"Serge Auckland" wrote in message
...
My subs (Meridian D1500) are designed to work with the D5000 mains, and
have
a 2nd order Butterworth response at 36 Hz. And yet, having one to the
side,
it's very obvious where the bass is coming from.

I built a single sub for my son some years ago, and it had to integrate
with
a pair of small Missions, which meant a rollover around 70Hz, 2nd order.
That was very noticeable, and disturbing when not between the main
'speakers. Either my room acoustics are peculiar, or I'm particularly
sensitive to bass positioning.

Nah you really need to use a fourth order network, or greater. Remember you
ear is more sensitive at higher bass frequencies than low bass, so a second
order network may hardly attenuate the higher bass frequencies much at all,
as far as your hearing is concerned anyway.

MrT.