if you want to use a variable as input before it gets filled, initialise it first.Say you want to do an allpass filter in direct formayprev init 0axprev init 0...ay = axprev - icoef*(ax + ayprev)axprev = axayprev = ayAlso, don't forget to set ksmps = 1 too, if you areusing feedback (as above). This can be done in a UDO withsetksmps 1 without forcing all instruments to use 1-sample blocks.Victor----- Original Message -----From: Aki Laaksovirta <akilaa@kotiposti.net>Date: Saturday, March 28, 2009 7:04 pmSubject: [Csnd] Physical modeling synthesisTo: csound@lists.bath.ac.uk> I have recently tried to establish some bidirectional delay > lines, but Csound always only replies that "***** used before > defined." So, my suggestion would be that the orchestra be split > up in two parts: first one, which describes the needed opcodes, > and second one, which describes the connections between the > opcodes. Would that sound fair?> > > Send bugs reports to this list.> To unsubscribe, send email sympa@lists.bath.ac.uk with body > "unsubscribe csound"Dr Victor Lazzarini, Senior Lecturer, Dept. of Music,National University of Ireland, Maynooth