How the options work
The options come in two groups. MIDI processing works on the notes, timing and controllers of the MIDI/KAR; Real-time sound and mix works on the sound already produced by FluidSynth. In both cases the original file is never modified and no audio files are created: the improved MIDI is a temporary copy used only while listening.
- Each checkbox is tied exactly to its function: ticked = applied, unticked = ignored.
- The options apply to MIDI and KAR. They have no effect on video, MP3 and CD+G.
- Pressing Apply during playback, the sound effects change immediately; the MIDI options apply from the next Play.
- The options are saved per song; Save as defaults uses them for all new songs.
MIDI processing
Clean up anomalous events and prevent stuck notes
What it is for: fixes the most common defects of downloaded MIDI/KAR files: notes left «hanging» (note-on without note-off, sustain not released), missing tempo, time signature and key signature, and average velocities that are too high or too low (if the average is above 110 or below 25 the velocities are brought back into that range). At the end of the song an all-notes-off message is sent.
Risk: very low. It changes neither the notes nor the lyrics.
Specific musical corrections per instrument family
What it is for: each family receives only the correction suited to how it is played. For winds and accordion/harmonica the pitch bends are halved (less «ribbon-like» slides), very short expression gaps (CC11) are removed and the expression volume is kept between 50 and 127, so the sound neither disappears nor deflates. For basses, guitars, strings, voices and pads the corresponding rules apply (for example the bass pitch bend always stays centered; on guitars the tiniest pitch wobbles, up to 25 cents, such as certain vibratos written in the file that make the guitar sound flat, are brought back to center, while real bends up to about 3 semitones are kept; long «slides» written with the pitch wheel that drop the note by more than 3.5 semitones are brought back to center) and for all non-drum instruments overlapping repeated notes are fixed.
- It applies after the style: if the style changes the instrument of a channel, the correction follows the new instrument.
- It coexists well with Humanization: winds are not lengthened by humanization precisely so as not to spoil the expression corrected here.
- Turn it off if the MIDI has hand-crafted expression you want to hear untouched.
Slightly humanize velocity and performance
What it is for: makes the performance less mechanical. Velocities are pulled toward half of their value and randomly varied by a few points (±3; drums less), then notes (drums excluded) are lengthened up to the next one, within a short limit, for a more legato sound. Winds are not lengthened. The result is reproducible: the same song always gives the same result.
- Electronic style (or dance/techno): the regularity of the machine is intended, turn humanization off.
- With Groove both act on the «feel», but on different channels: groove on mechanical channels, humanization on all. Together they work well; if the song sounds «soft», turn one off.
- Together with Piano dynamics it works in the same step: no problem.
- With Balance and Light compression the dynamics are leveled three times: if the song loses breath, turn the compression off.
Apply light groove to mechanical parts
What it is for: detects the «mechanical» channels (at least 16 notes and at least 85% at the same velocity, typical of sequencers and backing tracks) and adds a light groove to them, so they do not sound like a machine.
- Electronic and dance songs on a rigid grid: turn it off.
- Slow songs or songs already played by a musician: not needed, and it finds nothing to correct.
- The style quantizes first; the groove then puts a little life back into the quantized notes.
Balance levels between channels and instrument families
What it is for: analyzes the MIDI and recalibrates the velocities of channels that are too loud or too quiet relative to the others, so that no instrument covers the others.
It works on the note velocities (not on the volume rendered in LUFS as in CreaVideoLyrics, because here no audio is created).
- With duplicated parts it works in the same step: echo copies are first attenuated, then balanced.
- With Leveling and Light compression the volume is handled at several points: if the mix sounds flat, keep only balance and leveling.
- The mute removes a channel before the analysis: the balance does not count it.
Detect and attenuate parts duplicated at the unison or octave
What it is for: many MIDIs repeat the same melody (for example a sax in echo) on several channels, and the sound doubles or goes out of tune. Here the copies are recognized and attenuated; pan and instrument of the echo copies can be replaced with those suggested by the analysis.
- If the octave doubling is intended (strings and brass supporting the melody), the arrangement becomes sparser: turn the option off.
- With channel Balance they are meant to be used together, in the same step.
