Well if the audio was clipped, there would probably be some audible distortion. Perhaps if a code fragment was posted we could give a more informed opinion.
Victor On 26 Oct 2009, at 09:08, Jörn Nettingsmeier wrote: > 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 _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
