Another proposal
"mick" wrote in message
. uk...
On Mon, 14 Jan 2008 06:58:59 +1100, Trevor Wilson wrote:
snip
**I know. I'm here to tell you that you are wrong. Skin effect is not a
myth. It is a real, measurable electrical effect. Even power companies
need to be concerned with it and their product is one which operates at
50Hz/60Hz.
Quite correct.
Audio signals reach 20kHz.
Also correct.
Given long enough cables, with a
suitably low termination impedance, skin effect will be measurable and
audible.
Not necessarily.
**Perhaps you missed what I wrote. Read it again. I was VERY specific with
my words. Unlike our friend Iain, I do not make blanket pronouncements which
can easily be proven incorrect.
Skin effect is the tendency of the signal current to
flow at, or close to, the surface of the conductor. It isn't measurable
using any normal systems and almost certainly won't be audible.
**Read what I wrote.
Even 2
parallel conductors, exhibiting skin effect, will appear as 2 normal
stranded or solid conductors, with the same interactions between them.
Skin effect is only of real interest where high currents (think 1500A
here) make solid copper busbars very expensive or heavy. In that case
aluminium bars with a copper coating are often used, or tubular bars
(more often on HV systems). The other main problems with skin effect
appear at VHF - but you certainly ain't gonna hear that... :-)
**For the record: I cut my teeth on HF transmission (and satellite)
transmission equipment. I am familiar with the problems and solutions. My
words stand. Iain is wrong. Skin effect is not a myth.
More importantly, perhaps, is the fact that many exotic speaker
cables exhibit low INDUCTANCE figures. It is this characteristic which
may be very important for many users of ESLs, as even quite short cable
runs (10 Metres or even less in some cases) can benefit from low
inductance cables. IMO, skin effect is not an important parameter in the
vast majority of real world systems. Inductance, OTOH, may well be very
important.
Sorry, but I'm an unbeliever in speaker cable inductance - over any sane
length anyway. For me, any speaker cable over about 3m (i.e. loop length
6m) is too long and I just can't see that anything contributed by the
cable other than resistance (which is usually swamped by the speaker
impedance & amp output impedance anyway) is going to make the slightest
difference to the sound.
**I suggest you brush up on your electrical theory. My first experience with
the effects of speaker cables was in 1978. My client had quite long cable
runs (ca. 12-15 Metres) and speakers which exhibited rather difficult HF
impedance. Substituting low inductance cable made a substantial improvement
to the system. After some considerable effort, I placed the amplifiers under
the floor, directly beneath each speaker. The improvement was even more
pronounced.
Trevor Wilson
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