On Fri, 9 Jan 2004 21:14:31 +1100, "Tony Pearce"
wrote:

"Stewart Pinkerton" wrote in message
...
25 years ago, I was using a slide rule,

You were fairly slow to catch onto those "new fangled" calculators then :-)
30 years ago I was already using a HP35 calculator, having sold my slide
rule.

To be honest, I was probably using a Casio 25 years ago, but I still
have three slide rules, including the redoubtable Otis King
'truncheon'. Eeee, them were't days! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 9 Jan 2004 21:14:31 +1100, "Tony Pearce"
wrote:

"Stewart Pinkerton" wrote in message
...
25 years ago, I was using a slide rule,

You were fairly slow to catch onto those "new fangled" calculators then :-)
30 years ago I was already using a HP35 calculator, having sold my slide
rule.

To be honest, I was probably using a Casio 25 years ago, but I still
have three slide rules, including the redoubtable Otis King
'truncheon'. Eeee, them were't days! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 10:47:11 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 21:14:31 +1100, "Tony Pearce"
wrote:


"Stewart Pinkerton" wrote in message
...
25 years ago, I was using a slide rule,

You were fairly slow to catch onto those "new fangled" calculators then :-)
30 years ago I was already using a HP35 calculator, having sold my slide
rule.

TonyP.


You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk. I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great. I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 10:47:11 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 21:14:31 +1100, "Tony Pearce"
wrote:


"Stewart Pinkerton" wrote in message
...
25 years ago, I was using a slide rule,

You were fairly slow to catch onto those "new fangled" calculators then :-)
30 years ago I was already using a HP35 calculator, having sold my slide
rule.

TonyP.


You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk. I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great. I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 10:47:11 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 21:14:31 +1100, "Tony Pearce"
wrote:


"Stewart Pinkerton" wrote in message
...
25 years ago, I was using a slide rule,

You were fairly slow to catch onto those "new fangled" calculators then :-)
30 years ago I was already using a HP35 calculator, having sold my slide
rule.

TonyP.


You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk. I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great. I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 10:47:11 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 21:14:31 +1100, "Tony Pearce"
wrote:


"Stewart Pinkerton" wrote in message
...
25 years ago, I was using a slide rule,

You were fairly slow to catch onto those "new fangled" calculators then :-)
30 years ago I was already using a HP35 calculator, having sold my slide
rule.

TonyP.


You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk. I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great. I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 9 Jan 2004 22:12:09 +1100, "Tony Pearce"
wrote:

"Don Pearce" wrote in message
.. .
You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk.

Yeah I sold my best one and kept my cheapie. Since it's never been out of
the case in 30 years, I'm glad I sold the other while it was still worth
something. Then again maybe there are slide rule collectors now paying silly
money?

Hmmmmm, there's a thought. I have an old circular jobby, and the
classic Otis King 'truncheon' and Faber-Castell Novo Duplex, both in
mint condition in their original cases.

I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great.

Isn't that what log books are for?

I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I know what you mean, it took me a year to pay mine off at the time :-(
Even so I don't regret it.

Don't programs like Spice seem like cheating these days? :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 9 Jan 2004 22:12:09 +1100, "Tony Pearce"
wrote:

"Don Pearce" wrote in message
.. .
You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk.

Yeah I sold my best one and kept my cheapie. Since it's never been out of
the case in 30 years, I'm glad I sold the other while it was still worth
something. Then again maybe there are slide rule collectors now paying silly
money?

Hmmmmm, there's a thought. I have an old circular jobby, and the
classic Otis King 'truncheon' and Faber-Castell Novo Duplex, both in
mint condition in their original cases.

I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great.

Isn't that what log books are for?

I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I know what you mean, it took me a year to pay mine off at the time :-(
Even so I don't regret it.

Don't programs like Spice seem like cheating these days? :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 9 Jan 2004 22:12:09 +1100, "Tony Pearce"
wrote:

"Don Pearce" wrote in message
.. .
You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk.

Yeah I sold my best one and kept my cheapie. Since it's never been out of
the case in 30 years, I'm glad I sold the other while it was still worth
something. Then again maybe there are slide rule collectors now paying silly
money?

