ALESIS FUSION SOFTWARE RELEASE NOTES
Version: 1.24 Date: 11/13/06 Sound ROM: 1.
New Features/Changes: 1. Bug fixes: 1. Fixed bug where audio tracks did not synchronize properly with Synth tracks. Version: 1.23 Date: 8/8/06 Sound ROM: 1.
New Features/Changes: 1. Vast improvements to MIDI Sync. 2. Increased the tempo range by lower the minimum tempo to 30 BPM. 3. Improved response to MIDI Bank messages. It will now automatically respond to either Bank MSB or Bank LSB. 4. Locates, Rewind, and Fast-forward commands will send the following MIDI command sequence: STOP, LOCATE, and CONTINUE. 5. All Locates now send the Song Position messages via MIDI. 6. Song Position messages are now ignored while playing/recording. 7. Added an option in the Global mode (Settings-MIDI page) to listen to or ignore Song Select Messages. It will default to OFF. 8. Pressing [STOP] while a song is playing will now just stop the song and send a MIDI Stop message. Only pressing [STOP] while the song is not playing will send the All Notes Off message. Bug fixes: 2. Fixed bug where importing a MIDI song would not correctly translate songs of different PPQN. 3. Fixed bug where programs would not always load properly when loading a song with General MIDI set to ON. 4. Fixed bug where GM drum would not always map correctly. 5. Fixed bug where ARP and EQ knobs would send random MIDI messages when LOCAL is set to off. 6. Fixed bug where played notes from the keyboard would shut off in Song Mode when song would end. 7. Fixed bug where copying and pasting insert effects in Program mode would only copy and paste insert 1. 8. Fixed bug where multiple MIDI Start, Stop, and Continue messages would be sent out in song mode. 9. Fixed bug where alternate range was not working properly with external MIDI input.
Version: 1.22 Date: 3/27/06
Sound ROM: 1. Drum kits will no longer trigger the latched arpeggiator when pressing C1 (kick drum). Patterns are now triggered in areas of the keyboard without any drum sounds (at the extreme ends of the keyboard range).
New Features/Changes: 1. Bug fixes: 1. Fixed bug where storing a sample/song/program/multisample to a location at or above 256 would store to the wrong location and overwrite the item at that location. 2. Fixed bug where storing a song on top of itself with a new name would delete the audio files of that song. 3. Fixed bug where creating multiple samples and then storing them would result in samples being lost rather than stored. 4. Fixed bug where MIDI Note Off messages would not match MIDI Note On messages when the keyboard was transposed while keys where down. This would cause stuck notes to occur on MIDI applications. Version: 1.21 Date: 2/09/06 Sound ROM: 1. Added 10 new Groove mixes. 2. Added 6 new Split-Layer mixes. 3. Added 6 new programs. Two programs have been removed. 4. Added 16 new patterns. 5. Improved the playability of most Groove mixes. 6. Improved effects and EQ on most mixes. 7. Improved programs throughout all the banks. 8. Slightly re-ordered the mix and program banks. 9. Changed names of a few mixes. 10. Added sub-categories to Groove Mixes. The sub-categories describe the right-hand program.
New Features/Changes: 1. Added the ability to loop a song in Song mode. In Song:General page the user can enable song loop and set the song loop start and song loop end points. 2. Added the ability to create new Synth tracks while a song is playing/recording only if there are currently no audio tracks in the song. 3. Added the ability to start recording on key down if in record ready mode. To enter record ready mode, simply press [RECORD]. The Fusion will start recording upon pressing [PLAY] or pressing any key. 4. Added a re-initialize of the LCD that occurs every 5 seconds to refresh the screen if Electro-Static Discharge caused the LCD to blank out. 5. Item referencing is now case insensitive. Bug fixes: 1. Fixed bug where system would lock up when loading a mix/program/song after loaded several mixes/programs/songs containing arp patterns. 2. Fixed bug where system would sometimes lock up after loading a multisample into Sampler mode. 3. Fixed bug where pressing [JumpDes] button in the Mod page when jumping to an envelope would lock up the system. 4. Fixed bug where Out of Memory error message would show and programs would improperly load after loading a large number of programs. 5. Fixed bug where deleting audio tracks from a song and then copying that song would sometimes delete audio data from the original song. 6. Fixed bug where Osc 3 and 4 were not selectable in Utility:Edit Multisample menu in ALESIS FUSION SOFTWARE RELEASE NOTES 2

Program mode.

Version: 1.20 Date: 12/09/05
Sound ROM: 1. Improved Programs and Mixes throughout every bank.
New Features/Changes: 1. Insert effects can now be chained. 2. Sample algorithm programs now contain 4 oscillators. 3. Four new filter types: RP Low Pass, Vocal Formant 1, Vocal Formant 2, and Vocal Formant 3. 4. Control of envelope curve per stage. 5. A new parameter was added to synth oscillator: Monophonic Sample Reset. When set, this will reset the sample when played legato in monophonic mode. 6. Two new process functions available in Sampler Mode: Bit Quantize Region and Reverse Region. 7. Added the ability to Undo or Redo process functions in Sampler Mode. 8. Sample loop points can now be edited while a voice is playing. 9. Sampler Mode Process list has been rearranged for better access. 10. Increased polyphony for all algorithm types. 11. In mixer automation mode, all tracks set to auto arm will be armed. 12. Pattern Type is now also stored with the program/mix/song. When a program is loaded it will override the pattern types with its type. When a pattern is loaded it will set the type based on the pattern. 13. Added Mono Low and Mono High keyboard modes to Phrase Sequence arp. These are mono types that follow the lowest or highest played key. 14. Direct Selection buttons [A] [8] now default to enable/disable while in Edit mode. 15. Store page will remember the previously selected bank on this page while storing a new created program/mix/sample/song. 16. Fusion now displays Waiting For Input when [RECORD][PLAY] is pressed and record threshold has not yet been reached. 17. Added ability to copy a volume folder from the CF card to the HD and vice versa. Bug fixes: 1. Fixed bug where mod shape smoothing was not working correctly when a knob modulated pitch. 2. Fixed bug where there was no portamento with polyphony = 1 and portamento legato enabled. 3. Fixed bug where old sample parameter values would be retained after sampling a new sound. 4. Fixed bug where phantom button presses would occasionally occur. 5. Fixed bug where LFO trigger settings would interact with envelope trigger settings. 6. Fixed bug where mods to filter would not function in FM programs when osc 1 is disabled. 7. Fixed bug where osc 2 followed osc 1s crossfade mod routes when osc 1 is disabled. 8. Fixed bug where noise was sometimes heard at the end of a recorded sample. 9. Fixed bug where Fusion would sometimes crash when entering the import track page. 10. Playing a sample region with the [PLAY] button in Sampler mode will now play the whole sample when the process type is Normalize and play from the current start to the sample end for Insert Silence and Paste types. 11. The display value of the frequency parameters in the Effects section have been corrected. ALESIS FUSION SOFTWARE RELEASE NOTES 3

