novation Bass Station II Analog Synthesizer User Guide

novation Bass Station II Analog Synthesizer User Guide

Novation
A division of Focusrite Audio Engineering Ltd.
Windsor House,
Turnpike Road,
Cressex Business Park,
High Wycombe,
Bucks,
HP12 3FX.
United Kingdom

Tel: +44 1494 462246
Fax: +44 1494 459920
e-mail: sales@novationmusic.com
Web: http://www.novationmusic.com

Trademarks
The Novation trademark is owned by Focusrite Audio Engineering Ltd. All other brand, product and company names and any other registered names or trade marks mentioned in this manual belong to their respective owners.

Disclaimer
Novation has taken all possible steps to ensure that the information given here is both correct and complete. In no event can Novation accept any liability or responsibility for any loss or damage to the owner of the equipment, any third party, or any equipment which may result from use of this manual or the equipment which it describes. The information provided in this document may be modified at any time without prior warning. Specifications and appearance may differ from those listed and illustrated.

IMPORTANT SAFETY INSTRUCTIONS

1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus with water.
6. Clean only with dry cloth.
7. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
8. Do not defeat the safety purpose of the polarised or grounding-type plug. A polarised plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
9. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
10. Only use attachments/accessories specified by the manufacturer.
11. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
12. Unplug this apparatus during lightning storms or when unused for long periods of time.
13. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
14. No naked flames, such as lighted candles, should be placed on the apparatus.

WARNING: Excessive sound pressure levels from earphones and headphones can cause hearing loss.
WARNING: This equipment must only be connected to USB 1.1 or 2.0 type ports.

CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK). NO USER-SERVICABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

The lightning flash with arrowhead symbol within an equilateral triangle is 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 the risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the appliance.
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.

ENVIRONMENTAL DECLARATION

Compliance Information Statement: Declaration of Compliance procedure
Product Identification: Novation Bass Station II keyboard
Responsible party: American Music and Sound
Address: 4325 Executive Drive, Suite 300 Southaven, MS 38672
Telephone:800-431-2609

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

For USA
To the User:

1. Do not modify this unit! This product, when installed as indicated in the instructions contained in this manual, meets FCC requirements. Modifications not expressly approved by Novation may void your authority, granted by the FCC, to use this product.
2. Important: This product satisfies FCC regulations when high quality shielded USB cables with integral ferrite are used to connect with other equipment. Failure to use high quality shielded USB cables with integral ferrite or to follow the installation instructions within this manual may cause magnetic interference with appliances such as radios and televisions and void your FCC authorisation to use this product in the USA.
3. Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

For Canada
To the User:
This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.

RoHS Notice
Novation has conformed and product conforms, where applicable, to the European Union’s Directive 2002/95/EC on Restrictions of Hazardous Substances (RoHS) as well as the following sections of California law which refer to RoHS, namely sections 25214.10, 25214.10.2, and 58012, Health and Safety Code; Section 42475.2, Public Resources Code.

CAUTION:
The normal operation of this product may be affected by a strong electrostatic discharge (ESD). In the event of this happening, simply reset the unit by removing and then replugging the USB cable. Normal operation should return.

COPYRIGHT AND LEGAL NOTICES
Novation is a registered trade mark of Focusrite Audio Engineering Limited. Bass Station II is a trade mark of Focusrite Audio Engineering Limited.
2013 © Focusrite Audio Engineering Limited. All rights reserved.

INTRODUCTION

Thank you for purchasing this Bass Station II digitally-controlled analogue synthesiser.
Based on the classic 1990s Novation Bass Station synth, it combines traditional analogue waveform generation and processing with the power and flexibility of digital control, plus a set of effects and presets for the 21st century.

NOTE: Bass Station II is capable of generating audio with a large dynamic range, the extremes of which can cause damage to loudspeakers or other components, and also to your hearing!