Hmmmmm, there's a thought. I have an old circular jobby, and the
classic Otis King 'truncheon' and Faber-Castell Novo Duplex, both in
mint condition in their original cases.

I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great.

Isn't that what log books are for?

I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I know what you mean, it took me a year to pay mine off at the time :-(
Even so I don't regret it.

Don't programs like Spice seem like cheating these days? :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 9 Jan 2004 22:12:09 +1100, "Tony Pearce"
wrote:

"Don Pearce" wrote in message
.. .
You've sold your slide rule? My Thornton is still sitting in front of
me at the back of my desk.

Yeah I sold my best one and kept my cheapie. Since it's never been out of
the case in 30 years, I'm glad I sold the other while it was still worth
something. Then again maybe there are slide rule collectors now paying silly
money?

Hmmmmm, there's a thought. I have an old circular jobby, and the
classic Otis King 'truncheon' and Faber-Castell Novo Duplex, both in
mint condition in their original cases.

I still use it sometimes to explain logs to
the new generation - the wonder in their eyes when at last they
understand them is great.

Isn't that what log books are for?

I did get an HP35 when it came out though -
I'm still paying the mortgage off!

I know what you mean, it took me a year to pay mine off at the time :-(
Even so I don't regret it.

Don't programs like Spice seem like cheating these days? :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

Bob Stanton

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

Bob Stanton

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

Bob Stanton

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

Bob Stanton

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Here are my opinions, whaever they are worth... :
(Bob-Stanton) wrote in message
(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Good analogy

Likewise, either model method will give virtually the same answers.

This is "experience" (see below)

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

Probably you would know this by experience. Just as you know the hand
is enough to kill the mosquito. Of course, in case there is a doubt,
grab the magnum and see if the mosquito dies.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

I don't mind that sound arrives 100 ns late to my ears. This tells me
that RF models of cables ARE overkill (but applicable) and the great
margin tell me that simpler models probably would do OK. And even if a
really poor model would yield a delay of 1 ms, I would not mind.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

In my opinion, characteristic impedance and delay are unimportant in
the audio case. What I wonder is if the transmission line model
predicts frequency response changes in the audio band (like a simple
RLC model does), given a frequency-varying load. If you take a
typical, or better, a slightly ill-behaved load to get "worst case",
how much effect will the cable have on the frequency response, within
the audio band. I bet yo end up with less than 0.1 dB. IMO the
frequency-varying load in combination with the series resistance and
possibly inductance accounts for most of this level variation.

Anyway, how does the transmission line model you use work, actually?
Isn't it actually a large number of RLC elements connected in series
("one for each cm of the cable")?

Here are my opinions, whaever they are worth... :
(Bob-Stanton) wrote in message
(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Good analogy

Likewise, either model method will give virtually the same answers.

This is "experience" (see below)

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

Probably you would know this by experience. Just as you know the hand
is enough to kill the mosquito. Of course, in case there is a doubt,
grab the magnum and see if the mosquito dies.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

I don't mind that sound arrives 100 ns late to my ears. This tells me
that RF models of cables ARE overkill (but applicable) and the great
margin tell me that simpler models probably would do OK. And even if a
really poor model would yield a delay of 1 ms, I would not mind.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

In my opinion, characteristic impedance and delay are unimportant in
the audio case. What I wonder is if the transmission line model
predicts frequency response changes in the audio band (like a simple
RLC model does), given a frequency-varying load. If you take a
typical, or better, a slightly ill-behaved load to get "worst case",
how much effect will the cable have on the frequency response, within
the audio band. I bet yo end up with less than 0.1 dB. IMO the
frequency-varying load in combination with the series resistance and
possibly inductance accounts for most of this level variation.

Anyway, how does the transmission line model you use work, actually?
Isn't it actually a large number of RLC elements connected in series
("one for each cm of the cable")?

Here are my opinions, whaever they are worth... :
(Bob-Stanton) wrote in message
(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Good analogy

Likewise, either model method will give virtually the same answers.

