# Anvil

Anvil gives every bass note the same solid sub. Current version **0.2.0**.

In riddim and dubstep, each switch-up patch brings its own sub: a different level,
a different phase, sometimes two layers that cancel. The drop's weight jumps from
note to note and the kick lands differently on each one. Anvil removes the
original band below **Split** and puts a clean mono sine in its place. The sine
follows the bass pitch, has the same peak level on every note, and starts at the
same phase on every note.

![Anvil](assets/editor.png)

## Install on Windows

Copy `Anvil.clap` into `C:\Program Files\Common Files\CLAP\`. In FL Studio 2024.1
or newer, open Options → Manage plugins, enable Verify plugins, and Find installed
plugins. Load Anvil in the mixer slot of the bass bus. Keep the font license with
redistributed packages.

## Work with it

1. Put Anvil on the bass bus, after the sound design and before the bus
   compression or clipping.
2. Set **Split** just above the sub. 80–100 Hz suits most riddim basses.
3. Set **Sub level** once. Every patch on the bus now gets this level.
4. Use **Phase** to line the start of each note up with your kick. With
   **Retrigger** on, every note starts at this phase.
5. Turn on **Solo sub** to hear only the new sub; the scope shows the original
   low band (grey) against the new sub (accent).

Other controls:

- **Dynamics** at 0 % holds the level for the whole note. Raise it to let the sub
  follow the original's volume shape, for example a wobble.
- **Drive** adds upper harmonics so the sub reads on phones and laptops.
- **Octave** moves the sub against the detected note. Use −1 for a bass played
  one octave up.
- **Glide** slides between overlapping notes; 0 jumps.
- **Gate** is the input level that counts as a note. Raise it if tails or reverb
  start new notes.
- **Keep** blends some of the original low band back under the new sub.
- **Snap to semitone** rounds detected pitch. Turn it off for pitch bends and slides.

If Knurl is on the bass before the bus, use **MIDI**: Knurl's patterns make
detection read notes from C2 upwards an octave low. See
[Signal chain](../chain.md).

### Pitch from MIDI

Detection follows the audio by default. For heavy formant or FM basses where the
fundamental is unclear, select **MIDI** and route the bass's MIDI notes to Anvil.
In FL Studio, set the bass channel's MIDI output port and Anvil's input port to the
same number, or duplicate the notes into a pattern on a channel that feeds Anvil.

## Timing and limits

Detection uses 80 ms of lookahead, reported to the host for delay compensation,
so each note's pitch is known before its attack leaves the plugin. Pitch range is
25–250 Hz, one voice: chords and layered notes in the sub band are not separated.
Notes shorter than about 15 ms may not be recognised. A pitch move of more than
0.7 semitone that holds for two analysis hops (10 ms) starts a new note.

The crossover is a 4th-order Linkwitz–Riley pair, so with Keep at 100 % and no
note playing, the signal passes with flat magnitude. Stereo above the split is
kept; the new sub is mono.