Interview with Bob Yannes, creator of the SID chip (1996) | Hacker News Reader

Interview with Bob Yannes, creator of the SID chip (1996)

web.archive.org

97 pointsmmastrac28 comments

It's really amazing that he claimed to not have heard any music by famous composers on the platform.

I mean, it's not as if the world woke up in 2007 and thought "whoa, we can make cool music on this old computer" -- many of those (if not all, I'm no expert) composers were active in the 80s when the C64 was current, and it's hard to imagine him not seeing any of the hit games that came out on the computer he designed.

The quote in question:

  Have you heard the tunes by Rob Hubbard, Martin Galway, 
  Tim Follin, Jeroen Tel, and all the other composers ?


  I'm afraid not, are recordings available in the US?

I don't really know why, but that makes me feel sad.

1996. Before you could listen to every kind of music from everywhere at any time on Youtube.

But he is still alive, isn't he? I hope he has heard the tunes by now. With sites like https://c64audio.com/ and Kickstarter projects like https://www.kickstarter.com/projects/c64audio/back-in-time-s... there has been quite some public visibility of SID music.

For what it's worth I'm sure he's aware of music made with his later inventions at Ensoniq (which made the first low-cost sampler, as well as some of the most popular synths of the digital era of electronic music...huge swaths of the late 80s through mid 90s owe their sound to Ensoniq synths and samplers). The SID was a breakthrough for microcomputers, but it wasn't widely appreciated in the music industry, but his later work certainly was.

I used to put a tape recorder up against the TV to record C64 game music :)

What the hell happened to video game music though? It used to be fun and not afraid to sound nothing like any other genre. How did we go from (1) (2) to the sterile sameness where everybody tries to imitate either Hollywood'ish orchestra, hiphop or mainstream rock? I have to go far into the past to recall the last time the soundtrack of a Western game stuck with me.

1: https://www.youtube.com/watch?v=FA95o7RNjqA

2: https://www.youtube.com/watch?v=b68n5FZ1ASg

Nothing happened. Great game music is still being made. FTL [0] has an awesome soundtrack. As does RimWorld [1].

[0] https://www.youtube.com/watch?v=QBES0jOmbCs&list=OLAK5uy_noi...

[1] https://www.youtube.com/watch?v=uFzPW2mlg28&list=PLh4Eme5gAC...

This might be a little reactionary to say, but I think constraints breed creativity. I have noticed there's kinda a line in the sand temporally where not just game music but most music exhibits a cambrian explosion in quantity but not necessarily differentiation. I may have posted this [1] before but I think it's a great read, and you can likely see parallels between the points it makes in pop music as in VGM.

[1] https://thebaffler.com/downstream/streambait-pop-pelly

Civ IV won a BAFTA award for its music, but that was a while ago now. I think this is just a side-effect of AAA stagnation; everyone's trying to make the same game within a very narrow target market. Meanwhile in the Wild West of monetisation the cutting edge is A/B testing your loot box gambling systems on children.

It's still possible to find great creativity, but it's less likely in the mainstream.

Just off the top of my head, these are some stand-out soundtracks from the last while:

https://www.youtube.com/watch?v=vAzIuxldPhE

https://www.youtube.com/watch?v=CunwtlgsU1U

https://www.youtube.com/watch?v=uhesDs6FWpo

If you want music that sounds videogamey but isn't in an actual videogame:

https://elmc.bandcamp.com/track/ridebreak-170

https://archive.org/details/Hadron_Collider/TDS010/2)+Lacera...

https://www.youtube.com/watch?v=qtSJA_U4W1U

I mean taste in music is subjective but theres a lot of games out there with bomb soundtracks. Triple A games often have ambience instead of music so you'll have to look into solo projects or indie games. Here's a couple examples I really enjoyed.

[1] FTL OST https://www.youtube.com/watch?v=9pKamecDZco [2] Bastion OST https://www.youtube.com/watch?v=qPWmrwF4MOI [3] Transistor OST https://www.youtube.com/watch?v=41tIUr_ex3g [4] Cave Story https://www.youtube.com/watch?v=q09KoR7g018

Excerpts:

"The SID chip was my first attempt at a phase-accumulating oscillator, which is the heart of all wavetable synthesis systems."

[..]

"It's pretty brute-force, I didn't have time to be elegant. Each "voice" consisted of an Oscillator, a Waveform Generator, a Waveform Selector, a Waveform D/A converter, a Multiplying D/A converter for amplitude control and an Envelope Generator for modulation. The analog output of each voice could be sent through a Multimode Analog Filter or bypass the filter and a final Multiplying D/A converter provided overall manual volume control.

As I recall, the Oscillator is a 24-bit phase-accumulating design of which the lower 16-bits are programmable for pitch control. The output of the accumulator goes directly to a D/A converter through a waveform selector. Normally, the output of a phase-accumulating oscillator would be used as an address into memory which contained a wavetable, but SID had to be entirely self-contained and there was no room at all for a wavetable on the chip."

