The <groups> element (required)

In this section, we’ll find elements that pertain to samples and sample-mapping.

Every dspreset file should have one and only one <groups> element. This is where you specify the samples that make up your sample library. This element lives right underneath the top-level <DecentSampler> element. The basic structure is this:

<DecentSampler>
    <groups>
        <group>
            <sample /> <!-- This is where -->
            <sample /> <!-- the samples   -->
            <sample /> <!-- get defined   -->
        </group>
    </groups>
</DecentSampler>

Attribute		Description
volume	(optional)	The volume of the instrument as a whole. This will be reflected in the UI in the top-right corner. Value can be in linear 0.0-1.0 or in decibels. If it’s in decibels you must append dB after the value (example: “3dB”). Default: 1.0 (no volume change)
globalTuning	(optional)	Global pitch adjustment for changing note pitch. In semitones. For example 1.0 would be a half-step up. Default: 0
glideTime	(optional)	The glide/portamento time in seconds. A value of 0.0 would mean no portamento. This value can also be set at the <group> and <sample> levels, although most people will want to set it globally at the <groups> level. Default: 0.0
glideMode	(optional)	Controls the glide/portamento behavior. Possible values are: always (glide is always performed), legato (glide is performed only when transitioning from one note to another), and off. This value can also be set at the <group> and <sample> levels, although most people will want to set it globally at the <groups> level. Default: legato

The <group> element

Samples and oscillators live in groups. There can be many group elements under the <groups> element. It can be useful to sort your samples into groups in order to apply similar settings to them or to control them with a knob. Each group can contain <sample> elements, an <oscillator> element, or both together. The order of groups in a file matters insofar as bindings will often reference groups by using an index. The first group in a file is group 0, the second is group 1, etc.

Attribute	Description
enabled	Whether or not this group is enabled. Possible values: true, false. Default: true	(optional)
volume	The volume of the group. Value can be in linear 0.0-1.0 or in decibels. If it’s in decibels you must append dB after the value (example: “3dB”). Default: 1.0	(optional)
ampVelTrack	The degree to which the velocity of the incoming notes affects the volume of the samples in this group. 0 = not at all. 1 = volume is completely determined by incoming velocity. When the value is 1, a velocity of 127 (max velocity) yields a gain 1.0 (full volume), a velocity of 63 (half velocity) yields a gain of 0.5 (half volume), etc.	(optional)
groupTuning	Group-level pitch adjustment for changing note pitch. In semitones. For example 1.0 would be a half-step up and -1 would a half-step down. Default: 0	(optional)
pitchKeyTrack	A number from 0.0 to 1.0. 0 means that the pitch will stay the same regardless of what note is played. 1 means that the pitch will increase by one semitone when the note increases by one semitone (normal key pitch tracking). Applies to all samples and oscillators in the group. Default: 1	(optional)
glideTime	The glide/portamento time in seconds for samples and oscillators in this group. A value of 0.0 means no portamento. Can be overridden at the `` level. Inherits from `` level if not specified. Default: 0.0	(optional)
glideMode	Controls the glide/portamento behavior for samples and oscillators in this group. Possible values: `always` (glide is always performed), `legato` (glide only when transitioning from one note to another), `off` (no glide). Inherits from `` level if not specified. Default: `legato`	(optional)

The <sample> element

Underneath the <group> elements are <sample> elements. Each sample corresponds to a playable “zone” of your instrument. Attributes:

