bi-wire config question
 

Bob Latham wrote:
In article ,
Serge Auckland wrote:

[Snip]

All you are doing with bi or tri wiring is reducing the resistance from
already low values, increasing the capacitance from normally low values
to still low values, and reducing inductance. Any amplifier/'speaker
combination for which this makes ANY difference is only fit to be used
as a boat anchor.

I've seen these sort of comments before and simply don't understand, I
would be grateful for some clarification.

The amplifier will see the capacitance of two speaker cables and in this
sense they are in parallel which will add the capacitance of each. The
cables are not connected together at the speaker end and don't cover the
same frequency spectrum so in no sense are they in parallel for current
flow to the speaker. Therefore, to my mind, resistance is not changed
anywhere. Where could I connect my fictitious superbly accurate meter to
measure this change in resistance?

The change in "total" resistance comes from the doubling of the 'speaker
cables, and therefore a halving of the total resistance. As each
'speaker cable now carries a lower current, the already small loss down
each 'speaker cable becomes smaller still.

If bi-wiring is used with two identical speaker cables then I can see no
possibility that this will make any difference what so ever.

Correct for all normal lengths of normal 'speaker cable.

Current personal theory coming up. It maybe utter **** but makes sense to
me and matches my experience.

Bi-wiring opens up the possibility of using two different cables and that,
in my experience can make a difference even if it would require one of the
cables to be less than perfect in an engineering sense. In addition if
there is a small level change for a whole loudspeaker that is just less
than audible it has no effect. Take that change and apply it to just part
of the spectrum and now you change the balance of the speaker with the
other (frequency) part acting as a reference making the difference more
obvious. This may well tip the speaker away from the flat response it was
designed for but if this gives the owner more pleasure I don't have a
problem with it.

Again correct. If you change one 'speaker cable for something with a
high resistance, for example, this can modify the frequency response
audibly. If you change one cable for one with a very high capacitance,
and your amplifier is less than stable, then that too could affect the
sound you hear. Your comment above, that it is less than perfect in
engineering terms is apposite. At best bi-wiring makes no difference, at
worse, it makes differences that are perhaps better not made, or that
can be achieved more usually by tone control.

Any room you place the loudspeaker in will modify its
frequency response.

Make that perceived frequency response, and you are right again. There's
no mystery to any of this, it's another example of the hi-fi fraternity
accepting what some mags and shops tell them as truth, without any
engineering rigour being applied.

S.

bi-wire config question
 

In article , Bob Latham
wrote:
In article , Serge Auckland
wrote:

[Snip]

All you are doing with bi or tri wiring is reducing the resistance
from already low values, increasing the capacitance from normally low
values to still low values, and reducing inductance. Any
amplifier/'speaker combination for which this makes ANY difference is
only fit to be used as a boat anchor.

I've seen these sort of comments before and simply don't understand, I
would be grateful for some clarification.

The amplifier will see the capacitance of two speaker cables and in this
sense they are in parallel which will add the capacitance of each.

Yes.

The cables are not connected together at the speaker end and don't cover
the same frequency spectrum so in no sense are they in parallel for
current flow to the speaker.

In essence, correct. When bi-wired, the individual speaker unit won't have
any way of sensing what currents flow in the 'other cable' - i.e. the one
not connect to it.

Therefore, to my mind, resistance is not changed anywhere. Where could I
connect my fictitious superbly accurate meter to measure this change in
resistance?

The problem is that what Serge wrote only really explains the behaviour if
the cables are connected in parallel at both ends (and we ignore intercable
field interactions). My understanding is that is *not* what people normally
do when 'bi-wiring' loudspeakers. Hence your puzzlement is quite
understandable. :-) The webpages which I referred to in an earlier posting
outline the situation in more detail.

Briefly: The network when bi-wired has a topologically different
arrangement of nodes/paths to when conventionally wired. This means the
affects of the impedances have to be modelled in a suitably different
manner. However unless the bi-wires are connected together at *both* ends
(amp and speakers) the bi-wiring isn't simply described just by saying that
the series resistance halves and the shunt capacitance doubles. (Assuming
two nominal lengths of cable.)