I've heard people have decapped these and even recreated (in some fashion) versions of the masks, or circuit layouts. I'd love to figure out how to start a project making actual chips.

Because the SID deals with analog as well as digital signals, it's not that easy to clone, however you can get fpga versions such as the SwinSID - https://www.c64-wiki.com/wiki/SwinSID

Unfortunately, the SwinSID (and similar) do not sound anything like the original chips when playing music.

Consequently SID chips are quite expensive to buy (relative to what they are) - any effort to accurately clone a SID chip would be welcomed, as it will drive the cost down of these chips on ebay etc.

Sorry to be picking a nit here but the SwinSID is not FPGA based, it's a software emulator running on an AVR mcu.

There is an FPGA based version of the SID called (surprise) FGPASID (http://www.fpgasid.de/) which is pretty much indistinguishable from an original SID. The only real downside to it is the cost, it's not a cheap one.

The FPGASID was created by decapping and reverse engineering original SID chips and the result is pretty spectacular.

> Sorry to be picking a nit here but the SwinSID is not FPGA based, it's a software emulator running on an AVR mcu.

I sit corrected :)

>it's not a cheap one

80€. You're right, it's not cheap, but I actually expected much worse.

Wow, didn't know normal SID chips went for about $40,- nowadays.

And, it emulates two SID chips and has multiple modes (6581 and 8580), so it seems like a pretty darned good deal, honestly.

Real SIDs are pretty pricey these days, and they aren't making any more of them, so they will keep climbing in price for as long as people find them interesting. So, it's good to have an alternative.

There are other, newer alternatives, and they are getting difficult to distinguish from a real SID, especially given no two SIDs sound the same - e.g. http://dzi.n.cz/8bit/arm2sid/index_en.php

Original SID chips are often semi-broken as well. I had a few when they were cheaper and I was building a midibox SID. Most had weird VCA issues or oscillators leaking to the output always. Stuff like that. If you end up with a half decent one the oddities just become part of the charm.

There were two variants of the SID. The early one ran on 12v and the latter on 5v. As I understand it, the reduction in voltage greatly improved their reliability.

More than just the voltage, the 8581 had significantly revised circuitry and better opamps due because they had much more silicon area and a better process available.

It sounds disnctively different too.

Here is someone's heroic effort in reverse engineering the SID chip from decapped die shots, containing almost complete schematics of the entire chip [0], both the digital parts (oscillators, control logic) and the analog parts (filter, envelope, mixer).

Unfortunately, re-creating a SID chip is almost impossible given that we don't have 1970s era NMOS semiconductor manufacturing facilities available. It is very difficult to build analog circuitry with similar characteristics from discrete components or modern IC technology.

For example the filter section (see page ~9 of the forum post) is a dead simple state variable filter with 4 operational amplifier (opamp) stages and just a handful of resistors and capacitors. But the opamps in the original 6581 were not real opamps, but something hacked together from 3 MOSFET transistors due to silicon area constraints. The later revision SID (8581) had something more like an opamp, but SID enthusiasts claim it "doesn't sound as good" (and it definitely sounds different).

For a hobby synth project, I re-created the filter section with a standard quad opamp chip (TL084 or similar), and sure enough it behaves like a filter, but it doesn't sound like the original (the resonant peak is way too sharp). In particular, the original filter changes frequency response with the amplitude of the incoming signal.

If you look around the web, you can see several attempts at re-creating the circuitry (the filter in particular), but it's darn difficult to re-create it faithfully. And the original design is not a great musical filter design, its character is almost entirely due to the characteristics of the manufacturing process and the "bad" ompamp circuitry. For creating analog filters, the Moog transistor ladder and other classic synth circuits easier to get good sounds out of.

[0] http://forum.6502.org/viewtopic.php?f=8&t=4150

> Unfortunately, re-creating a SID chip is almost impossible given that we don't have 1970s era NMOS semiconductor manufacturing facilities available.

Do you have any idea how hard that would be to recreate? Would it be in the realm of possibilty for an ambitious amateur to fabricate a chip? (Maybe even if not something as relatively new as a SID, possibly something simpler?)

An ambitious amateur could probably figure out how to fab a chip of the same complexity in small quantities (using e.g. electron beam techniques), but I think recreating the process faithfully, with the same parameters and variation as the original process, would be almost impossible for anything short of a major corporate R&D project.

Jeri Ellsworth (who is far beyond "ambitious amateur") managed the first home CMOS process a few years ago, and I think the state of the art has advanced to about 1975 tech: http://sam.zeloof.xyz/first-ic/

It's a lot of work, obviously, and requires a big set of interdisciplinary tools.

I had an Ensoniq Mirage. When it didn't overheat, it was great for 8-bit 32Khz audio with analog filters.

Reply on news.ycombinator.com