it's desirable to return it to 16 bits using proper dithering, either by means of host, or plug-in itself.

If you want to reedit the track afterwards use not noiseshaped dithering. If you are sure you won't edit this track anymore use noise shaped dithering.

IMHO internal precision has nothing to do with the final word output...
cheers,
Macmod

of course it has.