v0.32.0: 8 new synth features, highpass filter, preset overhaul

Filter envelope, velocity→brightness, sub-oscillator, tremolo,
saturation, noise layer, phaser, configurable FM. Highpass filter.
Bowed and mallet envelopes. Improved strings_synth with additive
synthesis. All 38 instrument presets sanity-checked and enhanced.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,36 @@
 
 All notable changes to PyTheory are documented here.
 
+## 0.32.0
+
+- **8 new synth engine features:**
+  - Filter envelope: per-note lowpass sweep (`filter_amount`, `filter_attack`, `filter_decay`, `filter_sustain`)
+  - Velocity → brightness: harder notes = brighter filter (`vel_to_filter`)
+  - Sub-oscillator: octave-below sine for bass weight (`sub_osc`)
+  - Tremolo: amplitude LFO modulation (`tremolo_depth`, `tremolo_rate`)
+  - Saturation: even-harmonic tape/tube warmth (`saturation`)
+  - Noise layer: per-note breath/air texture (`noise_mix`)
+  - Phaser: swept allpass filter chain (`phaser`, `phaser_rate`)
+  - Configurable FM: `fm_ratio` and `fm_index` params
+- **Highpass filter** (12 dB/oct biquad) on any part
+- **2 new envelopes:** `bowed` (bow attack with sustain), `mallet` (strike with ringing sustain)
+- **Improved `strings_synth`:** additive synthesis with body resonance curve, per-harmonic phase randomization, delayed vibrato onset, bow pressure variation
+- **Instrument preset overhaul:** every preset sanity-checked against real instrument behavior
+  - Mallet instruments (vibraphone, celesta, music box, glockenspiel, tubular bells) now ring properly
+  - Trumpet uses sustaining envelope instead of pluck
+  - Woodwinds have breath noise, brass has velocity brightness
+  - Bass instruments have sub-oscillators, synth presets have filter envelopes
+  - Piano has velocity-to-brightness and subtle hammer noise
+- Signal chain: saturation → tremolo → distortion → chorus → phaser → highpass → lowpass → delay → reverb
+- Song #21: Cinematic Showcase (Orchestral)
+
+## 0.31.0
+
+- 3 new synth engines: Karplus-Strong pluck, Hammond organ, string ensemble with body formants
+- 38 instrument presets: `score.part("lead", instrument="violin")`
+- Keys, strings, woodwinds, brass, plucked, synth, and mallet categories
+- 13 total synth waveforms
+
 ## 0.30.0
 
 - Drums are a real Part — same effects pipeline as any voice

docs/guide/effects.rst

@@ -32,13 +32,26 @@ It's a well-tested order that sounds good by default.
 
 Effects are applied in this fixed order::
 
-    Signal --> Distortion --> Chorus --> Lowpass Filter --> Delay --> Reverb --> Mix
+    Signal --> Saturation --> Tremolo --> Distortion --> Chorus --> Phaser
+          --> Highpass --> Lowpass --> Delay --> Reverb --> Mix
 
-- **Distortion** first: drives the raw signal before filtering (like
-  plugging a guitar into a fuzz pedal before the amp).
-- **Chorus** second: thickens the distorted signal.
-- **Lowpass** third: shapes the tone (like a tone knob on an amp).
-- **Delay** fourth: echoes the shaped signal (tap delay / tape echo).
+Additionally, these per-note effects are applied before the part effects chain:
+
+- **Sub-oscillator**: octave-below sine mixed in at the oscillator stage
+- **Noise layer**: filtered noise mixed per-note for breath/transients
+- **Filter envelope**: per-note lowpass sweep (attack/decay/sustain)
+- **Velocity → brightness**: harder velocity = brighter filter cutoff
+
+Part-level effects:
+
+- **Saturation** first: subtle even-harmonic warmth (tape/tube color).
+- **Tremolo** second: amplitude LFO modulation.
+- **Distortion** third: drives the signal before filtering.
+- **Chorus** fourth: thickens the signal.
+- **Phaser** fifth: swept allpass notches.
+- **Highpass** sixth: removes low-frequency mud.
+- **Lowpass** seventh: shapes the tone (like a tone knob on an amp).
+- **Delay** eighth: echoes the shaped signal (tap delay / tape echo).
 - **Reverb** last: places everything in a space (room / hall).
 
 Distortion
@@ -498,6 +511,221 @@ whole mix will gasp for air:
        delay=0.2,
    )
 
+Saturation
+----------
+
+Saturation is the warm, subtle harmonic enhancement of analog tape
+machines and tube preamps. Unlike distortion (which uses ``tanh`` and
+adds harsh odd harmonics), saturation uses a polynomial waveshaper
+that adds even harmonics -- 2nd and 4th -- which the ear perceives as
+warmth and fullness. It's why records mixed through a Neve console
+sound "bigger" than the same mix done in the box.
+
+Parameters:
+
+- ``saturation``: Amount, 0.0--1.0 (default 0, off).
+
+  - 0.05--0.15 = subtle analog warmth (tape machine)
+  - 0.2--0.4 = noticeable color (tube preamp)
+  - 0.5+ = heavy coloring
+
+.. code-block:: python
+
+   # Warm up a bass
+   bass = score.part("bass", synth="saw", saturation=0.2)
+
+   # Glue a string ensemble
+   strings = score.part("strings", instrument="string_ensemble",
+                        saturation=0.1)
+
+Tremolo
+-------
+
+Amplitude modulation by a sine LFO. The classic vibrating-amp sound.
+Essential for vibraphone (the rotating discs in the resonator tubes),
+Rhodes electric piano, and surf guitar. Not to be confused with
+vibrato (pitch modulation).
+
+Parameters:
+
+- ``tremolo_depth``: Modulation depth, 0.0--1.0 (default 0, off).
+- ``tremolo_rate``: LFO speed in Hz (default 5.0).
+
+  - 3--5 Hz = classic tremolo
+  - 5--7 Hz = vibraphone motor speed
+  - 8+ Hz = ring-mod territory
+
+.. code-block:: python
+
+   # Classic Fender amp tremolo
+   guitar = score.part("guitar", synth="saw", envelope="pluck",
+                       tremolo_depth=0.3, tremolo_rate=4.0)
+
+   # Vibraphone with motor
+   vib = score.part("vib", instrument="vibraphone")  # built in
+
+Phaser
+------
+
+A chain of allpass filters whose center frequencies are swept by an
+LFO, creating moving notches in the spectrum. The classic "jet
+engine" or "underwater" effect. Think Small Stone, MXR Phase 90, or
+the intro to "Eruption." Different from chorus -- chorus adds a
+detuned copy, phaser cancels specific frequencies.
+
+Parameters:
+
+- ``phaser``: Wet/dry mix, 0.0--1.0 (default 0, off).
+- ``phaser_rate``: LFO sweep speed in Hz (default 0.5).
+
+  - 0.1--0.3 = slow, lush sweep
+  - 0.5--1.0 = classic phaser
+  - 2.0+ = fast, Leslie-like
+
+.. code-block:: python
+
+   # Slow sweep on a pad
+   pad = score.part("pad", synth="supersaw", envelope="pad",
+                    phaser=0.4, phaser_rate=0.2)
+
+   # Leslie sim on organ (built in)
+   organ = score.part("organ", instrument="organ")
+
+Highpass Filter
+---------------
+
+The opposite of lowpass -- removes low-frequency content below the
+cutoff. Useful for cleaning up mud from pads, keeping multiple bass
+parts from masking each other, or thinning out a sound to sit better
+in a mix.
+
+Parameters:
+
+- ``highpass``: Cutoff frequency in Hz (0 = off).
+
+  - 80--150 Hz = clean up sub rumble
+  - 200--400 Hz = thin out a pad
+  - 500+ Hz = telephone / radio effect
+
+- ``highpass_q``: Resonance / Q factor (default 0.707).
+
+.. code-block:: python
+
+   # Clean up sub rumble from a pad
+   pad = score.part("pad", synth="supersaw", highpass=120)
+
+   # Thin out rhythm guitar to leave room for bass
+   rhythm = score.part("rhythm", synth="saw", highpass=250)
+
+Filter Envelope
+---------------
+
+A per-note lowpass filter whose cutoff sweeps over time. This is the
+core of subtractive synthesis -- the reason a Moog bass goes "bwow"
+instead of "boop." The filter opens on the attack and closes during
+decay, giving each note a distinctive timbral shape.
+
+Parameters:
+
+- ``filter_amount``: Sweep range in Hz (0 = off). How far the filter
+  opens above the base cutoff.
+- ``filter_attack``: Time to reach peak cutoff, in seconds (default 0.01).
+- ``filter_decay``: Time to fall to sustain level (default 0.3).
+- ``filter_sustain``: Sustain level as fraction of amount, 0.0--1.0
+  (default 0.0 = filter closes completely after decay).
+
+.. code-block:: python
+
+   # Classic synth bass "bwow"
+   bass = score.part("bass", instrument="synth_bass")  # built in
+
+   # Acid squelch
+   acid = score.part("acid", instrument="acid_bass")  # built in
+
+   # Custom filter sweep on a lead
+   lead = score.part("lead", synth="saw",
+                     filter_amount=4000, filter_attack=0.01,
+                     filter_decay=0.4, filter_sustain=0.1)
+
+Velocity to Brightness
+~~~~~~~~~~~~~~~~~~~~~~
+
+Real instruments get brighter when played harder. ``vel_to_filter``
+maps note velocity to filter cutoff boost, so louder notes have more
+high-frequency content.
+
+- ``vel_to_filter``: Cutoff boost in Hz at max velocity (default 0, off).
+
+.. code-block:: python
+
+   # Piano: soft = mellow, loud = bright
+   piano = score.part("piano", instrument="piano")  # built in
+
+   # Manual: custom velocity mapping on a lead
+   lead = score.part("lead", synth="saw", vel_to_filter=3000)
+
+Sub-Oscillator
+--------------
+
+An octave-below sine wave mixed in with the main oscillator. Adds
+low-end weight without muddiness -- the sub fills in the fundamental
+while the main oscillator provides harmonic character above.
+
+- ``sub_osc``: Mix level, 0.0--1.0 (default 0, off).
+
+  - 0.1--0.2 = subtle weight (tuba, bass guitar)
+  - 0.3--0.5 = heavy sub (808, synth bass)
+
+.. code-block:: python
+
+   # Fat 808 kick-bass
+   bass = score.part("bass", instrument="808_bass")  # built in
+
+   # Add weight to any part
+   lead = score.part("lead", synth="saw", sub_osc=0.3)
+
+Noise Layer
+-----------
+
+White noise mixed into each note, following the same amplitude
+envelope. Adds breath for woodwinds, hammer/felt noise for piano,
+bow rosin for strings, and attack transients for percussion.
+
+- ``noise_mix``: Mix level, 0.0--1.0 (default 0, off).
+
+  - 0.02--0.04 = subtle texture (strings, piano)
+  - 0.05--0.08 = noticeable breath (woodwinds)
+  - 0.1+ = heavy air/texture
+
+.. code-block:: python
+
+   # Breathy flute
+   flute = score.part("flute", instrument="flute")  # noise_mix=0.08
+
+   # Add air to any synth
+   pad = score.part("pad", synth="supersaw", noise_mix=0.05)
+
+Configurable FM
+---------------
+
+The FM synth now accepts ``fm_ratio`` and ``fm_index`` parameters,
+letting you dial in specific FM timbres instead of using the defaults.
+
+- ``fm_ratio``: Modulator frequency as multiple of carrier (default 2.0).
+  Integer ratios = harmonic timbres; non-integer = metallic/inharmonic.
+- ``fm_index``: Modulation depth (default 3.0). Higher = more harmonics.
+
+.. code-block:: python
+
+   # Warm electric piano (low ratio, low index)
+   ep = score.part("ep", synth="fm", fm_ratio=1.0, fm_index=1.5)
+
+   # Bright metallic bell (high ratio, high index)
+   bell = score.part("bell", synth="fm", fm_ratio=3.5, fm_index=5.0)
+
+   # Glockenspiel
+   glock = score.part("glock", instrument="glockenspiel")  # built in
+
 Automation
 ----------
 