12. Fixed bug where Fusion would not detect filenames beginning with a period as being invalid filenames. 13. Fixed bug where edited icon would appear in Sampler Mode even if a multisample has not been changed. 14. Fixed bug where deleting a mod route would corrupt table assignments for the mod routes. 15. Fixed bug where Undo was not enabled for sync parameters while editing an LFO. 16. Fixed bug where the crop function in Song Mode was not working properly. 17. Fixed bug where Insert Silence process in Sampler Mode was not functioning correctly. 18. Fixed bug where samples could not be selected properly from within a drum program. 19. Fixed bug where Item Explorer would freeze or not work properly when moving a song, mix, or program. 20. Fixed bug where effect mod routings would become invalid once the effect type is changed. Changing the effect type will now disable any effect mod route routed to a parameter of the previous effect. 21. Fixed bug where automation snapshot was not occurring when a record count-in was used. 22. Fixed bug where dry volume setting was being carried over to Program mode from Mix mode. 23. Fixed bug where velocity offset could wrap when playing arp at maximum velocity. 24. Fixed bug where song selection abort was not working properly in Song Mode, sometimes causing (SEng) errors to sometimes appear. 25. Fixed bug where Arp segment 1 length was not being recalled properly when a program is loaded. 26. Fixed bug where edited icon would remain on if a pattern is edited and then the program is changed. 27. Fixed bug where (SEng) Invalid Handle would sometimes occur when storing a song with a newly added audio track. 28. Fixed bug where the No Stored Multisample to compare message would display as truncated. 29. Fixed bug where track loop functionality was not always working properly. Also fixed bug where track loop parameters would not always be restored to their saved value if set beyond the recorded length of the song. 30. Fixed bug where songs loaded with General MIDI set to On would not always properly load drumsets on MIDI channel 10 tracks. 31. Fixed bug where playing certain patterns would hang the unit with rapid playing of keys. Version: 1.11 Date: 12/02/05 Sound ROM: 1. Improved Programs and Mixes throughout every bank.

New Features/Changes: 1. Increased frequency range of effects EQ bands. Bug fixes: 1. None. Version: 1.10 Date: 11/10/05 Sound ROM: 1. Added PRESET 4 program bank with 128 new programs. 2. Added MORE program bank with 65 new programs. 3. Filled out SYNTH DRUM program bank by adding 110 new programs. 4. Divided mixes into two banks: GROOVE MIX (40 mixes) and SPLIT-LAYER (108 mixes), adding several new mixes. 5. Analog drum kits added within the SPLIT-LAYER mix bank. 6. Improvements to programs in PRESET 1, PRESET 2, PRESET 3, and 4

7. 8. 9.

ELECTRONICA program banks. Several new patterns have been added. Demo songs have been removed from the internal Sound ROM. These demo songs are available as a separate download. Unused multisamples have been removed from the internal Sound ROM. These multisamples will be available to the public at a later date.
New Features/Changes: 1. Added a dry level parameter to each track. This is a post-send level used to configure the wet/dry mix for send effects. This is on the Track-Output page along with being on the Effects-Bus-Select page. It is also added as an effect mod route destination. 2. Moved the track enable parameter to the Track-General page for Song mode and PartGeneral page for Mix mode. 3. Improvements to Mono Aftertouch response of the keybed. 4. Revised/Improved all Chorus effects. 5. Improvements to the Rotary effects. 6. Added tap tempo button. Tap [ARP] button at least 4 times to set tempo. 7. Added the ability to import MIDI files to Song Mode. Also the ability to export a song to a MIDI file. 8. Added ability to export all audio tracks in Song mode. 9. Audio Track Import utility now only shows supported files when user is selecting the file to import for easier browsing. 10. When the Optimize to Mono parameter in Program Mode is disabled, the cursor will jump to the pan parameter for immediate access. 11. Pressing [RECORD] only will place the Fusion in a record-ready state. Pressing [PLAY] or receiving a MIDI START message will then enter record mode. This enables the Fusion to enter record as a MIDI slave. 12. MIDI START message is now sent when record count-in ends rather than immediately when [RECORD]-[PLAY] is pressed. 13. Added a new arpeggiator parameter: Use Part Range. This provides the ability to set an arpeggiator to play part only within the parts range. This is useful for playing patterns for analog drum kits in Mix Mode. 14. Altered display format of error messages. Bug fixes: 1. Fixed bug where pressing [STOP] in Mixer mode would revert the knob row to the top row rather than keeping it disabled. This caused the tempo to change when turning knob 4 in Mixer mode. 2. Fixed bug where pressing a key while the arpeggiator was playing a fill would keep the arpeggiator within the fill forever. 3. Fixed bug where entering Sampler Edit mode from another mode would crash the system when Last Mode Only load option was used. 4. Improved clipping indication for sample metering. 5. Fixed bug where sustaining notes would click during large program load. 6. Fixed bug where tables would not properly delete and remained in sound and when stored. 7. Improved flanger effect with negative feedback parameter. 8. Fixed bug where flanger would self-oscillate using certain parameter values. 9. Fixed bug where Program Mode would accept a program change message from a MIDI channel that was not the Global MIDI channel. 10. Fixed bug where pressing [STOP] would cause the edited icon to appear when MIDI In was receiving the Fusions MIDI Out. 11. Fixed bug where Mod Wheel and assignable knobs would send duplicate values via MIDI. 12. Fixed bug where an illegal path was allowed to be created when creating a bank name. 13. Fixed bug where changing the global transpose parameter would leave a stuck note on the MIDI slave. 14. Fixed bug where sample loop points would not be set correctly after recording. ALESIS FUSION SOFTWARE RELEASE NOTES 5

