On Sun, Mar 16, 2008 at 7:08 AM, Simon Williams <simon@xxxxxxxxxxxxxxxxxxx> wrote: > Hello. > Part of my group project involves a music playing system. What we have > is a bunch of stages connected together with buffers and pipes. The > first stage decodes an mp3 file with mplayer and sends the raw audio > down the pipe in 44.1KHz 16bit. No headers are ever sent (as far as I > know). What I'm trying to do is add an EQ stage. The problem is that the > samples which come in seem to be equalised to the maximum level possible > with 16bit. Therefore if I increase the volume of any band it will cause > clipping. The only solution I can think of at the moment is to just EQ > down, but that sucks a bit. > > Can anyone shed some light on what it is I'm doing wrong? > Thanks. > Simon Simon, Actually, EQing down, as you call it, is really the right thing to do and the way that all good recording teachers/books will teach you to work with the audio. that said it isn't, for most people, the most natural thing to do for some reason and most of us had to learn to get through it. Keeping the audio at maximum values as far as you can through the audio chain is best for signal-to-noise, etc., and the audio at the start of your pipe is doing that. EQing is now a subjective step you are adding, presumably for good reason. To do this you cut the other EQ bands so as to allow the band you want to be more promenent to come through. You might just do this with a volume control at the front end of your EQ unit, or you might adjust each of the unwanted bands. The two options may have different sonic characteristics. Play with it and hear for yourself. Keep in mind that if you wanted 10% more of something and wanted to boost the band to get it you would have had to have had 10% less of everything in the first place to give you headroom to do it. Since there's no way to know whether you will want 10%, 20% or even 50% more of something down the road it's far better to keep everything as loud as it can be through the whole process, without clipping at the top, to maximize signal-to-noise and give you the most flexibility in all stages. Hope this helps, Mark _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
