Commodore Free 12/Commodore_Free_Issue_12_2007_Commodore_Computer_Club.d64/t.sid special

Text File | 2007-01-01 | 16.4 KB | 493 lines

uSID STILLS SOUNDS SO SPECIAL
By Andrew Fisher

Note: this is an updated version for
CBM Free Magazine of an article 1st
published in UCUGA CBM Digest in 2003

Inside every CBM 64/128 is a special
chip. The Sound Interface Device or
6581 chip (later to be replaced by the
8580) gave it the best sound of any
8-bit machine, & has left a legacy of
music & sound that is still important.

WIRED FOR SOUND
First of all, it is important to look
at the specifications of the chip
created by talented CBM engineer Bob
Yannes. 3 separate channels of sound
can play at once, giving depth & range.
Each channels envelope (shape of the
sound) & waveform (structure of the
sound) can be set independently or,
through the synchronisation & ring
modulation registers, work together to
create a new type of sound. There is
also another feature, the filter, which
can dramatically alter the tone &
resonance of a sound. At the time it
was only an option on expensive synth-
esizers or through sound editing, but
as we shall see there are drawbacks to
its use.
Finally, it is important to talk about
sound output. From the start SID had an
advantage the audio/video port on the
64 allows connection to exterior audio
equipment or a monitor for better
quality output. That same port also
allows an exterior INPUT into the SID
chip, which was uncommon at the time.

SCALES
The earliest form of SID music was a
BASIC program. Notes were stored as
DATA, read into an array & played back.
Many of these programs used a frequency
table to generate output, relying on
mathematical properties of sound. This
also meant the data could be entered in
something approaching musical notation
a note could be stored as C4, read back
by the program & converted into numeric
values that SID needed. There were many
programs like this, transcribing famous
music such as Rhapsody in Blue or
classical works.
CBM also worked on peripherals that
allowed the user to make music the
earliest being the Music Maker keyboard
overlay. This plastic frame fitted over
the computer keyboard & looked like a
piano keyboard. Pressing the approp-
riate key underneath. Later came the
play-along albums, & the more advanced
Sound Studio. The full-sized keyboard
that came with the Music Expansion
System (promoted by famous keyboard
player Rick Wakeman) works with the
Sound Expander cartridge & its built-in
Yamaha FM chip. While the software was
limited, the output was very high
quality for the time.

EFFECTS
Another area the SID chip excelled in
was generating sound effects. Early
arcade games had relatively simple
beeps, which developed into more real-
istic noises by the time the 64 came
along. The C64 could replicate them
perfectly, & even improve on them. By
combining different voices complicated
sounds like sirens & ticking clocks
were possible. One pertinent example is
the game CHAMELEON by Martin Walker. As
you play you will hear dripping water,
roaring fires, ticking clocks & many
other clever sounds. To start with,
many programmers did everything music,
code, graphics. Then a few talented
individuals became famous for their
music, & were employed solely on that
basis. Years later,their names are
still important Rob Hubbard, Martin
Galway, David Whittaker & the late (and
sadly missed) Richard Joseph.

REGISTERS
Of course, controlling SID was never
easy. With 30 different registers
(including the read-only settings) &
many of them doing multiple tasks,
there had to be an easier way.
Machine code & the design of the 64
offer an excellent way to reproduce
music. Using the raster register, SID
can be updated as fast as the TV screen
(50 or 60Hz depending on the broadcast
standard). So, the earliest musicians
wrote their own player routines, enter-
ing the note data in an assembler &
playing it back, each frame of the
screen update changing SID values. More
complex sounds could be generated,
leading to better tunes.
The next step forward was a dedicated
editor that allowed you to use the
music it produced in your own programs
Among the earliest was ELECTROSOUND,
which changed the jargon. Instead of
voices, we now had 3 tracks, just like
a recording studio. Each tune was built
up of sequences, allowing you to repeat
sections of the tune. The only drawback
was it used large amounts of memory.

