Peavey Spectrum Bass II User manual

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manual

Table of Contents
A Intended to alert the user to the presence of uninsulated "dangerous voltage" within the product’s enclosure
that may be of sufficient magnitude to constitute a risk of electric shock to persons.
A Intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the
literature accompanying the product.
CAUTION: Risk of electrical shock - DO NOT OPEN!
CAUTION: To reduce the risk of electric shock, do not remove cover. No user serviceable parts inside. Refer servicing to
qualified service personnel.
WARNING: To prevent electrical shock or fire hazard, do not expose this appliance to rain or moisture. Before using this
appliance, read the operating guide for further warnings.
SpectrumBass II

Contents
Table of Contents
QUICK START... 2
ABOUT THIS MANUAL.^ 4
Chapter 1 Introduction . 5
FEATURES.*5
Chapter 2 Overview . .. $
THE FRONT PANEL.<5
THE BACK PANEL.5
GETTING TO KNOW YOUR BASS II.^ 7
Chapter 3 Connections . g
SETUP..."*’*’* 8
CONNECTIONS.9
Chapter 4 Basic Operation . 1 2
TERMS YOU SHOULD KNOW.12
MIDI MODES AND MULTI SETUP.12
CONTROLLER USAGE.13
GLOBAL BEND RANGE (PRG, 0-24).14
PRESET CONTROL.
AUTOFLOW.' ^ 14
REINITIALIZATION. 1 4
Chapter 5 Beyond the Basics . 75
DID YOU KNOW.15
HOW SOUND IS GENERATED. 1 5
The Spectrum Bass II Synthesizer Architecture ..15
Oscillators.15
Wave Start Offset.1<5
Oscillator Sync. 1 5
DCAs .17
Pan . 1 7
Filters .17
MODULATION AND THE SPECTRUM BASS II..1.’.....".."..".. 18
Keyboard Scaling.19
Sample and Hold.19
Portamento.20
Low Frequency Oscillator (LFO).21
Envelopes. 2 1
MODULATION SOURCES/SAMPLE AND HOLD INPUT SOURCES.22
WAVEFORM REFERENCE LIST.22
Chapter 6 Advanced use with a PC 1600 . 2 3
Patch Editing Descriptions.24
Appendix A MIDI Implementation . 2 6
Appendix B Parameters Saved on Power Down . 2 7
Appendix C System Exclusive . 2 8
Hi
Peavey Electronics Corporation

Chapter 1 Introduction
QUICK START
Hey, we know not everyone likes to read manuals or even needs to read manuals, that’s why we are providing this
quick: start section. We want to make using your new Peavey equipment an easy, enjoyable experience.
▼ To get started quickly
1 . The first thing you need to do is to connect the Spectrum Bass II to your system configuration. Here are some
things to check first:
Make sure your amplification system is turned off.
Turn the Spectrum Bass ITs Volume knob fully counterclockwise.
^ Plug the MIDI Out from your keyboard to the MIDI In on the Spectrum Bass H
Connect the mono/right audio output of the Spectrum Bass II to the input of your keyboard amplifier. (If
possible use a stereo connection; you won’t be disappointed. Connect the left and right audio outputs to
your amplification system with mono cables or use a stereo cable connected to the stereo/left audio output.)
Connect the power jack of the Spectrum Bass n to an electrical outlet using the 16 - 16.5 volt AC 1000 mA
adapter provided.
Turn on your amplifier.
See the diagram below.
DPM* 4
KB" 300
2
Spectrum' Bass II

Chapter 1
Introduction
2 . It is now necessary to properly set up your Spectrum Bass n to send and receive MIDI information. To do this:
Setting the AUDI Mode
fa Press the button labeled Mode until the Poly LED lights. This puts you into poly mode. The poly mode allows
you to send and receive MIDI data on one channel only.
Setting the MIDI Channel
fa Press and hold the button labeled Channel; while holding this button, press the A or ▼ button until the
MIDI receive channel for the Spectrum Bass II matches the MIDI transmit channel of your keyboard. If in
doubt, try channel 1.
3 . Okay. Now it’s time to play.
fa Start playingyour keyboard; as you play, turn the Spectrum Bass P’s Volume knob clockwise until you reach
the desired volume.
fa The Spectrum Bass IPs display will show the current patch number. To select a different patch, use the A
and ▼ buttons.
4 . That's it!
Peavey Electronics Corporation
3

