A standard first order filter section. Filter coefficients are given directly rather than calculated for you. Formula is equivalent to:

### FOS.ar(in: 0.0, a0: 0.0, a1: 0.0, b1: 0.0, mul: 1.0, add: 0.0)

### FOS.kr(in: 0.0, a0: 0.0, a1: 0.0, b1: 0.0, mul: 1.0, add: 0.0)

#### Arguments:

in |
Signal input. |

a0 |
See formula above. |

a1 |
See formula above. |

b1 |
See formula above. |

mul | |

add | |