I updated my iPad2 to iOS this morning and, since, I've had problems with most of my musical apps. Some of Michael Eskin's apps, and apps I have from others, have the same problem...get more than 3 finger on the screen and the sound stops. Break contact and then it will work again, but it is start and stop. It's intermittent but enough to make the apps pretty useless.. Another musical app I have opens, but won't make a sound. This should be interesting. I'm sure it will get fixed in an update.

Dale, it's the new multi-touch for the multi-tasking. It's on by default in the OS, so you have to go change it there, the applications can't do so. It otherwise breaks all those keyboard apps, the concertina stuff by Mr. Eskin, and any app using 4-5 fingers down as well. So, you can fix it yourself by changing the default setting in the OS. Maybe in an update, they won't make it the default.

Thanks for the fix, k.

Unfortunately, Apple pulls this kind of thing every so often...

The multitasking gestures are unfortunately turned on by default in iOS5, and they break lots of instrument apps that use four or more fingers on the screen.

There isn't a way to programmatically disable them from within an app, so you have to go to the Settings and disable them.

Here's specific instructions from another app developer:
http://blog.cocoabox.com/post/110577344 ... es-warning