This is "experience" (see below)

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

Probably you would know this by experience. Just as you know the hand
is enough to kill the mosquito. Of course, in case there is a doubt,
grab the magnum and see if the mosquito dies.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

I don't mind that sound arrives 100 ns late to my ears. This tells me
that RF models of cables ARE overkill (but applicable) and the great
margin tell me that simpler models probably would do OK. And even if a
really poor model would yield a delay of 1 ms, I would not mind.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

In my opinion, characteristic impedance and delay are unimportant in
the audio case. What I wonder is if the transmission line model
predicts frequency response changes in the audio band (like a simple
RLC model does), given a frequency-varying load. If you take a
typical, or better, a slightly ill-behaved load to get "worst case",
how much effect will the cable have on the frequency response, within
the audio band. I bet yo end up with less than 0.1 dB. IMO the
frequency-varying load in combination with the series resistance and
possibly inductance accounts for most of this level variation.

Anyway, how does the transmission line model you use work, actually?
Isn't it actually a large number of RLC elements connected in series
("one for each cm of the cable")?

Here are my opinions, whaever they are worth... :
(Bob-Stanton) wrote in message
(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.


It may be that you object to using transmission line theory, because
it is quite unnessary to do so. It's like killing a mosquito with 44
magnum. Nevertheless, the mosquito end up dead whether you hit it
with your hand or shoot it with a magnum.

Good analogy

Likewise, either model method will give virtually the same answers.

This is "experience" (see below)

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.
I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

Probably you would know this by experience. Just as you know the hand
is enough to kill the mosquito. Of course, in case there is a doubt,
grab the magnum and see if the mosquito dies.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

I don't mind that sound arrives 100 ns late to my ears. This tells me
that RF models of cables ARE overkill (but applicable) and the great
margin tell me that simpler models probably would do OK. And even if a
really poor model would yield a delay of 1 ms, I would not mind.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

In my opinion, characteristic impedance and delay are unimportant in
the audio case. What I wonder is if the transmission line model
predicts frequency response changes in the audio band (like a simple
RLC model does), given a frequency-varying load. If you take a
typical, or better, a slightly ill-behaved load to get "worst case",
how much effect will the cable have on the frequency response, within
the audio band. I bet yo end up with less than 0.1 dB. IMO the
frequency-varying load in combination with the series resistance and
possibly inductance accounts for most of this level variation.

Anyway, how does the transmission line model you use work, actually?
Isn't it actually a large number of RLC elements connected in series
("one for each cm of the cable")?

On Sat, 10 Jan 2004 08:48:08 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!

I had a Z12, famous for going into meltdown at any power over about a
watt. Can't remember the claimed "Peak Music Power", but it was
something pretty enormous.

d

_____________________________

http://www.pearce.uk.com

On Sat, 10 Jan 2004 08:48:08 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!

I had a Z12, famous for going into meltdown at any power over about a
watt. Can't remember the claimed "Peak Music Power", but it was
something pretty enormous.

d

_____________________________

http://www.pearce.uk.com

On Sat, 10 Jan 2004 08:48:08 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!

I had a Z12, famous for going into meltdown at any power over about a
watt. Can't remember the claimed "Peak Music Power", but it was
something pretty enormous.

d

_____________________________

http://www.pearce.uk.com

On Sat, 10 Jan 2004 08:48:08 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:13:31 +0000, Don Pearce
wrote:

On Fri, 9 Jan 2004 18:16:56 +0000 (UTC), (Stewart
Pinkerton) wrote:

I did look at a 45 with the 'magic' gold function button - but IIRC it
cost more than my car! I always preferred the contemporaneous Texas
and Casio jobbies, as I never did like Reverse Polish notation......

Did you never get a Sinclair than? Interesting device - he couldn't
get enough memory to implement the trig functions properly, and it
gave errors. Sexy red on purple display, though.

IIRC, this beastie was indeed famous for being a calculator which
couldn't do sums...................

Just as the Sinclair X-10D amplifier was famous for having 0.1%
distortion at full power - and exactly the same level of artifacts at
any lower power!