Double strings, pads, organs, accordion, brass, sax, choirs and guitars
What it is for: while the song plays, a second synthesizer adds a «shadow» voice to some instruments. There are two modes, depending on the instrument. The MIDI file is not modified: the shadow exists only while listening.
1. Ensemble doubling (strings, synth strings, choirs and voices, organs, accordion, violin, pads): the same part is also played by a second voice, slightly detuned (4 to 11 cents), quieter and on the opposite side of the stereo space. The original channel drops by about 1.5 dB to compensate for the sum. This is the ensemble effect.
2. Timbral reinforcement (guitars, brass, sax, reeds and flutes): useful when the SoundFont gives these instruments little presence. Under the original instrument plays, quieter (40-50%) and at the same point of the stereo space, a complementary instrument that gives it body, with a difference of only 2 cents. The volume of the original does not change. Examples: clean electric guitar + steel guitar, nylon guitar + steel, jazz guitar + nylon, overdrive + clean, alto sax + tenor, tenor sax + alto, trumpet or trombone + horn, brass section + synth brass, oboe + clarinet, flute + pan flute.
Never doubled or reinforced: drums and percussion, basses, pianos, harp, vibraphone, muted guitar and plucked instruments.
Notice: once per song, after about half a second of playback of a MIDI/KAR, a window appears listing the channels with reinforcement or doubling (for example «Channel 3: clean electric guitar + steel guitar»). The music continues while it is open.
- In ensemble doublings, if two channels use instruments of the same family (for example two string tracks) the shadow is added to only one, so as not to sum parts that already overlap. In reinforcements this rule does not exist: each guitar or wind gets its own, up to a maximum of 6 reinforced channels together.
- The reinforcement neither turns off nor replaces the instrument of the file: if you do not like the result on a song, untick this option.
- With an external MIDI device chosen (see External MIDI output) doubling and reinforcement are disabled: only the expander plays.
- The option has a single switch for both modes: unticking it turns off ensemble doubling, reinforcement and the notice.
- Doubling uses more CPU (the second synthesizer plays in parallel): on slow computers, if the sound «skips», turn the option off.
- It applies at the next Play; while listening, a change of key, style or mute also restarts the song from the current point with the new setting.
- With Chorus and Stereo widening the width adds up: if the sound becomes too wide and confused, turn one of the three off.
- With duplicated parts it works in a complementary way: that one attenuates copies already present in the file, this one adds one where the part is single.
- If the song already has many ensemble instruments the sound becomes dense: turn it off.
- With the bass, low-mid and treble boosts, guitars and winds can become too full or harsh: judge by ear.
Breath of the winds
What it is for: winds are the weak point of MIDI: every note starts and ends the same, and the sax sounds like an organ. Here sax, single brass (trumpet, trombone, tuba, horn), oboe, bassoon, clarinet and flutes receive a human touch, on single notes only (never on chords or sections):
- Breath: the note starts a bit quieter and grows, the more so the longer it is (expression CC11).
- Natural vibrato: only on long notes, delayed, growing slowly, a few cents wide, with frequency and amplitude that change from note to note and within the note, and that fades out before the end. It does not use the mod wheel (whose regular vibrato sounds «keyboard-like») but small pitch movements.
- Scoop and fall (sax and brass): attack slightly under pitch at the beginning of a phrase, a small fall of the last long note before a rest.
- Legato: between two close notes of different pitch the first overlaps the second by 18 ms, with no gaps.
- Where the file already has expression (CC11), pitch bend or wheel on the channel, the corresponding intervention is skipped: the file's own prevails.
- With Per-family corrections it works after it and coexists well.
- With Doubling the shadow voice also follows breath and intonation.
- It applies at the next Play. Turn it off to hear the MIDI as written.
Protect the vocal
What it is for: in songs where the guide (usually channel 4, the one of the «mute guide» slider) sings a melody, sometimes one or more instruments (electric piano, piano, strings, guitars) play in the same register so loudly that they cover it, and when you remove the guide to sing yourself the voice ends up buried. This option lowers those instruments, only where the guide plays.
- The guide is read from the original file; the song is checked in windows of two quarter notes.