Attribute		Description
path	(required)	The relative path of the sample file to play for this zone. Supported audio formats are WAV (.wav), AIFF (.aif, .aiff), and FLAC (.flac).
rootNote	(required)	The MIDI note number (from 1 to 127) of the note.
loNote	(optional)	The MIDI note number (from 1 to 127) of the lowest note for which the zone should be triggered. Default: 0.
hiNote	(optional)	The MIDI note number (from 1 to 127) of the highest note for which the zone should be triggered. Default: 127.
loVel	(optional)	The lowest velocity for which this zone should be triggered. Default: 0
hiVel	(optional)	The highest velocity for which this zone should be triggered. Default: 127
loCCN hiCCN	(optional)	Using these parameter, you can use MIDI continuous controllers to filter whether or not a note should be played. This lets you, for example, have one set of samples that get played when the piano sustain pedal is down and another set that get played when it is up. Each time a MIDI CC value comes for a specific CC#, the engine stores that value. When a “note on” signal is received, the engine makes a decision (based on the last received value and the range defined by these attributes) about whether or not this sample should be played. If you use loCCN, you must also use a corresponding hiCCN for the same MIDI CC number so that you are defining a range of values. Example: loCC64="90" and hiCC64="127" would mean that a “note on” message will only trigger this sample if the last received value for CC64 (Sustain Pedal) is between 90 and 127. This can also be set at the <group> level. Default:-1 (off)
start	(optional)	The frame/sample position of the start of the sample audio. This is useful if the sample starts midway through the audio file. Default: 0
end	(optional)	The frame/sample position of the end of the sample audio. The is useful is the zone ends before the end of the audio file. Default: the file’s length in samples minus 1.
tuning	(optional)	A fine-tuning number (in semitones) for changing the note pitch. e.g 1.0 would be a half-step up. Default: 0
volume	(optional)	The volume of the sample. Value can be in linear 0.0-1.0 or in decibels. If it’s in decibels you must append dB after the value (example: “3dB”). Default: 1.0
pan	(optional)	A number of -100 to 100. -100 in panned all the way to the left, 100 is panned all the way to the right. This can also be set at the <group> or <groups> levels. Default: 0
pitchKeyTrack	(optional)	A number from 0.0 to 1.0. 0 means that the pitch will stay the same regardless of what note is played. 1 means that the pitch will increase by one semitone when the note increases by one semitone (i.e. normal key pitch tracking). This can also be set at the <group> level. Default: 1
glideTime	(optional)	The glide/portamento time in seconds for this sample. A value of 0.0 means no portamento. Inherits from `` or `` level if not specified. Default: 0.0
glideMode	(optional)	Controls the glide/portamento behavior for this sample. Possible values: `always`, `legato`, or `off`. Inherits from `` or `` level if not specified. Default: `legato`
trigger	(optional)	Valid values: attack means a sample is played when the note on message is received. release means the sample is played when the note off message is received (aka a release trigger). first means that the sample will only be played if no other notes are playing. legato means that the sample will only be played if some other notes are already playing. continuous means that the sample will always play. This can also be set at the <group> level. Default: attack.
releaseTriggerDecay	(optional)	Controls the volume decay rate for release-triggered samples based on how long the note was held. When a release trigger sample plays, its volume decreases based on the time elapsed since the note was initially pressed. The value can be specified in two formats: Decibel format (recommended): Append “dB” to specify decay in decibels per second. For example, "3dB" means the volume decreases by 3dB for each second the note was held. If you specify a positive dB value, it will be automatically converted to negative (decay direction). Linear format: A decimal value between 0.0 and 1.0 specifying the linear gain decay factor per second. For example, 0.3 means the volume decreases by a factor of 0.3 each second. This is useful for piano pedal-up samples and other release triggers where shorter notes should have louder release samples. This can also be set at the <group> or <groups> levels. Default: 0.0 (no decay).
tags	(optional)	A command-separated list of tags. Example: tags=”rt,mic1”. These are useful when controlling volumes using tags. See Appendix D.
onLoCCN onHiCCN	(optional)	If you want a sample to be triggered when a MIDI CC controller message comes in, for example for piano pedal down and pedal up samples, you use these attributes to specify the range of values that should trigger the sample. If you use onLoCCN, you must also use a corresponding onHiCCN for the same MIDI CC number. Example: onLoCC64="90" and onHiCC64="127" would mean that values of CC64 (Sustain Pedal) between 90 and 127 will trigger the given sample. This can also be set at the <group> level. Default:-1 (off)
playbackMode	(optional)	By default, the choice of playback engine is left up to the discretion of the user–they can set this in the Preferences screen. However, a sample creator can override this setting by setting the playbackMode for a specific sample, a group, or the entire instrument. Possible values are memory, disk_streaming, and auto (default).
delay	(optional)	A delay time before the sample starts playing. The value is a decimal number (integer or float) that specifies the delay amount. The unit of measurement is controlled by the delayUnit attribute. Default: 0
delayUnit	(optional)	Specifies the unit of measurement for the delay attribute. Valid values are: seconds (time-based delay), beats (tempo-based delay), and samples (sample-accurate delay). Default: seconds
retriggerEnabled	(optional)	Enables pattern retriggering for creating repeating sample sequences. When enabled, after the initial delay sequence completes, all samples in the group will retrigger according to the retriggerInterval. This allows creating looping drum patterns and rhythmic sequences from delayed samples. This can also be set at the <group> or <groups> levels. Default: false
retriggerInterval	(optional)	The time interval between pattern repetitions when retriggerEnabled is true. This determines how long to wait before retriggering the entire delay sequence. The unit is specified by the retriggerIntervalUnit attribute. This can also be set at the <group> or <groups> levels. Default: 4.0
retriggerIntervalUnit	(optional)	Specifies the unit of measurement for the retriggerInterval attribute. Valid values are: seconds (interval in seconds), beats (interval in musical beats - stays synchronized with host tempo), and samples (interval in audio samples). This can also be set at the <group> or <groups> levels. Default: beats

Looping

Attribute		Description
loopStart	(optional)	The frame/sample position of the start of the sample’s loop. If this is not specified, but the sample is a wave file with embedded loop markers, those will be used instead. Default: 0
loopEnd	(optional)	The frame/sample position of the end of the sample’s loop. If this is not specified, but the sample is a wave file with embedded loop markers, those will be used instead. Default: the file’s length in samples minus 1.
loopCrossfade	(optional)	When loop crossfades are used, instead of simply looping at a specific end point, a portion of the audio from before the loop point is faded in just as the audio from the end of the loop is faded out. In this way, smooth audio loops can be achieved on samples that weren’t specifically prepared as looping. This parameter is used for specifying the length of the crossade region in frames/samples. This can also be set at the <group> level. Default: 0 (crossfades off).
loopCrossfadeMode	(optional)	This parameter is used to specify the curve used for crossfading when loop crossfades are turned on. This can also be set at the <group> level. Value values: linear, equal_power. Default: equal_power.
loopEnabled	(optional)	A boolean value indicating whether or not the loop should be used. Valid values: true, false

Amplitude Envelope

Each sample has its own ADSR amplitude envelope.

Attribute		Description
ampEnvEnabled	(optional)	This turns the amplitude envelope on and off. Valid values are: false and true (default).
attack	(optional)	The attack time in seconds of the amplitude envelope of this zone. This can also be set at the <group> or <groups> levels.
decay	(optional)	The decay time in seconds of the amplitude envelope of this zone. This can also be set at the <group> or <groups> levels.
sustain	(optional)	The sustain level (0.0 - 1.0) of the amplitude envelope of this zone. This can also be set at the <group> or <groups> levels.
release	(optional)	The release time in seconds of the amplitude envelope of this zone. This can also be set at the <group> or <groups> levels.

The curve shapes of the attack, decay, and release zones can be changed as well. All three of the of the following parameters use the same system: a value from -100 to 100 that determines the shape of the curve. -100 is a logarithmic curve, 0 is a linear curve, and 100 is an exponential curve.

Attribute		Description	Default Value
attackCurve	(optional)	A value from -100 to 100 that determines the shape of the attack curve. This can also be set at the <group> or <groups> levels.	-100 (logarithmic)
decayCurve	(optional)	A value from -100 to 100 that determines the shape of the decay curve. This can also be set at the <group> or <groups> levels.	100 (exponential)
releaseCurve	(optional)	A value from -100 to 100 that determines the shape of the release curves. This can also be set at the <group> or <groups> levels.	100 (exponential)

Round Robins

Round robins allow different samples to be played each time a zone is triggered. This is especially useful with sounds that have short attacks (such as drums), and is a great way to keep your sample libraries from sounding fake. In order for round robins to work, you must specify both a seqMode and a seqPosition for all samples. If you have several different sets of round robins with different lengths, you’ll want to set the seqLength value as well. There are several round-robin modes:

• round_robin: This causes samples to be triggered sequentially according to their seqPosition values.