Key Features
• Classic analogue waveform generation
• Two multi-waveform oscillators plus separate sub oscillator
• Analogue signal path – filters, envelopes, modulation
• Traditional “single function” style rotary controls
• LP/BP/HP filters with variable slope
• Separate dual LFO section
• Ring Modulator (inputs: Oscs 1 and 2)
• Versatile 32-step arpeggiator with wide range of patterns
• 32-step sequencer with four memories
• Portamento with dedicated time control
• Pre-loaded with 64 brand new Killer Patches
• Memory for 64 additional User Patches
• Pitch and Mod wheels
• 25-note velocity-sensitive keyboard with aftertouch
• -5/+4 octave keyboard shift
• Key transpose function
• On-Key functions – use the keyboard to adjust non-performance sound parameters
• MIDI input and output
• LED display for patch selection, parameter adjustment, octave settings, etc.
• External DC input (for supplied AC PSU)
• Class-compliant USB port (no drivers required), for alternative DC power, patch dump and MIDI
• External audio input to mixer section
• Headphone output
• Sustain pedal socket
• Kensington Security Slot

About This Manual
We’ve tried to make this manual as helpful as possible for all types of user, and this inevitably means that more experienced users will want to skip over certain parts of it, while relative novices will want to avoid certain parts of it until they’re confident they’ve mastered the basics.

However, there are a few general points that are useful to know about before you continue reading this manual. We’ve adopted some graphical conventions within the text, which we hope all types of user will find helpful in navigating through the information to find what they need to know quickly:

Abbreviations, conventions, etc.
Where top panel controls or rear panel connectors are referred to, we’ve used a number thus: 1 to cross-reference to the top panel diagram, and thus: 1 to crossreference to the rear panel diagram. (See page 5 and page 6).

We’ve used BOLD TEXT (or Bold Text) to name top panel controls or rear panel connectors; we’ve made a point of using exactly the same names as appear on the Bass Station II. We’ve used SEVEN-SEGMENT DIGITS to denote numbers that appear on the top panel LED display.

Tips
These do what it says on the tin: we include bits of advice, relevant to the topic being discussed that should simplify setting up Impulse to do what you want. It’s not mandatory that you follow them, but generally they should make life easier.

These are additions to the text that will be of interest to the more advanced user and can generally be avoided by the novice. They are intended to provide a clarification or explanation of a particular area of operation.

What’s In The Box
Your Bass Station II has been carefully packed in the factory and the packaging was designed to withstand rough handling. Should the unit appear to have been damaged in transit, do not discard any of the packing material and notify your music dealer.
If practical, save all the packing materials in case you ever need to ship the unit again.
Please check the list below against the contents of the packaging. If any items are missing or damaged, contact the Novation dealer or distributor where you purchased the unit.

• Bass Station II synthesiser
• DC power supply unit (PSU)
• USB cable
• Bundle Code for registration

Registering your Bass Station II
Registration of your Bass Station II is optional, however in doing so you will gain access to a range of free bundled software and access to Novation Components standalone software.

Power Requirements
Bass Station II is shipped with a 9 V DC, 500 mA power supply. The centre pin of the coaxial connector is the positive (+ve) side of the supply. Bass Station II can either be powered by this AC-to-DC mains adaptor, or by a USB connection to a computer. To obtain the best possible audio performance from Bass Station II we recommend using the supplied adaptor.

There are two versions of the PSU, your Bass Station II will be supplied with the one appropriate to your country. In some countries the PSU comes with detachable adaptors; use the one that fits your country’s AC outlets. When powering Bass Station II with the mains PSU, please ensure that your local AC supply is within the range of voltages required by the adaptor – i.e., 100 to 240 VAC – BEFORE you plug it into the mains.

We strongly recommend that you only use the supplied PSU. Using alternative PSUs will invalidate your warranty. Power supplies for your Novation product can be purchased from your music dealer if you have lost yours.

If the synth is powered via the USB port, note that it will “go to sleep” if the host computer goes into power save mode. The synth can be “woken-up” again by pressing any key; however, this does not alter the power status of the computer.

A word about laptops:
If powering your Bass Station II via the USB connection you should be aware that although the USB specification agreed by the IT industry states that a USB port should be able to supply 0.5 A at 5 V, some computers – particularly laptops – are unable to supply this current. Unreliable operation of the synth will result in such a case. When powering Bass Station II from a laptop’s USB port, it is strongly recommended that the laptop is powered from AC mains rather than its internal battery.

Hardware Overview

GETTING STARTED

Bass Station II may be used as a standalone synthesiser, or with MIDI connections to/ from other sound modules or keyboards. It may also be connected – via its USB port – to a computer (Windows or Mac). The USB connection can supply power to the synth, transfer MIDI data to/from a MIDI sequencer application and allow Patches to be saved to memory.