15. Fixed bug where count-in would show corrupt timecode when meter is above 34/4. 16. Fixed bug where inserting a second note in a new pattern when the ARP ON/OFF is on would freeze the unit. 17. Fixed bug where receiving MIDI clock would incorrectly determine the tempo once the sync message is received after a long absence. 18. Fixed bug where creating a song from a mix would not correctly set the insert effects for each part. 19. Fixed bug where patterns would not play/record correctly with meter other than 4/4. 20. Fusion no longer responds to MIDI CC for Balance. It will only respond to MIDI CC for Pan. 21. Fixed bug where pressing [STOP] during a record count-in would keep the timecode in the count-in display. 22. Fixed bug where effects mod routings would not always store correctly. 23. Improved the system to eliminate noise for non-looped samples pitched extremely high. 24. Removed clicking that was recorded to a sample when playing the keyboard while recording in Sampler mode. 25. Fixed bug where users were not able to edit and store the Simple Drone pattern. 26. Fixed bug where sampled audio would have a discontinuity in the audio after the first 64 samples. 27. Fixed bug where Undo was not working correctly while editing a mod route. 28. Fixed bug where notes would stay on when disabling the keyboard parameter of a part or selecting a mix where the part had its keyboard parameter set to off. 29. Fixed bug where moving a mod route would not properly move all of its parameters. 30. Fixed bug where EDIT Env: text was clipped with certain mod routings. 31. Fixed bug where editing a pattern would not always show the edited icon. 32. Fixed bug where deleting the Volume ID of a CF card would cause the Fusion to display a corrupted volume ID in the Media-Info page. 33. Fixed bug where soft buttons would incorrectly appear in the Item Manager. Version: 1.05 Date: 10/17/05 Sound ROM: 1. Added 15 new arpeggiator patterns. 2. Added 5 new mixes to the Mix bank. 3. Improved piano envelopes 4. Added Aftertouch modulation to a few programs.
New Features/Changes: 1. None.
Bug fixes: 1. None. Version: 1.03 Date: 10/11/05 Sound ROM: 1. Added ELECTRONIC program bank. 2. Added SYNTH DRUM program bank. 3. Improved levels in a few groove mixes. 4. Replaced Oboe & Bassoon mix with Stringed Bassoon mix. 5. Tune improvements to trombone multisamples.
New Features/Changes: 1. Pressing [LOCATE]+key in the Program mode Play screen will allow the user to adjust the Global Transpose parameter. This is also allowed in the Play screen for Mix, Song, and Sampler modes. 2. When editing a parameter, pressing [LOCATE]+key will select a value. The keybed ALESIS FUSION SOFTWARE RELEASE NOTES 6

3. 4. 5. 6.

will scale the entire range of the parameter. The selected knob row is remember per mode and is initialized to the Arp row except for Program mode which is initialized to the Assign row. Pages named Edit have been renamed to Settings. Disabled the feature where the LCD was re-initialized every five seconds to deal with possible static discharge issues. Additional support for manufacturing.

Bug fixes: 1. Fixed bug where the clipboard would not correctly paste effects parameters. 2. Fixed bug where editing events within a song would not set the song edited flag. 3. Fixed bug where arpeggiator modulations were not occurring when played via a song or via MIDI. 4. Fixed bug where patterns were not be reset at the start of the song. 5. Fixed bug where the graphical arrow in the FM Router page was obscured. 6. Improved response of the pitch wheel. 7. Fixed bug where the Fusion would ignore program files with uppercase extensions when building program banks. 8. Fixed bug where volume and pan controller changes in patterns were ignored when the pattern was loaded. 9. Fixed bug where the tempo LED was not in sync with the song. 10. Fixed bug where the edited flag would be displayed when loading the initial mix, program, or song when Global option for loading is set to Last Mode Only. Version: 1.02 Date: 10/03/05 Sound ROM: 1. Added several new mixes. The Mix bank is now complete. All mixes were improved and reordered. Added more groove mixes. Added MIDI Template mix. 2. Added GM program bank. 3. Improvements to programs (including improvements to the Holy Grail Grand Piano). Hammond organ programs now have authentic percussion response. 4. Improvements to the demo songs.
New Features/Changes: 1. Support for General MIDI. When General MIDI mode is enabled the user will be brought to the MIDI Template mix in Mix mode. 2. Improvements to triggering the arpeggiator patterns. Tempo LED will sync to arpeggiator based on the first trigger. 3. Revised the interface on the Global-MIDI page. 4. Added options to the Global-MIDI page to allow the user to enable/disable sending and receiving MIDI sequencing commands. 5. Improved default programs created when the user changes the synth type in Program mode. 6. The pattern length selected by the user is now stored within a pattern and recalled when selecting that pattern. 7. Track volumes, pans, and send levels now update when received via MIDI controller messages. 8. Added the ability to set the song length. 9. Added an option in the Global-Option page to load either programs for all modes on startup or only the programs in the current mode on startup. 10. When the (Edit) [1]-[8] option is set to Enable/Disable in the Global-Options page, the [BANK] buttons can now be used to select the next/previous bank of 8 tracks for enabling and disabling. 11. Improved polyphony performance for high pole filters. 12. Additional support for manufacturing.

Bug fixes: 1. Fixed bug where arpeggiations triggered in succession in mix mode would lose sync. 2. Fixed bug where programs would sometimes fail to load and produce an Invalid File Format error message. 3. Fixed bug where latching the arp with the sustain pedal would cause keys that were once played to no longer trigger. 4. Fixed bug where mod route amount would restore to being 0.01% less than what was stored for certain values. 5. Fixed bug where loading new patterns would reset the tempo to 120 BPM. 6. Fixed bug where system would not respond to the foot pedal function when received via MIDI or via song playback. 7. Fixed bug where MIDI note off was not always being sent when note off occurred during a program change. 8. Improved the display of running timecode under heavy mixer automation. 9. Fixed bug where main Song mode screen would incorrectly show which tracks were armed (with underline indicator) when song was playing. 10. Fixed bug where arpeggiators were not properly turning off when a new mix was selected. 11. Fixed bug where the tuning type parameter was not properly working in Program mode. 12. Fixed bug where LFO trigger settings were interacting with other LFOs. 13. Improved how the envelope overlap release parameter functions. 14. Improved monophonic programs when the same key is repeatedly pressed. 15. Improved the problem where slight clicking was heard when the polyphony limit was reached. 16. Fixed bug where the Fusion would not always respond correctly when receiving MIDI in running status form. 17. Fixed bug where deleting songs with audio tracks would produce an error message. 18. Added fade out to recorded sample to prevent clicks at sample end. 19. Fixed bug where table points became unselectable when the first two points were equal. 20. Fixed bug where the certain parts would sometimes be silent after startup until the [STOP] button is pressed (when the foot pedal function was set to Mod + Volume). 21. Fixed bug where tables would not paste properly when using the Clipboard utility. 22. Fixed bug where effects parameter for ring modulator LFO rate would incorrectly wrap. 23. Fixed bug where Gated Reverse Reverb effect would clip. 24. Fixed bug where parameter overrides in mixes and songs would not always load properly when loading the mix or song. 25. Fixed bug where non-existing parts would sometimes be displayed in the Mix-Utility page. 26. Fixed bug where the category would not update properly with rapid changes in the Category mode. 27. Fixed bug where the system would lock up when zooming in completely on samples of certain lengths. 28. Fixed bug where parameter fields in the Song-Editor screens would reset when changing the start and end time parameters. 29. Fixed bug where recording patterns with quantization would not record notes when played as the pattern reloops. 30. Fixed bug where patterns would not switch between A and B variations correctly if the step was set to anything besides eighth note. 31. Fixed bug where mod routes would sometimes get corrupted when deleting or moving mod routes. 32. Fixed bug where mix mode would play added parts when in compare mode. 33. Fixed bug where HD error messages would be shown when leaving USB mode when the Fusion entered USB mode in Song mode with audio tracks armed. 34. Improved loading of mixes and songs. 35. Improved the Piano Roll and Event List editors. 36. Fixed bug where all LEDs would flash while loading programs when the mod wheel was set to just above the minimum or just below the maximum setting. ALESIS FUSION SOFTWARE RELEASE NOTES 8