Chapter 1 Introduction
ABOUT THIS MANUAL
Can it be? We thought that nobody ever read manuals anymore! Since we seem to be mistaken in our belief that
nobody reads manuals, we should probably give you some information that is useful. We’ll even try to present it
in an interesting manner (won’t that be unusual).
This manual covers several distinct sections. These sections are arranged in the same manner that a user may want
to learn them.
We have provided a Quick Start section, in case you suddenly decide that you don’t really want to read the manual.
Here is a brief description of what can be found in each section.
Chapter 1 , Intro, provides a brief introduction to the Spectrum Bass II along with the Quick Start guide.
Chapter 2 , Overview, provides a quick overview of the front and back panels of die Spectrum Bass H
Chapter 3 , Connections, shows some of the more common connection schemes for the Spectrum Bass n.
Chapter 4 , Basic Operation, provides you with some of the more basic knowledge needed to use the Spectrum
Bass II, such as: setting the MIDI channel, selecting the MIDI mode, change patches and tuning the unit.
Chapter 5 , Beyond the Basics, explains some basic synthesis information as used by the Spectrum Bass H
Chapter 6, Advanced Operation, provides power users with the information they need to interact with the Peavey
PC ™ 1600 .
Appendix A, MIDI Implementation, is a chart showing the MIDI implementation that the Spectrum Bass II
provides.
Appendix B, Parameter Saved on Power Down, provides a list of parameter settings saved when power
is turned off.
Appendix C, SysEx, provides system exclusive formats.
Spectrum ™ Bass II
4

Chapter 1
Introduction
Chapter 1 Introduction
Congratulations and thank you for purchasing the Spectrum ™ Bass H The Spectrum Bass II was designed to offer
the ultimate in bass sounds to the user. The sounds range from smooth flowing fredess to nasty synth basses in
16-bit resolution (24-bit internal), full MIDI compatibility, 24 oscillators, 12-voice polyphony, and 6-part multi-timbral
capability.
The Spectrum Bass n features classic bass waves, digital bass waves, and a selection of 4 and 5 string bass waves.
Couple this with Peaveyh dynamically modulated resonant filters and the results can range from realistic to totally
tortured, screaming sounds.
The Spectrum Bass n was designed to answer die need for bass synthesizer sounds in a package with current MIDI
technology and state-of-the-art synthesizer capabilities.
FEATURES
*•“ 2 MB 16-bit acoustic, classic analog and digital bass waveforms
*•* 256 presets; 192 ROM/64 RAM
24 oscillators (2 oscillators per voice)
12-voice polyphony
6-part multi-timbral
Hard Sync
12 dynamically modulated resonant filters
Portamento
Sample and Hold
<•* AHDSR envelopes for a classic feel
Custom patches for the Peavey PC ™ 1600 MIDI Controller ready to be downloaded from the
Spectrum Bass II
"•* Digital display of:
Program number
fa Fine tune
fa Transpose
fa Pitch bend range
fa MIDI channel
fa MIDI receive acknowledge
fa Number of channels recognized in multi mode
fa Autoflow enable
Peavey Electronics Corporation
5