When the demo scene started in Europe,
there was a need for more music. The
fledgling Compunet network saw lots
of demos featuring music ripped from
games, but now people wanted to start
composing their own. Along came
utilities like FUTURE COMPOSER & JCH
EDITOR, allowing more people to write
their own tunes & to cover real music.

SIDPLAYER
Craig Chamberlain was also an
important name for SID; in a book on
programming from Computes Gazette he
published the SIDPlayer format & the
editor.Now it became easier for USA
music fans to cover their favorite
songs or compose their own music.
Over time the format & the accompanying
player application developed. At first
you could read info on the tune & see
the notes on a piano keyboard. Later
players added options to see an
accompanying picture, read the lyrics
as the song played, & even hear the
tune in stereo (with the addition of a
second SID chip more on that later)
SIDPlayer music is still used by the
Loadstar disk magazine, & a large
Internet archive of the tunes exists at
www.c64music.co.uk.

FREE SPEECH
Another interesting development in the
early years of the C64 was speech
synthesis. CBMs Magic Voice & Currah
Speech cartridge plugged into the
expansion port & the audio/video port
(remember  I mentioned the external
input) to allow programs to create
speech. Words & phrases are broken down
into phonemes, short groups of sound,
& spoken by an artificial voice. The
next step was software synthesis, with
games like IMPOSSIBLE MISSION & BEACH
HEAD II reciting memorable phrases such
as Another visitor & Medic! Im hit
There was also the fantastic GHOST-
BUSTERS game by David Crane of Acti-
vision, whith several speech samples &
Sing-Along version of the Ray Parker
Jr. theme tune that displayed the
lyrics onscreen with a bouncing ball

Then another technique became
available. The new digital music format
of compact discs gave programmers the
idea to break sounds into bits of data.
A rapid series of clicks & silences can
then re-create sounds. This is samp-
ling, & the CBM can do it too. CBMs
own Sound Sampler, the high-quality
Microvox unit & the Datel Sampler all
allowed you to use a microphone or line
input to sample sounds into memory &
play them back. Typically only a few
seconds could be captured due to the
limited memory of the 64.

ONE, TWO, THREE
Of course, someone took it a step
further. How about playing digitised
sounds at the same time as SID music?
Games that talk like I, BALL & SLIMEYS
MINE have a lot of atmosphere generated from their funny samples. Then along
came ROCKMONITOR, giving a 4th track
for digitised sounds to play alongside
a SID composition. And the conversion
of arcade smash hit TURBO OUT RUN has
2 amazing tunes with digitised sounds,
ranging from speech samples to scratch-
ing records & all sorts of percussion.
It was created by Maniacs of Noise,
famous for their demo tunes & later
work on many hit games.

BACKGROUND MUSIC
At first, demos just played the music.
Later routines allowed music to fade in
or out, so the demo faded in or out
with it. Timing effects to music was
also popular, from a simple graphic
equaliser flashing in time with the 3
channels, then on to larger movements
of whole pictures. The game DELTA also
added a new phenomenon MIX-E-LOAD a
clever piece of software that allowed
you to mix drum & music patterns while
the main program loaded With the
invention of the IRQ-loader, music
could carry on while something was
loading from disk. That also led to the
development of the trackmo (track-demo)
with its continuous effects. Epic
pieces of music lasting many minutes
were required, often in techno style.

MIDI
While the C64 did not contain a MIDI
port like the Atari ST, interfaces
soon appeared to take advantage. Prog-
rams like the Advanced Music Studio can
playback or record from a MIDI key-
board, while more advanced software
from companies like Steinberg turned
the 64 into a basic recording studio.
One drawback is that there is more than
one type of interface available, & they
are not compatible with each other or
the software. One of the rarer items to
look out for is Moog Sound Producer,
which came with its own software & no
less 4 MIDI OUT ports.