37. Fixed bug where assign row would sometimes be blank on the main Program or Mix screen rather than displaying its assignment. 38. Fixed bug where release velocity would not be properly pasted when copying/pasting event data in Song-Editor pages. 39. Fixed bug where display would not show the transposed note in drum algorithms. Also the LOCATE+Key would not adjust to the program transpose value. 40. Fixed bug where storing patterns or songs would sometimes corrupt memory, corrupt media, and/or crash the Fusion. 41. Fixed bug where inserting a corrupted compactFlash card would crash the Fusion. 42. Fixed bug where voice engines sound memory usage was incorrectly displayed. 43. Fixed bug where effects mod routes would not reset its modulation effect when deleted or reassigned. 44. Added mod range display for envelope release decay and envelope time. 45. Fixed bug where notes in song would stop sustaining when changing the current edit track. 46. Fixed bug where undo function would not work properly across tracks in Song/Mix modes. 47. Fixed bug where portamento time was not displayed correctly in the mod page. 48. Fixed bug where the Overdrive Rotary would sometimes have its high rotor spin out of control. 49. Fixed bug where the Drum Quantity Assign keyboard mode could not be stored with the program. 50. Fixed bug where effect delay times were not correct. 51. Fixed bug where deleting an event from the pattern event editor would delete the piano rolls selected event instead. 52. No longer send All Notes Off, All Sound Off, All Controllers Off via MIDI on startup or when changing modes. 53. Fixed bug where controllers playing back from song would not modulate the effects. 54. Fixed bug where Octave Assign arpeggiator keyboard mode parameter was not properly working. 55. Fixed bug where arpeggiator keyboard modes other than Mono were not working properly in variations besides A. 56. Fixed bug where UI locate points could not be selected when the (Edit)[1]-[8] Global option was set to Enable/Disable. 57. Fixed bug where overwriting existing program name would load older program when saved. 58. Fixed bug where metronome would occasionally skip a beat. 59. Fixed bug where filter row settings would be retained through program change when the current know row was not set to the filter row. 60. Fixed bug where the system would not reset properly when changing the Voice Select function in Global mode. 61. Fixed bug where deleting a zone in Sampler mode would mute existing zones. 62. Fixed bug where programs would fail to load and show an error that a table could not be found. 63. Fixed bug where songs would not play through internal sounds when local was off. 64. Fixed bug where enable/disable would not always properly work when pressing 1-8 buttons. Version: 1.01 Date: 8/11/05 Sound ROM: 1. No changes to the Sound ROM.

New Features/Changes: 1. Improved knob graphic resolution. 2. Sound banks will now update after HD or CF format. 3. Allow sustain pedal to latch arpeggiator if ARP is enabled. 4. Additional support for manufacturing. ALESIS FUSION SOFTWARE RELEASE NOTES 9
Bug Fixes: 1. Improved graphic display response in Song mode. 2. Improved oversensitivity of aftertouch response at note on. 3. Fixed bug where voice engine would occasional fail to run on power up. 4. Fixed bug where switching the CF card would not be recognized through USB. 5. Fixed bug where storing drum programs to a new bank or device would cause referencing problems. Version: 1.00 Date: 8/05/05 New features/Changes: 1. Initial Release.

Bug fixes: 1.

ALESIS FUSION The basics.
ANALOG SYNTHESIS TUTORIAL
Since the early days of analog synthesisers back in the 60s, an analog synthesiser can be broken down into just a handful of basic components. These are: SOUND GENERATORS SOUND PROCESSORS / MODIFIERS CONTROLLERS
The sound generators take the form of OSCILLATORS and also NOISE GENERATORS The sound processors / modifiers take the form of FILTERS and AMPLIFIERS and also RING MODULATORS and, these days, effects units such as REVERB, DELAY, CHORUS, etc. The controllers take the form of ENVELOPE GENERATORS, LFOs (LOW FREQUENCY OSCILLATORS) plus real-time controllers such as KEYBOARD, PITCH BEND and MOD WHEELS, VELOCITY, AFTERTOUCH, etc. Dont worry about the jargon and terminology for now - we will look at these in detail throughout the course of this tutorial.

The history.

In the early days of synthesisers, all the different components mentioned above were available as separate modules and were connected together using patch cords:
Thus, to make a sound, you would typically patch a cord (cable) from the output of an oscillator to the input of a filter. Youd then patch a cord from the output of that filter to the input of an amplifier and the whole lot would be controlled by various controllers (all patched in with various cords). Apart from being big, bulky and expensive (not to mention somewhat temperamental and unreliable!), this made them unsuitable for use live on stage because each sound had to be made from scratch (there were no patch memories in those days!).

Introduction

Page 1

ALESIS FUSION

With that in mind, in 1971, Dr Robert Moog (largely regarded as the father of modern synthesis) released the seminal MiniMoog synthesiser. The oscillators, filters, amplifiers and controllers were pre-patched and all connections switched on and off using front panel switches. Although it had no patch memories to store sounds, the MiniMoog was portable and considerably easier to use both on stage and in the studio. The MiniMoog spawned all sorts of similar products from competing manufacturers such as ARP (their Odyssey) and, of course, Japanese manufacturers such as Roland, Yamaha and Korg who were making their first synthesisers in the early to mid-70s. Of course, at this time, all synthesisers were monophonic 1 - that is, you could only play one note at a time but in the mid-70s, we saw the release of polyphonic synthesisers that could play as many as eight (!!) notes simultaneously. The first of these was the Yamaha CS80 but it was Sequential Circuits Prophet 5 that set the pace for the next generation of synthesisers. Featuring 5-note polyphony, the Prophet 5 had one more trick up its sleeve - the settings of the front panel controls could be stored and recalled with a button press allowing you to flick between different sounds quickly and easily. However, worthy of note is the fact that the structure of each of the Prophets voices was pretty much exactly the same as the MiniMoogs. Other manufacturers released similar products all using the same basic layout as the Minimoog and development stayed rather dormant with no major innovations until 1982 when Yamaha released the legendary DX7 FM synthesiser. This was also the first synthesiser to feature the new Musical Instrument Digital Interface otherwise known as MIDI. Analogue synthesisers fell from grace almost overnight and you could barely give them away during the 80s - no-one wanted that analog sound anymore; instead, they wanted the fashionable FM sounds that littered almost every record of the time. The DX7 was an immediate success offering 16-voice polyphony (unheard of in those days), a velocity sensitive keyboard (also very rare back then) and loads of playable presets for about a fifth of the cost of an analog polysynth!!! In the mid-80s, affordable sampling also took off with products such as the Akai S900 and so youd think the fate of analog synthesisers was sealed. However, in the 90s, impoverished musicians were picking up these analog relics dirt cheap in second-hand shops or classifieds and they quickly became popular again. People also rediscovered their rich, warm and vibrant sound (especially after a decade of clean and detailed FM and static samples). As a result, prices soon started to escalate and instruments you couldnt give away a few years earlier were selling for more than their original price! However, these old things were unreliable (some notoriously so) and costly to maintain. It was also difficult to locate good examples of the old instruments (and, of course, they didnt have MIDI which by now, had become a vital part of the music making process). But still they remained popular and these old synths were now the new things to have! Advances in computing power meant that is was possible to model (i.e. re-create) the sound of analog synths using advanced digital sound processing (DSP) and so the virtual analog synth was born. Offering the characteristic richness of genuine analog synths, they overcame all of the reliability problems as well as offering greater facilities and higher polyphony at much lower cost. Which brings us to the present day. The VA (virtual analog) synth in Fusion is a powerful engine that offers a truly comprehensive specification that outperforms almost all of the old analog synths of yesteryear whilst retaining the warmth and character of those old classics. Lets now look at the various components that make up a typical analog synthesiser.

