In one corner there's this paper horn just sitting there and in the other there's my shiny new Galaxy S4 smart phone. Looks like a match made in paper heaven!

I've made a frame with a hole that lines up with the phone's loudspeaker. The other end of the tube accepts the horn.

Here's the horn fitted into place.

The phone sits on the stand with the loudspeaker over the inlet. Play some music and the horn gives the sound a lovely rich tone. It actually works! The only downside is that it would need a separate design stand for each type of phone. #1 Daughter and #truelove have iPhones and  #1 Son has a Galaxy S2. I'll see if I can create a download for those three phones at least. It'll look great with a bit of a Steampunk colour scheme!