I had a Z12, famous for going into meltdown at any power over about a
watt. Can't remember the claimed "Peak Music Power", but it was
something pretty enormous.

d

_____________________________

http://www.pearce.uk.com

On 10 Jan 2004 01:33:35 -0800, (Svante)
wrote:

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

You would have thought that given enough Ls and Cs (ie dividing the
lumped model very finely) you would end up with a perfect equivalent
of the transmission line model, but you don't. You just end up with an
ever steeper lowpass filter. Up to the cutoff point, this filter does
indeed behave remarkably like a true cable, though.

For much audio work a single L and C seem to do just fine, but there
are problems - like what order should you put them in? In theory you
can put the shunt C at either the start or end of the network, but if
you are modelling a very unmatched situation this won't work. For
example, if you are looking at an amplifier to a loudspeaker, the C
must be put at the speaker end - it has no effect on amplitude at the
amplifier end. In a matched scenario - equal impedances both ends, the
capacitance must be split and placed both ends if the model is to
work. So you must be careful in the application of a lumped model
cable, and understand the significance of the impedances at both ends
before you use it.

The true transmission line model has the advantage that all this is
taken care of, there is no anomalous lowpass filter effect to worry
about and it is really easy to change lengths - you just alter the
length term. It also works at any frequency. It is a sledgehammer to
crack a nut, though, and representing a cable as Ls and Cs (given the
caveats above) is perfectly proper, particularly if you are having to
hand-crank the results, or just doing a back-of-an-envelope
calculation. If you are using Spice, or something similar that
possesses native transmission line models, then why not use them? They
are easier to use, just as accurate for audio, and vastly more
accurate outside the audio band.

d

_____________________________

http://www.pearce.uk.com

On 10 Jan 2004 01:33:35 -0800, (Svante)
wrote:

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

You would have thought that given enough Ls and Cs (ie dividing the
lumped model very finely) you would end up with a perfect equivalent
of the transmission line model, but you don't. You just end up with an
ever steeper lowpass filter. Up to the cutoff point, this filter does
indeed behave remarkably like a true cable, though.

For much audio work a single L and C seem to do just fine, but there
are problems - like what order should you put them in? In theory you
can put the shunt C at either the start or end of the network, but if
you are modelling a very unmatched situation this won't work. For
example, if you are looking at an amplifier to a loudspeaker, the C
must be put at the speaker end - it has no effect on amplitude at the
amplifier end. In a matched scenario - equal impedances both ends, the
capacitance must be split and placed both ends if the model is to
work. So you must be careful in the application of a lumped model
cable, and understand the significance of the impedances at both ends
before you use it.

The true transmission line model has the advantage that all this is
taken care of, there is no anomalous lowpass filter effect to worry
about and it is really easy to change lengths - you just alter the
length term. It also works at any frequency. It is a sledgehammer to
crack a nut, though, and representing a cable as Ls and Cs (given the
caveats above) is perfectly proper, particularly if you are having to
hand-crank the results, or just doing a back-of-an-envelope
calculation. If you are using Spice, or something similar that
possesses native transmission line models, then why not use them? They
are easier to use, just as accurate for audio, and vastly more
accurate outside the audio band.

d

_____________________________

http://www.pearce.uk.com

On 10 Jan 2004 01:33:35 -0800, (Svante)
wrote:

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

You would have thought that given enough Ls and Cs (ie dividing the
lumped model very finely) you would end up with a perfect equivalent
of the transmission line model, but you don't. You just end up with an
ever steeper lowpass filter. Up to the cutoff point, this filter does
indeed behave remarkably like a true cable, though.

For much audio work a single L and C seem to do just fine, but there
are problems - like what order should you put them in? In theory you
can put the shunt C at either the start or end of the network, but if
you are modelling a very unmatched situation this won't work. For
example, if you are looking at an amplifier to a loudspeaker, the C
must be put at the speaker end - it has no effect on amplitude at the
amplifier end. In a matched scenario - equal impedances both ends, the
capacitance must be split and placed both ends if the model is to
work. So you must be careful in the application of a lumped model
cable, and understand the significance of the impedances at both ends
before you use it.