Sawtooth wave

The sawtooth wave is very rich in both odd numbered and even numbered harmonics. That is, it has harmonics that are twice, three times, four times, five times (and so on) the fundamental frequency. Thus if the fundamental (and first harmonic) frequency is 500Hz, the 2nd harmonic is 1kHz, the 3rd is 1.5kHz, the 4th is 2khz, etc. This creates a very bright sounding basic waveform and is useful as the basis of many different sounds including strings, brass, leadlines, basses. in fact, almost anything! The sawtooth shape of the waveform (which gives it its name) is how the signal would look if seen on an oscilloscope. If you looked at a trumpets waveform on an oscilloscope, it would look similar.
On most synths, the width or symmetry of the pulse wave can be varied for a wider range of tones. More later.

Sound generators

Page 4
ALESIS FUSION Square wave
The square wave is another very bright waveform but sounds different because it only contains odd numbered harmonics (X3, X5, X7, etc.). As a result it sounds hollow and not unlike a clarinet. It is useful for many sounds that require that quality and is very useful for reinforcing bass sounds, especially when tuned an octave down from the other oscillator(s).

Pulse wave

The pulse wave is a bit of an exception because the width of the pulse spike can be continuously varied and the distribution of the harmonics changes according to the width of the pulse. When the pulse is very thin, the sound is thin and nasal (like an oboe) and gets fuller as the width increases. The pulse wave is good for clavinet-like and other thin sounds. If you change the pulse width whilst it is sounding, you will hear a pleasing change in tone not unlike a chorus effect and if you use some controller to do that automatically, this is called Pulse Width Modulation (or PWM) and can be useful for creating thick, ensemble textures as we shall see later.

Triangle wave

The triangle wave is not unlike the square wave in that it only comprises odd numbered harmonics. However, the harmonics are very much lower in level resulting in a more mellow sound that is suitable for pure and simple sounds.

Page 5

ALESIS FUSION Sine wave
The sine wave is the simplest waveform known and has only a fundamental with no harmonics at all. As such, it is a very unnatural sounding waveform (there is no sound in nature or musical instrument that doesnt contain any harmonics) and therefore is very good for creating pure sounds. It is also very good for creating sci-fi sounds because the early electronic music pioneers of the 50s and 60s only had very simple sine wave oscillators to play with. The humble sine wave is also very useful for reinforcing the fundamental of other waveforms and comes into its own as a sub-bass reinforcing the fundamental of a bass sound an octave down where its not so much heard as felt. This is not a new technique - church organists have been using it for centuries!!!

Noise generators

So far, we have only looked at pitched waveforms. There are also sounds (such as drums and sound effects. wind, surf, etc.) that have unpitched elements. These are created on an analog synthesiser using a noise generator. Noise is made up of every frequency in the audio spectrum sounding at once. The most commonly known is white noise, so called because, like white light, it has an even distribution of frequencies across the spectrum. However, there are also other types of noise such as pink noise where the frequencies are balanced across the musical octaves. The technicalities are largely irrelevant - all you need to know is that white noise is bright and hissy and suitable for wind and breath sounds whilst pink noise has more rumble and is useful for thunder and surf sound effects. Fusion also offers a red noise option which is even more biased towards the low frequencies and is seriously menacing and rumbly. NOTE: Noise has no pitch parameter and is not possible to play noise in the conventional sense of the word - in other words, you cant pick out a tune using noise!!!

Page 6

ALESIS FUSION Oscillator pitch / tuning / frequency
As well as the basic choice of waveform, there is much you can do to govern the character of your sound by your choice of oscillator tuning. A single oscillator on its own can sound a bit sterile, lifeless and. well. electronic (although this can be a quality you might want of a sound). As a result, it is common practice for most analog synths to have two (or more) oscillators which can be detuned against each other to give a variety of chorus and ensemble sounds that are fatter and warmer than just a single oscillator in much the same way as an orchestral string section has a fuller sound than a single violin. The amount of detune can be ever so subtle to create a slowly changing sound or can be quite extreme to give a thick chorus effect. The diagram below shows the effect of combining two sawtooth waveforms that are very slightly detuned against each other.
You can see the new combined waveshape constantly changing over time which creates a much more pleasing and animated sound. As well as small amounts of subtle detune, however, you can tune the oscillators apart by an octave or maybe two. or you can tune them, say, a fifth (seven semitones) or other intervals apart. Of course, the more oscillators you have, the more scope there is for detune and tuning possibilities. The optimum number of oscillators appears to be three - fewer than that and your tuning options are limited; more than that can sometimes result in an audio mush. Fusions VA synth has three oscillators. NOTE: On Fusion, it is possible to pan each of the three oscillators separately so that as well as fattening a sound with detune, etc., you can also spread the sound across the stereo image with judicious use of oscillator pan. TIP: Although it is a good idea most of the time to employ two (or more) oscillators to create a fuller, more animated sound, sometimes a single oscillator is more appropriate. This can be especially true for creating solid bass sounds where the constantly changing phase relationship between oscillators can cause the bass sound to lose focus. Alternatively, use Oscillator Sync (described on the next page) to lock the oscillators for a solid sound. Just those possibilities - combining different waveforms at different tunings - allow you to create an enormous diversity of sounds. But theres more.

