----------------------------------------------------------------------------------- Copyright (C) 2003 Fons Adriaensen This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. ----------------------------------------------------------------------------------- -------------------------------------------------- blvco 0.3.0 -- 12/4/2004 -------------------------------------------------- Pulse-VCO : Anti-aliased dirac pulse oscillator (flat amplitude spectrum) Saw-VCO : Anti-aliased sawtooth oscillator (1/F amplitude spectrum) Rec-VCO : Anti-aliased square / rectange oscillator All three oscillators are based on the same principle of using a precomputed interpolated dirac pulse. For the sawtooth and rectangular versions, the 'edge' is made by integrating the anti-aliased pulse. Aliases should be below -80dB for fundamental frequencies below Fsamp / 6 (i.e. up to 8 kHz at Fsamp = 48 kHz). This frequency range includes the fundamental frequencies of all known musical instruments. Alpha versions of this plugin were evaluated by Matthias Nagorni, who compared their outputs to the sounds produced by his Moog Voyager and Doepfer synthesisers. Matthias reported that the plugins sounded quite 'harsh' when compared to his analogue instruments. Comparing the spectra, it became clear that a mathematically 'exact' spectrum was not desirable from a musical point of view. For this reason, I added the lowpass filters. The default setting (0.5) will give you a sawtooth that is identical to the output of the Moog Voyager. The rectangulare VCO and and sync inputs are very much experimental at this stage. Feedback appreciated.