# 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 |