Gear: The Sound of the Legendary SID Chip, Part 1

May 26, 2009 6:56 PM, By Ben McFarlane

In January of 2008, one of the most deranged music videos ever seen hit YouTube's featured videos rotation. It was called “Kokiriko Bushi,” an electronic re-make of a traditional Japanese song of the same name, produced by Omodaka of Japan's Far East Recording. The video – a puppet skeleton busting David Elsewhere's dance moves amid a strobing phantasmagoria of blue lights, disembodied hands and eyeballs – was impressive, but what really grabbed my attention was the song. Pretentious, yet clever – Kokiriko Bushi glitters with glitchy, low-bit timbres that take me back 24 years. In 1984, I was a pre-schooler, and spent hours atrophying in front of my Commodore 64, grooving to the themes of my favorite games: Commando, Archon, Gyrus. I thought of those sounds strictly as game music: ultimately not music at all, but I still loved them. I loaded Archon and Commando just so I could listen to the theme songs, and Gyrus was one of my favorite games because of the riveting techno-classical riffs and low-bit drum solos that accompanied the game-play. All those wry bleeps and blips come from a tiny integrated circuit: the now-legendary Sound Interface Device, or SID chip. The SID chip was designed for the Commodore 64 by engineer Bob Yannes (also founder of Ensoniq) in the hopes it would find widespread use in electronic music. This groundbreaking chip shattered the precedent that Atari and Intellivision set for inflexible sound chips and opened a new channel for unique and inspired music synthesis from every imaginable genre. A quarter of a century later, the SID has garnered a sizable sub-culture, appearing in the work of countless contemporary artists, including Timbaland, Diplo, 50 Cent, Trent Reznor and even Madonna. Yannes couldn't have hoped for higher accolades. The SID chip employs three digital oscillators, one programmable filter, ring modulation and oscillator synchronization. Each oscillator can use one of four waveforms: sawtooth, triangle, variable-width pulse and noise. Everything can be routed through the SID's analog filters and exits the chip through an analog audio output. Though it sounds dreadfully simple, it was an instant success, and it remains an icon of electronic music as one of the cornerstones of the feisty 8-bit (aka Chiptune) genre (YM Rockerz, 8 Bit Weapon and many others). There are several ways to equip your studio with a SID; some approaches are user-friendly, and some are user-hostile. To help the prospective buyer avoid the numerous pitfalls and dead ends of the SID universe, I've explored every feasible road to SID synthesis, including software emulation, stand-alone hardware and -- in Part 2 of this feature -- Commodore 64 direct MIDI interface hardware. Which path you choose will depend on your sense of authenticity, tolerance for noise, budget and patience.

Software Emulation

Software emulation of the SID falls under two broad categories; SID emulation for the purpose of producing music, and SID emulation for the purpose of listening to music. You can find the latter category embedded in C64 emulators such as the CCS64 (Freeware) or VICE (Freeware), the latter of which uses the ReSID emulator. ReSID is the most accurate software SID emulation, but so far is incompatible with real-time MIDI control.

Since programming the emulators to make music requires using Commodore Basic string command programs (which might have been fun 25 years ago,) I quickly gave up on full C64 emulators, and searched for something that could give me instant gratification: VST plug-ins. There's about a half-dozen VST instruments that approach the SID sound. None of them achieve it exactly, for reasons I explain below. However, these VST emulations have distinct advantages, and using them is a joy.

De La Mancha MiniSID

I started small: De La Mancha MiniSID (Freeware) is a plug-in that uses triangle saw, and square waves sampled from a 6581 chip in its two oscillators. There are three arpeggiator patterns with adjustable speed and octave range functions. I like this plug-in for its simplicity; it's a basic yet effective arpeggiator, but not a serious emulation.

• MiniSID audio example 1
• MiniSID audio example 2

I discovered numerous free plug-ins: DrSID, essentially a MIDI drum kit using diverse SID-based patches; SE64, which crashed Ableton Live 7 the first time I tried to use it; and Time Machine a handy bit/sample rate reducing plug-in. But I needed something with better emulation and control over parameters.

