I'm down for that one too. I was planning to add it myself after the one key event.

Actually, it was quicker than expected to implement audio feedback with AVAudioPlayer. I've used a shorter version (silence from start and end removed) of this sound. Now, the sound intensity can be controlled (or not) as well through that API.

@munsuri you should create a pull request with your modification

Sorry, I accidentally hit “Close issue” button, please ignore the last activities.

If anyone wants to play around with the old Mac OS 9 Platinum sounds for nostalgia purposes, I extracted them from the resource fork of the original sound set I found somewhere online. I'm a fan of 00548 "wopn".aiff, but there are a number of other good ones.

Mac OS 9 Platinum Sounds.zip

Okay, so I made a change to support sound effect 4cbef9f and some other features.
Since there are some concerns so didn’t merge this into master yet, once it’s solved I’ll post a new release.

@chrisballinger if you want to use that sound, you can add that sound as a resource to the project (Simply drag and drop to Resources group,) and modify line 45 of 4cbef9f to [[HTKSystemSound alloc] initWithPath:[[NSBundle mainBundle] pathForResource:@"wopn" ofType:@"aiff"].
Due to license, I think it’s not good idea to have that sound file in the repository, but, you can at least try it now. 😉

Yeah I agree about the licensing, probably not a good idea to ship those by default. Perhaps a few royalty free default sounds could be included, selectable via Sounds sub-menu. Then you could drop external sound files into ~/Library/Application Support/HapticKey/Sounds/ and enumerate them within the sub-menu along with the bundled sounds. I'd submit a PR for that once things settle down a bit.

@chrisballinger That approach sounds good!

As I described in the comments, added ”Sound Effect” feedback option in a commit 4cbef9f.
Also released HapticKey 0.4.1.