Page 7

ALESIS FUSION Pulse Width Modulation (PWM)
We have already seen this mentioned in the description of the pulse wave on Page 6. The width, symmetry or shape of the pulse wave can be varied from an equal square wave to a very thin pulse 3 as shown below:
When this happens, there is a pleasing chorus effect as the harmonic structure shifts and changes. When setting the pulse width manually, it allows access to an almost unlimited assortment of different sounds but when put under the control of something like an LFO or an envelope generator or a real-time controller such as the mod wheel, the possibilities increase dramatically. Controlled by a cyclic LFO, you can create lush, animated chorus and ensemble sounds. Controlled by an envelope generator, the pulse width can change over the course of a note. Controlled by the modwheel, the pulse width can become a performance parameter. However, unlike most synths, Fusion also provides the same facility with the sawtooth and triangle waves and instead of a switched choice between one or the other, you can morph gradually between the two:
As the waveform symmetry changes between the two extremes, interesting tonal modification and harmonic movement not commonly available on other synths takes place allowing Fusion to create some totally unique sounds. Like the traditional PWM described above, this can also be controlled by LFOs, envelopes and real-time controllers. More on that later.

Oscillator sync

Despite recommendations to detune oscillators to create a fatter sound, it can sometimes be appropriate for the oscillators to be perfectly phase-locked without any detune or beating. For example, you might want to set up a solid bass sound with the oscillators tuned an octave apart. Even if you fine tune them to exactly the same value, there will still be some phasing between them - by syncing the oscillators, you can achieve the solid sound you want without the slight detune and potential lack of focus. This is achieved using the SYNC facility. When this is switched on, the oscillators waveform cycles are locked to each other so that they are perfectly in tune. However, this has some interesting side effects and benefits..
In some jornals or articles, you might also see this referred to as the mark/space ratio and it represents the percentage of time the wavefom is up and down. For example, a mark/space ratio of 10:90 means that the pulse wave is up for 10% of the cycle and down for 90% of it.

Page 8

By tuning the oscillators apart in wide intervals with oscillator sync on, many interesting new waveshapes can be created that can sound distinctly un-analog and could almost have been created on a digital synthesiser. There are no rules for this - simply experiment using different waveforms and interval tuning combinations. However, a further side effect and benefit to this is that if the frequency of the syncd oscillator is changed during the course of a note, you get a distinctive tearing sound not unlike a very strong flanger effect. You can achieve this manually by controlling the pitch of the syncd oscillator using - say - the modwheel and using the effect as a performance parameter (a popular technique with early synth players such as Jan Hammer or 80s synth pop-meister, Howard Jones in What Is Love?) or you can automate it using LFOs and/or envelopes to create many distinctive and classic sync sweep sounds. We will be looking at the use of controllers for this and the PWM sounds later in this tutorial.

Balancing / mixing the oscillators
You dont always want to have the oscillators at full level all the time - you will want to mix and balance their relative levels. For example, you might have a sound where one oscillator is an octave or two up but you might only want a hint of that in the sound or you may want to emphasise a low octave in a bass sound. or you may have tuned the oscillators a fifth apart but dont want the fifth element to be too prominent. Or you may have mixed in a bit of white noise that needs balancing against the pitched element of other oscillators. whatever. All synths offer some way of balancing the relative levels of the various oscillators. Some two oscillator synths have a simple balance control (which can be inflexible) whilst other synths have an oscillator mixer. Some, however, (like Fusion) simply have an output level for each of the oscillators. As with most things about an analog synth, there are no rules - just adjust the relative levels according to taste and the requirements of the sound. More modern VA synths such as Fusion also offer oscillator pan whereby the oscillators can be spread across the stereo image for a wider sound. This can be particularly useful when creating certain large, ensemble sounds such as strings and pads to create a wide stereo sound (but can be a bit overpowering for bass sounds which typically fare better placed mono and central in the stereo image to create a solid foundation for the track). Again, no rules - just use your instinct. and experiment!
Sound generators - Conclusion
As you can see, the oscillators alone offer a huge range of sounds to be created even before we investigate the sound processors / modifiers and controllers. Its worth getting to know (and understand) the possibilities offered by the oscillators as they are the building blocks of any sound. as mentioned, they can be compared to the strings of an instrument and so play an important part in any sound. But dont let this intimidate you - just experiment with different waveform, tuning and mixing combinations until you arrive at something you like and progress from there. Remember - it doesnt matter what you do, you cant break anything by experimenting!

Page 9

ALESIS FUSION SOUND PROCESSORS / MODIFIERS Filters
If the oscillators are the strings of an analog synthesiser, the filter is the heart and a synth can stand or fall on the quality of its filter(s). Put simply, the filter is one big, drastic tone control that can modify the basic sound generated by the oscillators. We learned about harmonics in the first section of this tutorial - the filters job is to selectively filter out (or sometimes enhance) these harmonics, thus changing the tone or timbre of the sound. There are many types of filters around that perform different jobs. or rather, have a different effect on the raw sound they are processing. The most common filters are:

Lowpass filter

Allows low frequency harmonics to pass through unaffected, removing higher frequency harmonics above the cutoff frequency:
In this example, you can see that all harmonics above the 6th harmonic are cut off or filtered out. This is the most common filter found on ALL analog synthesisers. It closely replicates nature in that higher frequencies tend to have less energy and so dissipate and die away quicker than lower frequencies (which is why decaying instruments such as guitar, piano, etc., become softer or duller as the note dies away). It is also a natural phenomenon that if an instrument is played (i.e. plucked, bowed, hit, blown - whatever) harder, more high frequency harmonics are agitated and so the sound is brighter (and vice versa - if an instrument is played more softly, it sounds more muted). We can use the lowpass filter to mimic these (even if the sound is overtly synthy!).

Bandpass filter

Allows a band of harmonics to pass through but removes harmonics either side (below and above) that band:
From the diagram above, you can see clearly the effect it will have on the sound - the fundamental is attenuated and harmonics above the 8th are filtered out. As a result, lacking a strong fundamental frequency, the sound is going to be a bit weak and comprising only middle frequency harmonics, can sound bright and fizzy. Thats not to say this filter is not without its uses - its a popular filter in many dance/trance/techno genres for creating bright, fizzy leadlines and chordal stabs in anthemic Ibiza dance music.
Sound processors / modifiers

Page 10

ALESIS FUSION Highpass filter
Allows high frequency harmonics to pass through but filters out lower frequency harmonics below the cutoff frequency:
As you can see, the fundamental and second harmonic are filtered out (and the third is attenuated) which will result in a very thin sound.

Band Stop / Notch filter

This filter type allows lower and higher frequency harmonics to pass through but removes harmonics in between:

Of the two, the 24dB/Octave filter was generally preferred as it has a punchy sound and it was common on many American-made synths from Moog and Sequential Circuits. The 12dB/Octave filter, because of its gentler roll-off, allowed more harmonics above/below the cutoff point to pass through and so was regarded by many as a bit weak and fizzy. It was common on many Japanese-made synths but was also adopted by US manufacturer, Oberheim (although they offered a switchable 4-pole filter option in later models). Many Japanese manufacturers followed suit.

