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docs/ladder_filters.md

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+# Ladder Filters
+
+Ladder filters provide a classic analog-style filter sound with stronger resonance character than the standard SVF filters.
+
+## Ladder Lowpass
+
+```forth
+"saw" s 2000 llpf .   ( ladder lowpass frequency )
+"saw" s 0.7 llpq .    ( ladder lowpass resonance )
+```
+
+## Ladder Highpass
+
+```forth
+"noise" s 500 lhpf .  ( ladder highpass frequency )
+"noise" s 0.5 lhpq .  ( ladder highpass resonance )
+```
+
+## Ladder Bandpass
+
+```forth
+"pad" s 1000 lbpf .   ( ladder bandpass frequency )
+"pad" s 0.6 lbpq .    ( ladder bandpass resonance )
+```
+
+## Comparison with SVF
+
+Ladder filters have a different resonance character:
+- More aggressive self-oscillation at high resonance
+- Classic "squelchy" acid sound
+- 24dB/octave slope
+
+Standard SVF filters (`lpf`, `hpf`, `bpf`) have:
+- Cleaner resonance
+- Full envelope control (attack, decay, sustain, release)
+- 12dB/octave slope
+
+## Words
+
+| Word | Stack | Description |
+|------|-------|-------------|
+| `llpf` | (f --) | Set ladder lowpass frequency |
+| `llpq` | (f --) | Set ladder lowpass resonance |
+| `lhpf` | (f --) | Set ladder highpass frequency |
+| `lhpq` | (f --) | Set ladder highpass resonance |
+| `lbpf` | (f --) | Set ladder bandpass frequency |
+| `lbpq` | (f --) | Set ladder bandpass resonance |