A bit later than promised due to no time but here it is, a VoiceHook rewrite that's open source and works for both Steam voice and Speex. There's no extension interface yet (but there will be more), but there are forwards you can use to save decompressed voice data from a plugin.
I also attached a simple plugin that can make use of this.
Hopefully all binaries work, I only had time to test a few of them so let me know.
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