ReFX QuadraSID

By far the most extensive SID-based software is QuadraSID ($54.99; refx.com). QuadraSID emulates four SID chips operating simultaneously. Rather than striving for a straight emulation of the original SID, ReFX made its SID synthesis the core of a VSTi whose capabilities mark a significant departure from the original SID. Along with four editable envelopes and four LFOs, the QuadraSID also adds one oscillator per emulated SID, creating a total of 16 possible voices (though in the presets all 16 are rarely used.) The most interesting feature of QuadraSID to me is its Combiner section, which allows for hybrid modulation signals by using various rules to combine two modulation sources, routing them as one to a common destination.

The GUI is a bit daunting because of the scale and complexity of its capabilities, but it is well-organized, and easy to learn. Though I was happy to have found QuadraSID, the voices in its presets sounded a little too polished -- not like the original. On top of that, I was getting distracted; instead of using QuadraSID to create classic SID sounds, I became absorbed with drawing in my own envelopes, testing Combiner rules and the using the Wavetable section as a coarse step sequencer. It was loads of fun, but still not quite what I was looking for.

Odosynth Emulators

The virtual instruments that best match the original SID are free plug-ins called 38911Bytes and Unknown 64 Pro (donationware; www.odosynths.com). Both devices contain a retro GUI reminiscent of the C64. 38911Bytes, named for the amount of free memory displayed on a Commodore 64 screen upon startup, was more user-friendly. Both programs deliver great emulation of the SID oscillator and modulation sections. Instead of emulating the filters, Unknown 64 Pro adds bit crushing, pan and even a MIDI learn function. To me, these two instruments sound more like a true SID than QuadraSID does.

• 38911 Bytes audio example 1
• 38911 Bytes audio example 2
• 38911 Bytes audio example 3
• 38911 Bytes audio example 4
• 38911 Bytes audio example 5
• 38911 Bytes audio example 6
• 38911 Bytes audio example 7
• Unknown 64 Pro audio example 1
• Unknown 64 Pro audio example 2
• Unknown 64 Pro audio example 3
• Unknown 64 Pro audio example 4
• Unknown 64 Pro audio example 5
• Unknown 64 Pro audio example 6
• Unknown 64 Pro audio example 7

The software emulators provide an approximation of a widely idealized sound, but they're only a small part of the SID picture.

Modern Stand-Alone Hardware

Why use a real SID chip when perfectly stable software emulations can run from within your PC or Mac? In short, the reason is filtration. The analog filters of the SID chip, especially the earlier 6581 chips, would distort when saturated. It was a completely unique, lo-fi, yet organic-sounding distortion that only the 6581 chips (and to a lesser extent 8580 chips) can produce. Emulating the SID filter is a complicated game; the aforementioned ReSID is the only emulation that made a serious attempt, but so far no one has devised a facsimile capable of appeasing the connoisseurs. For that reason, many users opt to produce SID music using stand-alone hardware with the SID at its core.

In addition to DIY kits, and a few notable independent hardware projects, there have been four commercially manufactured SID hardware systems.

Sidstation

The now-discontinued Elektron Sidstation (last purchased new for $1,050) is by far the most legendary of all SID hardware. It was the one used by Timbaland on Nelly Furtado's Loose, and it is still the best-known SID device. This was Elektron's first synthesizer, and shipped with one pre-installed SID chip (expandable up to four). Since the SID contains three oscillators, the SID Station could be used as a single oscillator synth with three-note polyphony, or as a monophonic three-oscillator synth. Since it was discontinued, finding one for sale has been rare, but if you watch Ebay for long enough, you might get lucky. (At the time of writing, one is listed there for $1,299.99) Though this model is now a classic, its expense can only be justified by its collector value, because newer, more stable SID Hardware is available from Elektron and others.

HardSID4U

The HardSID 4U ($380, or $500 for the Studio Edition) comes from the European design team HardSID, and is probably the second most reputed stand-alone SID hardware. It is controlled by a VST interface, and it's the only SID hardware that can act as a modulation source for other VST audio outputs. As Teli Sandor of HardSID explains: “...you can then use that modulation source [any] way you want to in the modulation matrix. You can also use it in combiners to calculate complex signals using multiple modulation sources... You can do really wild things with it.”