Chapter 2
Overview
Chapter 2 Overview
16VACA/
1 AMP
o •
^^A RNIN <^^
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: to reduce the
RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS EQUIPMENT!
TO RAIN OR MOISTURE.
AVIS: RISQUE DE CHOC ELEC
TRlQUE-NE PAS OUVRIR.
MIDI
m
to to ito
OUT THRU
THE FRONT PANEL
1. Volume Knob
The Volume knob adjusts the overall volume of the Spectrum Bass H
2. LED Display
This is a three-digit, seven-segment display.
3. Up and Down Arrow Buttons ( ▼ and A)
These buttons are used to inc/dec through programs and to edit parameters.
4. Channel Button
The Channel button is used to select the MIDI receive channel. Channels 1-16 are available.
5. Transpose Button
The Transpose button is used to adjust the pitch. The Spectrum Bass II may be transposed any number of
semitones to ±2 octaves.
6. Fine Button
The Fine button is used to perform fine tune adjustments to the pitch. The range is ±99 cents.
7. Mode Select Button/LEDs
The Mode Select button is used to select the MIDI mode. There are six choices available: Omni, Poly, Multi,
Legato, Poly-Legato, and Multi-Legato. It is also used to edit the number of MIDI channels the unit will respond
to in multi-timbral mode.
THE BACK PANEL
1. Power Jack
Use only the 16-16.5 volt AC 1000 mA adaptor provided. (Peavey Part #00710160)
Caution : Use only the Peavey 16-16.5 volt power supply provided with this product. If the original power
supply must be replaced, consult your Peavey dealer or the factory for die correct replacement. Failure to use
6
Spectrum " Bass II

Chapter 2
Overview
5
3 4 6 7
5 6
the correct power supply could result in fire, shock hazard, extensive circuit damage, decreased performance,
or non-operation.
2. MIDI Out Jack
This is a standard 5-pin DIN jack used for sending MIDI overflow data and/or SysEx data from the
Spectrum Bass II to receiving unit(s).
3. MIDI Thru Jack
This is a standard 5-pin jack used to echo MIDI data received at the MIDI In jack. This means that the receiving
unit(s) will receive an exact copy of the MIDI data the Spectrum Bass II received.
4. MIDI In Jack
This is a standard 5-pin jack used for receiving MIDI data from the sending unit.
5. Mono/Right Jack
This is a standard l A" mono output jack. The output from this jack is the Right channel if a plug is inserted into
the Stereo/Left jack and is the summed Left and Right channels if no plug is inserted into the Stereo/Left jack.
6. Stereo/Leftjack
This is a standard Vf stereo output jack. The output from this jack is stereo when used with a stereo cable, with
the Left channel on the tip, and the Right channel on the ring.
Throughout the rest of the manual we will refer to the Spectrum Bass II as the Bass n.
GETTING TO KNOW YOUR BASS II
It’s pretty simple to tell whecj the Bass II is turned on; when it’s plugged in it should be on.
Using the Bass II is nearly as easy. The following sections provide information on: connecting the Bass n, sound
editing, front panel editing, MIDI modes and Multi setups, controller usage, autoflow, and of course the ever popular
MIDI implementation and system exclusive appendices. Enjoy!
Peavey Electronics Corporation 7

Chapter 3
Connections
Chapter 3 Connections
SETUP
When you power up the Bass II for the first time, you should see the program LED display come to life. In the display
will be three numbers, i.e., 001. This represents the current preset (or patch) number. Once you have connected
the Bass n to your MIDI keyboard (either using the diagrams in this chapter or the Quick Start guide) you should
set the MIDI receive channel. Set the MIDI receive channel by pressing and holding the button labeled Channel,
then use the ▼ or ▲ button to move to the desired channel. You probably want to set the MIDI mode as well. To
do this, press and release the Mode Select button until the LED above the desired mode is lit. If you are unsure which
mode you want, try using OMNI. For a more complete description of the MIDI modes see Chapter 4.
The rear panel consists of your stereo/mono outputs and MIDI In, Out and Thru jacks, and power input jacks.
To see if MIDI is being received, send MIDI data (notes, mod. wheel, etc); there should be a little dot in the bottom
right comer of the LED display showing the reception of any MIDI data.
8
SpectrumBass II

Chapter 3
Connections
CONNECTIONS
This chapter shows a couple of the more common connection schemes.
1. Basic Connection (keyboard)
The following diagram represents what might be considered a “typical” keyboard setup. In this connection we
have included the DPM® 4 keyboard, Spectrum Bass n, and KB® 300 keyboard amplifier.
D P M ® 4
Peavey Electronics Corporation 9

