"Jo" wrote in message
...
In ,
harrogate2 typed:
"Jo" wrote in message
...
I'm aware of the never ending discussion on interconnects and
speaker
cables, but I just want some advice on what to actually buy.
Nominal
impedance of speakers is 6 ohms. Room is quite large and so
amp/speaker distance will be 4-5 meters. Speakers are bi-wired.

I just need an idea of cross-sectional area and where I can get
some
suitable cable. I'm not convinced by the talk of OFC and so on.
Multistranded copper of sufficient thickness is fine by me.
Suggestions please ?

Jo



Just get a decent thick cable, 2.5mm mains or bigger - or
preferably
flex - will do.

You are right, there is much rubbish spoken and snake oil out
there,
but given that you have a fairly long run then thicker cable is
best
so that it doesn't become significant in the damping factor of the
speaker/amp interface. (Mail me off-net if you want that
explained.)


Thanks, I know about damping factor and the need to keep cable
resistance
well below actual speaker impedance across the audio range. I did
some rough
calcs and came up with a figure of 3-4 sq mm and was curious about
what the
experts here suggested.

Jo



It is nothing to do with the speaker load impedence, rather the amp
output impedence.

When the loudspeaker cone is extended by signal, if the signal is
removed then it is down to the mechanics of the cone mount to return
it to its rest position - except that it won't, it will follow a
decaying oscillation path. During this time, as the voicecoil is now
being moved mechanically in a magnetic field it becomes a generator,
so the lower the load that it sees - in this case the output impedence
of the amp plus cable resistance - the quicker the energy will be
dissipated. As an amp output impedence is typically around 0.1R (or
less sometimes) then the resistance of a thinner cable can become
significant, hence why thick is better.

I used to have a pair of BIG transmission line loudspeakers that could
rattle windows at 10 paces with only a few watts! I used 6mm power
cable used in the mobile radio industry (where I work) and they were
more than happy. When we moved to this house I initially couldn't get
under the floor to run the bigger cables so I ran some 0.75mm mains
cable - and the sound was AWFUL!! Bloated flabby bass with
considerable loss of LF detail (amongst other things we like pipe
organ music, the penalty of having a father-in-law who is an
organist!) When I fitted the thicker cable normality was restored.


--
Woody

harrogate3 at ntlworld dot com