THE SAME, BUT DIFFERENT
In 1987, CBM introduced a new model the
64C. As well as changing the outer case
(from the classic breadbox style to a
sleeker off-white) there were differ-
ences inside. Most dramatic was the SID
chip no longer the 6581 SID but a newer
8580 model. There were also changes on
the board, meaning you cannot put an
old SID into a 64C & vice versa. Even
the manual was different, missing sync
& ring mod features.

Most dramatic was the effect on
samples. The new chip was quieter in
that it suppressed voltage noise
better. This meant that samples
sounded very faint on the new chip, so
you had to turn up the volume on your
monitor/TV to hear them. (There are
ways round this, including a technique
called digiboost).The 128 has a similar
problem, in that accessing multiple
waveforms on the same voice can cause
the channel to lock or sound at a very
low volume.

FILTERS
This also brings us nicely to a disc-
ussion on filters. A filter is a way of
altering the sound passed thru it, &
the 64 has 4 types.LOW PASS means
anything below the set frequency is
unaltered, above it is filtered. HIGH
PASS does the opposite. BAND PASS
accentuates a narrow range of freq-
uencies, while combining LOW & HIGH
PASS creates a NOTCH filter, passing
only a narrow range of frequencies (the
opposite of BAND PASS). The RESONANCE
level affects filter strength.

The trouble is, filters are different
on every machine. As they are analogue
rather than digital, effectiveness
changes as the chip heats up. CBMs
official line was that the chips could
vary by as much as 20% between machines
& that it was an acceptable margin to
work within. Some games & demos allow
you to alter the filter, or they detect
which model of SID chip is being used &
alter the soundtrack accordingly.

EDITORS
In time, editors became more complex
with more commands. These included
trackers like VOICETRACKER, the Dutch
USA Teams MUSIC ASSEMBLER & the famous
DEMO MUSIC CREATOR (DMC). As musicians
stretched them, new & updated versions
of these tools would regularly appear.

The language of all the editors is
similar. You create PRESETS or
INSTRUMENTS or SOUNDS these are the
collections of settings for the SID
registers. Each of the 3 TRACKS is
built up of SEQUENCES, which can be
repeated or transposed. Each SEQUENCE
is a series of COMMANDS (e.g. SND00 to
change to SOUND 00, DUR08 for a note of
duration 8 beats) & NOTES (D#4, C-4 &
so on). Even today, new editors are
being written. Recent additions include
the PC based NINJA TRACKER & the
excellent SID DUZZ IT (SDI).

LIFE AFTER DEATH
When the commercial life of the 64 came
to a close, the music lived on. First
came a clever Amiga demo featuring
converted tunes. Then came SIDPlay, a
utility for playing individual tunes.
This was later ported to many different
operating systems including PC, MACs &
UNIX. Alternatives include SIDAmp plug-
in for Winamp, & Deliplayer. Websites
appeared devoted to music, composers &
keeping the spirit of SID alive. Among
the most successful is the HIGH VOLTAGE
SIDCOLLECTION at www.hvsc.c64.org,
which now contains over 30,000 SID
files from games & demos. Working
alongside the collection is the SID
TUNE INFORMATION LIST (STIL), telling
you more about each tune, the composer
& identifying which tunes are covers