@@ -528,9 +756,10 @@ processes each section independently:
    lead.set(lowpass=4000, distortion=0.7, reverb=0.3)
    lead.arpeggio("Gm", bars=4, pattern="updown", octaves=2)
 
-Any parameter can be automated: ``lowpass``, ``lowpass_q``, ``reverb``,
-``reverb_decay``, ``delay``, ``delay_time``, ``delay_feedback``,
-``distortion``, ``distortion_drive``, ``chorus``, ``volume``.
+Any parameter can be automated: ``lowpass``, ``lowpass_q``, ``highpass``,
+``reverb``, ``reverb_decay``, ``delay``, ``delay_time``, ``delay_feedback``,
+``distortion``, ``distortion_drive``, ``chorus``, ``phaser``, ``phaser_rate``,
+``saturation``, ``tremolo_depth``, ``tremolo_rate``, ``volume``.
 
 LFO Automation
 --------------

docs/guide/synths.rst

@@ -1,7 +1,7 @@
 Synthesizers
 ============
 
-PyTheory includes 10 built-in waveforms and 8 ADSR envelope presets.
+PyTheory includes 13 built-in waveforms and 10 ADSR envelope presets.
 Every sound is generated from scratch -- no samples or external audio
 files needed.
 
@@ -247,6 +247,8 @@ PyTheory includes 8 presets:
    play(tone, envelope=Envelope.ORGAN)     # Instant on/off, no shaping
    play(tone, envelope=Envelope.BELL)      # Instant attack, long ring
    play(tone, envelope=Envelope.STRINGS)   # Gradual bow attack
+   play(tone, envelope=Envelope.BOWED)     # Bow bite into sustain
+   play(tone, envelope=Envelope.MALLET)    # Strike with ringing sustain
    play(tone, envelope=Envelope.STACCATO)  # Short and punchy
    play(tone, envelope=Envelope.NONE)      # Raw waveform, no shaping
 
@@ -260,8 +262,10 @@ Name             Character
 ``"pluck"``      Sharp attack, fast decay -- guitar pick, harp
 ``"pad"``        Slow fade in, lush sustain -- strings, synth pads
 ``"organ"``      Instant on/off -- Hammond organ, no shaping
-``"bell"``       Instant attack, long ring -- vibraphone, tubular
+``"bell"``       Instant attack, no sustain -- short metallic ring
 ``"strings"``    Gradual bow attack -- orchestral strings, slow
+``"bowed"``      Bow bite into sustain -- solo strings, brass
+``"mallet"``     Strike with ringing sustain -- vibraphone, celesta
 ``"staccato"``   Short and punchy -- funk stabs, percussive hits
 ``"none"``       Raw waveform, no amplitude shaping at all
 ===============  ================================================
@@ -341,6 +345,89 @@ Reverb is also stereo — the left and right channels get different
 early reflection patterns, so the reverb tail occupies real space
 in the stereo field rather than sitting dead center.
 
+Physical Modeling
+-----------------
+
+Three synths go beyond traditional waveform synthesis into physical
+modeling territory — they simulate how real instruments produce sound.
+
+Karplus-Strong Pluck
+~~~~~~~~~~~~~~~~~~~~
+
+A burst of noise fed into a short delay line. The delay length sets
+the pitch, the feedback filter models the string decaying. This is
+how every physical modeling synth since 1983 does plucked strings.
+It sounds genuinely like a real guitar, harp, or koto.
+
+.. code-block:: python
+
+   guitar = score.part("guitar", synth="pluck_synth")
+   harp = score.part("harp", instrument="harp")  # uses pluck_synth
+
+Hammond Organ
+~~~~~~~~~~~~~
+
+Additive synthesis with drawbar harmonics — sine waves at the
+fundamental plus 2nd, 3rd, 4th, 5th, 6th, and 8th harmonics mixed
+at musical levels. Warm, round, unmistakably organ.
+
+.. code-block:: python
+
+   organ = score.part("organ", synth="organ_synth")
+
+String Ensemble
+~~~~~~~~~~~~~~~
+
+Filtered sawtooth with body resonance formants at ~500 Hz and ~1500 Hz,
+modeling the way a violin or cello body shapes the sound. Warmer and
+more "wooden" than a raw saw wave.
+
+.. code-block:: python
+
+   violin = score.part("violin", synth="strings_synth")
+
+Instrument Presets
+------------------
+
+Instead of choosing synth + envelope + effects manually, use an
+instrument preset — 38 predefined combinations that approximate real
+instruments:
+
+.. code-block:: python
+
+   piano = score.part("piano", instrument="piano")
+   violin = score.part("violin", instrument="violin")
+   guitar = score.part("guitar", instrument="acoustic_guitar")
+   organ = score.part("organ", instrument="organ")
+   bass = score.part("bass", instrument="upright_bass")
+
+Available instruments:
+
+**Keys**: piano, electric_piano, organ, harpsichord, celesta, music_box
+
+**Strings**: violin, viola, cello, contrabass, string_ensemble
+
+**Woodwinds**: flute, clarinet, oboe, bassoon
+
+**Brass**: trumpet, trombone, french_horn, tuba, brass_ensemble
+
+**Plucked**: acoustic_guitar, electric_guitar, distorted_guitar,
+bass_guitar, upright_bass, harp, sitar, koto
+
+**Synth**: synth_lead, synth_pad, synth_bass, acid_bass, 808_bass
+
+**Percussion**: vibraphone, marimba, xylophone, glockenspiel, tubular_bells
+
+Explicit kwargs override preset defaults:
+
+.. code-block:: python
+
+   # Piano with extra reverb
+   piano = score.part("piano", instrument="piano", reverb=0.5)
+
+   # Violin panned left
+   violin = score.part("v", instrument="violin", pan=-0.4)
+
 Choosing Synth and Envelope Combos
 ----------------------------------
 

