If dithering is applied when you 

SONAR reference guide
“render” audio (bounce, freeze, or apply effects).

 
Does this mean that when you export a finished mix it is dithered again?
 
Is this in anyway detrimental to the audio?

I sometimes turn off dithering because of what you mentioned and I would in my mind think it also slows down the rendering process...non-dithering will not degrade of repeated bounces and should be faster! :0 -S

I always have dithering off except when I'm exporting to a different bit depth, which is what I understand is the occasion when it should be used.

Wookiee
If dithering is applied when you 

SONAR reference guide
“render” audio (bounce, freeze, or apply effects).

 
Does this mean that when you export a finished mix it is dithered again?
 

 
Yes - if you have it turned on of course.
 

Is this in anyway detrimental to the audio?

Dither just adds noise.
 
But at bit depths above 16 it really doesn't matter one way or the other in the real world. Unless you're doing null testing or DSP programming or something, in which case you will want to take it into account.

I always keep it on whatever. If for instance one does an export from 24bit to 24bit one assumes Sonar is clever enough not to apply it anyway... I would be interested to hear from Cakewalk to see if this assumption is correct.

If it's the wrong assumption still should't make any real world difference.

It is however a big mistake to turn off dithering when rendering to different bit depths from the source.

And indeed it does look like the case...

https://www.cakewalk.com/...mp;help=Mixing.61.html

'SONAR uses dithering WHEN you export a higher-bit file at a lower resolution, or lower the bit depth of a project’s audio files by using the Utilities > Change Audio Format command, or when you “render” audio (bounce, freeze, or apply effects)'

So no unnecessary duplication. Just keep it on.

Dupe.

It's is a pity however that the forums isn't as good as Sonar when it comes to duplication...

You only need to dither once & at the final stage of exporting the master. For cd 16b, 24b dither for other formats such as mastered for iTunes.

carl
You only need to dither once & at the final stage of exporting the master. For cd 16b, 24b dither for other formats such as mastered for iTunes.

Yup and that's exactly what happens if you keep dither option on all the time.

The other scenario is you need to dither when you import samples of a different bit rate into the project.

Doktor Avalanche

carl
You only need to dither once & at the final stage of exporting the master. For cd 16b, 24b dither for other formats such as mastered for iTunes.

Yup and that's exactly what happens if you keep dither option on all the time.

The other scenario is you need to dither when you import samples of a different bit rate into the project.

Hmm. Not different, just lower. If the imports are of a lower bit rate than the project, then you don't need to dither. 16 bit source audio is perfectly happy in a 24 bit environment. The only time you should ever dither anything is when reducing its bit rate.