Chapter 3
Connections
3. Advanced Connection
In this diagram, we have taken a DPM C8p master controller keyboard and connected it to a PC 1600 MIDI
controller. We use this to provide sophisticated patch creating/editing capabilities. To this we have added two
Spectrum Bass II modules; the second is used to automatically catch and play any overflowed notes. Next, we
add an amplification system that includes a mixer (this allows you to connect audio outputs from both
Bass Us). The mixer is connected to a DPC 1000 digital amplifier and a pair of SP ™ 2XT speaker enclosures.
Of course everything represented here is made by Peavey and should be readily available at your local dealer.
DPM- C 8 p ■
SP 2XT SP 2XT
Peavey Electronics Corporation
11

Chapter 4
Basic Operation
Chapter 4 Bask Operation
TERMS YOU SHOULD KNOW...
Legato
Multi-timbral
Polyphonic
Portamento
Preset
Voice
Waveform
- A smooth and unbroken transition between successive notes.
- More than one distinct preset may sound at a time.
- The simultaneous combination of two or more sounds.
- The pitch glides between notes.
- A storage location for all parameters pertaining to a sound.
- The sound that is playing. If something is 4-voice, it means that four sounds can be playing
simultaneously.
- A wave (e.g., sine or sawtooth) that is used to create the sounds (voices) generated.
MIDI MODES AND MULTI SETUP
The Mode Select button (when pressed and released quickly) will advance you through all the possible MIDI modes
and variations that the Bass II is capable of. This selector will wrap around when advanced past the last selection.
The MIDI specification allows for four modes: Omni, Poly, Mono, and Multi. The Bass II adheres to the MIDI
specification for these modes but also allows for some new and innovative variations, as far as legato playing is
concerned.
The Bass H is up to 6-part multi-timbral. However, you may need less than six parts from the Bass n, but need the
other channels to drive other modules. In this case, you can tell the Bass II how many parts (channels) it should
respond to while in its MULTI, LEGATO or MULTI/LEGATO modes. (Adjustable from 2-6, in continuous order starting
at the MIDI receive channel).
As mentioned above, the MODE SELECT button will change the MIDI mode if pressed and immediately released
(mode changes on release). When it is first pressed down, the LED display will show the number of MIDI channels
the Bass II will respond to in the MULTI, LEGATO, and MULTI/LEGATO modes. The choices will be 2-6 (defaulting
to 6 when die unit is initialized). This value can be edited with the A and T buttons while the MODE SELECT button
is held. In this case, the release of the button will not cause a mode change. Also, if the MODE SELECT button is
pressed and held for more than one second, the Bass II assumes that you wanted to see the number of channels
on the LED and not change the mode. Therefore, in this case the release of the button will not change the mode.
The Legato mode selection will occupy 2-6 channels, each channel playing the same preset in a legato fashion. The
selection of diese channels is the same as just described below for die Multi mode. This mode is normally used with
a guitar or synth MIDI controller (the Peavey CyberBass, for instance), with each string sending MIDI data on a
separate channel.
If legato style playing is desired, yet you don’t want to bum extra MIDI channels in the process, advance the Mode
Select button until both the Poly and Legato LEDs are on. This setting will behave as in straight poly mode except
for the allocation of voices (offty one voice sounds). A word here on legato footswitch controller (controller #68):
The legato footswitch controller is a newly ratified addition to the MIDI controller list, which will toggle the playing
mode between normal and legato (see side bar for explanation of legato playing style). Certain patches will override
the front panel setting and force legato on or off upon recall. Neither this, nor the controller will affect the
Legato LED.
12
Spectrum " Bass II