docs/index.rst

@@ -77,11 +77,14 @@ What's Inside
   numbers), scale recommendation, modulation, voice leading
 - **Sequencing** — Score, Parts, arpeggiator, legato/glide, velocity,
   swing, humanize, tempo changes, song sections with repeat
-- **Synthesis** — 10 waveforms, 8 envelopes, detune, stereo pan/spread,
-  58 drum patterns (stereo panned), 21 fills
+- **Synthesis** — 13 waveforms (including Karplus-Strong pluck, Hammond organ,
+  bowed string), 10 envelopes, 38 instrument presets, configurable FM,
+  sub-oscillator, noise layer, filter envelope, velocity-to-brightness,
+  detune, stereo pan/spread, 58 drum patterns (stereo panned), 21 fills
 - **Effects** — reverb (algorithmic + 7 convolution IRs, stereo), delay,
-  lowpass (with resonance), distortion, chorus, sidechain compression,
-  automation, LFOs. Master bus compressor/limiter
+  lowpass/highpass (with resonance), distortion, saturation, chorus,
+  phaser, tremolo, sidechain compression, automation, LFOs. Master bus
+  compressor/limiter
 - **Instruments** — 25 presets with fingering generation
 - **Output** — stereo playback, WAV export, MIDI import/export
 - **Interface** — REPL with tab completion, CLI (15 commands), ``pytheory demo``

examples/songs.py

@@ -1116,6 +1116,94 @@ def temple_bell():
     play_song(score)
 
 
+def cinematic_showcase():
+    """Cinematic orchestral showcase — tubular bells, strings, organ, harp, acid bass."""
+    score = Score("4/4", bpm=100)
+
+    # Tubular bells — dramatic intro
+    bells = score.part("bells", instrument="tubular_bells",
+                       reverb=0.5, reverb_type="cathedral")
+    bells.add("A3", Duration.WHOLE)
+    for _ in range(7):
+        bells.rest(Duration.WHOLE)
+
+    # String ensemble — lush wide pad
+    strings = score.part("strings", instrument="string_ensemble",
+                         reverb=0.4, reverb_type="hall")
+    strings.rest(Duration.WHOLE)
+    for sym in ["Am", "F", "C", "G", "Dm", "Am", "E"]:
+        strings.add(Chord.from_symbol(sym), Duration.WHOLE)
+
+    # Cello — deep foundation
+    cello = score.part("cello", instrument="cello",
+                       reverb=0.3, reverb_type="hall")
+    cello.rest(Duration.WHOLE)
+    for n in ["A2", "F2", "C3", "G2", "D3", "A2", "E2"]:
+        cello.add(n, Duration.WHOLE)
+
+    # Violin — legato melody enters bar 3
+    violin = score.part("violin", instrument="violin",
+                        reverb=0.25, reverb_type="hall", legato=True)
+    violin.rest(Duration.WHOLE)
+    violin.rest(Duration.WHOLE)
+    for note, dur in [
+        ("E5", Duration.HALF), ("C5", Duration.HALF),
+        ("D5", Duration.QUARTER), ("E5", Duration.QUARTER), ("G5", Duration.HALF),
+        ("A5", Duration.HALF), ("G5", Duration.QUARTER), ("E5", Duration.QUARTER),
+        ("F5", Duration.WHOLE),
+        ("E5", Duration.HALF), ("D5", Duration.HALF),
+        ("C5", Duration.HALF), ("B4", Duration.HALF),
+        ("A4", Duration.WHOLE),
+    ]:
+        violin.add(note, dur)
+
+    # Organ — enters halfway, cathedral weight
+    organ = score.part("organ", instrument="organ",
+                       reverb=0.3, reverb_type="cathedral")
+    for _ in range(4):
+        organ.rest(Duration.WHOLE)
+    for sym in ["Dm", "Am", "E", "Am"]:
+        organ.add(Chord.from_symbol(sym), Duration.WHOLE)
+
+    # Harp — arpeggiated flourishes bars 3-4
+    harp = score.part("harp", instrument="harp")
+    harp.rest(Duration.WHOLE)
+    harp.rest(Duration.WHOLE)
+    for n in ["A3", "C4", "E4", "A4", "C5", "E5", "A5", "E5",
+              "G3", "B3", "D4", "G4", "B4", "D5", "G5", "D5"]:
+        harp.add(n, Duration.EIGHTH)
+    for _ in range(4):
+        harp.rest(Duration.WHOLE)
+
+    # Vibraphone — shimmer in last bars with delay
+    vib = score.part("vib", instrument="vibraphone",
+                     delay=0.25, delay_time=0.375, delay_feedback=0.35)
+    for _ in range(5):
+        vib.rest(Duration.WHOLE)
+    for note, dur in [
+        ("E5", Duration.QUARTER), ("D5", Duration.QUARTER),
+        ("C5", Duration.QUARTER), ("A4", Duration.QUARTER),
+        ("B4", Duration.HALF), ("E5", Duration.HALF),
+        ("A5", Duration.WHOLE),
+    ]:
+        vib.add(note, dur)
+
+    # Acid bass — gritty texture bars 4-5
+    acid = score.part("acid", instrument="acid_bass")
+    for _ in range(3):
+        acid.rest(Duration.WHOLE)
+    for n in ["C2", "C2", "E2", "G2", "G2", "G2", "A2", "E2",
+              "D2", "D2", "F2", "A2", "A2", "A2", "E2", "E2"]:
+        acid.add(n, Duration.EIGHTH)
+    for _ in range(2):
+        acid.rest(Duration.WHOLE)
+
+    # Half time drums
+    score.drums("half time", repeats=8)
+
+    play_song(score, "Cinematic Showcase — A minor")
+
+
 SONGS = {
     "1": ("Bossa Nova in A minor", bossa_nova_girl),
     "2": ("Bebop in Bb major", bebop_in_bb),
@@ -1137,6 +1225,7 @@ SONGS = {
     "18": ("Glass and Silk (Sine+Triangle)", glass_and_silk),
     "19": ("Dance Party at the Reitz House", dance_party),
     "20": ("Temple Bell (Japanese)", temple_bell),
+    "21": ("Cinematic Showcase (Orchestral)", cinematic_showcase),
 }
 
 if __name__ == "__main__":
@@ -1150,7 +1239,7 @@ if __name__ == "__main__":
             print(f"    {key:>2}. {name}")
 
         print()
-        choice = input("  Pick a song (1-20, or 'all'): ").strip()
+        choice = input("  Pick a song (1-21, or 'all'): ").strip()
         print()
 
         if choice == "all":

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "pytheory"
-version = "0.30.0"
+version = "0.32.0"
 description = "Music Theory for Humans"
 readme = "README.md"
 license = "MIT"

pytheory/__init__.py

@@ -1,6 +1,6 @@
 """PyTheory: Music Theory for Humans."""
 
-__version__ = "0.30.0"
+__version__ = "0.32.0"
 
 from .tones import Tone, Interval
 from .systems import System, SYSTEMS

pytheory/cli.py

@@ -230,7 +230,7 @@ def cmd_demo(args):
         {"name": "Bossa Nova", "key": ("A", "minor"), "drums": "bossa nova",
          "fill": "bossa nova", "bpm": 140,
          "prog": ("i", "iv", "V", "i"),
-         "lead": ("triangle", "strings", 0.2, -0.1),
+         "lead": ("pluck_synth", "none", 0.2, -0.1),
          "pad": ("fm", "pad", -0.2),
          "bass_lp": 600, "reverb_type": "plate"},
         {"name": "Jazz Club", "key": ("Bb", "major"), "drums": "jazz",
@@ -254,8 +254,8 @@ def cmd_demo(args):
         {"name": "Reggae", "key": ("G", "major"), "drums": "reggae",
          "fill": "reggae", "bpm": 80,
          "prog": ("I", "IV", "V", "IV"),
-         "lead": ("triangle", "strings", 0.25, 0.15),
-         "pad": ("pwm_slow", "pad", -0.3),
+         "lead": ("pluck_synth", "none", 0.25, 0.15),
+         "pad": ("organ_synth", "organ", -0.3),
          "bass_lp": 400, "reverb_type": "cathedral"},
         {"name": "Funk", "key": ("E", "minor"), "drums": "funk",
          "fill": "funk", "bpm": 100,
@@ -272,8 +272,8 @@ def cmd_demo(args):
         {"name": "Temple", "key": ("E", "minor"), "drums": "bolero",
          "fill": "bossa nova", "bpm": 65,
          "prog": ("i", "iv", "V", "i"),
-         "lead": ("triangle", "pluck", 0.3, 0.2),
-         "pad": ("sine", "pad", 0.0),
+         "lead": ("pluck_synth", "none", 0.3, 0.2),
+         "pad": ("strings_synth", "pad", 0.0),
          "bass_lp": 200, "reverb_type": "taj_mahal"},
     ]
 

pytheory/play.py

@@ -243,42 +243,71 @@ def organ_wave(hz, peak=SAMPLE_PEAK, n_samples=SAMPLE_RATE):
 
 
 def strings_wave(hz, peak=SAMPLE_PEAK, n_samples=SAMPLE_RATE):
-    """String ensemble — filtered saw with body resonance formants.
+    """Bowed string — additive synthesis with natural harmonic rolloff.
 
