On Mon, 6 Apr 2015 10:57:25 -0400
"jonetsu(a)teksavvy.com" <jonetsu(a)teksavvy.com> wrote:
  I used Option # 2 and started Ardour3 from the command
line.  I
 loaded the CALF Envelope Filter which systematically makes Ardour
 crash when the play button is pressed.  There were recorded tracks.
 Note that jackd was started as usual, through qjackctl, w/o any
 special consideration.
 When Ardour vanished from the desktop the following was shown:
 (ardour-3.5.403:3096): GLib-GObject-WARNING **: Attempt to add
 property
 gtkmm__CustomObject_N9Gtkmm2ext23CellRendererPixbufMultiE::active
 after class was initialised ardour-3.5.403:
 ../libs/ardour/process_thread.cc :102 : static ARDOUR::BufferSet&
 ARDOUR::ProcessThread::get_scratch_buffers(ARDOUR::ChanCount,
 bool): l'assertion « sb->available() >= count » a échoué.
 Abandon (core dumped) 
Update:
Using the exact same Calf git compile/install but this time with the
newly-released Ardour 4.0, everything is fine.  The plugin runs very
well.