A pretty simple app. If your phone doesn't notify you with a sound when is connected with a bluetooth headset/speaker or classic headphones, or if you need to filter only specific apps with sound, Headset Notifier is right for you!

It has a pretty simple UI (improvements are welcome), it let you add filters for those apps you want to be notified (with a sound you can choose) when you wear headphones/headset or when you smartphone is connected to a speaker.