On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

Also, being much closer to the impedance of a speaker it will have a
much flatter frequency response than a high impedance cable, which
will tend to wander away from flat at the top end.

d

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http://www.pearce.uk.com

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Don Pearce wrote:

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

The inductance is almost totally unaffected by the quantity of copper involved (
assuming an intelligent design ).

Graham

On Wed, 10 Jan 2007 11:17:20 +0000, Eeyore
wrote:



Don Pearce wrote:

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

The inductance is almost totally unaffected by the quantity of copper involved (
assuming an intelligent design ).

Graham

Not a first order effect, admittedly, but thin wire is more inductive
length-for-length than thick wire. The main factor, though as I said
is to bring the characteristic impedance down closer to that of the
speaker hanging on the far end in order to flatten the response.
Mostly that involves increasing the capacitance - for which you need
thicker wires closer together. This geometry change in itself lowers
the inductance.

d

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

Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

The inductance is almost totally unaffected by the quantity of copper involved (
assuming an intelligent design ).

Not a first order effect, admittedly, but thin wire is more inductive
length-for-length than thick wire. The main factor, though as I said
is to bring the characteristic impedance down closer to that of the
speaker hanging on the far end in order to flatten the response.
Mostly that involves increasing the capacitance - for which you need
thicker wires closer together. This geometry change in itself lowers
the inductance.

Yes, although I'm not clear why you'd look at it as a transmission line issue at
these frequencies and distances.

Graham

On Thu, 11 Jan 2007 10:10:51 +0000, Eeyore
wrote:



Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

The inductance is almost totally unaffected by the quantity of copper involved (
assuming an intelligent design ).

Not a first order effect, admittedly, but thin wire is more inductive
length-for-length than thick wire. The main factor, though as I said
is to bring the characteristic impedance down closer to that of the
speaker hanging on the far end in order to flatten the response.
Mostly that involves increasing the capacitance - for which you need
thicker wires closer together. This geometry change in itself lowers
the inductance.

Yes, although I'm not clear why you'd look at it as a transmission line issue at
these frequencies and distances.

Graham

Why wouldn't I? That is what it is, and I find it much more convenient
to simply use transmission line maths at all frequencies rather than
try to work out first the degree to which a lumped equivalent model
might or might not be good enough.

I have watched with some amusement other bits of these threads where
people have been discussing what length of wire, with what inductance
would result in an unacceptable degree of treble cut. Even a smidgen
of transmission line theory would reveal that this isn't how it works.
I mean a cable with 1mH of inductance will pass a 10GHz signal without
loss. While people think of these inductances in isolation from the
distributed medium these sorts of schoolboy howler errors will
persist.

d

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

"Don Pearce" wrote in message
...
On Wed, 10 Jan 2007 11:17:20 +0000, Eeyore
wrote:



Don Pearce wrote:

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the
problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

The inductance is almost totally unaffected by the quantity of copper
involved (
assuming an intelligent design ).

Graham

Not a first order effect, admittedly, but thin wire is more inductive
length-for-length than thick wire. The main factor, though as I said
is to bring the characteristic impedance down closer to that of the
speaker hanging on the far end in order to flatten the response.
Mostly that involves increasing the capacitance - for which you need
thicker wires closer together. This geometry change in itself lowers
the inductance.

**Much like the old Tocord, which allegedly possessed a characteristic
impedance of around 8 Ohms. It played merry Hell with Naim amps. Hugely
capacitive stuff.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

On Fri, 12 Jan 2007 11:26:37 +1100, "Trevor Wilson"
wrote:

Not a first order effect, admittedly, but thin wire is more inductive
length-for-length than thick wire. The main factor, though as I said
is to bring the characteristic impedance down closer to that of the
speaker hanging on the far end in order to flatten the response.
Mostly that involves increasing the capacitance - for which you need
thicker wires closer together. This geometry change in itself lowers
the inductance.

**Much like the old Tocord, which allegedly possessed a characteristic
impedance of around 8 Ohms. It played merry Hell with Naim amps. Hugely
capacitive stuff.


If it was 8 ohm cable, and it had an 8 ohm speaker hanging on the end
then it wasn't capacitive at all - it was purely resistive. Cables of
much greater impedance than the load are always inductive, and it was
this that Naim amps relied upon for their albeit marginal stability.

d

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

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Posted via a free Usenet account from http://www.teranews.com