Chapter 4
Basic Operation
The Bass n responds to this controller and can be used in the Poly and Multi modes to switch to legato playing style.
So, say for instance you are playing in Poly mode, and you send the Bass n a Legato footswitch message. The Bass
H will now behave as though you had selected the Poly-Legato mode with the Mode Select button (although the
LED status will still indicate just Poly). Sending a Legato footswitch message below threshold will bring you back
into normal playing. This is much more versatile and expressive than a straight Legato mode allows for.
Now, the same sort of playing styles are possible in Multi mode. Advancing the Mode Select button until both the
Multi and Legato LEDs are on will yield a MIDI Multi mode (2-6 channels, each capable of a distinct preset) but with
each channel playing in legato fashion. If you happen to be in straight Multi mode and you send the Bass II a Legato
footswitch message above the threshold value, that channel will then switch to a legato playing style. This allows
for a mixture of channels playing legato and normal, with the ability to switch back and forth on any of the six channels
in real time.
The Multi preset selections roll with the MIDI channel selection. Let’s take a second to explain this: If the MIDI channel
currently selected is 1, then the Bass n will respond multi-timbrally on channels 1-6 (if the number of channels is
set to 6—the maximum). A channel will play whichever preset was selected as a result of a program change message.
The Bass II is initialized at the factory to play presets 1-6. Now, changing the MIDI channel to channel 2, for instance,
causes Multi response to shift to channels 2-7; BUT, the preset selections remain the same. So, assuming the factory-
preset described above, if the MIDI channel is set to 2, channel 2 will play preset 1, channel 3 will play preset 2,
and so on. This a convenient way to accommodate altering your MIDI setup without having to change presets on
each channel.
The last presets sent to each channel are saved at power down and are available immediately at power up. Also,
the current MIDI mode is saved at power down.
CONTROLLER USAGE
The Bass II responds to several MIDI controller messages, adding a variety of expression not normally achieved -with
a sample playback device.
If your controller lacks the ability to transmit some of these messages, check out the Peavey PC 1600, which can
transmit any controller on sixteen separate sliders, as well as perform real time MIDI mixdown and Sysex control.
In addition to the usual mod wheel, aftertouch, and sustain messages, the Bass n responds to the following controllers:
Volume Controller (#7)
This can be used to control the volume via MIDI, either for overall level control as in Poly mode, or to mix
the levels of the six channels comprising the Multi.
«•* Pan Controller (#10)
This can be used to control the stereo placement of presets as follows:
Values 0-63 will result in placement from hard left to just left of center.
Values 64-127 will result in placement from center to hard right.
This can be used for a set and forget fixed value stereo placement, or in a real time pan sweep.
«•* Legato Footswitch Controller (#68)
This controller is used to switch the playing style between normal and legato as follows:
Values 0-63 will result in normal playing style.
Peavey Electronics Corporation 13

Chapter 4
Basic Operation
Values 64-127 will result in legato playing style.
See the section on MIDI Modes for more discussion on legato playing.
GLOBAL BEND RANGE (PRG, 0-24)
The pitch bend range used by the Bass II normally comes from each patch (powerup default). You can, however,
use this global override so that the bend range is constant for all patches. To see the bend range, press and hold
Transpose, then press Fine. At this point, the number can be edited with the ▼ and A buttons, (e.g., Prg = use
patch info, 0 = off, 24 = 2 octaves, etc.)
PRESET CONTROL
Use the ▼ and A buttons to select a preset. When you power down, the last preset will return on power up. To
increase the scrolling speed, press both the ▼ and A buttons. For instance, to scroll up faster first press the A button
then press the T button.
AUTOFLOW
Autoflow provides a simple and instant way to configure a second Bass n module for overflow purposes. When
a MIDI cable is connected from the MIDI Out of the first unit to the MIDI In of the second, overflow status is
automatically detected. Autoflow will cause the first unit in the chain to send out Note On and other events to the
second unit when the maximum polyphony (12 voices) has been exceeded.
Autoflow mode is intended to work with additional Bass II modules which have the same configuration as the first
in the chain-channel, MIDI Mode, Multi presets, etc. Using Autoflow with any other MIDI tone module may not
produce the expected results.
Note: If the Bass ITs MIDI output is connected to something other than another Bass II (like a MIDI patchbay or
librarian), you will want to disable the Autoflow feature so notes that you play are not sent over MIDI and
“ignored” by the unit on the other end. Press and hold Transpose, then press Channelto see the Autoflow
enable status. Switch it between “on” and “off’ with the T and A buttons.
REINITIALIZATION
This operation restores the factory default settings and patches, erases any RAM patches, and erases any edits you
have made. Ini tializat ion is used as a service procedure. Sometimes microprocessor controlled devices will “lock
up” due to spikes on the AC line, a static electricity jolt, or other gremlins. Initialization will reset the unit and in many
cases, prevent a trip to the repair shop. The Spectrum Bass II can be reinitialized using the following procedure:
▼ To reinitialize
1. Press and hold the ▼ and A buttons while applying power to the unit. The display will read “ini” for a short
time while initializing.
14
Spectrum " Bass II