The true transmission line model has the advantage that all this is
taken care of, there is no anomalous lowpass filter effect to worry
about and it is really easy to change lengths - you just alter the
length term. It also works at any frequency. It is a sledgehammer to
crack a nut, though, and representing a cable as Ls and Cs (given the
caveats above) is perfectly proper, particularly if you are having to
hand-crank the results, or just doing a back-of-an-envelope
calculation. If you are using Spice, or something similar that
possesses native transmission line models, then why not use them? They
are easier to use, just as accurate for audio, and vastly more
accurate outside the audio band.

d

_____________________________

http://www.pearce.uk.com

On 10 Jan 2004 01:33:35 -0800, (Svante)
wrote:

Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

OK, in my boat there are no transmission line models, but a lot of R,
L and Cs.

You would have thought that given enough Ls and Cs (ie dividing the
lumped model very finely) you would end up with a perfect equivalent
of the transmission line model, but you don't. You just end up with an
ever steeper lowpass filter. Up to the cutoff point, this filter does
indeed behave remarkably like a true cable, though.

For much audio work a single L and C seem to do just fine, but there
are problems - like what order should you put them in? In theory you
can put the shunt C at either the start or end of the network, but if
you are modelling a very unmatched situation this won't work. For
example, if you are looking at an amplifier to a loudspeaker, the C
must be put at the speaker end - it has no effect on amplitude at the
amplifier end. In a matched scenario - equal impedances both ends, the
capacitance must be split and placed both ends if the model is to
work. So you must be careful in the application of a lumped model
cable, and understand the significance of the impedances at both ends
before you use it.

The true transmission line model has the advantage that all this is
taken care of, there is no anomalous lowpass filter effect to worry
about and it is really easy to change lengths - you just alter the
length term. It also works at any frequency. It is a sledgehammer to
crack a nut, though, and representing a cable as Ls and Cs (given the
caveats above) is perfectly proper, particularly if you are having to
hand-crank the results, or just doing a back-of-an-envelope
calculation. If you are using Spice, or something similar that
possesses native transmission line models, then why not use them? They
are easier to use, just as accurate for audio, and vastly more
accurate outside the audio band.

d

_____________________________

http://www.pearce.uk.com

On 9 Jan 2004 15:05:32 -0800, (Bob-Stanton)
wrote:

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.

It may be that you object to using transmission line theory, because
it is quite unnessary to do so.

It's also utterly pointless, because you can never get anywhere near a
matched system.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.

It depends on the construction, obviously.

I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

No conventional speaker cable has a characteristic impedance even
close to 300 ohms, even the most extreme high-inductance commercial
cable (my Naim NACA5, as it happens) only has an impedance of around
120 ohms. One *could* of course use 300 ohm antenna feeder as speaker
cable, but it wouldn't work very well........................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 9 Jan 2004 15:05:32 -0800, (Bob-Stanton)
wrote:

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.

It may be that you object to using transmission line theory, because
it is quite unnessary to do so.

It's also utterly pointless, because you can never get anywhere near a
matched system.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.

It depends on the construction, obviously.

I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

No conventional speaker cable has a characteristic impedance even
close to 300 ohms, even the most extreme high-inductance commercial
cable (my Naim NACA5, as it happens) only has an impedance of around
120 ohms. One *could* of course use 300 ohm antenna feeder as speaker
cable, but it wouldn't work very well........................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 9 Jan 2004 15:05:32 -0800, (Bob-Stanton)
wrote:

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.

It may be that you object to using transmission line theory, because
it is quite unnessary to do so.

It's also utterly pointless, because you can never get anywhere near a
matched system.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.

It depends on the construction, obviously.

I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

No conventional speaker cable has a characteristic impedance even
close to 300 ohms, even the most extreme high-inductance commercial
cable (my Naim NACA5, as it happens) only has an impedance of around
120 ohms. One *could* of course use 300 ohm antenna feeder as speaker
cable, but it wouldn't work very well........................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 9 Jan 2004 15:05:32 -0800, (Bob-Stanton)
wrote:

(Stewart Pinkerton) wrote in message


I'm well aware of the underlying theory.
It is not sensibly applicable to speaker cable.

