Diamond Audio's DSP APP is a free Android multimedia program that allows the user to control the DSP for tone tuning. This app can be connected to the Diamond DSP device via Bluetooth, enabling the user to adjust the EQ, crossover, delay, and other functions of the DSP. The app also provides various vehicle scene options, making it a versatile tool for car audio enthusiasts.

The app's interface is user-friendly and easy to navigate. It offers a variety of features that allow for precise tuning of the audio system, including a graphic equalizer with multiple bands and the ability to customize crossover points. The app also includes a time alignment function to correct for any time delays in the audio system.

Overall, Diamond Audio's DSP APP is a useful tool for those looking to fine-tune their car audio system. With its Bluetooth connectivity and various tuning options, it provides a comprehensive solution for car audio enthusiasts.