Okay, so top posting is requested here?

Yea,  that's what it does actual.
you can *adds* a octave up/down with GxDetune. You can mixed dry / wet. (seperate controllers for dry and wet signal from 0 - 100 % for each). You can delay the added octave  for the latency, or you can compensate it internal, so that dry and wet signal comes in sync.

screenshot:

    http://oi62.tinypic.com/34njmo3.jpg


Am 01.06.2014 20:14, schrieb rosea grammostola:
The fun of these pedals is that it *adds* an octave (higher or lower) to the tone being played
http://www.jimdunlop.com/blog/new-bass-octave-deluxe-demo/


On Sun, Jun 1, 2014 at 8:09 PM, hermann meyer <brummer-@web.de> wrote:
Am 01.06.2014 19:37, schrieb hermann meyer:

Am 01.06.2014 19:21, schrieb rosea grammostola:
Hi,

Quite a few e-bass players here, seems to use an octaver pedal. Is there some plugin for it on Linux?

Regards,
~r


I've just added such a thing to guitarix (git) as gx and as LV2 plug. It's called GxDetune and could shift one octave up/down. Detune is possible for 1/4 semitone. Latency is ( in High Quality mode) 2048 samples minus jack-frame-size, but could as well set down to Lower rates down to realtime (true, quality get lost then)
Latency could be compensate internal for mix with dry signal, as well latency is reported to host (in LV2 version) so that the host could compensate the latency, if supported.

greets
hermann

Some more information here:

http://www.linuxmusicians.com/viewtopic.php?f=48&t=12300&start=15#p52208