Montage: change clip level also changes bit depth

Hi all …

I have only just noticed that changing the level of a clip in a 16 bit 44.1 kHz montage seems to result in that clip playing back at 24 bits.

Assemble a montage for a CD. All of the clips (CD tracks) in the montage are 16 bit 44.1 kHz. Lower one of the clips (CD tracks) relative to the others. Press play. The bit meter shows that this one clip is now at 24 bits for the purpose of ‘play’.

Restoring the clip level to ‘0’ results in the clip once again ‘playing’ at 16 bit depth.

I did not know of this behaviour.

It looks like in this situation I need to dither a second time (having already dithered in the Weiss to get to 16 bits) when creating a DDP?

Am I missing something?

This is totally normal. You should not change the gain or anything else on dithered files (or as you say, you need to re dither, which is not good).

Thank you PG …

As PG says, any calculation will change bit depth. Not just gain, any tiny change. Nature of the beast.

When possible I urge clients to stick to flat TPDF dither, and leave shaped dithers to me or final step. The build-up of multiple layers of flat dither aren’t nearly as audible as a couple pass of shaped dither rapidly become. It’s very useful avoid noise shaping for anything short of delivery (and Wavelab makes it easy to keep files full-resolution and apply in the last step to whatever you’re bouncing).