The HardSID 4U has a lot in common with the SID Station. First, it's capable of routing an external signal through the filters, an excellent feature given the eminent status of the SID chip's filter distortion. In addition, the HardSID 4U Studio Edition employs noise reduction circuitry similar to that of the SIDStation, since the SID is notoriously noise-prone. At half the price of a used SIDStation, the Studio Edition is well worth its asking price.

When I was searching for hardware to review, the HardSID 4U was shipping without a SID chip; you had to supply your own. This is an important topic; you don't want to get a bad SID. Extracting a hard-soldered IC from a circuit board is next to impossible without damaging it, but used SIDs are frequently sold on Ebay. Though in 2007 there was a rash of fake SID chips, as long as you check seller histories, and make sure the SID has been tested, you should end up with one that works.

Readers who are interested in the HardSID will be happy to know that currently they are well stocked with 8580 chips that you can buy for an additional $20. Though you can only buy two 8580 chips with any HardSID, the HardSID can accept up to four. For that reason, the HardSID ships with extensive documentation on installing and removing the SID chip, and it looks quite easy.

Elektron Monomachine SFX-60 mkII

The only stand-alone hardware I could get my hands on when I started writing this feature was the Elektron Monomachine SFX-60 mkII ($1,540), and it is a truly awesome piece. It draws from an array of diverse synthesis methods ranging from AM synthesis to analog emulation to our beloved SID.

Right away, however, I found that the Monomachine came up short as a SID Synthesis module. Perhaps the only advantages it has over other stand-alone hardware is its extremely low signal-to-noise ratio, and its self-contained operation (you don't have to use a VST-based controller).

The problem with the Monomachine is it uses only one SID oscillator, moreover the oscillator is an emulation instead of a real SID chip, hence no there's no filter distortion. Still, the Monomachine's own distortion paired up quite well with the SID oscillator and LFOs. All-in-all, I was satisfied with the emulation. The Monomachine uses comparatively few parameters to control its SID machine, but that's mainly a function of its using one oscillator. I could still switch between the four SID waveforms, change the pulse width and assign modulation and LFOs, wielding the classic SID timbres -- real enough.

Despite all that, SID synthesis is maybe 10 percent of the Monomachine's job. It's a solid synth module worth its heavy price tag, but not if you simply want a SID machine.

• Elektron Monomachine SFX-60 mkII audio example 1
• Elektron Monomachine SFX-60 mkII audio example 2
• Elektron Monomachine SFX-60 mkII audio example 3
• Elektron Monomachine SFX-60 mkII audio example 4
• Elektron Monomachine SFX-60 mkII audio example 5
• Elektron Monomachine SFX-60 mkII audio example 6
• Elektron Monomachine SFX-60 mkII audio example 7
• Elektron Monomachine SFX-60 mkII audio example 8
• Elektron Monomachine SFX-60 mkII audio example 9
• Elektron Monomachine SFX-60 mkII audio example 10
• Elektron Monomachine SFX-60 mkII audio example 11
• Elektron Monomachine SFX-60 mkII audio example 12

So is there any stand-alone hardware that ships with a SID and won't cost you your soul? Fortunately, yes.

HyperSynth HyperSID

The HyperSynth HyperSID ($299) is the newest addition to the ranks of SID hardware manufacturers. At the time of the writing, its HyperSID hardware was in stock and shipping with the SID on board, ready to plug and play.

Like the HardSID 4U, you control the HyperSID using a VST GUI. At a glance, I prefer the HyperSID GUI to the HardSID because it is well-laid out, and the smooth green graphics are very easy on the eyes. The HyperSID VST software also adds an improved modulation matrix, a software-based LFO section and a flexible step LFO section. User presets are stored in the software and can be loaded from any VST 2 host, SSL, Pro Tools, etc. Although the HyperSID cannot support multiple SID chips, it does provide true SID synthesis with a low cost, convenient package and a few bonuses thrown in. It's also available in a rackmountable version.

Read Part 2 of this feature to learn how to trigger a Commodore 64 via MIDI.

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