The simplest and quickest way of getting started with Bass Station II is to connect the rear panel jack socket marked LINE Output (7) to the input of a power amplifier, audio mixer, powered speaker, third-party computer sound card or other means of monitoring the output.

Loading Patches
Bass Station II can store 128 Patches in memory. 0 – 63 are pre-loaded with some great factory sounds. 64 – 127 are intended for storing user Patches, and are all pre-loaded with the same default “initial” Patch (see “Init Patch – parameter table” on page 22).

A Patch is loaded by simply scrolling up or down to the Patch number with the Patch buttons (8) ; the Patch is immediately active and the LED display shows the current
patch number. The Patch buttons can be held down for fast scrolling.

Note that when you change Patch, you lose the current synth settings. If the current settings were a modified version of a stored Patch, these modifications will be lost. Thus it is always advisable to save your settings before loading a new patch. See Saving Patches below.

Saving Patches

The Bass Station II Factory Patches can be downloaded from the Novation website and Novation Components if they have been accidentally overwritten. See “Importing Patches via SysEx”

Basic Operation – sound modification
Once you have loaded a Patch you like the sound of, you can modify the sound in many different ways using the synth controls. Each area of the control panel is dealt with in greater depth later in the manual, but a few fundamental points should be discussed here:

The LED display
The three-segment alphanumeric display will normally show the number of the currently-loaded Patch (0 to 127). As soon as you change any “analogue” parameter – i.e., turn a rotary control or adjust an On-Key function, it will display the parameter value (most are either 0 to 127 or -63 to +63), with one of two arrows being highlighted (at the right-hand side). These arrows indicate which direction the control needs to be turned in order to match the value stored in the patch. It reverts to the Patch number display after the control is released.

The Filter knob
Adjusting the frequency of the synth’s filter is probably the most commonly- used method of sound modification. For this reason, Filter Frequency has its own dedicated large rotary control (34) at the panel top right. Experiment with different types of patch to hear how changing the filter frequency alters the characteristic of different types of sound.

Pitch and Mod wheels
Bass Station II is fitted with a standard pair of synthesiser control wheels (2) adjacent to the keyboard, Pitch and Mod (Modulation). The Pitch control is spring-loaded and always returns to the centre position.

Moving Pitch will always raise or lower the pitch of the note(s) being played. The maximum range of operation is 12 semitones up or down, but this may be adjusted using On-Key function Oscillator: Pitch Bend Range (Upper C#).

The Mod wheel’s precise function varies with the patch loaded; it is used in general to add expression or various elements to a synthesised sound. A common use is to add vibrato to a sound.

It is possible to assign the Mod wheel to alter various parameters making up the sound – or a combination of parameters simultaneously. This topic is discussed in more detail elsewhere in the manual. See ‘On-key functions (mod wheel) on page 22.

Octave Shift
These two buttons (3) transpose the keyboard up or down one octave each time they are pressed, to a maximum of four octaves downwards, or five octaves upwards. The number of octaves by which the keyboard is shifted is indicated by the LED display.

Pressing both buttons together (Reset) returns the keyboard to its default pitch, where the lowest note on the keyboard is one octave below Middle C.

Transpose
The keyboard may be transposed up or down one octave, in semitone increments.
To transpose, hold down the Transpose button (4) , and hold down the key representing the key that you wish to transpose to. Transposition is relative to Middle C. For example, to shift the keyboard up four semitones, hold Transpose and press E above Middle C. To return to normal pitching, perform the same actions, only select Middle C as the target key.

SYNTHESIS TUTORIAL

This section covers the general principles of electronic sound generation and processing in more detail, including references to Bass Station II’s facilities where relevant. It is recommended that this chapter is read carefully if analogue sound synthesis is an unfamiliar subject. Users familiar with this subject can skip this section and move on to the next.

To gain an understanding of how a synthesiser generates sound it is helpful to have an appreciation of the components that make up a sound, both musical and non-musical.
The only way that a sound may be detected is by air vibrating the eardrum in a regular, periodic manner. The brain interprets these vibrations (very accurately) into one of an infinite number of different types of sound.

