On Tue, Jul 14, 2009 at 04:13:13PM -0700, Justin Smith wrote: > On Tue, Jul 14, 2009 at 3:56 PM, Fons Adriaensen<fons@xxxxxxxxxxxxxxx> wrote: > > On Tue, Jul 14, 2009 at 03:25:39PM -0700, Justin Smith wrote: > > > >> Try running a white noise source through the filter, then look at the > >> spectral graph output in your favorite spectrum analysis program. > >> Since white noise should have a flat spectrum, any peaks and valleys > >> in the output are those of the filter. > > > > For a more 'musical' analysis, use Japa. It has either > > a logarithmic or perceptual frequency scale. Pink noise > > source is built-in, and if you set the analyser response > > to 'Proportional' it will show a flat spectrum for pink > > noise. It can also show the difference between two spectra, > > e.g. input and output of a filter, and this produces much > > more stable displays when using a noise test signal. > > > > For the filter, you could try on of the four Moog VCF > > plugins I wrote years ago. Apart from the resonant > > lowpass they will also add some juicy distortion at > > high levels, as does the original Moog filter and > > probably all real analog Wah processors. Frequency > > control is logarithmic, which is probably what you > > want, and there are separate control inputs to > > set the static frequency and resonance and their > > modulation. One problem could be that the modulation > > inputs require audio rate signals (the filter were > > designed for use in AMS) but that can be changed > > easily if you want. If you want to play with them > > use AMS. > > > > But Japa and the filters to be found at > > http://www.kokkinizita.net/linuxaudio/downloads > > > > The filter plugins are in the MCP set. > > > > -- > > FA > > I used japa years ago, but forgot its name, thanks for this excellent > piece of software, which I am excited to have rediscovered. Mille grazie! I've got JAPA going on two platforms, but I've got to apologise for being a bit dense in figuring out how to use it. The UI looks a bit like an HP oscope, but, alas, i'm not much of an engineer, so I'm not sure to start. Is there a quick simple tutorial somewhere on how to use it? Anyone care to give me a few sentences of advice? I basically want to put white noise through some filters (prolly using JACK-RACK), and view the frequency response of it. Looks like JAPA already has a built-in white an pink noise generator, which is nice. What would I connect to what (using i.e. using jack_connect) and how would I set up the switches and control on JAPA to do this? A simple screenshot of the correct setup might be enough to get me going. Thanks again! -ken _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