It may be that you object to using transmission line theory, because
it is quite unnessary to do so.

It's also utterly pointless, because you can never get anywhere near a
matched system.

Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

My one objection toward component models of transmission lines is: how
do you know the model is right? I previously asked you to give us a
component model of 100 ft of 12 gage speaker wire, but you never did.

It depends on the construction, obviously.

I wanted to test your model to see if it met the simplest basic
requirement of a transmission line model, that the signal takes a
certain amount of time to pass through.

On my model, the group delay is 101.7 ns, which is about the velocity
of light. (It neglects the velocity factor.) And oh yes, if you prefer
shorter cables, my 10 ft long speaker cable model has 10.2 ns group
delay.

So, let us see your transmission line model. Let's see if it gets the
basics right. It should have 101.7 ns group delay, and it's
characteristic impedannce should be 300 Ohms.

No conventional speaker cable has a characteristic impedance even
close to 300 ohms, even the most extreme high-inductance commercial
cable (my Naim NACA5, as it happens) only has an impedance of around
120 ohms. One *could* of course use 300 ohm antenna feeder as speaker
cable, but it wouldn't work very well........................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

OK, since I started this whole horrible thread, I figure I can toss out
an answer to this one.

Pure knowledge. Modelling cables can prove what we know--that beyond
a very easily obtainable point, cables are irrelevant. Furthermore,
we can find out where that point is, and for lack of a better phrase,
how irrelevant the differnt factors are.

For instance, 12 gauge vs. 14 gauge wire isn't particularly important
in speaker cables, but it's a lot closer to being a valid factor than
say, capacitance or even worse, characteristic impedance.

So modelling helps those of us who DON'T know this stuff to learn it.
It also provides worthwhile information for those who are running long
(maybe in-wall?) speaker cables; and for that matter, also for those
who are designing their own amps.

Of course, that doesn't address which model to use, and the answer is
pretty obvious in any field: Use the model which most simply and closely
matches your conditions. For audio of any sort, that does NOT mean a
transmission line model!

Anyways, my two bits worth on why I asked about cables in the very
first place.

Colin

Stewart Pinkerton wrote:

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

OK, since I started this whole horrible thread, I figure I can toss out
an answer to this one.

Pure knowledge. Modelling cables can prove what we know--that beyond
a very easily obtainable point, cables are irrelevant. Furthermore,
we can find out where that point is, and for lack of a better phrase,
how irrelevant the differnt factors are.

For instance, 12 gauge vs. 14 gauge wire isn't particularly important
in speaker cables, but it's a lot closer to being a valid factor than
say, capacitance or even worse, characteristic impedance.

So modelling helps those of us who DON'T know this stuff to learn it.
It also provides worthwhile information for those who are running long
(maybe in-wall?) speaker cables; and for that matter, also for those
who are designing their own amps.

Of course, that doesn't address which model to use, and the answer is
pretty obvious in any field: Use the model which most simply and closely
matches your conditions. For audio of any sort, that does NOT mean a
transmission line model!

Anyways, my two bits worth on why I asked about cables in the very
first place.

Colin

Stewart Pinkerton wrote:

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

OK, since I started this whole horrible thread, I figure I can toss out
an answer to this one.

Pure knowledge. Modelling cables can prove what we know--that beyond
a very easily obtainable point, cables are irrelevant. Furthermore,
we can find out where that point is, and for lack of a better phrase,
how irrelevant the differnt factors are.

For instance, 12 gauge vs. 14 gauge wire isn't particularly important
in speaker cables, but it's a lot closer to being a valid factor than
say, capacitance or even worse, characteristic impedance.

So modelling helps those of us who DON'T know this stuff to learn it.
It also provides worthwhile information for those who are running long
(maybe in-wall?) speaker cables; and for that matter, also for those
who are designing their own amps.

Of course, that doesn't address which model to use, and the answer is
pretty obvious in any field: Use the model which most simply and closely
matches your conditions. For audio of any sort, that does NOT mean a
transmission line model!

