RE: Amp/speaker recommendations?

["Keith Doxey" <ukha@xxxxxxx>]

Hi Tony,

Any normal stereo amp can happily do this because you want 8 speakers which
just happens to be a very nice number.

Assuming a normal amp that can handle 4-8 ohms per channel and normal 8 ohm
speakers the wiring is like this.....


LEFT +  -----(+[SPKR1]-)-----(+[SPKR2]-)---- LEFT -


--(+[SPKR3]-)-----(+[SPKR4]-)--

RIGHT + -----(+[SPKR5]-)-----(+[SPKR6]-)---- RIGHT -


--(+[SPKR7]-)-----(+[SPKR8]-)--


The techie explanation is this.....

LEFT CHANNEL

SPKR 1 and SPKR 2 ( both 8 ohms ) in series gives an effective load of 16
ohms
SPKR 3 and SPKR 4 ( both 8 ohms ) in series gives an effective load of 16
ohms

The two 16 ohm loads in parallel (SPKR 1+2) and (SPKR 3+4) gives an
effective load of 8 ohms so the amp thinks it just has one speaker
connected. Each speaker will receive 25% of the power so for an amp capable
of 100W per channel each speaker would receive a maximum of 25W

Speakers 5,6,7,8 are the same for the RIGHT CHANNEL.

Because this presents an 8 ohm load and most amps are happy down to 4 ohms
you could actually add another 8 speakers because the two (effective) 8ohm
loads on the channel would equate to a 4 ohm load. With 8 speakers each
would receive 12.5% of the power.

All speakers should be identical to avoid different sound levels due to
different efficiencies.

Hope that helps

Keith

www.diyha.co.uk
www.kat5.tv


> -----Original Message-----
> From: Tony Butler [mailto:lists@xxxxxxx]
> Sent: 29 October 2003 13:17
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] Amp/speaker recommendations?
>
>
> hi kids,
>
> Looking for suggestions for a sound system to drive about 8
> speakers dotted
> around a large showroom, up to 30m from source.
> Just want gentle, low vol cd/radio sounds around the place.
>
> As ever, budget is minimal - just want a reasonable sound for
> a reasonable
> price.
> No need to different sources in different zones or anything like that.
>
> What are the cons (apart from physically fitting the damn
> things) of just
> wiring 8 speakers to a standard 2 channel amp?  I know ohms
> law comes into it
> somewhere ....
>
> Speaker-wise, sadly the requirement is not for in-ceiling or
> in-wall jobbies, -
> just something small and discreet.
>
> suggestions, as ever, very welcome.
>
> cheers,
>
>
> Tony
>
>
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