stereo

The MOS Technology SID by its nature is a sound chip that outputs one mono audio signal and the C64 came equipped with exactly one of these sound chips. Unsurprisingly the overwhelming majority of C64 songs found today was designed for this hardware configuration.

However some people used hardware extensions that allowed to add a second or third SID chip to the same C64 and then composed music for these more or less exotic configurations. Each of these additional chips then provided its own audio output and depending on the wiring of the used signal post-processing they would have been able to create stereo/mono signals after their taste.

Below some examples:

• Sad Song
  (2 SID chips)
• Stereophonik 8580
  (2 SID chips)
• Am I Melodic
  (2 SID chips)
• Roy G Biv
  (2 SID chips)
• Fratres Arvo Paert
  (2 SID chips)
• Blade Runner Main Titles
  (2 SID chips)
• Garage Party Jam
  (2 SID chips)
• The Tree Angle
  (3 SID chips)
• Do Nothing for 3 Minutes
  (3 SID chips)
• A Walk in the Countryside
  (3 SID chips)
• Quad Core
  (4 SID chips)

Breaking with the tradition of original SID chips, webSID not only allows to mix the output of different chips into a stereo signal but also allows to do this with individual SID voices (the original hardware obvisously did not support this). You might try this standalone webSID stereo page for more information.

The C64 hardware tinkering in recent years reached a point where a song using 10 SID chips has been composed and you might try this standalone The Tuneful Eight page for an example that uses 8 SID chips. Sadly the "standard" SID file format does not allow to use more that 3 SID chips and webSID uses a proprietary extension of the file format to support songs that use an arbitrary number of SID chips. (Hardware configurations with more SID chips are obviously more expensive to emulate, i.e. the "CPU load" burden placed on the Web browser grows with each additional SID chip and slow machines may experience playback stuttering when the load exceeds the capabilities of the machine.)

PS: The quickest way to find the latest multi-SID songs is probably to input "_3SID" (etc) into DeepSID's "search" field.