• random: This causes random samples to be chosen from within the group of samples. If there are more than two round robins, then the algorithm makes sure not to hit the same one twice in a row.

• true_random: This causes random samples to be chosen from within the group of samples.

• always: This just turns round robins off.

Attribute		Description
seqMode	(optional)	Valid values are random, true_random, round_robin, and always. A value indicating the desired round robin behavior for this sample or group of samples. This can also be set at the <group> and <groups> levels. Default: always
seqLength	(optional)	The length of the round robin queue. This can also be set at the <group> or <groups> levels. If this is left out, then the engine will try to auto-detect the length of the roudn robin sequence. Default: 0
seqPosition	(optional)	A number indicating this zone’s position in the round robin queue. This can also be set at the <group> level. Default: 1

Voice-Muting / Legato

Looping

Attribute		Description
silencedByTags	(optional)	A command-separated list of tags. Example: tags=”rt,mic1”. If a sample containing one of these tags gets triggered, then this sample will be stopped. This is useful when setting up drums as it will allow you mute one hi-hat when another hi-hat plays. See Appendix D.
silencingMode	(optional)	Controls how quickly voices get silenced. fast = immediately; normal = triggers the sample’s release phase. This second option, when used in conjunction with the release attribute, allows you to specify a longer release time. Values: fast, normal. Default: fast
silencingDecay	(optional)	Specifies a custom fade-out time in seconds when a voice is silenced by the silencedByTags mechanism or tag polyphony limits. When set to a value greater than 0, this overrides the silencingMode behavior and uses the specified decay time for the fade-out. This provides precise control over silencing transitions. For example, silencingDecay="0.05" creates a 50ms fade-out. Default: 0 (uses silencingMode instead)
previousNotes	(optional)	Only play this sample if the previously triggered note equals one of these notes. Format: a comma-separated list of MIDI note numbers (from 1 to 127) of the note.
legatoInterval	(optional)	This is similar to the previousNote attribute. This causes the engine to only play the sample if the previously triggered note is exactly this semitone distance from the previous note. For example, if the note for which this sample is being triggered is a C3 and the legatoInterval is set to -2, then the sample will only play if the previous note was a D3 because D3 minus 2 semitones equals C3. Format: This can be a positive or negative whole number.

Routing Audio

My default all audio is routed to the main output. However, using the attributes below you can route audio to any of the 16 buses or directly to any one of the 16 auxiliary outputs. You can also specify the volume of the audio being sent to each output.

Attribute		Description
output1Target	(optional)	The first audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are MAIN_OUTPUT (the main audio output), NO_OUTPUT (audio is not routed anywhere), BUS_1 (the first bus defined in the <buses> element), BUS_2 (the second bus), …, BUS_16 (bus 16), AUX_STEREO_OUTPUT_1 (auxiliary output 1), AUX_STEREO_OUTPUT_2 (auxiliary output 2), …, AUX_STEREO_OUTPUT_16 (auxiliary output 16). Default: MAIN_OUTPUT
output2Target	(optional)	The second audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output3Target	(optional)	The third audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output4Target	(optional)	The fourth audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output5Target	(optional)	The fifth audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output6Target	(optional)	The sixth audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output7Target	(optional)	The seventh audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output8Target	(optional)	The eighth audio output for this sample. This is a string that specifies the audio output that the sample should be routed to. The available options are the same as for output1Target. Default: NO_OUTPUT
output1Volume	(optional)	The volume of the audio being sent to the sample’s first output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output2Volume	(optional)	The volume of the audio being sent to the sample’s second output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output3Volume	(optional)	The volume of the audio being sent to the sample’s third output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output4Volume	(optional)	The volume of the audio being sent to the sample’s fourth output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output5Volume	(optional)	The volume of the audio being sent to the sample’s fifth output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output6Volume	(optional)	The volume of the audio being sent to the sample’s sixth output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output7Volume	(optional)	The volume of the audio being sent to the sample’s seventh output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0
output8Volume	(optional)	The volume of the audio being sent to the sample’s eighth output. This is a floating-point number between 0.0 and 1.0, where 0.0 is silent and 1.0 is full volume. Default: 1.0

The <oscillator> element

The <oscillator> element allows you to add synthesized waveforms to your instrument, which can be used alongside or instead of traditional audio samples. Oscillators are useful for creating sub-bass layers, adding harmonic content, or building entirely synthesized instruments within DecentSampler.

Oscillators live inside <group> elements, just like <sample> elements. Each group can contain samples, an oscillator, or both, allowing you to layer oscillators with samples within the same group or create multi-oscillator patches by using multiple groups.

Basic Usage:

The simplest oscillator configuration requires only a waveform type:

<group name="Sub Bass" volume="0.6" groupTuning="-12">
    <oscillator waveform="sine" />
</group>

This creates a sine wave oscillator tuned one octave below the played note.