Remarkably, any sound may be described in terms of just three properties, and all sounds always have them. They are:
• Pitch
• Tone
• Volume

What makes one sound different from another is the relative magnitudes of the three properties as initially present in the sound, and how the properties change over the duration of the sound.

With a musical synthesiser, we deliberately set out to have precise control over these three properties and, in particular, how they can be changed during the “lifetime” of the sound. The properties are often given different names: Volume may be referred to as Amplitude, Loudness or Level, Pitch as Frequency and Tone as Timbre.

Pitch

As stated, sound is perceived by air vibrating the eardrum. The pitch of the sound is determined by how fast the vibrations are. For an adult human, the slowest vibration perceived as sound is about twenty times a second, which the brain interprets as a bass type sound; the fastest is many thousands of times a second, which the brain interprets as a high treble type sound.

If the number of peaks in the two waveforms (vibrations) are counted, it will be seen that there are exactly twice as many peaks in Wave B as in Wave A. (Wave B is actually an octave higher in pitch than Wave A). It is the number of vibrations in a given period that determines the pitch of a sound. This is the reason that pitch is sometimes referred to as frequency. It is the number of waveform peaks counted during a given period of time which defines the pitch, or frequency.

Tone
Musical sounds consist of several different, related pitches occurring simultaneously.
The loudest is referred to as the ‘fundamental’ pitch and corresponds to the perceived note of the sound. Other pitches making up the sound which are related to the fundamental in simple mathematical ratios are called harmonics. The relative loudness of each harmonic as compared to the loudness of the fundamental determines the overall tone or ‘timbre’ of the sound.

Consider two instruments such as a harpsichord and a piano playing the same note on the keyboard and at equal volume. Despite having the same volume and pitch, the instruments still sound distinctly different. This is because the different notemaking mechanisms of the two instruments generate different sets of harmonics; the harmonics present in a piano sound are different to those found in a harpsichord sound.

Volume
Volume, which is often referred to as the amplitude or loudness of the sound, is determined by how large the vibrations are. Very simply, listening to a piano from a metre away would sound louder than if it were fifty metres away.

Having shown that just three elements may define any sound, these elements now have to be related to a Musical synthesiser. It is logical that a different section of the Synthesiser ‘synthesises’ (or creates) these different elements.

One section of the synthesiser, the Oscillators, provide raw waveform signals which define the pitch of the sound along with its raw harmonic content (tone). These signals are then mixed together in a section called the Mixer, and the resulting mixture is then fed into a section called the Filter. This makes further alterations to the tone of the sound, by removing (filtering) or enhancing certain of the harmonics. Lastly, the filtered signal is fed into the Amplifier, which determines the final volume of the sound.

Additional synthesiser sections – LFOs and Envelopes – provide further ways of altering the pitch, tone and volume of a sound by interacting with the Oscillators, Filter and Amplifier, providing changes in the character of the sound which can evolve over time. Because LFOs’ and Envelopes’ only purpose is to control (modulate) the other synthesiser sections, they are commonly known as ‘modulators’.

These various synthesiser sections will now be covered in more detail.

The Oscillators And Mixer
The Oscillator section is really the heartbeat of the synthesiser. It generates an electronic wave (which creates the vibrations when eventually fed to a loudspeaker).
This Waveform is produced at a controllable musical pitch, initially determined by the note played on the keyboard or contained in a received MIDI note message. The initial distinctive tone or timbre of the waveform is actually determined by the waveform’s shape.

Many years ago, pioneers of musical synthesis discovered that just a few distinctive waveforms contained many of the most useful harmonics for making musical sounds.
The names of these waves reflect their actual shape when viewed on an instrument called an oscilloscope, and they are: Sine waves, Square waves, Sawtooth waves,
Triangle waves and Noise. Bass Station II’s Oscillator section can generate all these waveforms.

Each waveform shape (except Noise) has a specific set of musically-related harmonics which can be manipulated by further sections of the synthesiser.
The diagrams below show how these waveforms look on an oscilloscope, and illustrate the relative levels of their harmonics. Remember, it is the relative levels of the various harmonics present in a waveform which determine the tone of the final sound.

Sine Waves

These possess just one harmonic. A sine waveform produces the “purest” sound because it only has this single pitch (frequency).

Triangle Waves

These contain only odd harmonics. The volume of each decreases as the square of its position in the harmonic series. For example, the 5th harmonic has a volume 1/25th of the volume of the fundamental.