- In each sung window the level of the guide is compared with the sum of the other melodic instruments in its own note zone (±1 octave). If they exceed it, the velocity of the loudest is lowered, up to a maximum of −55% (pianos −60%) in slow songs and −35% (pianos −40%) in fast ones (over 110 bpm, gradual from 80), with a smooth transition between windows.
- Toms, congas and splash that are too loud (over 0.85 times the snare) are limited throughout the song. The bass (programs 32-39) is kept below 0.85 times the guide, with a maximum cut of −25%. Notes outside the guide's register are not touched. The pad rises where the song gets more intense (full drums, e.g. the chorus); the drums, if they exceed 0.7 times the level of the guide, drop by up to a maximum of −32% and, if they dropped by at least 20% and use the Standard kit, switch to the Room kit (softer). With a style selected the drums are not touched. A guide with fewer than 32 notes does not count as a vocal line. Short pauses between two sung phrases stay protected.
- In the status bar, at start, it shows which channels were lowered and by how much.
- With the «mute guide» slider at 0 the guide is recognized by itself (the channel with the most likely melody, otherwise channel 4); the guide stays audible and only the other instruments are lowered. If it is not recognized, a notice appears in the status bar.
- It acts after Balance, Re-arrangement and Retouch, and before Breath of the winds.
- It applies at the next Play. Untick it to hear the balance without this correction.
- Soften vocal protection: the slider in the main window, under the reverb, decides how much of the calculated reductions is applied. 100% = full reductions, 0% = none; the suggestion is 30%, so as not to create too much volume difference between sung and unsung passages. If in a song you still hear the guide covered, raise it; if the volume difference between verses and instrumental parts seems too much, lower it. The maxima indicated above (−55%, −60%, −25%...) hold at 100%: at 30% 30% of each reduction is applied. The value is saved per song; you hear it at the next Play or, while listening, when you release the slider (playback restarts from the current point). It has no effect if Protect the vocal is off.
External MIDI output
What it is for: sends in real time the same MIDI already improved by this window (cleanup, corrections, humanization, style, transposition...) to a real MIDI device connected to the computer, besides the sound produced internally by FluidSynth. For the program there is no difference between a hardware expander connected by USB, an audio interface with a MIDI port or a virtual synthesizer such as VirtualMIDISynth: they all appear in the same drop-down list.
- The MIDI output menu lists the MIDI devices found on the system; Internal (FluidSynth) (default) sends nothing outside.
- What reaches the device is identical to what FluidSynth hears: same corrections, same key. The original MIDI file is not touched.
- With an external device chosen, FluidSynth's internal sound is silenced: you only hear the expander. For the same reason the timbral reinforcement (doubling with the second synthesizer) is disabled, and the related notice does not appear.
- Stop, Pause and a move on the progress bar reset all notes on the external device, so no stuck sounds remain.
- If the chosen device is no longer connected, it stays selected at the end of the menu as «(not connected)» instead of disappearing: playback continues with the internal audio only.
- Available only on Windows for now; on Linux and macOS the menu lists only Internal (FluidSynth).
- It applies at the next Play: changing device during playback does not move it on the fly.
Make piano dynamic jumps more regular
What it is for: corrects the «spring» effect of the piano (instruments 0-7): a note cannot drop by more than 15 velocity points compared with the previous one, so the sound does not jump from loud to very faint.
Fix double hits and abnormal drum panning
What it is for: in «crooked» MIDIs the drums may play all on one side or with every hit doubled (double volume and out-of-phase sound). The option brings the pan back to center beyond ±20, removes the balance (CC8) and reduces double hits (same note, same instant) to one, with the highest velocity. It applies to channel 10 only.
Warn if transposition takes notes out of range
What it is for: changing the key, some notes may leave the range of the MIDI or the instrument. With the box on, the status line warns how many notes are out of range and which instruments (guitars, basses) were raised by an octave. It does not modify the notes, it only informs.
The octave correction for guitars and basses when the key is lowered is instead always automatic: the warning concerns only the message.
↑ indexReal-time sound and mix
How the sound effects work
The effects act on the stereo mix produced by FluidSynth, while it plays, without creating files. Order: tube warmth, multiband bass, bass and treble, low-mids, harmonic brightness, convolution reverb, compression, stereo widening, final limiter. You can change them even while listening with Apply.
