plea for knowledge - cab query

hi y'all. i want to use existing parts to make an extension speaker
cab for higher frequencies in my bass rig. (about 1k on up) i only
wish to use one speaker. i have a passive three-way crossover i'd like
to use. it has both a pos. and ground outputs for mids and highs.
should these mid and high outputs be wired to the one speaker in series
or in parallel?
Conservatives are not necessarily stupid.
but most stupid people are conservatives."
- John Stuart Mill

You will need the top of a two way crossover. This
could be made as simply as one capacitor in series with
the HF driver or if you have a separate amp as simple
as a small cap in series with the amp channel input
that is driving the HF driver.

Conservatives are not necessarily stupid.
but most stupid people are conservatives."
- John Stuart Mill

i have a setup similar to that which i am using now--a foster
(or fostex) horn in a box that crosses over at 3.5k. i think i prefer
cones to horns for bass and want to test my theory on the rig at a gig.
but. I have a ten with a whizzer cone that's good up to 10k. I want to set
it up with a crossover that's bypassable so i have a little full range
rehearsal cab that i can also use as a high end driver at gigs.

thanks for the input. i could buy a two-way crossover. but i hate to
wait for shipping. i'm not good at building. and i have this three-way
right now.
i run a bridged amp into a 2x15 cab and take a parallel speaker lead
from the 2x15 out to the high frequency driver. the crossover needs to
handle 50 to 100 watts. thanks again.