audiofilters.Filter fails when assign 'filter' property

[todbot]

CircuitPython version and board name

Adafruit CircuitPython 9.2.6 on 2025-03-23; Raspberry Pi Pico 2 with rp2350a

Code/REPL

import time, board, audiobusio, synthio, audiofilters

audio = audiobusio.I2SOut(bit_clock=board.GP20, word_select=board.GP21, data=board.GP22)
synth = synthio.Synthesizer(channel_count=1, sample_rate=44100)
effect = audiofilters.Filter(buffer_size=1024, channel_count=1, sample_rate=44100, mix=1.0)
effect.filter = synth.low_pass_filter(frequency=2000, Q=1.25)
effect.play(synth)
audio.play(effect)

note = synthio.Note(261)
while True:
    synth.press(note)
    time.sleep(0.25)
    synth.release(note)
    time.sleep(5)

Behavior

Traceback (most recent call last):
  File "code.py", line 10, in <module>
TypeError: object in filter must be of type AnyBiquad, not float

Description

The above code is from the demo code in documentation for audiofillters.Filter https://docs.circuitpython.org/en/latest/shared-bindings/audiofilters/index.html#audiofilters.Filter

It fails with the same error if you try to use the newer BlockBiquad, e.g.:

effect.filter = synthio.BlockBiquad(synthio.FilterMode.LOW_PASS, frequency=2000, Q=1.25)

Additional information

No response

[todbot]

Fixed by (I think) commit 05a50b8. Thanks @relic-se!

[relic-se]

@todbot Tested this on my end with the new PR, and it works without error. The only other change is that in 10.x, you'll need to use synthio.Biquad instead of synthio.BlockBiquad.