SoundFont Player

Semantic type: SoundFontPlayer · Category: others

Plays MIDI events with a prepared SF2, SF3, or SFZ instrument bank and adds the result to the input.

See Assets and bundles before using this effect.

This type can intentionally generate output from zero input at an active setting. See Processing model.

Contract

• Seeded: yes
• Catalog sample rates: not declared; this does not mean unsupported
• Assets: soundFont (soundFont)
• Catalog-declared latency: zero

Playing MIDI

assets.soundFont takes a bank prepared as described in SoundFont banks. Streams accept note, control change, program change, and pitch bend messages as MIDI events, and an EffeTuneNode accepts them in real time through sendMidi(). One-shot process() on an effect or Chain does not accept MIDI; there, previewMidi is the only way to make the player sound. Graphs cannot deliver MIDI, so a Graph that contains this effect, even a disabled one, raises ValidationError with GRAPH_UNSUPPORTED_CAPABILITY when it is created. The output is added to the input, so silent input yields the instrument alone. MIDI to WAV renders a MIDI file.

Parameter values

• midiChannel: 0 (default) follows all 16 MIDI channels; 1 to 16 follows only that channel.
• sampleQuality: 0 (default) is FIR (64 taps), 1 is FIR (32 taps), and 2 is Cubic (4 points). The library default is FIR (64 taps), unlike the app’s FIR (32 taps) default described below.
• previewMidi: -1 (default) is off; 0 to 127 holds that MIDI note until the value changes.
• previewChannel: the zero-based MIDI channel of the preview note, so 0 is MIDI channel 1 and 15 is channel 16.

EffeTune app documentation

The following section is reproduced from the English EffeTune app documentation. It describes the app UI, so it can mention controls, meters, and displays that the library does not provide, and its parameter names and values can differ from the API through transforms or value maps. Only the parameters in the Contract table above, plus the telemetry described in Compatibility, are part of the library API; the Contract is authoritative. Some parameters take effect only when a related setting enables them.

SoundFont Player

Play MIDI songs with an SF2/SF3 SoundFont collection or an SFZ instrument, then adjust the sound with the effects that follow it. Incoming audio passes through unchanged, with the instrument added at this position in the pipeline.

Getting Started

Open a .mid file, add SoundFont Player, and open SoundFont Library…. Import an .sf2 / .sf3 file, or an .sfz file together with its samples, then choose Load. The desktop app reads the original files; the web app stores imported files on your device. Start at 0 dB Instrument Level and lower it if the combined output is too loud.

SF3 (.sf3) uses compressed samples; import and select its sounds in the same way as SF2. SF3 playback requires Vorbis decoding support in your browser. If it is unavailable, choose an SF2 SoundFont or use a compatible browser.

SoundFont Library… imports, searches, loads, and deletes instruments. Clear unloads the instrument without deleting it from the library. Instruments in use cannot be deleted. If you change instruments during a song, the MIDI timeline continues while the new instrument is prepared. Once ready, it plays subsequent MIDI events with the current controller settings; earlier notes are not replayed.

MIDI Mixer

The MIDI Mixer tab has one row for each of the 16 MIDI channels. An SF2/SF3 collection can provide a different sound for each channel; Bank Select and Program Change messages choose the sounds, and channel 10 uses the drum bank by default. GS/XG drum-part messages can assign percussion to other channels or return a channel to melodic sounds. Program Change selects an available drum kit in the loaded SoundFont. An SFZ instrument uses its own mappings.

Before a Program Change, melodic channels use program 1 in bank 0 and channel 10 uses the standard drum kit, if those sounds are available. If the requested SF2/SF3 sound is missing, melodic channels try the same program in bank 0, then program 1 in bank 0; drum channels try the standard drum kit. Patch shows the sound actually used. If none of these sounds exists, or Automatic Fallback is off, the channel has no sound to play.

• Patch selects a named sound from the loaded SF2/SF3 collection for that channel. New notes use the selected sound; notes already sounding keep their original sound.
• Notes lights each channel’s keys while MIDI notes are held, from Note On to Note Off. Releasing a note turns its key off even if a sustain pedal or release tail keeps the sound playing. Voices counts the actual sample voices still sounding, including releases, against Max Voices. One note can use several sample voices. When Max Voices is reached and a new note has to stop a sounding voice, the Voices readout changes color for three seconds: orange if the stopped voice was already releasing, red if it was still being played.
• Drag across a channel’s keys with the mouse, touch, or a pen to play the loaded instrument at the pitch of the key under the pointer, using that channel’s current Patch and mixer settings. Moving to another key or releasing works like a MIDI Note Off: the previous note fades with the instrument’s own release, so notes with a slow release overlap. This works independently of the song and MIDI input, so it sounds on top of a playing song. A channel with Mute on stays silent, and only rows with active mixer controls respond.
• Vol. (CC7, 0–127) adjusts the channel level. EXP (expression, CC11, 0–127) is an additional level control. Higher values make the channel louder; setting either to 0 silences it.
• Pan (CC10, 0–127) moves the sound from left to right, with 64 at the center.
• Rev. (CC91) and Cho. (CC93) adjust effect sends from 0 to 127. Higher values send more sound to the corresponding effect; the audible result depends on the instrument’s effect support and settings.
• Level shows each channel’s measured audio after its volume, expression, pan, and Mute/Solo controls. The colored bar follows the signal, and the thin marker briefly holds recent peaks. Shared reverb and chorus returns are not included.
• Mute (M) silences that channel. Solo (S) lets you hear only channels with Solo enabled. Use these to compare parts of a song.

