Play Audio from Microphone through Speakers

Question

I'm wondering how I can, in Java, preferably using DataLine capture audio from the microphone, and play it directly to the speakers, even if there is some delay.

Basically, I want to be able to take the audio from the microphone, store a buffer of a finite number of samples, be able to modify each sample in some way, and play it back out through the speakers with as little time for each sample between being recorded and played. Sort of like writing a Java program to use my computer as an effects pedal; is this possible?(Assuming I already know how to modify the samples). Just to be clear, I don't want to record a finite number of samples from the microphone, stop recording, modify, then play; I want it to be continuously recording and playing.

Answer 1

This is a matter of reading from a TargetDataLine into a byte buffer and then writing it to a SourceDataLine in a loop indefinitely.

The resulting latency will be highly dependent on the size of audio buffer you use. The larger your buffer the larger the latency.

Take a look at the AudioLoop example here.