# Prop audio improvement



## MansionHaunter (Sep 20, 2006)

A couple of weeks ago I was given a large "Lurking Butler" prop that stands 7' tall and speaks one of three phrases when its light sensor is triggered.

But the sound was very flat, given the fact that it was one little speaker in a small box.

So I built an audio waveguide, shown below, out of 2" ABS pipe and fittings and some old 2" speakers I'd scavanged from a no-longer-working computer speaker set.

The key is to have the short section of waveguide be 1/3 the length of the longer section. I found that 2" pipe works fairly well, and that there is no advantage to longer or wider pipes.

The waveguide fits inside the prop and delivers an incredibly rich, deep sound, worthy of a 7 foot tall figure.


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## Dr Morbius (Sep 21, 2004)

Isn't that the same principle Bose Acoustic Wave Radios use? Nice. I'll bet it sounds great!


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## MansionHaunter (Sep 20, 2006)

Exactly. That was my inspiration, and it works great. The combination of length and pipe diameter I used provides good results without sounding like somebody talking through a tube.


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