-    Goes beyond raw sawtooth by modeling the resonant body of a
-    stringed instrument. Two formant peaks (at ~500 Hz and ~1500 Hz)
-    shape the spectrum the way a violin or cello body does — boosting
-    certain frequencies and cutting others.
-
-    The result is warmer and more "wooden" than a raw saw wave,
-    with the characteristic nasal quality of bowed strings.
+    Models bowed string physics:
+    - Additive harmonics with 1/n rolloff shaped by body resonance
+    - Delayed vibrato (develops ~200ms in, like a real player)
+    - Subtle bow pressure variation (amplitude modulation)
+    - Per-harmonic phase randomization for natural timbre
+    - Gentle spectral tilt to avoid synthetic brightness
     """
-    # Base: sawtooth (all harmonics, like a bowed string)
-    length = SAMPLE_RATE / float(hz)
-    omega = numpy.pi * 2 / length
-    xvalues = numpy.arange(int(length)) * omega
-    onecycle = scipy.signal.sawtooth(xvalues, width=1)
-    wave = numpy.resize(onecycle, (n_samples,)).astype(numpy.float64)
+    t = numpy.arange(n_samples, dtype=numpy.float64) / SAMPLE_RATE
+    rng = numpy.random.default_rng(int(hz * 100) % 2**31)
 
-    # Body resonance formants — two bandpass peaks
-    # Formant 1: ~500 Hz (body resonance)
-    f1 = 500
-    bw1 = 200
-    b1, a1 = scipy.signal.butter(2, [max(20, f1 - bw1), f1 + bw1],
-                                  btype='band', fs=SAMPLE_RATE)
-    formant1 = scipy.signal.lfilter(b1, a1, wave)
+    # Delayed vibrato: ramps in over ~200ms, like a real bow
+    vib_rate = 5.2 + rng.uniform(-0.3, 0.3)  # slight randomness per note
+    vib_depth = hz * 0.003  # ~5 cents
+    vib_onset = numpy.clip(t / 0.2, 0.0, 1.0)  # ramp over 200ms
+    vibrato = vib_depth * vib_onset * numpy.sin(2 * numpy.pi * vib_rate * t)
 
-    # Formant 2: ~1500 Hz (bridge/top plate)
-    f2 = 1500
-    bw2 = 400
-    b2, a2 = scipy.signal.butter(2, [f2 - bw2, f2 + bw2],
-                                  btype='band', fs=SAMPLE_RATE)
-    formant2 = scipy.signal.lfilter(b2, a2, wave)
+    # Additive synthesis — build harmonics with natural rolloff
+    nyquist = SAMPLE_RATE / 2.0
+    n_harmonics = min(40, int(nyquist / hz))
+    wave = numpy.zeros(n_samples, dtype=numpy.float64)
 
-    # Mix: original (attenuated) + formants
-    mixed = wave * 0.3 + formant1 * 0.4 + formant2 * 0.3
+    # Body resonance curve — emphasizes certain harmonic regions
+    # Modeled after violin/cello response: peaks around 300Hz, 1kHz, 2.5kHz
+    def body_response(f):
+        """Approximate string instrument body resonance."""
+        r = 1.0
+        # Main air resonance (~280 Hz for violin, scales with pitch)
+        air_f = max(200, min(400, hz * 1.5))
+        r += 0.6 * numpy.exp(-((f - air_f) / 100) ** 2)
+        # Wood resonance (~1 kHz)
+        r += 0.4 * numpy.exp(-((f - 1000) / 300) ** 2)
+        # Bridge resonance (~2.5 kHz) — the "presence" peak
+        r += 0.3 * numpy.exp(-((f - 2500) / 500) ** 2)
+        return r
 
-    return (peak * mixed).astype(numpy.int16)
+    for n in range(1, n_harmonics + 1):
+        f_n = hz * n
+        if f_n >= nyquist:
+            break
+        # Amplitude: 1/n rolloff (sawtooth-like) shaped by body
+        amp = (1.0 / n) * body_response(f_n)
+        # Even harmonics slightly weaker (bowing point ~1/8 from bridge)
+        if n % 2 == 0:
+            amp *= 0.85
+        # Random phase per harmonic — prevents the "buzzy" coherent-phase sound
+        phi = rng.uniform(0, 2 * numpy.pi)
+        wave += amp * numpy.sin(2 * numpy.pi * (f_n * t + vibrato * n / hz) + phi)
+
+    # Normalize
+    max_val = numpy.abs(wave).max()
+    if max_val > 0:
+        wave /= max_val
+
+    # Subtle bow pressure variation — slow amplitude wobble
+    bow_pressure = 1.0 + 0.03 * numpy.sin(2 * numpy.pi * 3.7 * t)
+    wave *= bow_pressure
+
+    # Gentle lowpass — real instruments don't have infinite bandwidth
+    cutoff = min(10000, hz * 10)
+    bl, al = scipy.signal.butter(2, cutoff, btype='low', fs=SAMPLE_RATE)
+    wave = scipy.signal.lfilter(bl, al, wave)
+
+    return (peak * wave).astype(numpy.int16)
 
 
 def _apply_envelope(samples, attack, decay, sustain, release, sample_rate=SAMPLE_RATE):
@@ -346,7 +375,9 @@ class Envelope(Enum):
     PLUCK = (0.002, 0.15, 0.0, 0.1)
     PAD = (0.4, 0.2, 0.7, 0.5)
     STRINGS = (0.15, 0.1, 0.8, 0.3)
+    BOWED = (0.04, 0.08, 0.75, 0.25)
     BELL = (0.001, 0.3, 0.0, 0.5)
+    MALLET = (0.002, 0.05, 0.6, 0.8)
     STACCATO = (0.005, 0.05, 0.0, 0.02)
 
 
@@ -1458,6 +1489,41 @@ def _apply_lowpass(samples, cutoff, q=0.707, sample_rate=SAMPLE_RATE):
     return scipy.signal.lfilter(b, a, samples).astype(numpy.float32)
 
 
+def _apply_highpass(samples, cutoff, q=0.707, sample_rate=SAMPLE_RATE):
+    """Apply a 2nd-order Butterworth highpass filter (12 dB/octave).
+
+    Removes low-frequency content below the cutoff. Useful for cleaning
+    up mud from pads, keeping bass parts from masking each other, or
+    thinning out a sound.
+
+    Args:
+        samples: Float32 numpy array.
+        cutoff: Cutoff frequency in Hz.
+        q: Resonance / Q factor (default 0.707 = Butterworth flat).
+        sample_rate: Sample rate in Hz.
+
+    Returns:
+        Float32 array with filter applied.
+    """
+    if cutoff <= 0 or cutoff >= sample_rate / 2:
+        return samples
+
+    w0 = 2 * numpy.pi * cutoff / sample_rate
+    alpha = numpy.sin(w0) / (2 * q)
+
+    b0 = (1 + numpy.cos(w0)) / 2
+    b1 = -(1 + numpy.cos(w0))
+    b2 = (1 + numpy.cos(w0)) / 2
+    a0 = 1 + alpha
+    a1 = -2 * numpy.cos(w0)
+    a2 = 1 - alpha
+
+    b = numpy.array([b0/a0, b1/a0, b2/a0])
+    a = numpy.array([1.0, a1/a0, a2/a0])
+
+    return scipy.signal.lfilter(b, a, samples).astype(numpy.float32)
+
+
 def _apply_chorus(samples, mix=0.5, rate=1.5, depth=0.003,
                    sample_rate=SAMPLE_RATE):
     """Apply a chorus effect — slightly detuned delayed copy mixed in.
@@ -1503,6 +1569,171 @@ def _apply_chorus(samples, mix=0.5, rate=1.5, depth=0.003,
     return samples * (1 - mix * 0.5) + wet * mix * 0.5
 
