On Friday 05 January 2007 01:44, florentberthaut(a)no-log.org wrote: Well, that's what JACK is doing anyway - or there would be wrapping in the float -> int conversion, which sounds a lot worse than clipping. It's just not possible to represent larger amplitudes than [-1, 1] in the integer domain (that is, [-32768, 32767] or whatever, depending on resolution), which is what DACs deal with. Yep, that's all there is to it, really - and it's the user's responsibility to keep volumes low enough to avoid driving the output into clipping. This is true on hardware synths and samplers too. The only reason some of them appears not to have this problem is that they use various tricks to hide it. For example, the old Roland JV-1080 had 18 bit DACs, where the two extra bits were pretty much used for extra headroom above the "normal" max amplitude of a single voice. Even so, it was pretty easy to drive it into clipping by using resonant filters and/or lots of loud voices. I wouldn't be surprised if some synths and samplers use 20 och 24 bit DACs for even more headroom, waveshaping to make the last 12 dB or so non-linear (soft saturation, sort of), dynamic output gain control and stuff like that. Now, if you're dealing in digital, extra DAC bits and dynamic output gain control is out, obviously. (Goes for plugins and JACK clients as well as hardware devices with digital outputs.) So, either you set your sampler's 0 dB level at -12 dB or something (allows mixing four maximized samples at maximum volume without clipping), or you leave that to the user. If you really want to make the impression sqeezing in more than there's room for, you'll have to add some dynamics processing. There is of course no way of doing this without some sort of distortion, but even a simple waveshaper to "flatten out" peaks above 12 dB below clipping sounds a great deal better than hard clipping. However, I'd rather see that kind of stuff left to the user. Those of us who use 20+ bit sound cards would rather have it all linear and undistorted right into the amplifier. There is always the option of inserting some serious multiband compressor last thing in the JACK chain. Might actually be a good idea anyway, if you like playing loud and don't want to ruin your ears if some synth or effect freaks out. //David Olofson - Programmer, Composer, Open Source Advocate .------- http://olofson.net - Games, SDL examples -------. | http://zeespace.net - 2.5D rendering engine | | http://audiality.org - Music/audio engine | | http://eel.olofson.net - Real time scripting | '-- http://www.reologica.se - Rheology instrumentation --'