On 10/26/2009 07:33 AM, Drip Stone wrote: > Hi everybody, > > I have a question regarding amplifying a PCM frame. For each frame, I > get a float number, and multiply this number by 2, and then output > frames to alsa one by one using function snd_pcm_writei. But the wav > file sounds the same to me, nothing gets amplified. Could anyone explain > this to me? I appreciate your help!
you should hear an amplification by roughly 6dB... what might happen is this: your file already has a peak at 1.0f. after your operation, it will peak at 2.0f, which your DAC can't handle. so the file will have to be clamped between -1.0f and 1.0f, effectively undoing your gain operation. just a guess. or you might be expecting the wrong thing... times two doesn't feel "twice as loud". then again, +6dB is quite audible in any case. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
