Thank you everyone for the feedback on the phono-horn project. I've been delighted with the response it has received. It has had over 102k viewers on the Instructables website and countless downloads from here.

One of the suggestions was to make the model stable. The current version falls over when you take the phone off the stand. With that in mind I've put together this modified base prototype. 

I've changed the design so that the horn is further back and centred over the stand. It is now nice and stable.

I'm working on a set of generic instructions so that you will be able to adapt the unit to suit your phone. It should work with most phones where the speaker is either on the back of the phone or along the base.

Here it is with my Samsung Galaxy S4 in place. I've been using it all day as my source of music and though I say so myself, it sounds remarkably good!