Bass Roll Off

[WGTP]

For example, if you have 3 successive gain stages and a .1uf cap on the output of each, assuming other things are equal, does this constitute an 18db/oct. filter with the corner frequency at whatever the cap and resistance value work out to be? :?

[Joep]

Yes, basically you can say you are right.

You have to take in mind that depending on how the gainstages are designed (in- and output resistance) they can influence the -3dB freq. of the used RC combination.

[Gus]

Yes it would be a 3rd order filter:  However built as 3 buffered simple rc networks it would be 9Db down if all filters are the same time constant.  

A very good book is "Active-filter cookbook" by Don Lancaster.  I own a fisrt edtion 5th printing one ISBN 0-672-21168-8

[WGTP]

Thanks.  I guess the same is true of caps to ground to cut the treble.