[LAU] Explodomatica - explosion sound effect generator

[Jeremy Salwen]

Very cool.  I was playing around with it.  I do have one suggestion though:
It seems you are introducing unwanted artifacts due to clipping.

First, you probably don't want clipping.  However, it is showing up, even in
your demo samples.

Second, you might want clipping (Probably we've ingrained digital clipping
in our perception of explosion sounds), but if you do, you're not clipping
in the right way.  I haven't looked at your code, but because I had the
exact same symptoms while using libsndfile, I'm guessing that what you are
doing is feeding libsndfile floats with values >1 or <-1.  If you want
proper clipping, these samples would be pulled to the closest value within
the range [-1,1].  However, due to performance reasons (I'm guessing), this
is not what libsndfile does, but instead it wraps around.  So 1.1 will be
interpreted as the amplitude of -0.9.

Here's what it looks like:  http://i.imgur.com/sselM.png

That image is from demo0.wav.  This causes the "clicking" artifacts you hear
in the file.  In order to fix this, just go through and find any samples > 1
and replace them with 1, and similarly with -1, right before you write the
data out with libsndfile.  This should give you proper "chopped peaks"
clipping.  Or, if you don't want clipping at all, just calculate the max
amplitude and divide every sample by it before outputting.

Good luck and thanks,
Jeremy



On Fri, Oct 28, 2011 at 2:05 PM, Stephen Cameron <smcameron at yahoo.com>wrote:

>
> I made a little explosion sound effect generator, the idea being to help
> out people looking for such things for making video games, and so on.  It
> relies on portaudio, libsndfile, and gtk2.
>
> I don't really know what I'm doing when it comes to DSP, so probably some
> of you will laugh when you see my algorithms.  But it does more or less make
> explosion sounds.
>
> It's here:
> http://smcameron.github.com/explodomatica
>
> Enjoy
>
> -- steve
>
> _______________________________________________
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> Linux-audio-user at lists.linuxaudio.org
> http://lists.linuxaudio.org/listinfo/linux-audio-user
>
>
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