 
+def _apply_filter_envelope(samples, base_cutoff, amount, f_attack, f_decay,
+                           f_sustain, q=0.707, vel_cutoff_boost=0.0,
+                           sample_rate=SAMPLE_RATE):
+    """Apply a per-note filter envelope — cutoff sweeps over time.
+
+    This is the core of subtractive synthesis: the filter opens on the
+    attack and closes during decay, giving notes a characteristic
+    "bwow" or "wah" shape.
+
+    Uses block-based processing (64-sample blocks) with biquad coefficient
+    interpolation for efficiency and smooth sweeps.
+    """
+    n = len(samples)
+    if n == 0 or amount <= 0:
+        return samples
+
+    block_size = 64
+    out = numpy.empty_like(samples)
+
+    # Build the filter cutoff envelope
+    a_samps = int(f_attack * sample_rate)
+    d_samps = int(f_decay * sample_rate)
+    sustain_level = f_sustain * amount
+
+    cutoff_env = numpy.full(n, sustain_level + base_cutoff + vel_cutoff_boost,
+                            dtype=numpy.float64)
+    # Attack ramp: 0 → amount
+    if a_samps > 0:
+        a_end = min(a_samps, n)
+        cutoff_env[:a_end] = (base_cutoff + vel_cutoff_boost +
+                              numpy.linspace(0, amount, a_end))
+    # Decay ramp: amount → sustain_level
+    if d_samps > 0:
+        d_start = min(a_samps, n)
+        d_end = min(a_samps + d_samps, n)
+        if d_end > d_start:
+            cutoff_env[d_start:d_end] = (base_cutoff + vel_cutoff_boost +
+                                         numpy.linspace(amount, sustain_level,
+                                                        d_end - d_start))
+
+    # Clamp cutoff to valid range
+    cutoff_env = numpy.clip(cutoff_env, 20.0, sample_rate / 2 - 1)
+
+    # Block-based biquad processing with varying cutoff
+    # State variables for the filter
+    x1 = x2 = y1 = y2 = 0.0
+    pos = 0
+    while pos < n:
+        end = min(pos + block_size, n)
+        block = samples[pos:end]
+        # Use cutoff at block midpoint
+        mid = (pos + end) // 2
+        fc = cutoff_env[mid]
+        # Compute biquad coefficients
+        w0 = 2 * numpy.pi * fc / sample_rate
+        sin_w0 = numpy.sin(w0)
+        cos_w0 = numpy.cos(w0)
+        alpha = sin_w0 / (2 * q)
+        b0 = (1 - cos_w0) / 2
+        b1 = 1 - cos_w0
+        b2 = (1 - cos_w0) / 2
+        a0 = 1 + alpha
+        a1 = -2 * cos_w0
+        a2 = 1 - alpha
+        # Normalize
+        b0 /= a0; b1 /= a0; b2 /= a0
+        a1 /= a0; a2 /= a0
+        # Process block sample by sample (maintaining state)
+        out_block = numpy.empty(len(block), dtype=numpy.float32)
+        for i in range(len(block)):
+            x0 = float(block[i])
+            y0 = b0 * x0 + b1 * x1 + b2 * x2 - a1 * y1 - a2 * y2
+            out_block[i] = y0
+            x2 = x1; x1 = x0
+            y2 = y1; y1 = y0
+        out[pos:end] = out_block
+        pos = end
+
+    return out
+
+
+def _apply_saturation(samples, amount=0.5):
+    """Apply tape/tube saturation — subtle even-harmonic warmth.
+
+    Unlike distortion (tanh, odd harmonics), saturation uses a
+    polynomial waveshaper that adds 2nd and 4th harmonics — the
+    warm, pleasing character of analog tape and tube preamps.
+    """
+    if amount <= 0:
+        return samples
+    # Asymmetric polynomial: x + k*x^2 adds even harmonics
+    driven = samples + amount * samples * samples
+    # Normalize to prevent gain buildup
+    driven = driven / (1.0 + amount)
+    # Soft clip any overs
+    return numpy.clip(driven, -1.0, 1.0).astype(numpy.float32)
+
+
+def _apply_tremolo(samples, depth=0.5, rate=5.0, sample_rate=SAMPLE_RATE):
+    """Apply tremolo — amplitude modulation by a sine LFO.
+
+    The classic vibrating amp sound. Essential for vibraphone,
+    electric guitar, and organ Leslie speaker simulation.
+    """
+    if depth <= 0:
+        return samples
+    t = numpy.arange(len(samples), dtype=numpy.float64) / sample_rate
+    lfo = 1.0 - depth * 0.5 * (1.0 + numpy.sin(2 * numpy.pi * rate * t))
+    return (samples * lfo).astype(numpy.float32)
+
+
+def _apply_phaser(samples, mix=0.5, rate=0.5, stages=4,
+                  sample_rate=SAMPLE_RATE):
+    """Apply phaser — swept allpass filter chain.
+
+    Creates moving notches in the frequency spectrum by passing
+    the signal through a chain of allpass filters whose center
+    frequencies are modulated by an LFO. Classic effect for
+    electric piano, pads, and guitar.
+    """
+    if mix <= 0:
+        return samples
+    n = len(samples)
+    block_size = 64
+    t = numpy.arange(n, dtype=numpy.float64) / sample_rate
+
+    # LFO sweeps center frequency between 200Hz and 4000Hz (log scale)
+    lfo = 0.5 + 0.5 * numpy.sin(2 * numpy.pi * rate * t)
+    center_freqs = 200.0 * (20.0 ** lfo)  # 200Hz to 4000Hz
+
+    # Process through allpass stages
+    wet = samples.copy().astype(numpy.float64)
+    for _stage in range(stages):
+        out = numpy.empty(n, dtype=numpy.float64)
+        # Allpass state
+        x1 = x2 = y1 = y2 = 0.0
+        pos = 0
+        while pos < n:
+            end = min(pos + block_size, n)
+            mid = (pos + end) // 2
+            fc = center_freqs[mid]
+            # Allpass biquad coefficients
+            w0 = 2 * numpy.pi * fc / sample_rate
+            alpha = numpy.sin(w0) / 2.0  # Q=0.5 for wide sweep
+            cos_w0 = numpy.cos(w0)
+            b0 = 1 - alpha
+            b1 = -2 * cos_w0
+            b2 = 1 + alpha
+            a0 = 1 + alpha
+            a1 = -2 * cos_w0
+            a2 = 1 - alpha
+            b0 /= a0; b1 /= a0; b2 /= a0
+            a1 /= a0; a2 /= a0
+            for i in range(pos, end):
+                x0 = wet[i]
+                y0 = b0 * x0 + b1 * x1 + b2 * x2 - a1 * y1 - a2 * y2
+                out[i] = y0
+                x2 = x1; x1 = x0
+                y2 = y1; y1 = y0
+            pos = end
+        wet = out
+
+    return (samples * (1 - mix) + wet.astype(numpy.float32) * mix).astype(numpy.float32)
+
+
 def _apply_distortion(samples, drive=1.0, mix=1.0):
     """Apply soft-clip distortion (tanh waveshaping).
 
@@ -1534,7 +1765,13 @@ def _apply_distortion(samples, drive=1.0, mix=1.0):
 
 def _apply_effects_with_params(samples, params, skip_reverb=False):
     """Apply effects using a params dict. Used for both static and automated rendering."""
-    # Signal chain: distortion → chorus → lowpass → delay → reverb
+    # Signal chain: saturation → tremolo → distortion → chorus → phaser
+    #             → highpass → lowpass → delay → reverb
+    if params.get("saturation", 0) > 0:
+        samples = _apply_saturation(samples, amount=params["saturation"])
+    if params.get("tremolo_depth", 0) > 0:
+        samples = _apply_tremolo(samples, depth=params["tremolo_depth"],
+                                 rate=params.get("tremolo_rate", 5.0))
     if params.get("distortion_mix", 0) > 0:
         samples = _apply_distortion(samples,
                                     drive=params.get("distortion_drive", 3.0),
@@ -1544,6 +1781,12 @@ def _apply_effects_with_params(samples, params, skip_reverb=False):
                                 mix=params["chorus_mix"],
                                 rate=params.get("chorus_rate", 1.5),
                                 depth=params.get("chorus_depth", 0.003))
+    if params.get("phaser_mix", 0) > 0:
+        samples = _apply_phaser(samples, mix=params["phaser_mix"],
+                                rate=params.get("phaser_rate", 0.5))
+    if params.get("highpass", 0) > 0:
+        samples = _apply_highpass(samples, params["highpass"],
+                                  params.get("highpass_q", 0.707))
     if params.get("lowpass", 0) > 0:
         samples = _apply_lowpass(samples, params["lowpass"],
                                  params.get("lowpass_q", 0.707))
@@ -1568,11 +1811,18 @@ def _apply_effects_with_params(samples, params, skip_reverb=False):
 def _apply_part_effects(samples, part):
     """Apply all effects configured on a Part to a float32 buffer."""
     params = {
+        "saturation": part.saturation,
+        "tremolo_depth": part.tremolo_depth,
+        "tremolo_rate": part.tremolo_rate,
         "distortion_mix": part.distortion_mix,
         "distortion_drive": part.distortion_drive,
         "chorus_mix": part.chorus_mix,
         "chorus_rate": part.chorus_rate,
         "chorus_depth": part.chorus_depth,
+        "phaser_mix": part.phaser_mix,
+        "phaser_rate": part.phaser_rate,
+        "highpass": part.highpass,
+        "highpass_q": part.highpass_q,
         "lowpass": part.lowpass,
         "lowpass_q": part.lowpass_q,
         "delay_mix": part.delay_mix,
@@ -1716,11 +1966,17 @@ def _total_samples_from_tempo_map(total_beats, tempo_map):
 def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
                          synth_fn, envelope_tuple, volume, bpm,
                          swing=0.0, tempo_map=None, humanize=0.0,
-                         detune=0.0, spread=0.0, stereo_buf=None):
+                         detune=0.0, spread=0.0, stereo_buf=None,
+                         sub_osc=0.0, noise_mix=0.0,
+                         filter_attack=0.01, filter_decay=0.3,
+                         filter_sustain=0.0, filter_amount=0.0,
+                         vel_to_filter=0.0, filter_q=0.707,
+                         synth_kwargs=None):
     """Render a list of Notes into an existing buffer at the correct positions."""
     import random as _rnd
 