If bi-wiring is used with two identical speaker cables then I can see no
possibility that this will make any difference what so ever.

See the analysis I refer to above. In principle, it can alter the frequency
response by an amount that would be quite measurable. What is unclear is
if, in practice, this happens to a degree that would be audible. On that
point I have my doubts as I've never seen a single reliable test whose
results showed this.

Bi-wiring opens up the possibility of using two different cables and
that, in my experience can make a difference even if it would require
one of the cables to be less than perfect in an engineering sense.

Yes. If you wished to deliberately use cables with wildly different series
resistances, etc, then they could then interact with the load impedances of
the speaker units and alter the overall response accordingly. However the
levels of resistance required for this would probably more cheaply and
controllably be obtained by deliberately adding low-value series resistors
and shunt capacitors, etc, at the speakers. This is usually called
"modifying the crossover networks"... ;-

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

bi-wire config question
 

In article , Dave Plowman (News)
wrote:
In article , Bob Latham
wrote:
The amplifier will see the capacitance of two speaker cables and in
this sense they are in parallel which will add the capacitance of
each. The cables are not connected together at the speaker end and
don't cover the same frequency spectrum so in no sense are they in
parallel for current flow to the speaker.

Unless the cables have significant capacitance inductance resistance etc
they are effectively in parallel at the speaker end. And are carrying
exactly the same signal since they are paralleled at the source of that
signal.

I am trying to recall how a Flag Officer is supposed to comment when his
Admiral says something that perhaps isn't quite correct... :-)

If the amplifier has an o/p impedance that is essentially 'nil' then the
speakers won't be affected by cable capacitance. The individual units will
be affected by the individual series resistance and inductance of the cable
connected to that unit - but not that connected to the other unit. If the
amp has a non-zero o/p impedance then there will be a resulting
interaction.

The 'signals' involve both current and voltage. The amp may be asserting
the same voltage pattern at the (common) amp end of the bi wired cables.
But the currents in the cables may differ, and the individual cable-speaker
impedance interactions are in different paths.

Please see the webpages I've referred to previously as they should clarify
this topic.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

bi-wire config question
 

In article , Serge Auckland
wrote:
Bob Latham wrote:


The change in "total" resistance comes from the doubling of the 'speaker
cables, and therefore a halving of the total resistance. As each
'speaker cable now carries a lower current, the already small loss down
each 'speaker cable becomes smaller still.

Serge: Are you assuming the two cables are being connected together at
*both* ends? If so, I'd agree with what you say. But if not, the statement
that the "total" resistance halves leads to the question - which device in
the system experiences a current that passes through this "total"
resistance?

I can see that the amp would be such a device. But not the individual
speaker units.

[snip]

There's no mystery to any of this, it's another example of the hi-fi
fraternity accepting what some mags and shops tell them as truth,
without any engineering rigour being applied.

With this I am inclined to agree. The curious thing is that I did the
webpages I've referred to back in 2002. Perhaps I should try writing a
magazine article on this sometime as it continues to be a 'mystery' in the
magazines... :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

bi-wire config question
 

Jim Lesurf wrote:
In article , Serge Auckland
wrote:
Bob Latham wrote:


The change in "total" resistance comes from the doubling of the 'speaker
cables, and therefore a halving of the total resistance. As each
'speaker cable now carries a lower current, the already small loss down
each 'speaker cable becomes smaller still.

Serge: Are you assuming the two cables are being connected together at
*both* ends? If so, I'd agree with what you say. But if not, the statement
that the "total" resistance halves leads to the question - which device in
the system experiences a current that passes through this "total"
resistance?

I just re-read what I wrote earlier, and it's complete tosh! Crossover
distortion of the brain.... The amp would still see each individual
drive unit and its crossover components, and each part of the cable
would still carry the same individual current to each drive unit.
Consequently, there would be no change in "total" resistance.

S.



I can see that the amp would be such a device. But not the individual
speaker units.

[snip]

There's no mystery to any of this, it's another example of the hi-fi
fraternity accepting what some mags and shops tell them as truth,
without any engineering rigour being applied.

