SID

= Sound Interface Device =

Sound Interface Device (SID) is the Commodore 64 sound chip. Original model used designation 6581 (later R3 and R4) and 12V auxiliary voltage. Refined model used designations 6582 (C64) and 8580 (C128) and 9V auxiliary voltage. The original model SID chips are known for their "dirty" sound caused by suboptimal implementation of analog parts, especially the filters. The original model chips also had a lot of process variation, which made tunes perform a bit different on every chip. The refined model has cleaner sound and less process variation.

Basically SID is a three voice subtractive synthesis device, capable of multiple waveforms, tunable filtering and some special functions like ring-modulation. However, the beauty of SID is that the chip has been pushed way over the original specification for the chip.

How to use
So how do you use the SID chips?

First and foremost, you can use a Commodore 64 computer. Each computer has a chip. There is a lot of software available for C64 to produce tunes.

The easiest way nowadays is to use emulation. Libsidplay2 is the main library for such thing. ReSID was a project to implement better quality emulation. https://sourceforge.net/projects/sidplay-residfp/ Libsidplayfp] is a branch of libsidplay2 project that integrates a higher-quality ReSID-FP engine. Emulators are integrated to C64 emulators, like Vice, and cross-development music editors, like Goattracker.

Harder way is to integrate physical SID chips into devices. Classic commercial products that did that are: You may have noticed a certain trend with the devices? SID chips have not been manufactured since the 80's, thus there is no stock to manufacture devices in commercial volume. Only hackers, collectors and retroactivists have SID chips.
 * HardSID, a series of devices consisting of a ISA-card (original HardSID and Quattro model) and USB devices (HardSID 4U). Manufacturer has some trouble and devices out of manufacture.
 * Elektron Sidstation a Midi-instrument usign SID-chips. Out of manufacture, due to lack of SID chips.
 * Catweasel floppy controller, model MK3 supported one SID chip and models MK4/MK4plus supported two SID chips. These are reported to have noise in the SID output, which was attempted to be filtered in model MK4plus.  Devices are out of manufacture.

There are multiple hobbyist projects that use SID chips:
 * Hybrid SID player, SID attached to a PIC32 to create a portable SID player.
 * Midibox is an open source project with a custom non-commercial license.
 * Midibox platform SID module, SID module a part of Midibox playform.
 * Midibox SID SID-based MIDI synthesizer.
 * SammichSID, Midibox SID "no-excuses" model kit. Out of manufacture.
 * Shops that sell Midibox kits and ...