     a, d, s, r = envelope_tuple
+    _skw = synth_kwargs or {}
     beat_pos = 0.0
     for note_index, note in enumerate(notes):
         if note.tone is not None:
@@ -1747,8 +2003,14 @@ def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
                     pitches = [t.pitch() for t in note.tone.tones]
                 else:
                     pitches = [note.tone.pitch()]
-                # Render oscillators
-                waves = [synth_fn(hz, n_samples=n_samples) for hz in pitches]
+                # Render oscillators (pass synth_kwargs for FM etc.)
+                waves = [synth_fn(hz, n_samples=n_samples, **_skw)
+                         for hz in pitches]
+                # Sub-oscillator: octave-below sine
+                if sub_osc > 0:
+                    for hz in pitches:
+                        sub = sine_wave(hz / 2, n_samples=n_samples)
+                        waves.append(sub)
                 # Detune: add oscillators shifted by ±cents
                 detune_up = None
                 detune_down = None
@@ -1758,8 +2020,8 @@ def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
                     for hz in pitches:
                         hz_up = hz * (2 ** (detune / 1200))
                         hz_down = hz * (2 ** (-detune / 1200))
-                        up_waves.append(synth_fn(hz_up, n_samples=n_samples))
-                        down_waves.append(synth_fn(hz_down, n_samples=n_samples))
+                        up_waves.append(synth_fn(hz_up, n_samples=n_samples, **_skw))
+                        down_waves.append(synth_fn(hz_down, n_samples=n_samples, **_skw))
                     if spread > 0 and stereo_buf is not None:
                         # Spread: detuned oscillators go to opposite channels
                         detune_up = sum(w.astype(numpy.float32) for w in up_waves) / SAMPLE_PEAK
@@ -1768,14 +2030,44 @@ def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
                         waves.extend(up_waves + down_waves)
                 n_osc = len(waves)
                 mixed = sum(w.astype(numpy.float32) for w in waves) / (SAMPLE_PEAK * max(1, n_osc))
+                # Mix sub-oscillator with appropriate gain
+                if sub_osc > 0:
+                    # Sub was already included in waves; scale the mix
+                    # Boost the sub contribution relative to main
+                    sub_count = len(pitches)
+                    main_count = n_osc - sub_count
+                    if main_count > 0:
+                        # Re-render: main only + sub at controlled level
+                        main_waves = waves[:n_osc - sub_count]
+                        sub_waves = waves[n_osc - sub_count:]
+                        main_mix = sum(w.astype(numpy.float32) for w in main_waves) / (SAMPLE_PEAK * max(1, len(main_waves)))
+                        sub_mix = sum(w.astype(numpy.float32) for w in sub_waves) / (SAMPLE_PEAK * max(1, len(sub_waves)))
+                        mixed = main_mix * (1.0 - sub_osc * 0.3) + sub_mix * sub_osc * 0.3
+                # Noise layer: add noise following the note
+                if noise_mix > 0:
+                    noise = numpy.random.uniform(-1, 1, n_samples).astype(numpy.float32)
+                    mixed = mixed * (1.0 - noise_mix * 0.5) + noise * noise_mix * 0.5
+                # Amplitude envelope
                 if a > 0 or d > 0 or s < 1.0 or r > 0:
                     mixed = _apply_envelope(mixed, a, d, s, r)
-                # Apply per-note velocity scaling + humanize velocity
+                # Per-note velocity
                 vel = getattr(note, 'velocity', 100)
                 if humanize > 0.0:
                     vel_jitter = int(humanize * 15)
                     vel = max(1, min(127, vel + _rnd.randint(-vel_jitter, vel_jitter)))
                 vel_scale = vel / 127.0
+                # Filter envelope (per-note subtractive filter sweep)
+                if filter_amount > 0:
+                    base_cut = 200.0  # base cutoff before envelope opens it
+                    vel_boost = vel_to_filter * vel_scale if vel_to_filter > 0 else 0.0
+                    mixed = _apply_filter_envelope(
+                        mixed, base_cut, filter_amount,
+                        filter_attack, filter_decay, filter_sustain,
+                        q=filter_q, vel_cutoff_boost=vel_boost)
+                elif vel_to_filter > 0:
+                    # Velocity brightness without filter envelope
+                    vel_cutoff = vel_to_filter * vel_scale + 1000
+                    mixed = _apply_lowpass(mixed, vel_cutoff, q=filter_q)
                 end = min(start + len(mixed), total_samples)
                 buf[start:end] += mixed[:end - start] * volume * vel_scale
                 # Spread detuned oscillators into stereo L/R
@@ -1940,6 +2232,11 @@ def render_score(score):
             env_tuple = _resolve_envelope(part.envelope)
             # Use part swing if set, otherwise score swing
             effective_swing = part.swing if part.swing is not None else score.swing
+            # Build synth-specific kwargs (e.g. FM ratio/index)
+            synth_kwargs = {}
+            if part.synth in ("fm",):
+                synth_kwargs["mod_ratio"] = part.fm_ratio
+                synth_kwargs["mod_index"] = part.fm_index
             if part.legato:
                 _render_legato_to_buf(
                     part.notes, part_buf, samples_per_beat, total_samples,
@@ -1955,7 +2252,16 @@ def render_score(score):
                     humanize=part.humanize,
                     detune=part.detune,
                     spread=part.spread,
-                    stereo_buf=stereo_buf)
+                    stereo_buf=stereo_buf,
+                    sub_osc=part.sub_osc,
+                    noise_mix=part.noise_mix,
+                    filter_attack=part.filter_attack,
+                    filter_decay=part.filter_decay,
+                    filter_sustain=part.filter_sustain,
+                    filter_amount=part.filter_amount,
+                    vel_to_filter=part.vel_to_filter,
+                    filter_q=part.lowpass_q,
+                    synth_kwargs=synth_kwargs)
 
             # Apply effects — segmented if automation exists
             auto_points = part._get_automation_points()
@@ -1973,8 +2279,10 @@ def render_score(score):
                     params = part._get_params_at(seg_start_beat)
                     segment = part_buf[seg_start:seg_end].copy()
                     has_fx = any(params.get(k, 0) > 0 for k in
-                                ["distortion_mix", "chorus_mix", "lowpass",
-                                 "delay_mix", "reverb_mix"])
+                                ["saturation", "tremolo_depth",
+                                 "distortion_mix", "chorus_mix", "phaser_mix",
+                                 "highpass", "lowpass", "delay_mix",
+                                 "reverb_mix"])
                     if has_fx:
                         segment = _apply_effects_with_params(segment, params)
                     # Apply volume automation
@@ -1983,9 +2291,11 @@ def render_score(score):
                         segment = segment * (seg_vol / part.volume) if part.volume > 0 else segment
                     part_buf[seg_start:seg_end] = segment
             else:
-                has_fx = (part.lowpass > 0 or part.delay_mix > 0
-                          or part.reverb_mix > 0 or part.distortion_mix > 0
-                          or part.chorus_mix > 0)
+                has_fx = (part.saturation > 0 or part.tremolo_depth > 0
+                          or part.distortion_mix > 0 or part.chorus_mix > 0
+                          or part.phaser_mix > 0 or part.highpass > 0
+                          or part.lowpass > 0 or part.delay_mix > 0
+                          or part.reverb_mix > 0)
                 if has_fx:
                     part_buf = _apply_part_effects(part_buf, part)
             # Apply sidechain compression if enabled
@@ -2092,7 +2402,10 @@ def render_score(score):
             part_stereo[start:start + hit_len] += panned
 
