adding loud speakers to an amp

Factual Questions
1

hi all …
i have an amplifier with a pair of 4 ohm speakers.
(with me so far ?!)
say i want to add another pair … i could do this in
series (and change the impedance to 8 ohms) or parallel
(and change the impedance to 2 ohms) - either of which
would degrade the amp’s performance …
Anyone got a circuit which would match the impedance
to the amp’s output ?

(i could get a box from radioshack/maplins but i suspect
it would only require a resistor and a capacitor and a piece
of string or something )

2

You’d be better with an additional amp.

Paralleling two pair of 4-ohm speakers will put a 2-ohm load on the amp, which will most likely result in blown fuses or outputs.

Putting them in series will result in an amp-friendly 8 ohms, but this only works well if the speakers are identical because of how different speakers have different impedance at different frequencies - this results in varying amounts of power getting to the speakers and it can really mess up frequency response.