On Tue, Mar 06, 2012 at 10:43:06PM +0000, James Mckernon wrote: > Hi all, > > I have a few questions about using ecasound and/or nama with slightly more > complex, 'non-linear' chains of audio effects. By this I mainly mean > 'forking' chains - such as highpassing a signal and applying a delay loop > to the high-frequency components of the sound, and a distortion to the > rest, for example. > > This kind of thing would generally be straightforward enough to implement > in hardware with physical cables, but elegant implementations in DSP seem > rarer -- at least in linux. One of the reasons I am interested in ecasound > is that I gather from its 'examples' webpage that it handles exactly this > kind of thing quite elegantly: > 'Ok, let's next do some parallel processing: two chains are created and the > input and output files are connected to them. As a result, the input signal > is processed with two sets of effects, and then mixed back together. You > can create as many chains this way as you want.' ( > http://www.eca.cx/ecasound/Documentation/examples.html#effects) > > However, I suspect that ecasound in its raw form could be somewhat unwieldy > for the sort of work I'd like to do, so I'd like to be able to use nama > instead. Would this sort of 'forking' signal chain be as easy to set up in > nama as it seems to be in ecasound? Also, in nama, is it possible/easy to > adjust and play with the effects path (and effect parameters) on the fly, > without interrupting playback? Hi, With Ecasound, you can change effect parameters without interrupting playback. Adding and removing effects can create a pop, which Nama hides by briefly muting the track. Changing effect parameters can also change effect latency, which would create a pop. Nama doesn't protect you in that case. The first example of signal processing you give is easy to do, presuming you've spend a little time to learn the Nama or Ecasound ways of doing it! > Relatedly, another thing I'd like to be able to do is a delay effect, with > effect(s) (i.e. filters or certain kinds of distortion, followed by a gain > reduction) applied 'inside' the delay loop, such that the effect is > recursively, cumulatively applied to the looped material. Might sound like > a strange requirement, I know, but it's actually a fairly central effect to > the kind of music I'd like to make (dub reggae). Unfortunately, this is > difficult to achieve easily in Linux. You may have to roll your own. > Since no delay plugin that I know of > includes the kind of internal effects that I want, the only way to achieve > this is with some kind of 'circular' DSP chain, which most programs don't > allow. Does anyone know if this kind of 'circular' DSP chain might be > achievable in any way in ecasound - for example, by feeding a track's > output back to itself? I haven't seen an example with Ecasound. Regards, -- Joel Roth _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