         # Apply this drum Part's effects
-        has_drum_fx = (drum_part.lowpass > 0 or drum_part.delay_mix > 0
+        has_drum_fx = (drum_part.saturation > 0 or drum_part.tremolo_depth > 0
+                          or drum_part.phaser_mix > 0
+                          or drum_part.highpass > 0 or drum_part.lowpass > 0
+                          or drum_part.delay_mix > 0
                        or drum_part.reverb_mix > 0 or drum_part.distortion_mix > 0
                        or drum_part.chorus_mix > 0)
         if has_drum_fx:

pytheory/rhythm.py

@@ -15,105 +15,124 @@ INSTRUMENTS = {
     # ── Keys ──
     "piano": {
         "synth": "fm", "envelope": "piano",
+        "fm_ratio": 1.0, "fm_index": 1.5,
         "detune": 5, "chorus": 0.1, "chorus_rate": 0.3,
-        "lowpass": 6000,
+        "lowpass": 6000, "saturation": 0.1,
+        "vel_to_filter": 3000, "noise_mix": 0.02,
     },
     "electric_piano": {  # Rhodes/Wurlitzer
         "synth": "fm", "envelope": "piano",
+        "fm_ratio": 1.0, "fm_index": 2.0,
         "detune": 6, "chorus": 0.2, "chorus_rate": 1.0,
-        "lowpass": 4000,
+        "lowpass": 4000, "saturation": 0.15,
+        "tremolo_depth": 0.15, "tremolo_rate": 4.5,
     },
     "organ": {
         "synth": "organ_synth", "envelope": "organ",
         "chorus": 0.2, "chorus_rate": 5.5,
         "lowpass": 5000,
+        "phaser": 0.15, "phaser_rate": 0.4,
     },
     "harpsichord": {
         "synth": "pluck_synth", "envelope": "none",
         "lowpass": 3500,
     },
     "celesta": {
-        "synth": "fm", "envelope": "bell",
+        "synth": "fm", "envelope": "mallet",
+        "fm_ratio": 3.0, "fm_index": 5.0,
         "lowpass": 8000,
         "reverb": 0.3, "reverb_type": "plate",
     },
     "music_box": {
-        "synth": "sine", "envelope": "bell",
+        "synth": "sine", "envelope": "mallet",
         "lowpass": 6000,
         "reverb": 0.25, "reverb_type": "plate",
     },
 
     # ── Strings ──
     "violin": {
-        "synth": "strings_synth", "envelope": "strings",
-        "detune": 4, "lowpass": 5000,
-        "humanize": 0.15,
+        "synth": "strings_synth", "envelope": "bowed",
+        "detune": 2, "lowpass": 5000,
+        "humanize": 0.15, "vel_to_filter": 1500,
+        "noise_mix": 0.03,
     },
     "viola": {
-        "synth": "strings_synth", "envelope": "strings",
-        "detune": 4, "lowpass": 3500,
-        "humanize": 0.15,
+        "synth": "strings_synth", "envelope": "bowed",
+        "detune": 2, "lowpass": 3500,
+        "humanize": 0.15, "vel_to_filter": 1200,
+        "noise_mix": 0.03,
     },
     "cello": {
-        "synth": "strings_synth", "envelope": "strings",
-        "detune": 4, "lowpass": 2500,
-        "humanize": 0.15,
+        "synth": "strings_synth", "envelope": "bowed",
+        "detune": 2, "lowpass": 2500,
+        "humanize": 0.15, "vel_to_filter": 1000,
+        "noise_mix": 0.02,
     },
     "contrabass": {
-        "synth": "strings_synth", "envelope": "strings",
-        "detune": 3, "lowpass": 1500,
-        "humanize": 0.1,
+        "synth": "strings_synth", "envelope": "bowed",
+        "detune": 2, "lowpass": 1500,
+        "humanize": 0.1, "vel_to_filter": 800,
+        "sub_osc": 0.15,
     },
     "string_ensemble": {
         "synth": "strings_synth", "envelope": "pad",
-        "detune": 12, "spread": 0.6,
+        "detune": 10, "spread": 0.5,
         "chorus": 0.2, "chorus_rate": 0.5,
         "lowpass": 4000,
+        "noise_mix": 0.02, "saturation": 0.05,
     },
 
     # ── Woodwinds ──
     "flute": {
         "synth": "sine", "envelope": "strings",
         "lowpass": 4000,
-        "humanize": 0.2,
+        "humanize": 0.2, "noise_mix": 0.08,
+        "vel_to_filter": 2000,
     },
     "clarinet": {
         "synth": "square", "envelope": "strings",
         "lowpass": 3000,
-        "humanize": 0.15,
+        "humanize": 0.15, "noise_mix": 0.05,
+        "vel_to_filter": 1500,
     },
     "oboe": {
         "synth": "saw", "envelope": "strings",
         "lowpass": 3500, "lowpass_q": 1.2,
-        "humanize": 0.15,
+        "humanize": 0.15, "noise_mix": 0.04,
+        "vel_to_filter": 1000,
     },
     "bassoon": {
         "synth": "saw", "envelope": "strings",
         "lowpass": 2000,
-        "humanize": 0.15,
+        "humanize": 0.15, "noise_mix": 0.04,
+        "vel_to_filter": 800,
     },
 
     # ── Brass ──
     "trumpet": {
-        "synth": "saw", "envelope": "pluck",
+        "synth": "saw", "envelope": "bowed",
         "detune": 3, "lowpass": 4000, "lowpass_q": 1.1,
-        "humanize": 0.15,
+        "humanize": 0.15, "vel_to_filter": 2000,
+        "saturation": 0.1,
     },
     "trombone": {
         "synth": "saw", "envelope": "strings",
         "detune": 3, "lowpass": 2500,
-        "humanize": 0.15,
+        "humanize": 0.15, "vel_to_filter": 1500,
+        "saturation": 0.1,
     },
     "french_horn": {
         "synth": "saw", "envelope": "strings",
         "detune": 4, "lowpass": 2000,
         "chorus": 0.1,
-        "humanize": 0.15,
+        "humanize": 0.15, "vel_to_filter": 1200,
+        "saturation": 0.1,
     },
     "tuba": {
         "synth": "saw", "envelope": "strings",
         "detune": 3, "lowpass": 1200,
-        "humanize": 0.1,
+        "humanize": 0.1, "vel_to_filter": 600,
+        "sub_osc": 0.2,
     },
     "brass_ensemble": {
         "synth": "saw", "envelope": "strings",
@@ -136,18 +155,18 @@ INSTRUMENTS = {
     "distorted_guitar": {
         "synth": "saw", "envelope": "pluck",
         "detune": 8, "distortion": 0.6, "distortion_drive": 5.0,
-        "lowpass": 3000,
+        "lowpass": 3000, "saturation": 0.3,
         "humanize": 0.15,
     },
     "bass_guitar": {
         "synth": "triangle", "envelope": "pluck",
         "lowpass": 1000,
-        "humanize": 0.1,
+        "humanize": 0.1, "sub_osc": 0.2,
     },
     "upright_bass": {
-        "synth": "sine", "envelope": "pluck",
+        "synth": "triangle", "envelope": "pluck",
         "lowpass": 800,
-        "humanize": 0.15,
+        "humanize": 0.15, "saturation": 0.1,
     },
     "harp": {
         "synth": "pluck_synth", "envelope": "none",
@@ -170,49 +189,65 @@ INSTRUMENTS = {
         "synth": "saw", "envelope": "pluck",
         "detune": 8, "lowpass": 3000,
         "delay": 0.2, "delay_time": 0.25, "delay_feedback": 0.3,
+        "filter_attack": 0.01, "filter_decay": 0.3,
+        "filter_sustain": 0.2, "filter_amount": 3000,
     },
     "synth_pad": {
         "synth": "supersaw", "envelope": "pad",
         "detune": 12, "spread": 0.6,
         "chorus": 0.2,
+        "phaser": 0.3, "phaser_rate": 0.3,
+        "sub_osc": 0.2,
     },
     "synth_bass": {
         "synth": "saw", "envelope": "pluck",
         "lowpass": 800, "lowpass_q": 1.3,
+        "filter_attack": 0.005, "filter_decay": 0.2,
+        "filter_sustain": 0.0, "filter_amount": 2000,
+        "sub_osc": 0.4,
     },
     "acid_bass": {
         "synth": "saw", "envelope": "pad",
         "legato": True, "glide": 0.03,
         "distortion": 0.7, "distortion_drive": 8.0,
         "lowpass": 800, "lowpass_q": 5.0,
+        "filter_attack": 0.005, "filter_decay": 0.15,
+        "filter_sustain": 0.0, "filter_amount": 4000,
+        "vel_to_filter": 3000,
     },
     "808_bass": {
         "synth": "sine", "envelope": "pluck",
         "distortion": 0.4, "distortion_drive": 2.5,
         "lowpass": 200, "lowpass_q": 1.5,
+        "sub_osc": 0.5, "saturation": 0.2,
     },
 