Attributes:

The <oscillator> element itself has only one attribute:

Attribute	Required/Optional	Description	Default
waveform	(optional)	The waveform shape. Valid values: sine, saw, square, triangle, noise (or white_noise), pluck1, wavetable, fm6op.	sine
damping	(optional)	Only for pluck1 waveform. Controls the decay time of the plucked string. Range: 0.0 to 1.0. Lower values (closer to 0.0) create heavily damped, shorter sounds. Higher values (closer to 1.0) create minimal damping with longer, more resonant decay. This simulates the natural damping characteristics of string materials and playing techniques.	0.5
pluckType	(optional)	Only for pluck1 waveform. Blends between different excitation signals to control the timbral character. Range: 0.0 to 1.0. At 0.0, the oscillator uses a smooth triangle wave excitation producing a softer, mellower tone. At 1.0, it uses a noise burst excitation producing a brighter, more aggressive attack with richer harmonics. Intermediate values blend between the two extremes.	0.5
wavetableFile	(optional)	Only for wavetable waveform. Path to the multi-frame wavetable .wav file, relative to the .dspreset file. The file should contain all wavetable frames concatenated in a single audio file. If the file contains a clm RIFF chunk (Serum-compatible format), the frame size is detected automatically.	(none)
wavetableFrameSize	(optional)	Only for wavetable waveform. Number of audio samples per wavetable frame. When the wavetable file contains a clm RIFF chunk, this value is read automatically and any explicit setting is overridden.	2048
wavetablePosition	(optional)	Only for wavetable waveform. The initial playback position within the wavetable, expressed as a normalized value from 0.0 (first frame) to 1.0 (last frame). Intermediate values produce a linear crossfade between adjacent frames. Can be animated using the OSCILLATOR_WAVETABLE_POSITION binding parameter.	0.0
randomPhase	(optional)	Only for wavetable waveform. When true, each note-on randomizes the oscillator’s start phase instead of always resetting to zero. Strongly recommended when layering multiple wavetable groups (e.g. detuned unison voices) to prevent phase cancellation between voices. Has no effect on other waveform types.	false
wavetableFrameInterpolation	(optional)	Only for wavetable waveform. Controls whether adjacent wavetable frames are linearly crossfaded as the position moves. When true (default), the position knob smoothly interpolates between adjacent frames — ideal for morphing wavetables where intermediate timbres are musically meaningful. When false, the oscillator snaps to the nearest integer frame with no crossfading — useful for wavetables that contain discrete, unrelated shapes (e.g. sine, triangle, saw, square) where blended intermediates are unwanted. Can be changed at runtime via the OSCILLATOR_WAVETABLE_FRAME_INTERPOLATION binding parameter.	true

When using waveform="fm6op", set the FM parameters on the parent <group> element (they are inherited by the oscillator). All FM attributes are optional:

Attribute	Description	Default
fmAlgorithm	DX7-compatible algorithm number (1–32). Selects the operator routing topology—which operators are carriers (produce audio) and which are modulators.	1
fmOp1Ratio	Frequency ratio for operator 1 (primary carrier in most algorithms). Multiplies the played note frequency. 2.0 = one octave up, 0.5 = one octave down.	1.0
fmOp1Detune	DX7-compatible pitch detune for operator 1. Range -7 to +7. Uses the classic DX7 detune algorithm: higher pitch offsets at lower notes, smaller offsets at higher notes. 0 = no detune, positive values sharpen, negative values flatten.	0
fmOp1Mode	Frequency mode for operator 1. ratio (default) = frequency is a ratio of the played note. fixed = absolute frequency in Hz specified by fmOp1FixedFreq.	ratio
fmOp1FixedFreq	Fixed frequency in Hz for operator 1 when fmOp1Mode="fixed". Ignored when mode is ratio. Useful for metallic/bell-like timbres.	440.0
fmOp1Level	Output/modulation level for operator 1. Range 0.0–1.0.	1.0
fmOp1VelocitySensitivity	Velocity sensitivity for operator 1. Range 0–7 (DX7 convention). 0 = no velocity response (full level regardless of velocity). 7 = maximum velocity scaling (level varies from 0 at vel=1 to full at vel=127).	0
fmOp1Feedback	Self-feedback amount for operator 1. Range 0.0–1.0. Note: only the physically correct feedback operator for each algorithm produces sound (usually Op6).	0.0
fmOp1Attack	ADSR attack time (seconds) for operator 1’s internal envelope. A value of -1 means the operator has no independent envelope and is gated only by the outer group ADSR.	0.0
fmOp1Decay	ADSR decay time (seconds) for operator 1.	0.0
fmOp1Sustain	ADSR sustain level (0.0–1.0) for operator 1.	1.0
fmOp1Release	ADSR release time (seconds) for operator 1. A value of -1 (sentinel) lets the outer group ADSR control the release.	-1.0
fmOp2Ratio … fmOp6Ratio	Frequency ratios for operators 2–6. Same semantics as fmOp1Ratio.	1.0
fmOp2Detune … fmOp6Detune	Pitch detune for operators 2–6. Range -7 to +7. Same semantics as fmOp1Detune.	0
fmOp2Mode … fmOp6Mode	Frequency modes for operators 2–6. ratio or fixed. Same semantics as fmOp1Mode.	ratio
fmOp2FixedFreq … fmOp6FixedFreq	Fixed frequencies in Hz for operators 2–6 when respective mode is fixed.	440.0
fmOp2Level … fmOp6Level	Output/modulation levels for operators 2–6. Range 0.0–1.0.	1.0
fmOp2VelocitySensitivity … fmOp6VelocitySensitivity	Velocity sensitivity for operators 2–6. Range 0–7. Same semantics as fmOp1VelocitySensitivity.	0
fmOp2Feedback … fmOp6Feedback	Self-feedback amounts for operators 2–6. fmOp6Feedback is the primary feedback and affects all algorithms.	0.0
fmOp2Attack … fmOp6Attack	ADSR attack times for operators 2–6.	0.0
fmOp2Decay … fmOp6Decay	ADSR decay times for operators 2–6.	0.0
fmOp2Sustain … fmOp6Sustain	ADSR sustain levels for operators 2–6. Range 0.0–1.0.	1.0
fmOp2Release … fmOp6Release	ADSR release times for operators 2–6. -1 = sentinel (outer ADSR controls).	-1.0

DX7-compatible operator envelope (optional). Each operator can alternatively use a 4-stage DX7-style envelope instead of the ADSR above. Set fmOpNEgType="dx7" on the group to activate it, then provide the eight rate/level parameters:

