I had made an midi controller that send midi values from arduino uno board to my laptop over the usb cable ,i want an audio output from the arduino uno board (the only connection between my board and laptop is the usb cable )i researched about my topic and came to know something called as DAC ... So what is it about how can i get audio output ..?
You can't use an Arduino UNO, but a Teensy 3.x is perfectly capable of doing what you want.
Here's my Control Surface library, it's an improved fork from my MIDI Controller library, but it's not finished yet.
You need the revision-4 branch.
https://github.com/tttapa/Control-Surface/blob/revision-4/examples/Audio/VUMeterLEDs-USB-DAC/VUMeterLEDs-USB-DAC.ino
This is an example that plays USB audio using an I²S DAC, a potentiometer for volume control, and three shift registers with LED VU meters that display the USB audio level.
You can check the other examples on how to add MIDI control elements to the sketch.
Pieter