How does the volume adjustment kernel handle crescendos and decrescendos if there isn't any background music for reference? For example, Metallica's Unforgiven - wouldn't the crescendo at the beginning come out as having a constant volume?

Just like any compressor, it ends up behaving differently depending on the character of the wave data it's being fed. Some fade-ins and fade-outs sound very natural, others have a very flattened volume curve so that they do sound almost constant in volume. It depends on where the peaks lie in the track- I don't own that song so I don't know.

But that's the whole point of a dynamic compressor: to compress the dynamics. In our case, to compress it enough so that the quiet parts come up above the car's noise floor, or so that the quieter songs sound closer to the volume of the loud ones. Yes, in some cases this would tend to destroy crescendos, but that's a choice you have to make: Do you want the first half of the crescendo buried beneath the car's noise floor, or do you want to hear the whole thing? To hear the whole thing, you either have to play it really loud or you have to compress it.

Right now, the parameters of this program are hard-coded. When it gets integrated with the player software, the parameters will be adjustable, and you'll be able to tweak it so that it behaves the way you want it to.

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Tony Fabris