On Sat, Jun 15, 2013 at 02:56:13PM +0100, Aurélien Leblond wrote: > - in some cases (or let say modules of a synth), clipping is > implemented more to copie what an analogue system would do than a > mandatory part of the algorithm... Let's take an example: 2 sin waves > mixed together of amplitude -1/1 will just have an amplitude of -2/2 > (as long as they are in phase)... A digital mixer without clipping > would be able to cope with that, but an analogue one wouldn't... and > that's why the analogue system would clip the signal......right?
An analogue system with enough headroom wouldn't clip. A DAC will clip in those circumstances. > - What method of clipping is used will give a "personality" to the > module: hard clipping, soft clipping, the method used for soft > clipping, etc...right? You'd also need to avoid generating harmonics above fs/2 to prevent aliasing, unless that's part of the "personality" you're going for. > - Hard clipping is something of the digital world - it doesn't exist > in the analogue world... right? Wrong. An analogue amplifier with lots of negative feedback, eg. a typical op amp or power amp, will usually hard clip. > - Soft clipping will deform any waves of amplitude -1/1 even if it > doesn't exceed the accepted threshold, because just before reaching > the threshold the algorithm will take over and softly make the signal > reach the maximum amplitude and keep it there until the original > signal goes back under a set threshold.....right? Yes, although clipping threshold can be any level you like (within reason) in floating point. > - Is there a preferred stage for clipping? In the case of a filter, > should we clip before filtering, after or both? Or are all these > options valid and that's what will give an additional personality to > the filter? That depends on whether you want to modify the frequency response before or after the clipping harmonics are added. Both can be valid options. John _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
