Baudline is just what I was after it seems. It does indeed let me scale the amplitude and zoom without restarting which I don't think are possible with jack-oscrolloscope. Its also nice as it incorporates both spectrum analysis and a scope display so I have one less app to deal with now.

Finally, Baudline is also notable as it appears to be a motif/lesstif app and I thought I'd seen the last of that toolkit last millenium!

On Sun, Jun 24, 2012 at 5:38 PM, Robin Gareus <robin@gareus.org> wrote:
On 06/24/2012 06:19 PM, Dan MacDonald wrote:
> I'm currently using jack-oscrolloscope
>
> http://das.nasophon.de/jack_oscrolloscope/
>
> as a jack scope but I've been wondering if there's not a better one, like
> with rt zoom and adjustment of other params? I know about jack.scope in
> jack tools and meterbridge but jack-oscrolloscope suits me better than
> those - it having a resizable display for one.

YASS: "Yet Another Scrolling Scope. Main features: up to 32 channels,
variable scrolling speed, automatic gain control, and very light on CPU
usage" - http://kokkinizita.linuxaudio.org/linuxaudio/

Baudline: gratis, not free, but really handy: http://www.baudline.com/

some more:
http://wiki.linuxaudio.org/apps/categories/scopes_and_realtime_visualizers

ciao,
robin