Sawtooth Waves

These are rich in harmonics, and contain both even and odd harmonics of the fundamental frequency. The volume of each is inversely proportional to its position in the harmonic series.

Square / Pulse Waves

These contain only odd harmonics, which are at the same volume as the odd harmonics in a sawtooth wave.

It will be noticed that the square waveform spends an equal amount of time in its ‘high’ state as in its ‘low’ state. This ratio is known as the ‘duty cycle’. A square wave always has a duty cycle of 50% which means it is ‘high’ for half the cycle and ‘low’ for the other half. Bass Station II lets you adjust the duty cycle of the basic square waveform to produce a waveform which is more ‘rectangular’ in shape. These are often known as Pulse waveforms. As the waveform becomes more and more rectangular, more even harmonics are introduced and the waveform changes its character, becoming more ‘nasal’ sounding.

The width of the pulse waveform (the ‘Pulse Width’) can be altered dynamically by a modulator, which results in the harmonic content of the waveform constantly changing.
This can give the waveform a very ‘fat’ quality when the pulse width is altered at a moderate rate.

A pulse waveform sounds the same whether the duty cycle is – for example – 40% or 60%, since the waveform is just “inverted” and the harmonic content is exactly the same.

Noise
Noise is basically a random signal, and has no one fundamental frequency (and therefore no pitch property). All frequencies are present in noise, and all have the same volume. Because it possesses no pitch, noise is often useful for creating sound effects and percussion type sounds.

The Mixer
To extend the range of sounds that may be produced, typical analogue synthesisers have more than one Oscillator. By using multiple Oscillators to create a sound, it is possible to achieve very interesting harmonic mixes. It is also possible to slightly detune individual Oscillators against each other, which creates a very warm, ‘fat’ sound. Bass Station II’s Mixer allows you create a sound consisting of the waveforms of Oscillators 1 and 2, the separate sub-octave oscillator, a Noise source, the Ring Modulator output and an external signal, all mixed together as required.

The Filter
Bass Station II is a subtractive music synthesiser. Subtractive implies that part of the sound is subtracted somewhere in the synthesis process.

The Oscillators provide the raw waveforms with plenty of harmonic content and the Filter section subtracts some of the harmonics in a controlled manner.

7 types of Filter are available on Bass Station II; they are all variations of the three basic filter types: Low Pass, Band Pass and High Pass. The type of Filter most commonly used on synthesisers is Low Pass. On a Low Pass Filter, a “cut-off frequency” is chosen and any frequencies below this are passed, while frequencies above are filtered out, or removed. The setting of the Filter Frequency parameter dictates the point above which frequencies are removed. This process of removing harmonics from the waveforms has the effect of changing the sound’s character or timbre. When the Frequency parameter is at maximum, the filter is completely “open” and no frequencies are removed from the raw Oscillator waveforms.

In practice, there is a gradual (rather than a sudden) reduction in the volume of the harmonics above the cut-off point of a Low Pass Filter. How rapidly these harmonics reduce in volume as frequency increases above the cut-off point is determined by the Filter’s slope. The slope is measured in ‘volume units per octave’. Since volume is measured in decibels, this slope is usually quoted as so many decibels per octave (dB/ oct). The higher the number, the greater the rejection of harmonics above the cutoff point, and the more pronounced the filtering effect. Bass Station II’s filter section provides two slopes, 12 dB/oct and 24 dB/oct.

A further important parameter of the Filter is its Resonance. Frequencies at the cut-off point may be increased in volume by the Filter Resonance control. This is useful for emphasising certain harmonics of the sound.

As Resonance is increased, a whistling-like quality will be introduced to the sound passing through the filter. When set to very high levels, Resonance actually causes the filter to self-oscillate whenever a signal is being passed through it. The resulting whistling tone being produced is actually a pure sine wave, the pitch of which depends on the setting of the Frequency knob (the filter’s cut-off point). This resonanceproduced sine wave can actually be used for some sounds as an additional sound source if wished.

The diagram below shows the response of a typical low pass filter. Frequencies above the cut-off point are reduced in volume.

When resonance is added, the frequencies around the cut off point are boosted in volume.

In addition to the traditional Low Pass Filter type, there are also High Pass and Band Pass types. On Bass Station II, the Filter type is selected with the Shape switch 32 .

A High Pass Filter is similar to a Low Pass Filter, but works in the “opposite sense”, so that frequencies below the cut-off point are removed. Frequencies above the cutoff point are passed. When the Filter Frequency parameter is set to zero, the filter is completely open and no frequencies are removed from the raw Oscillator waveforms.

When a Band Pass Filter is used, only a narrow band of frequencies centered around the cut- off point are passed. Frequencies above and below the band are removed. It is not possible to fully open this type of Filter, and allow all frequencies to pass.

Envelopes And Amplifier
In earlier paragraphs, the synthesis of the pitch and the timbre of a sound was described. The next part of the Synthesis Tutorial describes how the volume of the sound is controlled. The volume of a note created by a musical instrument often varies greatly over the duration of the note, according to the type of instrument.

For example, a note played on an Organ quickly attains full volume when a key is pressed. It stays at full volume until the key is released, at which point the volume level falls instantly to zero.

A String Section emulation only attains full volume gradually when a key is pressed. It remains at full volume while the key is held down, but once the key is released, the volume falls to zero fairly slowly.

In an analogue synthesiser, changes to a sound’s character which occur over the duration of a note are controlled by a section called an Envelope Generator. Bass Station II has two Envelope Generators; one (Amp Env) is always related to the Amplifier, which controls the note’s amplitude – i.e., the volume of the sound – when the note is played. Each envelope generator has four main controls, which are used to adjust the shape of the envelope (often referred to as the ADSR parameters).

Attack Time
Adjusts the time it takes after a key is pressed for the volume to climb from zero to full volume. It can be used to create a sound with a slow fade-in.

Decay Time
Adjusts the time it takes for the volume to fall from its initial full volume to the level set by the Sustain control while a key is held down.

Sustain Level
This is unlike the other Envelope controls in that it sets a level rather than a period of time.
It sets the volume level that the envelope remains at while the key is held down, after the Decay Time has expired.

SIMPLIFIED BLOCK DIAGRAM

Bass Station II Block diagram

Oscillator modulation controls

Release Time
Adjusts the time it takes for the volume to fall from the Sustain level to zero once the key is released. It can be used to create sounds that have a “fade-out” quality.

Most synthesisers can generate multiple envelopes. One envelope is always applied to the amplifier to shape the volume of each note played, as detailed above. Additional envelopes can be used to dynamically alter other sections of the synthesiser during the lifetime of each note. Bass Station II’s second Envelope Generator (Mod Env) can be used to modify the filter cut-off frequency, or the pulse width of the Oscillators’ Square Wave outputs.

LFOs
Like the Envelope Generators, the LFO section of a synthesiser is a Modulator. Thus instead of being a part of the sound synthesis itself, it is used to change (or modulate) other sections of the synthesiser. In Bass Station II, for example, the LFOs can be used to alter Oscillator pitch, or Filter cutoff frequency.

Most musical instruments produce sounds that vary over time both in volume and in pitch and timbre. Sometimes these variations can be quite subtle, but still contribute greatly towards characterising the final sound.

Whereas an Envelope is used to control a one-off modulation over during the lifetime of a single note, LFOs modulate by using a repeating cyclic waveform or pattern. As discussed earlier, Oscillators produce a constant waveform, which can take the shape of a repeating sine wave, triangle wave etc. LFOs produce waveforms in a similar way, but normally at a frequency which is too low to produce a sound that the human ear could perceive directly. (LFO stands for Low Frequency Oscillator.) As with an Envelope, the waveforms generated by the LFOs may be fed to other parts of the synthesiser to create the desired changes over time – or ‘movements’ – to the sound. Bass Station II has two independent LFOs, which may be used to modulate different synthesiser sections and can run at different speeds.

Imagine this very low frequency wave being applied to an Oscillator’s pitch. The result is that the pitch of the Oscillator slowly rises and falls above and below its original pitch.

This would simulate, for example, a violinist moving a finger up and down the string of the instrument whilst it is being bowed. This subtle up and down movement of pitch is referred to as the ‘Vibrato’ effect.

A waveshape often used for an LFO is a Triangle wave.

Alternatively, if the same LFO signal were to modulate the Filter cut-off frequency instead of the Oscillator pitch, a familiar wobbling effect known as ‘wah-wah’ would be the result.

Summary
A synthesiser can be broken down into five main sound generating or sound modifying (modulating) blocks:

1. Oscillators that generate waveforms at a various pitches
2. A Mixer that mixes the outputs from the Oscillators together (and add Noise and other signals)
3. Filters that remove certain harmonics, changing the character or timbre of the sound
4. An Amplifier controlled by an Envelope generator, which alters the volume of a sound over time when a note is played
5. LFOs and Envelopes that can be used to modulate any of the above

Much of the enjoyment to be had with a synthesiser is with experimenting with the factory preset sounds (Patches) and creating new ones. There is no substitute for ‘hands on‘ experience. Experiments with adjusting Bass Station II’s various controls will eventually lead to a fuller understanding of how the various synth sections alter and help shape new sounds. Armed with the knowledge in this chapter, and an understanding of what is actually happening in the synth when tweaks to the knobs and switches are made, the process of creating new and exciting sounds will become easy. Have fun!

BASS STATION II IN DETAIL

The Oscillator Section

Negative values of LFO 1 depth “invert” the modulating LFO waveform; the effect of this will be more obvious with non-sinusoidal LFO waveforms.

Adding LFO Modulation can add a pleasing vibrato when a sine or triangle LFO waveform is used, and the LFO speed is set neither too high nor too low. A sawtooth or square LFO waveform will produce rather more dramatic and unusual effects. Adding envelope modulation can give some interesting effects, with the oscillator pitch altering over the duration of the note as it is played. The control is “centre-off”, the LED display shows a range of -63 to +63 as it is adjusted. With the parameter value set to maximum, the oscillator pitch will vary over eight octaves. A parameter value of 8 shifts the pitch of the oscillator by one octave for the maximum level of the modulation envelope (e.g., if sustain is at maximum). Negative values invert the sense of the pitch variation; i.e., the pitch will fall during the attack phase of the envelope if Mod Env depth has a negative setting.

Oscillator Error
To create a bit more carnage it’s now possible to introduce random detune to your oscillators each time a key is pressed. The error follows a pseudo-random function, so it should be different every time you press and give you impression of an older analogue synthesiser.

To turn on oscillator error: hold the function key and press Pitch Bend Range twice.
The screen will change to:E-0. Use the patch value keys to change this value from 0-7. 0 is no error, and 7 represents an error of maximum approximately 1 semitone.

Oscillator error can be saved in the patch. By default it will be 0 (no error). When in paraphonic mode the error will be different for each part.

Extended Sub-Oscillator Tuning
By default the Sub-Oscillator follows the pitch of oscillator 1. The Sub- Oscillator can now be detuned from oscillator 1 using the Coarse/Fine controls. This means all 3 oscillators can be tuned to different pitches to create interesting intervals and triad chords with single key presses.

To adjust the tuning of the Sub-Oscillator press and hold the Function key whilst adjusting the oscillator Coarse/Fine tune controls.

When the Sub-Oscillator detune is set to 0, it will match the detune of Oscillator 1, which is the default.

The Mixer Section

The Filter Section

Envelope Retriggering must be turned on for this feature to be effective. To turn on Envelope Retriggering, hold Function and press the Amp-Env or Mod-Env function keys twice (until the display changes to r-0), then use Patch </> buttons to select r-1. To set the number of times the envelope will loop, hold Function and press the Amp-
Env or Mod-Env key three times (until the display changes to c-0). When set to c-0 the envelope will loop indefinitely, this is the default setting. Select from c-[1-16] (using the Patch </> buttons) to set the number of loops from 1 to 16. Fixed Duration Sustain Envelopes

The sustain period of both the amp and mod envelopes can be set to a fixed time. This is especially useful for using the Bass Station II to design drum sounds.

When active, the envelope will move to the release stage a set period of time after the sustain stage, regardless of whether the triggering note is released or not.

When you enable fixed duration sustain, the decay stage is removed from the envelope.
The decay slider will now determine the duration of the sustain stage of the envelope.
To change the envelopes to a fixed-duration mode, hold Function and press the Amp- Env or Mod-Env key four times (until the display changes to d-0). Set the display to d-1 to enabled fixed duration envelopes.

When enabled, fixed duration sustain envelopes override the envelope retriggering feature.

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