I'm surprised with other bad comments. I use this tuner with an electric guitar and it does well. I noticed that with a mono cable (only the left channel is heard on the Mac), this software is not accurate (it's difficult to tune). But if I use a cable providing sound on both sides, it's perfect software. This kind of cable is mandatory so I don't see any problem. Thanks to the autor. This is free and it's doing well. Geat.