vcsbeatbox - an Atari 2600 drum machine copyright 2024 Sam Brauer aka Faux Woodgrain on AtariAge forums Classic drum machine step sequencing for your Atari VCS/2600. Make lo-fi beats with the raw Atari sounds you love. This isn't a game. There are no enemies. There is no score. There is no death. Just make beats and have fun :) WARNING: This program may potentially trigger seizures for people with photosensitive epilepsy. Viewer discretion is advised. Be sure to start the program with Left Difficulty Switch set to B to disable flashing effect. Feature overview: - step sequencer with 16-step drum grid - controlled with two joysticks (no keypad needed) - 4 tracks: kick, snare, hihat and misc percussion/synth - 3 patterns can be arranged into a longer loop up to 16 bars long - you can make changes "live" while the sequencer is playing; only stop playback when you want to stop it - synth track can be changed to any of the sound waves or frequencies the Atari TIA chip is capable of producing - track muting - optional flashing colors (WARNING: may trigger seizures) The screen is divided into four quadrants. Three are pattern editors. The fourth is the arrangement editor. +----------------+----------------+ | | | | Pattern A | Pattern B | | | | | | | +----------------+----------------+ | | | | Pattern C | Arrangement | | | | | | | +----------------+----------------+ Each pattern represents a one bar (16 step) drum loop. Each pattern editor has 4 rows. Each row is a track of 16 drum trigger steps. The first row from the bottom is the kick. The second row is the snare. The third row is the hihat. The fourth (top) row is the synth part (by default it plays a bass note). Use the left joystick to move the cursor around the grid. Press the fire button to toggle a step. The two vertical lines are playheads. There's one pattern playhead and one arrangement playhead. Use the TV Type switch to start and stop the sequencer. Color = running BW = not running Quickstart By now you've read enough to start playing around. Just stick to Pattern A (the upper left quadrant) and ignore the Arrangement for now. Enable some steps. I'd suggest starting with a kick then maybe add a snare. These will form the backbone of your beat. If you don't hear anything and the two playheads aren't moving, change the TV Type switch from BW to Color. If you've step sequenced drums before, you should feel at home. Feeling a little lost? Try putting kicks on steps 1 and 9 and snares on steps 5 and 13 like this: ----S-------S--- K-------K------- 1 5 9 1 3 That's a solid starting point for further exploration. Steps 5 and 13 are very natural places to put the snares. (If you've ever clapped to a song, those are the beats where you would typically clap.) Try moving the second kick a couple steps to the right like this: ----S-------S--- K---------K----- 1 5 9 1 3 That small difference changes the whole feel. Try other steps or adding more kicks. Then try adding Hihats like this: --H---H---H---H- ----S-------S--- K---------K----- 1 5 9 1 3 Or maybe you want four-on-the-floor (like disco, house, techno, etc). Remove the snares and put kicks on the four beats like this: K---K---K---K--- 1 5 9 1 3 Note that there are 3 rows on the grid that you can't reach with your cursor. Those are rulers to help you visualize the step grid and the 4 beats of each bar. Play around. Experiment. Make some noise. If you want to change the tempo, hold down the Fire button then tap Up (faster) or Down (slower). When you're ready, continue reading to learn how to use the arrangement editor and other features. The arrangement editor is similar to the pattern editors except that: 1. Each step represents a whole pattern bar. 2. The bottom three rows determine which pattern is to be played. The first/bottom row is Pattern A. The second row is Pattern B. The third row is Pattern C. The pattern steps are mutually exclusive. Enabling a pattern automatically disables whatever other pattern was enabled for that step. 3. The top row contains reset triggers. When the playhead reaches a step with reset enabled, the arrangement is reset (or looped) back to the start of the arrangement. When there are no reset triggers, there is an implicit reset after the 16th step. You can set multiple reset triggers. (For example, you might have a 8 bar loop but temporarily want a shorter loop like 4 bars or less.) Setting reset on the first step is a special case. Instead of resetting immediately (which would result in a loop where no sound is ever made), the first step of the pattern is repeated resulting in a stutter effect. If you want a one bar loop, enable reset on the 2nd step. The default arrangement has all the pattern steps set to A and a reset on the 2nd step. In other words, the default arrangement loops pattern A over and over. The idea behind the arrangement is that you will create one "main" pattern and one or two variations or breaks or fills. You can then arrange those patterns into a bigger pattern. Here are some example arrangements (where R=reset): ABR (2 bar loop that effectively combines patterns A and B into a 32-step pattern) AAABR AABBR AABCR ABACR AAABAAACR ABABABACR AAAAAAABAAAAAAAC (all 16 bars with implicit reset at end) AAABAAABAAABAAAC (ditto) These are just