Chapter 5 Beyond the Basks
Chapter 5 Beyond the Basics
Not everyone wants or even needs to learn to program their synth modules; in a way programming a synth module
is an art unto itself. As such, it is not possible to learn everything you need to know in a short period of time or from
one “tell all” source, instead it may take years of experimenting to achieve the expertise you may desire. What we
will try to do in this chapter is provide some background information on modulation, oscillators, etc. In addition,
we will list the various patches and controllable parameters available when you use the Spectrum Bass n with a
PC 1600 MIDI Controller. While it is possible to control these same parameters using various computer software
programs and the system exclusive section of this manual, using the PC 1600 is easier since we have taken the time
to develop the necessary sysex strings required to control the Bass II. Either way, were sure you’ll find the Spectrum
Bass II a very versatile and extremely powerful tool for creating those special bass sounds you seek.
DID YOU KNOW...
Early synthesizers consisted of various hardware modules, some of which generated signals, and some of which
modified those signals. To create as general-purpose a device as possible, patch cords connected the inputs and
outputs of the various signal generating and processing modules (which is why particular synth sounds were called
patches). Changing a patch involved manually repositioning patch cords and adjusting knobs and switches;
recreating a patch at some later time required writing down all the patch settings on paper so they could be duplicated
later. Even then, due to the vagaries of analog electronics, the patch might not sound exactly the same.
Over the years, certain combinations of modules seemed to work better than others, and since patch cords were
troublesome to deal with, eventually these modules were wired together in a “normalized” configuration.
Synthesizers such as the Minimoog, Prophet-5, and others eliminated the need for patch cords by containing a
normalized collection of sound modules.
HOW SOUND IS GENERATED
The Spectrum Bass II Synthesizer Architecture
The following figure shows the signal flow for a two or four wave voice (total of twelve or six voices, respectively).
Oscillator
1
Generates
Raw
Waveforms
DCA 1
Filter
Alters
Waveform
Dynamics
Alters
Waveform
Timbre
Amp Env
Alters
Signal
Dynamics
Left Output
Right Output
Sets overall
Level and
Panning
Peavey Electronics Corporation
15

Chapter 5 Beyond the Basics
Generates Alters Alters Alters
Raw Waveform Waveform Signal
Waveforms Dynamics Timbre Dynamics
Left Output
Right Output
Sets overall
Level and
Panning
Oscillators
The four digital oscillators (OSC1 through OSC4) provide the actual raw sounds, called loaves. These can draw from
any of the 78 on-board wavesamples. Each oscillator allows for adjustable wave pitch and modulation. Modulation
is the process of varying a parameter dynamically over time; with the oscillators, the pitch can be modulated by
various control sources, as described later.
Five oscillator combinations are possible:
Oscillators 1 and 2
Oscillators 3 and 4
All four oscillators layered (limits the polyphony to 6 notes)
Oscillator pairs cross switch (uses all four oscillators with a switch point to cross from the first pair to
the second).
Oscillator pairs crossfade (uses all four oscillators with a switch point to crossfade from the first pair to
the second).
Wave Start Offset
Each waveform is divided into 128 potential start points. By changing the start point, it is possible to change the phase
relationship between two waves.
Oscillator Sync
Oscillator Sync ON allows two^bscillators which are tuned fairly close to be “synced” or locked together in pitch.
To achieve a very cool effect, change the pitch of the second oscillator. This will cause the second oscillator’s pitch
to produce successive harmonics of oscillator one’s fundamental. Give it a try.. .you’ll love it.
16
SpecrtumBass II