Reverb
What it is for: turns on FluidSynth's internal reverb, which gives room and body to the sound. On by default.
If in the main window you chose a room from the Reverb menu (convolution reverb), this internal reverb is turned off automatically: the two do not add up.
Chorus
What it is for: a light doubling with a small pitch variation that gives width to some timbres (strings, pads, guitars). Off by default.
Leveling and peak protection
What it is for: a final limiter (threshold 0.97, release 300 ms) that keeps peaks from distorting, especially after boosted bass and treble. On by default.
Harmonic brightness
What it is for: makes the sound clearer and more open without raising the treble with EQ. It is a harmonic exciter: it takes the part of the sound above about 3 kHz, saturates it slightly to create new harmonics and adds a small amount to the original. The treble level does not change, but cymbals, voice and strings sound sharper. On by default; it replaces the old «Presence on vocal frequencies».
- It has no conflicts with the bass, but together with Treble boost the sound can become harsh: use only one.
- It also boosts the hiss of certain SoundFonts a little: listen again before keeping it.
- Does it apply to the «no reverb» drums? No: only the fixed EQ applies to the separate drums.
Light compression of the mix
What it is for: a compressor on the whole mix (threshold -24 dB, ratio 3:1, attack 20 ms, release 200 ms) that «glues» the instruments and makes them more uniform. Off by default.
Stereo widening
What it is for: widens the stereo image by reinforcing the sides (strength 1.5). Off by default.
Bass boost
What it is for: a +5 dB shelf at 100 Hz to give weight to kick and bass when the SoundFont sounds thin. Off by default.
Low-mid boost
What it is for: a +4 dB bell at 300 Hz that gives body and warmth to guitars, piano, male voices and strings, when they sound «empty». Off by default.
Treble boost
What it is for: a +5 dB shelf at 3 kHz to give brilliance if the SoundFont sounds dull. Off by default.
Full multiband bass
What it is for: gives weight and presence to bass and kick without the usual «boom». The sound below 120 Hz is separated from the rest, made more uniform with light compression (3:1 beyond -24 dB) and summed back with about 45% more. In addition the harmonics of the bass (above 150 Hz) are added: the ear uses them to «rebuild» the low sound, and the bass is heard even on small speakers, phones and cheap headphones, where a simple boost would not be heard. Off by default.
The low band is treated in mono (as is done in mixing for bass and kick): the stereo image does not change.
- With Bass boost it does the same job twice: in the Options window they exclude each other. Choose one.
- On songs with kick and bass already very full (disco, dance) it can weigh down: turn it off.
- Keep Leveling on to avoid peaks.
Tube warmth
What it is for: adds the light saturation typical of a tube amplifier: a touch of even and odd harmonics that makes the sound fuller, softer and less «digital», and gently compresses the peaks. It acts only on the sound below 5 kHz, so the highs stay clean and no hiss is heard. On very quiet signals it does almost nothing: the warmth appears when the sound is full. Off by default.
- With Light compression and Leveling the dynamics are reduced several times: if the song ends up squashed, turn the compression off.
- With Treble boost or Harmonic brightness the added harmonics are brightened and the sound can become harsh.
- On piano and clear voices it may seem an extra color: listen again before keeping it.
- It acts before the convolution reverb, which therefore is not saturated.
Recommended combinations
| Song | Options |
|---|---|
| Default (fine almost always) | All MIDI corrections on, Reverb, Chorus and Leveling on; the rest off |
| Dance, disco, electronic | Turn off Humanization, keep Cleanup and Stereo drums; Electronic style; no bass/treble boost; Chorus off |
| Slow, ballad, jazz | Groove and Compression off; Per-family corrections on (winds and strings); Reverb on |
| Thin «MIDI-like» sound | Harmonic brightness or Treble boost (not both) plus Low-mids; Leveling on |
| Solo piano | Piano dynamics off if the contrasts are intended; Compression off |
| Listening in mono | Stereo widening off; Chorus off |
Defaults, Save as defaults, Cancel, Apply
- Defaults: brings all boxes back to the initial values (the style chosen in the main window stays as it is).
- Save as defaults: uses the current values for all new songs.
- Cancel: closes without changing anything.
- Apply: saves the options for the current song; sound effects change immediately, MIDI options from the next Play.