     # ── Percussion / Mallet ──
     "vibraphone": {
-        "synth": "fm", "envelope": "bell",
+        "synth": "fm", "envelope": "mallet",
+        "fm_ratio": 1.0, "fm_index": 1.0,
         "lowpass": 5000,
+        "tremolo_depth": 0.3, "tremolo_rate": 5.5,
         "reverb": 0.3, "reverb_type": "plate",
     },
     "marimba": {
-        "synth": "sine", "envelope": "pluck",
+        "synth": "sine", "envelope": "mallet",
         "lowpass": 3000,
     },
     "xylophone": {
         "synth": "fm", "envelope": "pluck",
+        "fm_ratio": 3.0, "fm_index": 5.0,
         "lowpass": 6000,
     },
     "glockenspiel": {
-        "synth": "fm", "envelope": "bell",
+        "synth": "fm", "envelope": "mallet",
+        "fm_ratio": 4.0, "fm_index": 6.0,
         "lowpass": 8000,
         "reverb": 0.2,
     },
     "tubular_bells": {
-        "synth": "fm", "envelope": "bell",
+        "synth": "fm", "envelope": "mallet",
+        "fm_ratio": 2.0, "fm_index": 3.0,
         "reverb": 0.4, "reverb_type": "cathedral",
     },
 }
@@ -1571,6 +1606,7 @@ class Part:
                  reverb_type: str = "algorithmic",
                  delay: float = 0.0, delay_time: float = 0.375,
                  delay_feedback: float = 0.4,
+                 highpass: float = 0.0, highpass_q: float = 0.707,
                  lowpass: float = 0.0, lowpass_q: float = 0.707,
                  distortion: float = 0.0, distortion_drive: float = 3.0,
                  legato: bool = False, glide: float = 0.0,
@@ -1582,7 +1618,22 @@ class Part:
                  sidechain_release: float = 0.1,
                  detune: float = 0.0,
                  pan: float = 0.0,
-                 spread: float = 0.0):
+                 spread: float = 0.0,
+                 # ── New synth engine params ──
+                 sub_osc: float = 0.0,
+                 noise_mix: float = 0.0,
+                 filter_attack: float = 0.01,
+                 filter_decay: float = 0.3,
+                 filter_sustain: float = 0.0,
+                 filter_amount: float = 0.0,
+                 vel_to_filter: float = 0.0,
+                 saturation: float = 0.0,
+                 tremolo_depth: float = 0.0,
+                 tremolo_rate: float = 5.0,
+                 phaser: float = 0.0,
+                 phaser_rate: float = 0.5,
+                 fm_ratio: float = 2.0,
+                 fm_index: float = 3.0):
         self.name = name
         self.synth = synth
         self.envelope = envelope
@@ -1597,6 +1648,8 @@ class Part:
         self.delay_mix = delay
         self.delay_time = delay_time
         self.delay_feedback = delay_feedback
+        self.highpass = highpass
+        self.highpass_q = highpass_q
         self.lowpass = lowpass
         self.lowpass_q = lowpass_q
         self.distortion_mix = distortion
@@ -1609,6 +1662,21 @@ class Part:
         self.detune = detune
         self.pan = pan
         self.spread = spread
+        # New synth engine params
+        self.sub_osc = sub_osc
+        self.noise_mix = noise_mix
+        self.filter_attack = filter_attack
+        self.filter_decay = filter_decay
+        self.filter_sustain = filter_sustain
+        self.filter_amount = filter_amount
+        self.vel_to_filter = vel_to_filter
+        self.saturation = saturation
+        self.tremolo_depth = tremolo_depth
+        self.tremolo_rate = tremolo_rate
+        self.phaser_mix = phaser
+        self.phaser_rate = phaser_rate
+        self.fm_ratio = fm_ratio
+        self.fm_index = fm_index
         self.notes: list[Note] = []
         self._drum_hits: list[_Hit] = []
         self._drum_pattern_beats: float = 0.0
@@ -1673,6 +1741,8 @@ class Part:
                 mapped["distortion_mix"] = v
             elif k == "chorus":
                 mapped["chorus_mix"] = v
+            elif k == "phaser":
+                mapped["phaser_mix"] = v
             else:
                 mapped[k] = v
         self._automation.append((beat_pos, mapped))
@@ -1683,10 +1753,14 @@ class Part:
         # Start with initial values
         params = {
             "volume": self.volume,
+            "saturation": self.saturation,
+            "tremolo_depth": self.tremolo_depth, "tremolo_rate": self.tremolo_rate,
             "reverb_mix": self.reverb_mix, "reverb_decay": self.reverb_decay,
             "reverb_type": self.reverb_type,
             "delay_mix": self.delay_mix, "delay_time": self.delay_time,
             "delay_feedback": self.delay_feedback,
+            "phaser_mix": self.phaser_mix, "phaser_rate": self.phaser_rate,
+            "highpass": self.highpass, "highpass_q": self.highpass_q,
             "lowpass": self.lowpass, "lowpass_q": self.lowpass_q,
             "distortion_mix": self.distortion_mix,
             "distortion_drive": self.distortion_drive,
@@ -2075,6 +2149,7 @@ class Score:
              reverb_type: str = None,
              delay: float = None, delay_time: float = None,
              delay_feedback: float = None,
+             highpass: float = None, highpass_q: float = None,
              lowpass: float = None, lowpass_q: float = None,
              distortion: float = None, distortion_drive: float = None,
              legato: bool = None, glide: float = None,
@@ -2086,7 +2161,22 @@ class Score:
              sidechain_release: float = None,
              detune: float = None,
              pan: float = None,
-             spread: float = None) -> Part:
+             spread: float = None,
+             # New synth engine params
+             sub_osc: float = None,
+             noise_mix: float = None,
+             filter_attack: float = None,
+             filter_decay: float = None,
+             filter_sustain: float = None,
+             filter_amount: float = None,
+             vel_to_filter: float = None,
+             saturation: float = None,
+             tremolo_depth: float = None,
+             tremolo_rate: float = None,
+             phaser: float = None,
+             phaser_rate: float = None,
+             fm_ratio: float = None,
+             fm_index: float = None) -> Part:
         """Create a named part with its own synth voice and effects.
 
         Args:
@@ -2179,6 +2269,7 @@ class Score:
             "reverb_type": reverb_type,
             "delay": delay, "delay_time": delay_time,
             "delay_feedback": delay_feedback,
+            "highpass": highpass, "highpass_q": highpass_q,
             "lowpass": lowpass, "lowpass_q": lowpass_q,
             "distortion": distortion, "distortion_drive": distortion_drive,
             "legato": legato, "glide": glide,
@@ -2187,6 +2278,14 @@ class Score:
             "swing": swing, "humanize": humanize,
             "sidechain": sidechain, "sidechain_release": sidechain_release,
             "detune": detune, "pan": pan, "spread": spread,
+            "sub_osc": sub_osc, "noise_mix": noise_mix,
+            "filter_attack": filter_attack, "filter_decay": filter_decay,
+            "filter_sustain": filter_sustain, "filter_amount": filter_amount,
+            "vel_to_filter": vel_to_filter,
+            "saturation": saturation,
+            "tremolo_depth": tremolo_depth, "tremolo_rate": tremolo_rate,
+            "phaser": phaser, "phaser_rate": phaser_rate,
+            "fm_ratio": fm_ratio, "fm_index": fm_index,
         }
         for k, v in _locals.items():
             if v is not None:

test_pytheory.py

@@ -4248,7 +4248,7 @@ def test_parallel_modes_g_major():
 @needs_portaudio
 def test_envelope_enum_presets():
     from pytheory.play import Envelope
-    assert len(Envelope) == 8
+    assert len(Envelope) == 10
     for e in Envelope:
         a, d, s, r = e.value
         assert a >= 0
@@ -6471,9 +6471,10 @@ def test_instrument_violin():
     score = Score("4/4", bpm=120)
     p = score.part("v", instrument="violin")
     assert p.synth == "strings_synth"
-    assert p.envelope == "strings"
+    assert p.envelope == "bowed"
     assert p.humanize == 0.15
     assert p.lowpass == 5000
+    assert p.detune == 2
 
 
 def test_instrument_override():
@@ -6512,7 +6513,7 @@ def test_instrument_effects():
     assert p.reverb_mix == 0.3
     assert p.reverb_type == "plate"
     assert p.synth == "fm"
-    assert p.envelope == "bell"
+    assert p.envelope == "mallet"
 
 
 def test_instrument_808_bass():

uv.lock

@@ -707,7 +707,7 @@ wheels = [
 
 [[package]]
 name = "pytheory"
-version = "0.30.0"
+version = "0.32.0"
 source = { editable = "." }
 dependencies = [
     { name = "numeral" },