Page 15

Recent advances in DSP technology means that almost any roll-off can be defined and we can have anything from 1-pole (6dB/Octave) to 8-pole (48dB/Octave):
And if you are wondering what the dB/Octave refers to.. its the amount of attenuation of level per octave. Thus a 6dB/Octave filter cuts 6dBs (decibels) for every octave and a 24dB/Octave filter cuts 24dBs for every octave and therefore has a more dramatic (some would say punchy) effect on the sound. You can largely forget the technicalities though - the rule of thumb is that a 1-pole (6dB/Octave) filter is going to have a mild effect on the sound whereas a 4-pole (24dB/Octave) or higher filter is going to have a more dramatic effect. In practice, 2-pole and 4-pole filters are the most commonly used as they are arguably the most musical.

Filters - Conclusion

To regard the filters as static tone controls is only half the story - they come to life when their cutoff frequency changes over time. This can be done in several ways but almost always involves using a controller of some sort such as an envelope generator, LFO or real-time controller (such as a mod wheel). Almost all sounds vary in tone/timbre over time and the filter is the ideal tool to mimic that phenomenon. Even if your intention is not to replicate acoustic sounds, synth sounds can be significantly improved if they also have harmonic movement and change during the course of a note - for example, a resonant synth bass sound can benefit greatly from having cutoff frequency controlled by a decaying envelope as well as having the cutoff frequency controlled by velocity so that the sound is brighter when played hard and vice versa. We will come to this soon when we look at envelope generators and later when we examine modulation. For now, lets look at another sound modifier..

Ring Modulator

The ring modulator is a curious device that has been around since the early days of electronic music. It takes two audio inputs and produces the sum and difference frequencies of those inputs at the output:
X Inputs RING MODULATOR Y Output
So, for example, if the frequency of the signal at Input X is 440Hz and the frequency of the signal at Input Y is 1kHz, the output will have 1.44kHz and 560Hz - the sum and difference of the two respectively. Mix in the originals and you have a complex sound comprising 440Hz, 560Hz, 1kHz and 1.44kHz.

The ring modulator has been around for many decades, actually long before the synthesiser as we know it and as such, many of the sounds you can create with a ring modullator are highly reminiscent of and synonymous with early electronic music from such pioneers as Louis and Bebe Barron who created the first ever all-electronic music film score for the classic movie, Forbidden Planet, and also the BBCs Radiophonic Workshop who provided electronic soundtracks and sound effects for many BBC TV and radio production during the 60s including Dr Who.

Page 17

ALESIS FUSION Amplifier
Strictly speaking, the amplifier in the audio chain of an analog synth is not really a processor as such other than it allows you to control level, typically at the end of the signal chain before the signal reaches the outside world. However, the beauty of the amplifier is that its output level can be controlled by other devices such as envelope generators and/or LFOs. We will come to this in a moment. Many (if not most) modern synths final amplifiers are now stereo and also offer panning allowing you to position and/or spread the signal across the synths left/right outputs. This may also be controlled with LFOs, etc., for a wide range of dynamic stereo sounds.
Sound processors / modifiers - Conclusion
So far, we have looked at ways to generate a sound and then modify that in various ways. In the next phase of our voyage of discovery, we will see how we can change the nature of a sound over time as we embark upon our first foray into the world of controllers.

Page 18

ALESIS FUSION CONTROLLERS
Before we look at the various controllers, we are going to take a trip back in time to take a basic lesson in voltage control because with an understanding of how synths used to work, we can better understand how controllers work in a modern environment. Today, the late Dr Robert Moog is largely regarded as the father of modern synthesisers. However, synthesisers and electronic music had been around in one form or another for a some time before Moog brought his products to the market. However, these were often test laboratory oscillators and graphic equalisers, ring modulators, simple tape delays, etc., and early electronic music pioneers had to record small snippets of sounds created with this equipment and, using tape splicing techniques, painstakingly assemble a piece of electronic music. It was a laborious and time-consuming affair as you can imagine and a few seconds of electronic music could take days to make!! What Moog did was rationalise the process: by splitting the various elements of sound into different components such as we have so far discussed - sound generators and sound processors. However, what was unique to Moogs synthesisers was voltage control which allowed predictable control of these different components (such as pitch, waveshape, tone, amplitude, etc.) 5. The idea is simple - apply a varying voltage to the control input of an oscillator and the pitch will change; apply a varying voltage to the cutoff frequency of a filter and the tone will change; apply a varying voltage to the control input of an amplifier and the amplitude/level will change. Also, Moog devised the idea of the 1Volt/Octave (1V/8ve) rule - i.e. if the voltage doubles, so does the pitch of the oscillator (or the frequency of the filters cutoff or the amplifiers output level):

Page 21

However, we can also apply an envelope to filter cutoff - in this way we can vary a sounds tone over time during the course of a note. For example, you will remember that when we looked at harmonics, we discovered that in nature, high frequencies tend to have less energy and so tend to die away quicker than low frequencies and indeed, if you have played a note on a piano or plucked a string on a guitar, you will have heard this - as the sound dies away, it tends to get softer in tone over time. By applying an envelope to a lowpass filter, we can go some way to replicating this phenomenon - when the envelope receives a trigger, the voltage rises (thus opening the filter and allowing all the harmonics to pass through) and as the voltage falls to the sustain level, it will bring the filter cutoff frequency down (thus gradually reducing the higher harmonics over time) and when the note is released, the cutoff frequency will be pulled further down. as occurs on most acoustic sounds. These are the most common applications for envelope generators - to shape the amplitude and tone of a sound over time. However, they can also be used for other purposes. For example, knowing what we know about how pitch reacts to incoming voltage changes, what do you imagine would happen if this shape was applied to an oscillator:

+2V +1V 0V

Thats right - the pitch would slowly rise two octaves then drop an octave where it would remain constant. When the note is released, the sound would slowly fall in pitch again. So were getting a feel for this now. Lets recap. The higher the voltage, the higher the pitch when applied to the oscillators (and vice versa) The higher the voltage, the brighter the tone when applied to the filter (and vice versa) The higher the voltage, the louder the level when applied to the amplifier (and vice versa)
However, it is also possible to apply these controllers to other parameters. You will remember when we looked at waveforms, we discussed variable width waveforms such as the pulse wave. By applying an LFO to pulse width, you can automatically vary the width:
You could do the same by applying the output voltage of an envelope generator to pulse width.

Page 22

We can also apply these varying voltages to pan position:
Centre Right Centre Left Centre Right Centre Left Centre Right Centre Left
But what of other controllers? Well, given that we now know the basic rule about how voltage can control pitch, timbre, amplitude, waveshape and panning (and other things as we shall see), we can devise other controllers. What if, for example, we place a wheel next to the keyboard - when we move it forward, the voltage it sends to the oscillators is higher and when we move the wheel down, the voltage is lower. Youve just added a pitch bend wheel! We can do the same with joysticks, rotary and other controls What if we make a keyboard that, when you hit it harder, it generates a higher voltage and we route that to the filter and amplifier?