examples. You don't have to start with A. Use the Reset switch to move the playheads back to the start of the arrangement and the first pattern at any time. Holding down the left Fire button while pressing Reset will reinitialize/clear all pattern and arrangement data. Use the Select switch to make random tweaks to the 3 non-synth drum parts. Since the changes are random and the tweaks are small, you may not hear a difference. Just press Select again till you like the sounds. You can return to the default drum kit by holding down the left Fire button as you press Select. You can change the speed/tempo with the left joystick. Press and hold the Fire button to enter time mode. While continuing to hold the button, tap Up to speed up or Down to slow down. Release the button when you're done changing the tempo. Use the Left Difficulty switch to enable (A) or disable (B) "flash" mode. WARNING: Flash mode at fast speeds may produce a strobe effect. Synth part The Synth part can make a wide variety of sounds. You can use it as another percussive sound or as a bass or melodic sound. Use the right joystick to change the Synth sound settings. Tap the Fire button to (randomly) change the sound wave. Some of the options are noise or rather dissonant. You'll hear a lot of familiar Atari tones. Note that the actual audio frequencies may vary from sound to sound. That's just the way the Atari TIA works and gives the VCS/2600 audio its unique character. Tap Right to raise the frequency (or pitch). Tap Left to lower the frequency. Note that the upper and lower values wrap around. In other words, if you keep tapping Right you'll eventually get to the highest frequency. Tapping once more will wrap around to the lowest frequency. Tapping Left past the lowest frequency will wrap around to the highest. If you continuously hold Right or Left, the values will continue to change until you release the stick. Pro tip: You can play simple melodies or basslines by moving the pitch up or down as your sequence is playing. Pushing Up or Down slides (or pitch bends) the frequency up or down while you hold the stick. When you release, the pitch will reset to its original value. Try adding slides to accent certain beats or add interest. The synth part also has an LFO which is enabled with the Right Difficulty switch (A = enabled / B = disabled). The LFO is a sawtooth that ramps the frequency up or down. The direction and the depth of the LFO is randomly set whenever you press the right joystick Fire button to change the synth sound. You can control the LFO rate by tapping Left (slower) or Right (faster) on the left joystick while in time mode (entered by holding down Fire on the left joystick). Hold left or right to make bigger jumps. The fastest rates are useful for sound effects. Slower rates (around the length of a single step or longer) can produce interesting note patterns. Try experimenting with the LFO rate and the tempo to see how they interact. When they are the same it sounds like a chromatic sequence or arpeggio. When the two are out of sync it can sound drunk or seasick, but you can find sweet spots that sound sick (in a good way). Try doing slides and changing the synth pitch while the LFO is enabled to create more effects. Mute Mode You can disable (or mute) each of the four tracks independently. Use the right joystick to mute/unmute tracks. Press and hold the Fire button to enter mute mode. You will see four (flickery) boxes to the left of the Pattern A tracks. A solid box indicates an enabled (unmuted) track. A hollow box indicates a disabled (muted) track. While continuing to hold down Fire, tap the joystick in one of the four directions to toggle the enabled/mute state. Down = Kick Left = Snare Up = Hihat Right = Synth The hollow box indicators will remain on screen after releasing the Fire button for any muted tracks as a visual reminder that they are muted. Technical notes The Atari's TIA chip has two audio channels so at any given moment only two different sounds can be produced. What happens if you enable more than two tracks for the same step? Priority is given to the top tracks (in other words, synth has the highest priority and kick has the lowest). Muted tracks have no priority. The frequencies that the TIA chip provides are not very musical. Very few of the values match up with frequencies that you're used to hearing in music ("12 tone equal temperament"). Refer to Paul Slocum's excellent "Atari 2600 Music And Sound Programming Guide" for more information. It was an invaluable reference for me while developing vcsbeatbox. https://www.qotile.net/files/2600_music_guide.txt The tempo in vcsbeatbox is not in terms of BPM (as it would be for a "normal" drum machine or sequencer). Instead the tempo is set in terms of the number of times the screen is redrawn per step. The fastest setting is 1 redraw per step. This is pretty crazy fast. You can make the tempo really crazy slow too: all the way down to 32 redraws per step. The default is 8 (not too fast or too slow). The default LFO rate is also 8, so by default the LFO is synced with the tempo. You can increase or decrease both together to keep them in sync if desired. If they get out of sync and you want them back in sync, just use your ears as you make adjustments.