im new to synths. I was thinking about making this SID for fun. I do not own a keyboard/synth controller…
is it possible to run the sounds through my soundcard to the midibox?
Yes 
Audio/Midi application * => Soundcard Midi Out => Midibox SID Midi In
Audio/Midi application => Soundcard Gameport to Midi (adapter) => Midibox SID
Audio/Midi application => Serial (RS232 Adapter) => MBHP LTC ** => Midibox SID
* Audio/Midi application such as cubase sx
** http://www.ucapps.de/mbhp/mbhp_ltc.pdf
http://www.ucapps.de/midibox_to_com.html
Greetings,
Lemonhorse