With this I am inclined to agree. The curious thing is that I did the
webpages I've referred to back in 2002. Perhaps I should try writing a
magazine article on this sometime as it continues to be a 'mystery' in the
magazines... :-)

Slainte,

Jim

Some difficult questions regarding bi-wiring
 

What would happen when you have bi-wiring if some of the electrons went down
the wrong wire and didn't realise it until they got to the speaker. They
would have to come back and go down the right wire. The ones coming back
would have to crash into some going down.

If the wire was hard and brittle couldn't these crashes cause cracks in the
wire because of the impact. The cracks would have to affect sound quality
because of the reduction in cross sectional area of the wire at the crack.

When these electron crashes occur, wouldn't this disrupt the "electron
traffic flow" and result in a noticible degradation of the sound quality.

Also, the electrons that went down the wrong wire and have to go back would
actually arrive at their speaker later then they should. Wouldn't this muddy
the sound.

Some difficult questions regarding bi-wiring
 

Dopey wrote:

What would happen when you have bi-wiring if some of the electrons went down
the wrong wire and didn't realise it until they got to the speaker. They
would have to come back and go down the right wire. The ones coming back
would have to crash into some going down.

If the wire was hard and brittle couldn't these crashes cause cracks in the
wire because of the impact. The cracks would have to affect sound quality
because of the reduction in cross sectional area of the wire at the crack.

When these electron crashes occur, wouldn't this disrupt the "electron
traffic flow" and result in a noticible degradation of the sound quality.

Also, the electrons that went down the wrong wire and have to go back would
actually arrive at their speaker later then they should. Wouldn't this muddy
the sound.

I'm sure the lunatics at Audio Asylum would be very concerned about this
! ;~)

Graham

bi-wire config question
 

Serge Auckland wrote:

Are you seriously trying to tell us that tri or bi-wiring makes (or
even can make) a difference? Have you done the sums to see what
effect bi or tri wiring makes?

I've done several comparisons, using one then two runs of identical
cable (originally tested it with Gale XL-105). When I switched to
bi-wiring the sound was clearer, switching back to single wiring made it
sound muddy.

Interestingly a few years back I went with a friend to dem some new
speakers at Richer Sounds, the guy who'd wired the system up had
bi-wired them but hadn't taken the bridging straps off (so the speakers
were in fact single-wired) [1]. After commenting that I thought the
sound was "a bit muddy" I had a quick look behind the speakers and
noticed this. I didn't tell my friend the way it was set up, just said
to him "pause the CD for a moment", removed the straps (making sure he
couldn't see what I was doing!) and said "ok, carry on".

His reaction was something along the lines of "bloody hell, that sounds
way better, what did you do?" I showed him the bridging straps that I'd
removed...

More recently I did some tests using my own setup, single-wiring using
two of the four cores of Chord Rumour 4, then bi-wiring, then bi-amping.
Could hear a significant difference in clarity between single and
bi-wired, but couldn't hear any difference between bi-wired and bi-amped
[2]. So the cables were identical on both tests, just with bi-wiring two
runs of the same type of cable (or in this case a 4-core bi-wire cable)
were in use.

"Doing the maths" only tells half the story. A few years back at the
Bristol Sound & Vision show I heard a classic example of this, how a
particular manufacturer (TAG McLaren if memory serves correctly) had
done all these calculations to make sure this CD player, amplifier and
speaker combo was "the best in the world". The guy then put on a CD.

It sounded horrible.

Thinking it was just a badly mastered CD, I got him to play one of the
test CDs I'd brought with me.

It still sounded horrible.

So much for the maths...

[1] I didn't realise the speakers were single-wired when I commented
that it sounded a bit muddy. Just to avoid any confusion,
misinterpretation etc that usually happens on here.

[2] Bi-amping implies bi-wiring, just to state the bleeding obvious - as
someone previously asked how I managed to bi-amp without bi-wiring... duh!