Anyways, my two bits worth on why I asked about cables in the very
first place.

Colin

Stewart Pinkerton wrote:

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?

OK, since I started this whole horrible thread, I figure I can toss out
an answer to this one.

Pure knowledge. Modelling cables can prove what we know--that beyond
a very easily obtainable point, cables are irrelevant. Furthermore,
we can find out where that point is, and for lack of a better phrase,
how irrelevant the differnt factors are.

For instance, 12 gauge vs. 14 gauge wire isn't particularly important
in speaker cables, but it's a lot closer to being a valid factor than
say, capacitance or even worse, characteristic impedance.

So modelling helps those of us who DON'T know this stuff to learn it.
It also provides worthwhile information for those who are running long
(maybe in-wall?) speaker cables; and for that matter, also for those
who are designing their own amps.

Of course, that doesn't address which model to use, and the answer is
pretty obvious in any field: Use the model which most simply and closely
matches your conditions. For audio of any sort, that does NOT mean a
transmission line model!

Anyways, my two bits worth on why I asked about cables in the very
first place.

Colin

(Stewart Pinkerton) wrote in message


It may be that you object to using transmission line theory, because
it is quite unnessary to do so.

It's also utterly pointless, because you can never get anywhere near a
matched system.

Using a transmission line model does not necessitate having a matched
system. One can uses a voltage source and any impedance for a
termination.


Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?




This thread started with someone asking about the inductance of
various cable geometrys. Many people have the belief that speaker
cable inductance is always seen by the amplifier. If they saw a
component model of an 8 Ohm speaker cable, they might find out this is
not always true. For example, look at the following 8 Ohm speaker
cable model:

------0.267 uH--------0.267 uH-------0.267 uH------------
| | | | |
Gen 0.0042uf 0.0042uF 0.0042uF 8 Ohms
| | | | |
----------------------------------------------------------

The cable wire's inductance is 0.800 uH, but the generator sees a pure
resistance. No inductive reactance,(no inductance) and no roll off, at
high frequencies.

So, a simple cable model could dispell a common misconception.



No conventional speaker cable has a characteristic impedance even
close to 300 ohms, even the most extreme high-inductance commercial
cable (my Naim NACA5, as it happens) only has an impedance of around
120 ohms. One *could* of course use 300 ohm antenna feeder as speaker
cable, but it wouldn't work very well........................

You are right, the characteristic impedance is 120 Ohms.

Bob Stanton

(Stewart Pinkerton) wrote in message


It may be that you object to using transmission line theory, because
it is quite unnessary to do so.

It's also utterly pointless, because you can never get anywhere near a
matched system.

Using a transmission line model does not necessitate having a matched
system. One can uses a voltage source and any impedance for a
termination.


Likewise, either model method will give virtually the same answers.
Nowadays, it is quicker and easier (less typing) to enter a
transmission line model, than to type in a componet (L,C) model. Use
whatever way floats your boat.

That's likely true, but again, why bother to do *any* kind of speaker
cable modelling?




This thread started with someone asking about the inductance of
various cable geometrys. Many people have the belief that speaker
cable inductance is always seen by the amplifier. If they saw a
component model of an 8 Ohm speaker cable, they might find out this is
not always true. For example, look at the following 8 Ohm speaker
cable model:

------0.267 uH--------0.267 uH-------0.267 uH------------
| | | | |
Gen 0.0042uf 0.0042uF 0.0042uF 8 Ohms
| | | | |
----------------------------------------------------------

The cable wire's inductance is 0.800 uH, but the generator sees a pure
resistance. No inductive reactance,(no inductance) and no roll off, at
high frequencies.

So, a simple cable model could dispell a common misconception.



No conventional speaker cable has a characteristic impedance even
close to 300 ohms, even the most extreme high-inductance commercial
cable (my Naim NACA5, as it happens) only has an impedance of around
120 ohms. One *could* of course use 300 ohm antenna feeder as speaker
cable, but it wouldn't work very well........................

You are right, the characteristic impedance is 120 Ohms.

Bob Stanton