Hello there, I read an old book on 1960s analog electronic music on Bülent Arel and he writes in a letter , he invented a method to generate all possible sounds with two tapes , one feedback and one bandpass filter. I looked to bandpass filter schematics from Krohnhite and B&K and they have least 10 to 20 inductance coils which making difficult , needs meter and lots of trouble.
I read someone suggests LM567 as a bandpass filter. I looked to it , it costs half an dollar here in istanbul. Is it digital ? works alone ? how to set bands ? Is there a schematic to use on breadboard ? Do I need DAC and ADC ?

 

https://www.ti.com/lit/gpn/LM567C


Datasheet, its an Analogue chip.

 

The LM567 is not a bandpass filter.
It detects when a frequency within its bandwidth is present and closes a transistor switch.

From the datasheet:
The LM567 and LM567C are general purpose tone
decoders designed to provide a saturated transistor
switch to ground when an input signal is present
within the passband.

 

Analog audio filters are now usually generated using op amps in an active-filter configuration, which involve no inductors.
Sallen-Key, multiple-feedback, state-variable, and biquad, are common types.

 

An audio bandpass filter usually reduces bass and reduces treble sounds and makes music sound awful.
Sometimes an audio bandpass filter was used to reduce hum and hiss interference and makes music and speech sound awful.

In the 1960s I played high fidelity vinyl records with no bandpass filter.