Attribute	Description	Default
fmOp1EgType	Envelope type for operator 1. adsr = standard ADSR (default). dx7 = 4-stage DX7-compatible envelope using integer rate/level parameters below.	adsr
fmOp1EgRate1 … fmOp1EgRate4	Envelope rates R1–R4 for operator 1 (DX7 mode only). Range 0–99. Higher values are faster. R1 = attack rate, R2 = decay rate, R3 = sustain rate (holds at L3 while key is held), R4 = release rate.	99, 99, 0, 99
fmOp1EgLevel1 … fmOp1EgLevel4	Envelope target levels L1–L4 for operator 1 (DX7 mode only). Range 0–99. L1 = peak after attack, L2 = level after first decay, L3 = sustain level (held while key is down), L4 = level after release.	99, 99, 99, 0
fmOp2EgType … fmOp6EgType	Envelope types for operators 2–6. Same as fmOp1EgType.	adsr
fmOp2EgRate1 … fmOp6EgRate4	Envelope rates R1–R4 for operators 2–6 (DX7 mode only). Same semantics as fmOp1EgRate1–fmOp1EgRate4.	99, 99, 0, 99
fmOp2EgLevel1 … fmOp6EgLevel4	Envelope levels L1–L4 for operators 2–6 (DX7 mode only). Same semantics as fmOp1EgLevel1–fmOp1EgLevel4.	99, 99, 99, 0

The DX7 rate/level envelope uses the same integer parameter conventions as classic 6-operator DX7 synthesizers: rates and levels are both in the range 0–99, and the values are directly compatible with patch data from vintage hardware and standard DX7 patch banks. See How to Use FM Synthesis for worked examples.

DX7-compatible operator envelope (optional). Each operator can alternatively use a 4-stage DX7-style envelope instead of the ADSR above. Set fmOpNEgType="dx7" on the group to activate it, then provide the eight rate/level parameters:

Attribute	Description	Default
fmOp1EgType	Envelope type for operator 1. adsr = standard ADSR (default). dx7 = 4-stage DX7-compatible envelope using integer rate/level parameters below.	adsr
fmOp1EgRate1 … fmOp1EgRate4	Envelope rates R1–R4 for operator 1 (DX7 mode only). Range 0–99. Higher values are faster. R1 = attack rate, R2 = decay rate, R3 = sustain rate (holds at L3 while key is held), R4 = release rate.	99, 99, 0, 99
fmOp1EgLevel1 … fmOp1EgLevel4	Envelope target levels L1–L4 for operator 1 (DX7 mode only). Range 0–99. L1 = peak after attack, L2 = level after first decay, L3 = sustain level (held while key is down), L4 = level after release.	99, 99, 99, 0
fmOp2EgType … fmOp6EgType	Envelope types for operators 2–6. Same as fmOp1EgType.	adsr
fmOp2EgRate1 … fmOp6EgRate4	Envelope rates R1–R4 for operators 2–6 (DX7 mode only). Same semantics as fmOp1EgRate1–fmOp1EgRate4.	99, 99, 0, 99
fmOp2EgLevel1 … fmOp6EgLevel4	Envelope levels L1–L4 for operators 2–6 (DX7 mode only). Same semantics as fmOp1EgLevel1–fmOp1EgLevel4.	99, 99, 99, 0

The DX7 rate/level envelope uses the same integer parameter conventions as classic 6-operator DX7 synthesizers: rates and levels are both in the range 0–99, and the values are directly compatible with patch data from vintage hardware and standard DX7 patch banks. See How to Use FM Synthesis for worked examples.

All FM operator parameters can be modulated in real time using bindings with the parameter names OSCILLATOR_FM_ALGORITHM, OSCILLATOR_FM_OP1_LEVEL … OSCILLATOR_FM_OP6_LEVEL, OSCILLATOR_FM_OP1_RATIO … OSCILLATOR_FM_OP6_RATIO, and OSCILLATOR_FM_OP1_FEEDBACK … OSCILLATOR_FM_OP6_FEEDBACK. See Appendix B fo independent per-operator ADSR envelope, and an optional DX7-compatible 4-stage rate/level

All other oscillator parameters are inherited from the parent <group> element.

Waveform Types:

• `sine`: A pure sine wave with no harmonics. Ideal for sub-bass and clean tones.

• `saw`: A sawtooth wave with rich harmonics. Great for bright, cutting sounds.

• `square`: A square wave with odd harmonics. Useful for hollow, reed-like tones.

• `triangle`: A triangle wave with fewer harmonics than saw. Produces a mellower tone.

• `noise` (or `white_noise`): White noise generator. Perfect for percussion textures, hi-hats, snares, wind sounds, and adding grit to other sounds.

• pluck1: A physical modeling oscillator based on digital waveguide synthesis that simulates plucked string behavior. Unlike traditional waveforms that cycle continuously, pluck1 generates a single excitation (like plucking a string) that decays naturally over time. Ideal for synthesizing plucked string instruments like guitar, bass, harp, koto, gayageum, and other stringed instruments. This oscillator includes two parameters for controlling the sound character: damping and pluckType.

• wavetable: A user-defined wavetable oscillator that reads frames from a multi-frame .wav file. The playback position (which frame is played) is controlled by the wavetablePosition attribute and can be scanned in real time using the OSCILLATOR_WAVETABLE_POSITION binding parameter—allowing LFOs, envelopes, MIDI CCs, or UI knobs to sweep through timbres. Supports Serum-compatible wavetable files with automatic frame size detection via the clm RIFF chunk.

