Gaps is an ear training tool that listens to what you play on guitar. It will help you train your ear and your fretboard visualization skills simultaneously. Features Use your guitar as an input device for the exercises. Practice scale degrees against a drone note. Practice playing melodies by ear. Practice ascending and descending intervals. Learn to visualize scale degree and interval positions on the guitar neck. To use your guitar with Gaps you'll need one of the following: An external audio interface (Recommended). A guitar cable to 3.5mm TS/TRS adapter and a microphone port on your desktop PC. (*) A microphone plugged into your PC (Can also be a laptop's internal mic).(*) Most modern laptops contain a single port for both microphone and headphones which only takes in TRRS cables. In this case you'll also need a 3.5mm TRS to TRRS adaptor. Keep in mind some laptop models sometimes fail to recognize an input device is plugged into their port because of limitations in their hardware. If you're using a laptop the only guaranteed way to connect your guitar is through an audio interface.