On Sun, 4 Jan 2009 08:42:59 -0800 (PST), molipix
wrote:

I'm building up a sound system for our living room using second hand
parts. I would like to keep things as small and unobtrusive as
possible. So far I have a Cyrus II amp - this has outputs for one pair
of speakers (rated at 8 Ohms). My plan is to connect two small
bookshelf speakers like the Tannoy Revolution R1s and add a subwoofer.
The options as far as I can see a

1) connect a passive subwoofer in parallel with the bookshelf speakers
2) connect a passive subwoofer in series with the bookshelf speakers
3) connect a subwoofer with a built in amp

I think 1 risks blowing the amp, 2 could affect the sound quality so
I'm leaning towards 3 but this seems a bit of a waste of the power
available from the Cyrus II. Any opinions?

The built-in amp option is easiest to implement, but if you have a
driver, there is no reason why you shouldn't power it from the Cyrus
II, which is flat down to about 1Hz. Search the Internet and find a
circuit for a crossover unit and scale the values of L and C so it
operates at about 100Hz (or whatever your sub needs). Use this to
split the power between the sub and the normal speakers - you will
have to choose a channel to operate from, you can't use both.

Provided you have chosen a sub driver with an output level similar to
the Tannoys, you will have a decent starting point for the long slow
job of bringing the sub into line with the mains.

This will be option 4)

d
--
Pearce Consulting
http://www.pearce.uk.com