• fm6op: A 6-operator FM synthesizer implementing the 32 classic Yamaha DX7 algorithm topologies. Each algorithm defines which operators are carriers (they produce the final audio output) and which are modulators (they phase-modulate another operator to add harmonics). Every operator has its own frequency ratio, output level, feedback amount, an independent per-operator ADSR envelope, and an optional DX7-compatible 4-stage rate/level envelope. Set fmAlgorithm plus the fmOp1–fmOp6 family of attributes on the parent <group> element. See How to Use FM Synthesis for a full guide. Group-Level Parameters:

Oscillators inherit and respect most of the same parameters as samples when set at the <group> level, including:

• `groupTuning` - Pitch adjustment in semitones

• `loNote` / `hiNote` - Note range triggering

• `attack`, `decay`, `sustain`, `release` - ADSR envelope parameters

• `attackCurve`, `decayCurve`, `releaseCurve` - Envelope curve shapes

• `volume` - Oscillator group volume

• `pan` - Stereo positioning

• `ampVelTrack` - Velocity sensitivity

• `pitchKeyTrack` - Keyboard pitch tracking (0.0 to 1.0). A value of 0 means the oscillator stays at a fixed pitch regardless of which key is pressed. A value of 1 means normal keyboard tracking (default)

• `glideTime` - Portamento/glide time in seconds (inherited from `` level if not specified)

• `glideMode` - Portamento behavior: `always`, `legato`, or `off` (inherited from `` level if not specified)

Modulation Support:

Oscillators fully support modulation through bindings and modulators, just like samples:

• GROUP_TUNING - Modulate oscillator pitch (e.g., for vibrato LFOs)

• GLOBAL_TUNING - Global pitch modulation affects all oscillators

• GROUP_VOLUME - Modulate oscillator amplitude

• AMP_VOLUME - Control oscillator volume with UI controls or MIDI

Example with LFO vibrato:

<modulators>
    <lfo shape="sine" frequency="5.0" modAmount="0.15" scope="global">
        <binding type="amp" level="group" position="0" parameter="GROUP_TUNING" 
                 modBehavior="add" translation="linear" 
                 translationOutputMin="-0.5" translationOutputMax="0.5"/>
    </lfo>
</modulators>

Multi-Oscillator Example:

Here’s a practical example showing how to layer multiple oscillators to create a rich synthesized sound:

<DecentSampler minVersion="1.15.0">
    <groups>
        <!-- Fundamental saw wave -->
        <group name="Fundamental" volume="0.5" attack="0.01" decay="0.3" sustain="0.7" release="0.5">
            <oscillator waveform="saw" />
        </group>
        
        <!-- Sine wave octave up for brightness -->
        <group name="Octave Up" volume="0.3" groupTuning="12" attack="0.02" decay="0.3" sustain="0.7" release="0.5">
            <oscillator waveform="sine" />
        </group>
        
        <!-- Sub bass (limited to lower notes) -->
        <group name="Sub Bass" volume="0.6" groupTuning="-12" loNote="0" hiNote="60" 
               attack="0.01" decay="0.3" sustain="0.7" release="0.8">
            <oscillator waveform="sine" />
        </group>
        
        <!-- Detuned oscillators for stereo width -->
        <group name="Detuned Left" volume="0.25" pan="-50" groupTuning="-0.1" 
               attack="0.01" decay="0.3" sustain="0.7" release="0.5">
            <oscillator waveform="saw" />
        </group>
        
        <group name="Detuned Right" volume="0.25" pan="50" groupTuning="0.1" 
               attack="0.01" decay="0.3" sustain="0.7" release="0.5">
            <oscillator waveform="saw" />
        </group>
    </groups>
    
    <effects>
        <effect type="lowpass" frequency="8000.0" resonance="1.0"/>
        <effect type="reverb" wetLevel="0.15" roomSize="0.5"/>
    </effects>
</DecentSampler>

Monophonic Lead Synth with Portamento:

Here’s a complete example of a Moog-style monophonic lead synthesizer with portamento:

<DecentSampler minVersion="1.15.0">
  <ui width="812" height="375">
    <tab name="main">
      <labeled-knob x="10" y="20" width="90" label="Attack" type="float" 
                    minValue="0.0" maxValue="2.0" value="0.01">
        <binding type="amp" level="instrument" position="0" parameter="ENV_ATTACK"/>
      </labeled-knob>
      <labeled-knob x="110" y="20" width="90" label="Glide Time" type="float" 
                    minValue="0.0" maxValue="2.0" value="0.3">
        <binding type="general" level="instrument" position="0" parameter="GLIDE_TIME"/>
      </labeled-knob>
      <labeled-knob x="210" y="20" width="90" label="Cutoff" type="float" 
                    minValue="0" maxValue="22000" value="2000.0">
        <binding type="effect" level="instrument" position="0" parameter="FX_FILTER_FREQUENCY"/>
      </labeled-knob>
      <labeled-knob x="10" y="130" width="90" label="Detune" type="float" 
                    minValue="-1" maxValue="1" value="0.1">
        <binding type="amp" level="group" position="1" parameter="GROUP_TUNING"/>
      </labeled-knob>
    </tab>
  </ui>
  
  <!-- glideTime and glideMode set at groups level apply to all oscillators -->
  <groups glideTime="0.3" glideMode="legato" attack="0.01" decay="0.3" 
          sustain="0.7" release="0.5" volume="0.8">
    <!-- Two detuned saw oscillators for thickness -->
    <group name="Osc1" tags="osc1">
      <oscillator waveform="saw" />
    </group>
    <group name="Osc2" tags="osc2">
      <oscillator waveform="saw" />
    </group>
  </groups>
  
  <effects>
    <effect type="lowpass" frequency="2000.0" resonance="0.3" 
            envelope_amount="3000.0" envelope_attack="0.01" 
            envelope_decay="0.3" envelope_sustain="0.0" envelope_release="0.5"/>
  </effects>
  
  <modulators>
    <!-- LFO vibrato -->
    <lfo shape="sine" frequency="5.0" modAmount="0.15" scope="global">
      <binding type="amp" level="group" tags="osc1,osc2" parameter="GROUP_TUNING" 
               modBehavior="add" translation="linear" 
               translationOutputMin="-0.5" translationOutputMax="0.5"/>
    </lfo>
  </modulators>
  
  <!-- Use tag polyphony to enforce monophonic behavior -->
  <tags>
    <tag name="osc1" volume="1" pan="0" polyphony="1" />
    <tag name="osc2" volume="1" pan="0" polyphony="1" />
  </tags>
</DecentSampler>

