@court_hot I have never made one. Someone might reply with their design though, or be able to give you a clue.
In the meantime, as I think you are mostly on track have a look at this...... VOCODER_BOOK_document.pdf
It's a schematic for a hardware version, but for each filter-bank it gives a frequency gain and Q.
Try setting your filters to those values and let us know if you are then close to what you are looking for.
David.

@court_hot Looking harder.... it seems you will be massively overloading your sound card.
PD should send out audio in the range of 0 to 1.
You have the output of the filters multiplied by 5 and then raised by up to the power of 3.
Those are very big numbers.
David.

@court_hot Hello again..... sorry, can show you more easily in the thread than in a chat......
On the left side of the pdf are all the values used for a commercial hardware version....

It has 12 filters and the values are given at the top left of the circuit diagram for each filter..... in the screenshot 395Hz with an added gain of 2.5dB and a Q of 3.7.
You can ignore all the electronic circuit as you are doing the same in Pd instead.
Some of the filters have positive gain and some negative.
David.

@whale-av that's amazing, thank you! I'll let you know how it goes