Cannot get playback to "wait" when using Volume

[TheIcemanCometh]

I'm trying to use the library to play MP3 files in an Elgato Stream Deck plugin, and running into a bit of an issue. Before adding the Volume logic, I had this, and it was working as I expected:

done := make(chan bool)  
speaker.Play(beep.Seq(streamer, beep.Callback(func() {  
    done <- true  
})))  
<-done  
// more stuff  

But when I add the option for Volume, it's playing the file fine; but it's not waiting for it to finish before moving on to the rest of my logic. This is what I'm trying to use:

done := make(chan bool)  
ctrl := &beep.Ctrl{Streamer: beep.Seq(streamer, beep.Callback(func() {  
	done <- true  
})), Paused: false}  
volume := &effects.Volume{  
	Streamer: ctrl,  
	Base:     10,  
	Volume:   vol / 10,  
	Silent:   false,  
}  
speaker.Play(volume)  
<-done  
// more stuff  

Any ideas?

[tslocum]

This is nearly identical to my usage in ditty except the pipeline is beep.Seq -> volume -> ctrl -> speaker.Play (swapped volume and ctrl).