This preset demonstrates:

• Portamento/Glide: Set via `glideTime` (0.3 seconds) and `glideMode` (legato - only glides between connected notes)

• Monophonic behavior: Achieved using tag polyphony limits (`polyphony=”1”`)

• Detuned oscillators: Two saw waves with slightly different tuning for a fatter sound

• Modulation: LFO vibrato applied to both oscillators via GROUP_TUNING binding

• Filter envelope: Adds movement to the timbre

Combining Oscillators with Samples:

You can combine oscillators and samples within the same group or across separate groups. Here’s an example mixing them in a single group to add a sub-bass layer to piano samples:

<groups>
    <!-- Piano samples with built-in sine wave sub-bass -->
    <group name="Piano with Sub" volume="1.0">
        <sample path="Samples/Piano/C3.wav" rootNote="60" loNote="59" hiNote="61" />
        <sample path="Samples/Piano/D3.wav" rootNote="62" loNote="61" hiNote="63" />
        <!-- more samples... -->
        <!-- Oscillator mixed in the same group -->
        <oscillator waveform="sine" />
    </group>
</groups>

Or use separate groups for independent control:

<groups>
    <!-- Sample-based piano sound -->
    <group name="Piano Samples" volume="1.0">
        <sample path="Samples/Piano/C3.wav" rootNote="60" loNote="59" hiNote="61" />
        <!-- more samples... -->
    </group>
    
    <!-- Sine wave sub-bass layer -->
    <group name="Sub Layer" volume="0.3" groupTuning="-12" hiNote="60">
        <oscillator waveform="sine" />
    </group>
</groups>

Physical Modeling with pluck1:

The `pluck1` waveform uses digital waveguide synthesis to simulate plucked string instruments. Unlike traditional oscillator waveforms that cycle continuously, pluck1 generates a transient excitation that decays naturally, making it ideal for realistic plucked string sounds:

<DecentSampler minVersion="1.15.0">
    <ui width="812" height="375">
        <tab name="main">
            <labeled-knob x="10" y="20" width="90" label="Damping" type="float" 
                          minValue="0.0" maxValue="1.0" value="0.5">
                <binding type="general" level="group" position="0" 
                         parameter="OSCILLATOR_DAMPING"/>
            </labeled-knob>
            <labeled-knob x="110" y="20" width="90" label="Pluck Type" type="float" 
                          minValue="0.0" maxValue="1.0" value="0.5">
                <binding type="general" level="group" position="0" 
                         parameter="OSCILLATOR_PLUCK_TYPE"/>
            </labeled-knob>
        </tab>
    </ui>
    
    <groups attack="0.001" decay="0.1" sustain="0.8" release="0.2">
        <group name="Plucked String" volume="0.8">
            <oscillator waveform="pluck1" damping="0.5" pluckType="0.5" />
        </group>
    </groups>
</DecentSampler>

In this example:

• `damping=”0.5”`: Moderate decay time - the string sustains for a reasonable duration

• `pluckType=”0.5”`: Balanced between smooth (triangle wave) and bright (noise burst) excitation

• OSCILLATOR_DAMPING and OSCILLATOR_PLUCK_TYPE binding parameters allow real-time control from the UI

The pluck1 oscillator is particularly effective for:

• Bass guitars: Use lower `damping` values (0.3-0.5) with higher `pluckType` (0.6-0.8) for percussive attack

• Acoustic guitars: Medium `damping` (0.5-0.7) with balanced `pluckType` (0.4-0.6)

• Harps and lyres: Higher `damping` (0.7-0.9) with lower `pluckType` (0.2-0.4) for softer, sustained tones

• Ethnic stringed instruments: Experiment with `pluckType` to match the excitation character of traditional instruments like koto, sitar, gayageum, etc. User-Defined Wavetable Oscillator:

The wavetable waveform lets you load any multi-frame .wav file as a wavetable. Each frame is a fixed-size window of samples that the oscillator cycles through at the correct pitch. Moving the position between frames transitions between different timbres, enabling classic wavetable scanning effects.

Wavetable File Format:

• The file must be a standard .wav containing all frames concatenated in sequence (e.g., 128 frames × 2048 samples = 262144 samples total).

• If the file contains a clm RIFF chunk (Serum-compatible format), the frame size is detected automatically. Files exported from Serum or other compatible tools include this chunk.

• If no clm chunk is present, the frame size defaults to 2048 samples. You can override this by setting wavetableFrameSize on the <oscillator> element.

Wavetable Scanning with a Knob:

<DecentSampler minVersion="1.15.0">
    <ui width="812" height="375">
        <tab name="main">
            <labeled-knob x="10" y="20" width="90" label="Position" type="float"
                          minValue="0.0" maxValue="1.0" value="0.0">
                <binding type="general" level="group" position="0"
                         parameter="OSCILLATOR_WAVETABLE_POSITION"
                         translation="linear"
                         translationOutputMin="0.0" translationOutputMax="1.0"/>
            </labeled-knob>
        </tab>
    </ui>

    <groups attack="0.01" decay="0.5" sustain="1.0" release="0.5">
        <group name="Wavetable Oscillator">
            <oscillator waveform="wavetable"
                        wavetableFile="Wavetables/MyWavetable.wav"
                        wavetablePosition="0.0"/>
        </group>
    </groups>
</DecentSampler>

Wavetable Scanning with an LFO:

<DecentSampler minVersion="1.15.0">
    <ui width="812" height="375">
        <tab name="main">
            <labeled-knob x="10" y="20" width="90" label="LFO Rate" type="float"
                          minValue="0.1" maxValue="10.0" value="1.0">
                <binding type="modulator" level="instrument" modulatorIndex="0"
                         parameter="FREQUENCY"/>
            </labeled-knob>
            <labeled-knob x="110" y="20" width="90" label="LFO Depth" type="float"
                          minValue="0.0" maxValue="1.0" value="0.5">
                <binding type="modulator" level="instrument" modulatorIndex="0"
                         parameter="MOD_AMOUNT"/>
            </labeled-knob>
        </tab>
    </ui>