Chapter 5 Beyond the Basics
DCAs
Each oscillator is followed by a DCA, which can modulate the level of the wave either statically (you set a particular
volume level) or dynamically (the level changes over time in a specific way).
Having four DCAs allows for, among other effects, cross-fades between the four oscillators. Example: One DCA could
fade out a flute sound while the other DCA fades in a synth waveform to create a synth flute sound.
The “Amp Env” is a DCA that follows the filter. The ampenv generally sets the overall dynamics.
Pan
This sets the panning modulation of an oscillator pair and sends it to die audio outputs.
Filters
This is a 2 or 4 pole “analog-sounding” filter with resonance. There is one filter for each oscillator pair. This can be:
0-2 pole Loiv Pass Passes the frequencies up to the Cutoff point.
1-4 pole Low Pass Passes the frequencies up to the Cutoff point with a steeper cutoff rate.
2 - Band Pass Passes only a narrow band of frequencies.
3 - High Pass Passes the frequencies above the Cutoff point.
Peavey Electronics Corporation 17

Chapter 5 Beyond the Basics
MODULATION AND THE SPECTRUM BASS II
Modulation modifies some aspect of a sound over a period of time. Since synthesizers inherently make static sounds
(unlike acoustic instruments, whose timbre and dynamics change—often radically—over the duration of a note),
modulation can be the key to making rich and expressive sounds. The Bass II has a variety of modulation sources,
shown in the chart on page 22. Here’s an overview of the main modulation categories.
«•* Modulation signals generated by the way you play the keyboard or other controller driving the Bass II (velocity,
note position, and pressure)
Envelope generators (these produce a programmable modulation change over time)
LFOs (these produce periodic, cyclic modulation changes over time, such as vibrato or tremolo)
Performance controls (modulation wheel, foot pedal, and data slider, which are designed to be manipulated
in real time, as you play)
*•“ External MIDI control. This allows external MIDI control signals (e.g., from a sequencer) to control some aspect
of die Bass IPs sound.
The Bass II arranges its modulation source outputs and modulation destination inputs into a “matrix” so that virtually
any output can feed virtually any input. The Wave, DCA, Filter, and Pan modules have two independent inputs that
can be assigned to any modulation source. The LFO has one independent input that controls modulation amplitude
(depth), an input that controls modulation rate, plus a separate modulation wheel control for LFO depth and rate.
Each non-normed modulation input includes two parameters: modulation source (including OFF if no modulation
is desired) which lets you choose from die various modulation sources mentioned above, and modulation amount.
The modulation amount can be positive or negative. With positive amounts, an increasing control signal increases
the value of the parameter being controlled. With negative amounts, an increasing control signal decreases the value
of the parameter being controlled. A setting of 00 is equivalent to turning off the modulation source.
Note that having two modulation inputs available allows for interaction between two modulation signals. Example:
If a parameter responds to keyboard velocity and an envelope generator, the parameter will follow the general
envelope shape but also be influenced by the velocity.
If a “baseline” setting exists, modulation amounts add or subtract values from that setting. Example 1: If the filter cutoff
is set to a certain frequency, positive modulation amounts will increase that frequency, and negative modulation
amounts will decrease that frequency. However, modulation cannot force a value beyond its maximum range.
Example 2: If die filter cutoff is at die lowest possible frequency, then maximum positive modulation will vary the
filter cutofffrom the lowest to the highest frequency. Applying negative modulation will not affect the filter frequency
because if it’s at its lowest value, it cannot go any more negative.
To achieve modulation, you must first assign a source. This source can be something you physically move
(Modulation Wheel, Aftertouch (pressure), Foot Pedal, Velocity (how hard you play a note), Pitch wheel, keyboard
(specific notes) etc., or synthesizer parameters such as the Envelopes, LFO, Sample & Hold, Key Scalar, etc. Next,
the source must be assigned To a DESTINATION (die parameter that is actually going to be modulated).
18 Specrtum “ Bass II