There are also many fascinating bits of
trivia contained in STIL, contributed
by the composers themselves or the
dedicated HVSC team, & most SID players
will display the text as a tune plays.
If you want to see what the composers
look like, check out composers.c64.org
for Peter Sandens archive of photo-
graphs & choice of the best tunes. HVSC
also links up with the incredible
Gamebase collection, allowing you to
play a SID from a game & see a picture
of the composer.
There are also devoted fans remixing &
re-making their favourite SID tunes
using new technology & musical equip.
From straightforward covers to modern-
sounding dance mixes with vocals to
orchestral interpretations, there are
remixes of every sort. REMIX64
(www.remix64.com) & RKO( remix.kwed.org
maintained by Jan Lund Thomsen)
continue to be the showcase for amazing
new takes on old SID tunes. (The recent
controversy over producer Timberlakes
use of a sampled 64 tune in a song for
Nelly Furtado is an example of how the
scene stays together, & how the out of
date machine still influences music)
You can even buy remix CDs, mainly
thanks to the efforts of Chris Abbott.
Chris used his experience in studio
work to create BACK IN TIME, the first
ever remix CD. More have followed,
along with CDs published by Chris for
other artists. Reyn Ouwehand, a famous
composer himself, tackled Martin
Galways famous tunes & more recently
released his new album The Blithe, The
Blend & The Bizarre. Instant Remedy
made a CD of dance mixes, which sounds
like a commercial dance album. Press
Play on Tape, a group from Denmark,
play SID music on guitars, keyboard &
drums.
The REMIX64 team created a 1980 themed
CD (vol 1), remixing famous game tunes
in the style of 80s composers like
Vangelis & the Art of Noise, then
followed it up with the orchestral
splendour of volume 2 subtitled Into
Eternity. The revamped 64 Audio website
at www.c64audio.com sells many of these
CDs, along with digital downloads &
bonus tracks for those who purchase.

One of the more unusual CDs was
PROJECT GALWAY. This 2-CD set gathers
together every tune created by Martin
Galway, but it is not a remix album.
Instead every track is a recording of
the original tune playing on Martins
own SID chip. As an added bonus there
are some previously unheard tracks,
such as the soundtrack to the
unfinished STREET HAWK game by Ocean,
recovered from the original source
disks. The Digital Memories DVD
contains footage of many classic demos
along with a separate audio jukebox.

And theres more. BACK IN TIME LIVE has
been a series of events aimed at
launching the new remix CDs & getting
together the fans & composers. The 1st
2 events saw DJs mixing together SID
dance music, the 3rd had live perform-
ances from groups like Press Play on
Tape, which included Ben Daglish join-
ing them on flute for a rendition of
his tunes. Famous composers like Martin
Galway & Rob Hubbard, who both now work
in the USA, flew back especially for
the events. Heroes like Jon Hare of
Sensible Software & Jeff Minter mingled
with fans. The events also went inter-
national, with Back in Time Live
Germany & 2005s Retro Concert in
Copenhagen. The latest event in London
saw Reyn Ouwehand put on a masterful
performance of live remixing as he
played multiple instruments.

MORE, MORE, MORE
SID music does not stand still.
Multiple speed players, where the
sounds & notes are updated more than
once a frame, allow better quality.
Hardware experts worked out how to add
a second SID chip using a different
area of memory, giving you six voices
instead of 3. This also led to the
Stereo SID cartridge from CMD, which is
unfortunately no longer available. But
that didnt stop the development.

The HardSID & QuattroSID boards for PC
allow perfect reproduction of SID
sounds through an emulator or SIDPlay.
The SIDStation allows you to compose
music via MIDI, & VSTi plug-ins like
QuadraSID recreates the 8 bit sound.

CMDs SuperCPU added another dimension
to sound, with its DMA capabilities.
With extra memory & speed the use of
samples becomes easier & faster, & the
amount that can be sampled increased.
The game METAL DUST released through
Protovision proves what is possible
digitised music plus speech all playing
while large amounts of graphics are
moved around onscreen, thanks to the
power of the SuperCPUs 20MHz proces-
sor. With an IDE64 interface it is even
possible to stream music from a CD &
output it through SID.

LIFE GOES ON
As long as people are producing demos,
games & diskmags for the 64, there will
be musicians making music. As long as
demo parties continue competitions for
best music, there will be people trying
to do something new & interesting with
SID. As long as the remix community
keeps expanding & broadening horizons,
people will listen to the tunes & say,
I remember that. As long as the
Internet survives, there will be
digital data that can be converted into
melodies/sounds of SID. Its comforting.