    <groups attack="0.01" decay="0.5" sustain="1.0" release="0.5">
        <group name="Wavetable Oscillator" wavetablePosition="0.5">
            <oscillator waveform="wavetable"
                        wavetableFile="Wavetables/MyWavetable.wav"/>
        </group>
    </groups>

    <modulators>
        <lfo shape="sine" frequency="1.0" modAmount="0.5" scope="voice">
            <binding type="general" level="group" position="0"
                     parameter="OSCILLATOR_WAVETABLE_POSITION"
                     modBehavior="add"
                     translationOutputMin="0.0" translationOutputMax="0.5"/>
        </lfo>
    </modulators>
</DecentSampler>

In this example, the LFO continuously sweeps the wavetable position around a center value of 0.5, scanning through timbres at the LFO rate. The modBehavior="add" means the LFO value is added on top of the static wavetablePosition set on the group.

Selecting the active wavetable from a menu:

Because wavetableFile cannot be changed at runtime via a binding, the way to offer a wavetable selector is to define one <group> per wavetable (each with a unique tag) and use a <menu> with TAG_ENABLED bindings to switch between them:

<ui width="812" height="375">
    <tab name="main">
        <menu x="20" y="68" width="220" height="26" value="1">
            <option name="Growl 01">
                <binding type="amp" level="tag" identifier="growl" parameter="TAG_ENABLED"
                         translation="fixed_value" translationValue="true"/>
                <binding type="amp" level="tag" identifier="fm"    parameter="TAG_ENABLED"
                         translation="fixed_value" translationValue="false"/>
            </option>
            <option name="FM 01">
                <binding type="amp" level="tag" identifier="growl" parameter="TAG_ENABLED"
                         translation="fixed_value" translationValue="false"/>
                <binding type="amp" level="tag" identifier="fm"    parameter="TAG_ENABLED"
                         translation="fixed_value" translationValue="true"/>
            </option>
        </menu>
    </tab>
</ui>

<groups>
    <group tags="growl">
        <oscillator waveform="wavetable" wavetableFile="Wavetables/Growl/Growl 01.wav" randomPhase="true"/>
    </group>
    <group tags="fm" enabled="false">
        <oscillator waveform="wavetable" wavetableFile="Wavetables/FM/FM 01.wav" randomPhase="true"/>
    </group>
</groups>

Each menu option enables exactly one tag and disables all others. The initial enabled="false" on non-default groups matches the menu’s default selection (value=”1” = first option).

Tips for Wavetable Sounds:

• Use Serum-format wavetables (exported from Serum or compatible tools) for automatic frame size detection.

• A knob scanning the position gives manual timbral control, while an LFO creates evolving, animated textures.

• Combine with envelope modulation on OSCILLATOR_WAVETABLE_POSITION for timbral sweeps triggered by note velocity or the amplitude envelope.

• Pair with groupTuning detuning and panning for unison-style / supersaw-like layering.

• Always set randomPhase="true" when layering multiple wavetable groups. Without it, all voices start at phase zero and cancel each other. UI Control for Oscillators:

You can create UI controls to switch waveforms dynamically:

<ui width="812" height="375">
    <tab name="main">
        <menu x="10" y="70" width="150" height="30" value="1">
            <option name="Sine">
                <binding type="general" level="group" position="0" 
                         parameter="OSCILLATOR_WAVEFORM" 
                         translation="fixed_value" translationValue="sine"/>
            </option>
            <option name="Saw">
                <binding type="general" level="group" position="0" 
                         parameter="OSCILLATOR_WAVEFORM" 
                         translation="fixed_value" translationValue="saw"/>
            </option>
            <option name="Square">
                <binding type="general" level="group" position="0" 
                         parameter="OSCILLATOR_WAVEFORM" 
                         translation="fixed_value" translationValue="square"/>
            </option>
        </menu>
    </tab>
</ui>

Tips and Best Practices:

1. Layer multiple waveforms: Combine different waveform types at different octaves for complexity.

2. Use detuning: Create stereo width by layering slightly detuned oscillators panned left and right.

3. Limit note ranges: Use `loNote` and `hiNote` to restrict certain oscillators to specific registers (e.g., sub-bass only on low notes).

4. Add envelope variation: Use different ADSR settings on each oscillator group for evolving textures.

5. Monophonic leads: Use tag polyphony (`polyphony=”1”`) combined with `glideMode=”legato”` for classic synthesizer lead sounds.

6. Modulation: Apply LFOs and envelopes to `GROUP_TUNING` for vibrato, tremolo, and evolving textures.

Feature Parity with Samples:

As of DecentSampler 1.15.0, oscillators support most sample features including:

• Pitch key tracking (pitchKeyTrack) - Control how oscillators respond to keyboard pitch

• Portamento/Glide (glideTime, glideMode) - Smooth pitch transitions between notes

• Modulation bindings - Full support for GROUP_TUNING, GLOBAL_TUNING, and GROUP_VOLUME modulation

• Tag-based polyphony - Use tags with polyphony limits for monophonic/polyphonic control

• ADSR envelopes - Complete amplitude envelope control with curve shaping

• Effects chains - Group-level and global effects apply to oscillators

• Velocity tracking - ampVelTrack for velocity-sensitive volume

• Note range filtering - loNote/hiNote for keyboard zones

Limitations:

• Oscillators do not support looping parameters (`loopStart`, `loopEnd`, etc.) since they generate continuous waveforms.

• Round-robin sequencing (`seqMode`, `seqPosition`) is not applicable to oscillators.

• Sample-specific features like `start`/`end` positions and embedded loop markers don’t apply.

Version Requirements:

Oscillators were introduced in DecentSampler version 1.15.0. All oscillator features including portamento and modulation support require version 1.15.0 or higher. Set the appropriate `minVersion` attribute:

<DecentSampler minVersion="1.15.0">