Someone very wise once told me that the ideal combination would be three pairs of VCOs. Each pair could be 'normally' coupled by FM, Sync and PWM. As yet I only have three singles... Regards, Tony Allgood Penrith, Cumbria, England Oakley Sound Systems www.oakleysound.co.uk Modular Synthesisers www.oakleysound.co.uk/projects.htm