We have a velocity sensitive keyboard that can control tone and amplitude according to how hard or softly we play it! Of course, because the velocity voltage can be routed anywhere you want, velocity could also be used to control pulse width, panning, even pitch. This is the principle of voltage control and it was the backbone of analog synthesis for decades until it was replaced by the microprocessor after which such tasks were performed not using varying voltages but with digital data streams. And this is why voltage control is described here. Even though it has been many years since we used true voltage control 7, the way that digital control is implemented in modern synths is almost identical to the way that true voltage control worked on the original analog synths but somehow, it is easier to understand the concept of pitch rising as a voltage rises rather than the more abstract passage of 01101010001010 accumulating in a software multiplier! Take the time to re-read this if you are unsure about the principles involved because they are the key to understanding controllers and modulation which lie at the heart of analog synthesis. With that under our belt, we can look at the actual controllers themselves.
Other than in specialised analogue modular synths being made today, of course, from manufacturers such as Doepfer, Analogue Systems, Synthesisers.com and others.

Page 23

ALESIS FUSION Envelope generators
Also known as envelope shapers or (on Moog synths) contour generators, the purpose of the envelope generator is to generate a programmable control shape every time a trigger is received:

ENVELOPE GENERATOR

Typically, the trigger comes from the keyboard so every time you press a key, the envelope is triggered. Almost without exception, an envelope generator is connected to the final amplifier to shape the sounds overall amplitude but another envelope generator will almost always be connected to the filter to shape tonal variation. Lets just remind ourselves of the basic synth layout again:

Page 24

Page 27

The same is true of the filter envelope (if applied) - quite dramatic changes to the sound can be made with simple manipulation of the filters envelope parameters. Heres an example of a lowpass filter being swept by a decaying envelope:
At note-on, the envelope opens and so opens the filter allowing the sound to pass through unaffected. As the envelope decays, it brings the filter cutoff frequency down and so the upper harmonics are gradually filtered out and the sharp, harmonically rich square wave gradually becomes a sine wave with no harmonics over the course of the note.
Envelope generators - conclusion
That just about concludes our look at envelope generators for the moment. On an original analog synth, this is pretty much all you would need to know (in fact, on an original analog synth, this is pretty much all there is to know!). However, whilst the basic principles still apply, a modern VA synth such as Fusion can offer so much more such as velocity (and other external) control of envelope times but to discuss those here might only serve to confuse the issue. For now, well conclude by saying that the envelopes are typically responsible for shaping a sounds tone and/or amplitude - so. get messing with those ADSR controls!!!

Page 28

ALESIS FUSION Low Frequency Oscillators (LFOs)
In the early days of modular synths, there was no such thing as an LFO - you simply put the audio oscillators into a very low frequency mode so that instead of the oscillators chucking out their waveforms at 100 or 440 or 1,000 cycles per second, whatever (i.e. 100Hz, 440Hz, 1kHz respectively), they produced much slower cycles. like much, much slower cycles. like one cycle every few seconds! In this mode, the audio oscillators were running at fractions of a cycle per second. like 0.05Hz (one cycle every 20 seconds!).Thus they could be applied to filter cutoff for long filter sweeps. Running slightly faster at, say 6Hz (still sub-audio), they could be used for vibrato (pitch modulation) and tremolo (amplitude modulation) or filter bubbles. However, as synths developed, it was deemed unnecessary to employ an expensive audio oscillator and so some manufacturers included simpler low frequency oscillators with a limited frequency range purely for the purpose of controlling other modules. An LFO is almost identical to an audio oscillator except, as mentioned, they operate at a much lower and slower frequency or rate. The waveshapes are identical but, because they are running so slowly, you can predict the effect they will have when applied to pitch, tone, amplitude, whatever. For example:
If applied to oscillator frequency, this waveform will cause pitch to rise and fall according to the rate of the LFO.
If applied to oscillator frequency, this sawtooth wave will cause pitch to rise slowly and then fall abruptly according to the rate of the LFO.
This would cause the pitch to jump abruptly between the two extremes. As such, LFOs are simple to understand - just looking at the waveshape allows you to predict the effect it will have (and fortunately, unlike some other synths, Fusion displays the waveshape graphically so you can predict at a glance what effect the LFO will have!).

Ok - for those interested in early synth trivia. the Minimoog didnt have an LFO - instead,you had to use Oscillator 3 in its low frequency setting. As such, when used as an LFO, it was free running with no re-trigger. However, its rival - the contemporaneous ARP Odyssey - had an LFO dedicated to the task but it re-triggered with every new note. Many claimed at the time that the Minimoog had a more fluid sound as a result - vibrato was somehow more natural because it picked up at random in the cycle and slow filter filter sweeps flowed with the musical phrase.

Page 31

More recently, many LFOs allow their rate to be controlled by some other controller. For example, you could control LFO rate with velocity so that playing the keyboard hard will make the LFO rate faster and vice versa. playing softer yields a slightly slower LFO rate. Or it could be controlled by another LFO or envelope generator a real-time controller (see below). endless possibilities A few synths allow the shape or symmetry of the LFOs waveforms to be altered as well for even more control flexibility. Fusion allows all of these and more but thats probably enough to be going on with for now!!!

Sample & Hold

This is another old module from the early days and it falls somewhere between being a controller and a control processor. Basically, it takes an incoming control signal, samples it 9 and produces a stepped output according to the rate of the clock:
Sample & Hold Input Output
Clock Rate Here, with a slowly rising control input signal, we get a rising stepped output which, if connected to pitch, would give us a kind of arpeggio effect. This is how they all relate:
The S&H processor takes (samples) the level of the incoming signal at each clock pulse and holds that value for the duration of the clock step whereupon it takes the value of the incoming signal at the next clock pulse and holds that level and so on. So, in this case, the signal is low at the first clock pulse so the output is held low until the next clock pulse. At that point, the input signal is higher so that level is sampled and held. At the next pulse, the input is slightly higher so that is held but at the next pulse, the input signal is lower as is the output level. etc.
9 This is not to be confused with sampling audio signals for use in a sampler. Although the principles are actually the same, the sample & hold units clock is operating at sub-audio frequencies/rates and is thus for control purposes only.

Page 32

Because the speed of the input signal is not synchronised to the clock, some interesting alleatoric (i.e. unpredictable almost self-compositional) results can be created where the arpeggios are constantly weaving and changing and evolving over time. By playing with the rate of the incoming signal and the S&Hs clock rate, some very interesting sounds and patterns can be created and this was a popular technique in the early days of advant garde electronic music composers to create abstract soundscapes. Almost any signal can be fed into the S&H input. For example, can you predict what the output might be with an envelope signal as the input? Thats right: