Editing Instrument parameters is usually quicker and easier than editing the underlying Samples
themselves. In addition, creating Custom Instruments (as opposed to custom Samples) has a negligible
effect on user download times. We would encourage you to experiment with Instrument
editing, even if you aren't creating your own Custom Samples.
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- Note: You can only edit Custom Instruments, not the Built-In Instruments. You can create
new Instruments from scratch, or copy built-in Instruments to the Custom bank, then edit
them. Instruments can be copied and pasted (or dragged and dropped) between Sessions.
The Instrument Editor has five Pages:
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Assigns specific Samples (built-in or custom) to ranges MIDI
notes
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Sets the peak frequency spacing and resonance used by Beatnik's
comb filter, and the tone control
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Controls the amplitude envelope applied to each note
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Sets the Instrument's position in the left-right stereo mix
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Defines up to five modulation sources to further manipulate
an Instrument's sound
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Keymap
The Keymap Page defines which Samples are played across an Instrument's keyboard. As a Sample
is played further from its original pitch, transposition artifacts become more apparent. So,
modern samplers and wavetable synthesizers use multiple samples to create a single Instrument.
For instance, a piano could use half a dozen samples originally recorded across a range of pitches.
An Instrument can contain from 1 to 128 of these zones.
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- See also: Keymap Page in the Instrument Editor window section.
Filter
The Filter Page is the second block in the signal path. Each Instrument can use its own Comb Filter
and tone control. The Comb Filter has both peak frequency spacing and resonance settings.
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In general, the Filter can liven up the sound of an Instrument, as well mask aliasing or noise in a
Sample. The only drawback is that each Filter uses some CPU power, particularly when its resonance
is turned up. When you have a Song that uses a lot of Instruments with Filters, keep an eye
on the CPU Load meter in the Player window to make sure it's performing within acceptable limits.
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The most important Comb Filter setting is its peak frequency spacing. A comb filter has multiple,
fixed peaks evenly spaced across the frequency spectrum. Frequencies in between the peaks are
turned down, removing those components. Peak frequency spacing can be set to a fixed frequency
from 175 to 11,200 Hz. The sound will get progressively brighter and duller as you play across the
keyboard from low notes to high notes, depending on how wide the spacing is.
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There is an alternate to a fixed frequency spacing: The Track Pitch option causes the filter frequency
spacing to increase and decrease as the pitch of the played notes goes up and down the
keyboard. When Track Pitch is enabled, you can allow all notes to have a similar tonal character.
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Another important filter control is Resonance. Resonance creates a hump or frequency boost centered
around the cut-off frequency. The higher the resonance setting, the more audible this hump
becomes. The resonant frequency will follow behavior of the cut-off frequency as described in the
Track Pitch option.
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In addition to the Comb Filter, there's also a Tone Control - a gentle high or low frequency rolloff
filter with a Depth setting:
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- When the Tone setting is positive, the Tone Control rolls off high frequencies.
- When the Tone setting is negative, the Tone Control rolls off low frequencies, and the Comb
Filter is bypassed.
Note that you have the option to dynamically sweep any or all of the continuous filter settings
(comb filter frequency peak spacing and resonance, and tone control) - see the Modulation section.
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- See also: Filter Page in the Instrument Editor window section.
Player Sample Rate and Filter Frequency
- Note: An Instrument with prominent filtering will sound significantly different depending
on whether the listener's Beatnik playback software is operating at 22kHz or 44.1 kHz.As a
result, you should set the Player window playback settings to the same sample rate as the
playback system where you plan your music to be played. For the Beatnik Player for Web
browsers, this is 22kHz. For the Beatnik Xtra, JavaSound, or the Beatnik Audio Engine,
check with your programmer to see what sample rate they intend to use. As you work on
your Instrument in the Beatnik Editor, you may want to listen to your song at a number of
different sample rates, evaluate the sound character of each.
Volume
The Volume Page contains a flexible Envelope Generator that controls the attack, sustain and
release levels of each Instrument's sound. These levels are shown as an editable, graphical curve
defining the note's overall volume contour over time.
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- See also: Volume Page in the Instrument Editor window section.
Output
The Output Page is the simplest part of the Instrument editor. Here, you can set the Instrument's
default Stereo Pan position. You can also disable reverb for the Instrument.
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- See also: Output Page in the Instrument Editor window section.
Modulation
Modulators can make an Instrument more dynamic and interesting, but they make no sound of
their own. Instead, they work by changing (modulating) various parameters of the instrument
dynamically in real time. Parameters like volume, filter settings, or pitch can be modulated by low
frequency oscillators (LFO's) and envelopes. You may have up to five simultaneous modulators
per instrument; it's also OK if your instrument doesn't use any.
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- See also: Modulation Page in the Instrument Editor window section.
As you may know, modulation is a two-part proposition; each modula-tor controls a modula-tee,
if you will. Beatnik has four different types of modulators, and six different Instrument parameters
can be modulated.
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Modulator Destinations
Volume
Modulating the volume of an instrument creates a fluctuation in the Instrument's level. Those
familiar with the classic guitar amplifier tremolo effect will know exactly how this sounds.
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Pitch
Normally, an Instrument's pitch is controlled by the MIDI note being played, and the pitch bend
wheel (if used). Applying a modulator to the pitch of an Instrument will add a pitch vibrato, warble,
bend or other gesture to every note played.
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Stereo Pan position
There are three ways to adjust the stereo position of an Instrument's sound: The Stereo Position
setting in the Instrument Output tab, the use of MIDI controller 10 (pan) and a modulator set to
control Stereo Pan position. Using an LFO to change an Instrument's pan is an effect often heard
with electronic pianos, giving the sound a back-and-forth motion.
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Filter Tone
Use care when modulating the Filter Tone, especially when going back and forth between positive
and negative values. The Comb Filter is disabled when the Tone control value is negative, and
bad-sounding artifacts can occur when the Comb Filter suddenly cuts in or out.
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Filter Frequency
Modulating the filter peak frequency spacing of an Instrument allows you to create electronic
swishing and sweeping sounds, without altering the note's fundamental pitch - sounds you'll recognize
from electronic dance music. This effect is most apparent on Instruments with higher filter
resonance settings.
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Filter Resonance
Modulating filter resonance tends to add a pulsating character to each note. If you turn on Track
Pitch (on the Filter page), then you can create a pulsing harmonic at a pitch above or below the
key played by using a semi-tone offset.
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Note that filter resonance is perhaps the most subtle modulation destination. When the filter is not
set to Track Pitch, the effects of resonance in general vary depending on the pitch of the note
played. When Track Pitch is enabled, the behavior of different pitches is more consistent.
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Modulator Types
The Beatnik synthesizer supports four different modulator types, all of which are based on two
signal sources - a Low Frequency Oscillator (LFO) and an Envelope generator. Choosing a modulator
type is easier once you understand how they differ:
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Low Frequency Oscillator (LFO)
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An LFO applies a continuously repeating wiggle to an
Instrument parameter, such as pitch or volume. This wiggle
continues as long as the note is held.
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You can think of an LFO as an invisible monkey turning an
Instrument control knob up and down at a certain rate. If the
knob the monkey is turning happens to be "volume," you'll
hear the level of that instrument rise and fall periodically,
like the tremolo effect on an old guitar amp.
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LFO's have three important settings: how fast the knob is
wiggled, how far the knob gets wiggled relative to its starting
position and the "shape" of the wiggling gesture. In the
Modulation window, these three parameters are represented
by Period, Depth and Shape.
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An Envelope applies a one-time gesture to each note. Once
the envelope is complete, the note continues normally until
released. Use envelopes for any gesture that begins anew
each time a note is struck - for example: a filter sweep, a
pitch bend, etc.
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The difference between an Envelope and an LFO is that
LFOs produce a continuously repeating wiggle; by contrast,
Envelopes happen just once per note, regardless of how long
that note is held.
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If you've worked with MIDI or digital audio software that
supports mix automation, you might want to think of an
Envelope as an automation curve. When a note is triggered,
the envelope will begin playing, modulating the Instrument
parameter to which it is attached. The difference between
envelopes and automated mixing is that the envelope has the
option to "freeze" during the sustain portion of the note,
then continue after the note is released.
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LFO with Depth Modulator
(Envelope)
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LFO with Depth Modulator uses the Envelope to vary the
Depth parameter of the LFO. This creates a wiggling effect
who's intensity changes over time. Notice how the shape
combines elements of the previous two modulator types -
the envelope modulates the LFO's depth, but not it's frequency
or shape.
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The actual result of this type of modulator is determined by
multiplying the LFO's Depth setting (0-100%) and the current
value of the Depth Modulator envelope (-100%-100%).
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When using this type, you may want to set the LFO Depth
to 100%, as this gives you maximum control and flexibility
with the Depth Modulator envelope.
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Negative Depths: In some cases, an envelope with points at
levels less than zero (in the range of 0 to -100%) may have
the same result as if the point was simply at zero. In cases
where negative modulation values have an effect, be mindful
of envelopes that have points both above and below the
zero line - the modulation's destination will "invert" its
behavior when the envelope crosses from negative to positive,
which can produce interesting and complex sound
behaviors. Predicting the results before you hear them will
take practice!
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Offset Modulator combines the LFO and Envelope in a different
way. In this type, the LFO's Depth is still controlled
by the envelope, but the Envelope shape is also added
together with the LFO's shape. The result is an "offset,"
which you can seen by comparing the diagram with the LFO
with Depth Modulator immediately above.
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The Offset Modulator adds an Amount to use as ADSR %
slider to the Modulator page.
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Modulation Tips
Modulation is a classic synthesis technique. Here's how to get some familiar modulation-based
effects:
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- Vibrato: Use an LFO mapped to Pitch. Usually the LFO depth will be set quite low. Note that
if there is a Pitch Change LFO present in an Instrument, the Mod Wheel (MIDI controller 1)
will affect its depth. Otherwise, Mod Wheel will activate a default Pitch Change LFO that cannot
be edited by the user. Using an LFO with a Depth Modulator envelope that slowly ramps
up or down can be very effective.
- Stereo Panning Effect: Use an LFO mapped to Stereo Pan. This can be an adequate substitute
for using a stereo sample; the triangle wave shape offers the smoothest result, square and sawtooth
are more striking. Using an LFO with a Depth Modulator envelope that slowly ramps up
or down can be very effective.
- Tremolo: Use an LFO mapped to Volume, or to Filter Frequency with a low filter resonance
setting. Using an LFO with a Depth Modulator envelope that slowly ramps up or down can be
very effective.
- Filter Sweep: Use an LFO mapped to Filter Frequency with a high filter resonance setting.
The LFO rate should be very low (long period). Achieving your desired effect will probably
require a lot of experimentation with adjusting the LFO and Filter parameters.
- Arpeggiator Effects: Modulate Pitch from two or three LFOs with different but arithmetically
related frequencies. This will create repeating arpeggiator-like effects. For example, examine
Special Bank #99, Analog Sequence. Alternatively, offsetting the LFO frequencies by smaller
arbitrary amounts can create interesting and complex effects.
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