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

bi-wire config question
 

"Jim Lesurf" wrote in message
...
In article , Serge Auckland
wrote:

snip

To see the analysis, go to the 'Scots Guide' (URL in my sig), use the link
to the 'Analog and Audio' section, scroll down that page, and use the
links
to the pages on "An explanation of bi-wiring", etc, to see the analysis
and
results. These show that bi wiring can change the frequency response - but
by only a small amount even when using cables of exceptionally high series
resistance. Hence changes in measured behaviour are possible. But are they
audible in any sensible arrangement?... My reaction tends to be that if I
wanted a change in frequency response of a few tenths of a dB I'd move my
head slightly whilst listening. :-)


Ah yes - the issue of listening position! Something I've noticed is that
when listening to music if I happen to tilt my head so that I'm either
looking upwards or downwards then there is a discernable change in the
sound - I hear more or less treble. I suspect that the actual shape of my
ears influences how well certain frequencies are heard. So (assuming that
I'm not the only one that this affects) unless we're going to restrain our
heads in some sort of clamp then any comparitive test of speaker
connectivity is more likely than not going to have to deal with 'is my head
in exactly the right position to make it a fair trial' and indeed if moving
one's head slightly can affect the sound heard then is there any point in
worrying about minor changes that might be imparted via the speaker cable
arrangement? Unfortunately in my case I also know that my ears are not equal
with regard to how well they 'hear' various frequencies - I have had both
eardrums repaired because infections created perforations and minor auditory
nerve damage so I have had my hearing tested a few times! I imagine others
hear differently with left and right ears just as our vision isn't always
perfectly matched left to right.

Why seek perfection when more than likely the most imperfect part of the
system is ourselves?!

Howard

bi-wire config question
 

Glenn Richards wrote:
Serge Auckland wrote:

Are you seriously trying to tell us that tri or bi-wiring makes (or
even can make) a difference? Have you done the sums to see what
effect bi or tri wiring makes?

I've done several comparisons, using one then two runs of identical
cable (originally tested it with Gale XL-105). When I switched to
bi-wiring the sound was clearer, switching back to single wiring made it
sound muddy.

Interestingly a few years back I went with a friend to dem some new
speakers at Richer Sounds, the guy who'd wired the system up had
bi-wired them but hadn't taken the bridging straps off (so the speakers
were in fact single-wired) [1]. After commenting that I thought the
sound was "a bit muddy" I had a quick look behind the speakers and
noticed this. I didn't tell my friend the way it was set up, just said
to him "pause the CD for a moment", removed the straps (making sure he
couldn't see what I was doing!) and said "ok, carry on".

His reaction was something along the lines of "bloody hell, that sounds
way better, what did you do?" I showed him the bridging straps that I'd
removed...

More recently I did some tests using my own setup, single-wiring using
two of the four cores of Chord Rumour 4, then bi-wiring, then bi-amping.
Could hear a significant difference in clarity between single and
bi-wired, but couldn't hear any difference between bi-wired and bi-amped
[2]. So the cables were identical on both tests, just with bi-wiring two
runs of the same type of cable (or in this case a 4-core bi-wire cable)
were in use.

"Doing the maths" only tells half the story. A few years back at the
Bristol Sound & Vision show I heard a classic example of this, how a
particular manufacturer (TAG McLaren if memory serves correctly) had
done all these calculations to make sure this CD player, amplifier and
speaker combo was "the best in the world". The guy then put on a CD.

It sounded horrible.

Thinking it was just a badly mastered CD, I got him to play one of the
test CDs I'd brought with me.

It still sounded horrible.

So much for the maths...

[1] I didn't realise the speakers were single-wired when I commented
that it sounded a bit muddy. Just to avoid any confusion,
misinterpretation etc that usually happens on here.

[2] Bi-amping implies bi-wiring, just to state the bleeding obvious - as
someone previously asked how I managed to bi-amp without bi-wiring... duh!

You've obviously convinced yourself that it makes a difference. I've
never managed to hear any myself, and when I do the sums, I'm not a bit
surprised. By the way, if you are indeed sure it does make a difference,
have you tried to analyse why and how? What mechanism can be acting to
make the sound better (or even different)?

S.