Cascading two 2-pole resonant bandpasses (~4 pole) vs. just one 2-pole reso BP? Ie. Calculating decay times? Bandwidth?

[mikejm]

What would be expected to happen if you cascaded two 2-pole bandpass filters in sequence? ie. Using a Moog type ~4-pole bandpass like this one:
https://github.com/ddiakopoulos/MoogLad ... /Filters.h

Thanks

Edit: Never mind, I tested it, and once you set the Q to give a roughly equal decay rate, they behave identically. ie there is no difference.

[Music Engineer]

here are impulse responses of casacaded first order lowpasses (from 1 unit to 4 units) - they should give the envelopes of the cascaded 2nd order bandpasses (if i'm not mistaken):

https://sagecell.sagemath.org/?z=eJyrNF ... &lang=sage

so it seems, a bit counter-intuitively, the ultimate decay-rate stays the same as you chain more and more filters of the same type. just the attack gets smoothed out more and more