[PD] iem filters - best for isolating frequencies?

[Paris Treantafeles]

Hello List,

I have some Gem patches that react to incoming sound in various ways.
Up until now, I would take the adc~ input and use 3 vcf~ 's  (one for  
bass, mid and high) and with the right settings of Hz and Q, I was  
getting fairly good envelopes.
Looking at this again and wanting to improve it, I have been  
experimenting with iemlib filters:
http://pd.iem.at/iemlib/abstract.html

I was wondering if anyone can recommend which of these would be best  
for trying to isolate, say a bass drum or a hi hat from an incoming mix?

I read the Bessel filters are often used in cross overs but from just  
experimenting a bit it seems some of the others (e.g. vcf_lp2~) are  
giving me a better response.

Thanks,
p