tl.crossover4~ "quality" available?

    Feb 16 2006 | 12:38 am
    Hi list and Trond,
    I'm using the tl.crossover4~ (thanks, Trond, it saved me from having to kludge my own crossover filter).
    Some other tl filters (like butter*) have a "quality" option to make smooth sweeps. crossover4 doesn't appear to have it. Is there some other command I can use? I might need to switch the frequency during a performance. If I do an an abrupt switch, there's a momentary loud distortion. If I use a line object, the distortion is quieter but lasts longer.

    • Feb 16 2006 | 6:42 pm
      I didn't implement quality for crossover~. The reason was that I needed it myself to filter out frequencies below 80 Hz when using some nxt flat panel speakers. I was in a rush, and also thought that maybe the object would mainly be used with static parameters. As far as I remember you can't feed frequency as signal.
      I could try to add a method for using signal to alter frequency with ditto quality stuff, but I'm not sure if I'll be able to do so in the next coupple of weeks. I have some pressing issues that will require all or most of my attention for the next weeks. When do you need it?
      Best, Trond
    • Feb 17 2006 | 2:05 pm
      Hi, Trond,
      Don't rush for me. Turns out I don't need the functionality for this specific project (for a performance on 3/8). If you want to do it for your own sake, I'm happy to be a beta tester.
      I also want to send you a report on the behavior I'm seeing with sweeping frequencies, but I don't have time to formalize it right now.
      Basic setup -- Need to switch frequencies on tl.crossover4~ while signal is passing through it. It's technical need, not creative. Done maybe once or twice during a 45 minute performance. -- Use a [line] object to sweep the frequency from point A to point B -- Tried various [line] times, from 100ms to 2000ms -- With [tl.crossover4~ low], I *think* there are no audio glitches as long as a reasonable line time is used (like >100ms). Need to double check. -- With [tl.crossover4~ high], I definitely get noticeable overload/distortion. I *think* it only happens when the sweep gets into the low region, i.e., under approx. 85hz. Need to double check.
      I'll work more on the patch this weekend and get confirm the above. Also, maybe I'll take this off the forum unless someone else is interested in the results.