If you mean a literal “IR blaster”, those generally modulate onto a 38kHz carrier. (I built an IR blasting device out of a 555 timer and an LED once, and it worked great, and no, I did not use precision resistors or capacitors. I admit I’m not actually sure whether a standard IR blaster contains a modulator or whether the device supplying the signal is expected to pre-modulate it.). You’re not going to get anything resembling acceptable audio quantity over consumer IR tech.