I have been working on a major update to iDjembe for several weeks. The major new feature is Virtual Drum Circle, which lets you broadcast to other players on the local network using Bonjour.
I’ve also drastically improved the responsiveness, and in the process learned a lot about iPhone audio. The current version uses the simple Audio Services to play the sounds, which has some major limitations such as being able to play only one sound at a time. Since the samples have a long trailing end as they fade to complete silence, during that time it isn’t possible for any other sounds to play, which makes it unresponsive.
I did a lot of experimentation with different sound APIs and I’ve settled on using OpenAL which seems to give the best performance and is the least ugly.
In the current version, I handle taps in a single view, where I do my own hit testing to determine the location to decide which sound to play. I’ve changed it to use custom buttons, which performs just as well and gives a nice highlight effect for the tapped area.
I hope to have this update out in 2 weeks or less.