AC3 has reduced sonic impact after encoding - any tweaks to change that...?

[LordClick]

I have a surround mix done in Nuendo, and when I encode into AC3 (with the standard settings), most of it sounds good, but if there is a loud impact, e.g. from a bomb, it loses all the power. it sounds great in Nuendo (it's not peaking), but as an AC3 the deep frequencies and/or the volume seem to be reduced during these parts. Can I get the AC3 to sound just like I hear the original mix?

I tried SoftEncode and the Nuendo Dolby Digital plugin, and they both give me the same/similar results.

[nuked]

hmm... sounds like maybe you have Dynamic Range Compression turned on. Try turning it off, or optionally leave it on and use AC3filter to disable it on playback. DRC in AC3 is actually done by setting bit stream info that is used to compress the dynamic range on playback. I'm completely ignorant about what nuendo even is. It's possible you already compressed the raw sound in the process of decoding the source... in which case don't do that.

[LordClick]

I think I turned Dynamic Range Compression off, but I'll try it again. Can I only choose from the preset settings (film standards etc.), not define my own? The sound is original, created in Nuendo (it's like Cubase, also from Steinberg).

But yeah it kinda sounds like a compression issue... i'll try, thanks :)

[DIggedy]

Another tip is to set the dialog normalisation to -31db. At this setting it does not adjust volume levels and combined with DRC being switched OFF, the resulting ac3 should sound a similar volume to the source.

[nuked]

oh yeah.. if you dont' know if you turned on DRC or not you can find out with ac3filter. Play it with ac3filter and check the drc box. Then play through some bits with very different volumes. If the DRC gain slider starts moving around on it's own.. then you recorded DRC info in the AC3. Of course if you hard coded the dynamic compression into the sound somehow(like using boost in besweet for example), this will not show it.
I think there's a sticky here about the dialog normalization stuff and if gives LOTS of details on the issue. I think it matters more though when DRC is ON than when it's off since it sorta determines the volume to compress everyrhing towards if that makes any sense. By the way ac3 may be DVD sound... oooh, ahh.. but it's still pretty compressed. There will likely be some quality loss if you've got the ears to notice it. I wouldn't really expect bass to lose it's power though.

[LordClick]

Thanks a lot for the helpful hints! I got it sounding pretty good now...! But I guess I gotta take it to a couple of places and check what the result sounds like on various players....