Drag the knobs vertically, or focus a knob and use the arrow keys. Mixer changes are temporary and are not saved with presets, shared links, or backups. Patch and controller changes use the incoming MIDI state; subsequent matching MIDI messages can overwrite them. All mixer changes, including Mute and Solo, reset for the next song or a GM, GS, or XG reset message.

When incoming MIDI changes the displayed Patch or a knob value, that control briefly highlights.

Settings

The Settings tab contains the saved playback settings:

• MIDI Channel plays All channels by default, or only the selected channel from 1–16.
• Instrument Level adjusts the generated sound from -60 to +12 dB (default 0 dB), without changing incoming audio.
• Max Voices limits simultaneous sample voices, including releases, to 1–1024 (default 256). Higher values preserve more overlapping sounds and use more processing.
• Automatic Fallback (on by default) replaces a missing SF2/SF3 sound with a similar available one, as described above. Turn it off to keep channels that request a missing sound silent, which makes gaps in the SoundFont easy to notice.
• Interpolation chooses how the instrument’s samples are resampled. FIR (64 taps) uses the standard SF2/SF3 filter or the SFZ instrument’s own quality setting. FIR (32 taps) (default) uses less processing for SF2/SF3; it uses 32 taps when no downsampling is needed, while FIR filters grow when playback requires downsampling to limit aliasing. Cubic (4 points) uses light interpolation, but lacks an anti-alias low-pass filter, so strongly raised notes or samples rich in high harmonics can produce aliasing. FIR and Cubic override an SFZ instrument’s quality setting.
• SF2 Compatibility chooses how SF2/SF3 sounds are interpreted; SFZ instruments are not affected. Standard (default) behaves like common SoundFont synthesizers and the original SoundFont hardware, which most SoundFonts are tuned for: each sound’s attenuation setting is applied at 40% strength, and the specification’s default velocity-to-filter rule is ignored, so softer notes are not automatically darker. SF2.04 Strict follows the SoundFont 2.04 specification literally: attenuation is applied in full, so sounds that use attenuation play quieter than their authors likely intended, and softer notes sound darker. Use it to hear how a SoundFont sounds when the specification is followed to the letter.

The selected instrument and these settings are saved normally. The Music Player’s volume and mute also control the MIDI instrument. Presets, shared links, and backups store the instrument reference, not its samples; keep the original files available in the desktop app and for use on another device.

Color changes only the keyboard display. Normal uses the common graph color, Note Colors uses the Note Spectrogram note palette, and Channel Colors gives each MIDI channel a different color. The color choice is not saved with presets.

Instrument Details

The loaded instrument summary shows its sample and preset counts, source file size, and playback memory when available. Large instruments stream the sample data needed for playback rather than loading the entire source into memory. The source size can therefore be much larger than the playback memory.

The status shows reading, instrument or sample-cache preparation, readiness, or a loading error. Progress shows completed work against the total when that total is known; otherwise, the indicator remains indeterminate. If loading fails, check that the original files are available or choose another instrument. When preloading is limited, you can still play, but some notes may start late.

In Settings, expand Instrument Details to read the SFZ instrument’s labels for keys, MIDI controllers (CC), outputs, groups, layers and keyswitches. These labels explain the instrument’s own mappings; they are not additional controls. When a labeled keyswitch is active, Keyswitch shows the selected articulation for each channel. Artwork appears when supplied by the instrument; if it declares several images, the last one is shown.

Live MIDI Input

Live MIDI performance is available in the desktop app and web/PWA player. It is not supported in the Android app; Controller Mapping remains available there.

To play from a MIDI keyboard or a virtual MIDI port, close Music Player. In Audio Configuration, choose Refresh MIDI Devices, allow MIDI access if asked, and select MIDI Input Device. Keep an instrument loaded in SoundFont Player. An open Music Player takes priority even while paused; choose None to stop live MIDI input. Without a loaded instrument, MIDI continues silently. Loading an instrument makes subsequent MIDI events audible; past notes are not replayed. Live MIDI input is not relayed to MIDI Output Device, which sends only MIDI file playback from Music Player to an external device.

In the desktop app, websites in Browser that use Web MIDI can also play SoundFont Player through a MIDI output named EffeTune. From its first MIDI message, the page takes over live MIDI input until you click Close on the browser toolbar, leave the page, or reload it; live MIDI input then returns to the selected MIDI Input Device.

SFZ Instruments

An SFZ instrument can shape each note’s volume, pitch and tone over time, combine filters and built-in effects, and control sample loops and release sounds. Beat-synchronized playback and effects follow the MIDI song’s tempo and playback speed. These settings belong to the instrument file; use the effects after SoundFont Player to adjust the combined sound yourself.

amp_veltrack_random lets an SFZ instrument vary its velocity-to-volume response for each new note. The default value 0 adds no random variation. It changes how playing strength affects volume, rather than changing the MIDI velocity itself.

Large instruments read sample data as needed within the configured memory budget. Keep the definition and its required samples together when importing; embedded samples and files used only by the instrument’s effects are also included. If a sample fails its content check, restore the original file or import the instrument again. Instruments with separate outputs need an output configuration with enough channels.

An SFZ file can choose sample storage with load_mode: 0 (default) uses 32-bit floating-point, and 1 uses 16-bit PCM to reduce sample memory. Higher-precision sources lose precision in 16-bit mode. In EffeTune, load_start and load_end specify the first and last source sample frames to keep in memory, with the last frame included. When a range is specified, an omitted start means 0 and an omitted end means the sample’s end. Data outside that range streams as needed; this does not trim playback or shift loop positions. Without either bound, streaming remains automatic.

Compatibility varies by instrument, and some vendor-specific behavior is unavailable. See the SFZ compatibility reference for the supported profile and its limits. SoundFont Note Player uses the same instrument preparation, but its detected notes do not supply a MIDI song’s controller changes or tempo.

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