Speaker jumpers or bi wire ?

[andyjm]

For anyone who cares, its not so much about the wire/jumper (its so short it really doesn't make any difference - though thicker and shorter is always better), its more about the contact with the binding post.

Compression contacts are quite an art, and getting a good gas tight seal to avoid corrosion is tricky. Some of the banana plugs I see on supposedly fancy speaker cable are laughable. As suggested above, a decent solution is just to bare a longer length of cable and run it through both posts. Make sure the binding posts are tight, and there isn't a stray strand shorting out or that can get expensive.

 

[MajorFubar]

Look at the gauge of the speaker wire coming from the x-over to the drivers. Or for that matter, at the thickness of the copper traces on the amp circuitboard from the output transistors to the speaker terminals, and on the x-over board itself. All those things would cause a bigger bottleneck than anything used to link the terminals together, were there a bottleneck at all. However someone with way more technical knowledge than your average audiofool has decided that all those things are perfectly adequate. Yet exchanging the two inches of wire/copper strip/brass links for some other equally adequate conductor makes a noticeable difference. Come off it. Is this April 1st or what?

 

[Andrewjvt]

Been told that you can only hear the benefits of quality audiophile cable once your room has been treated.

What I don't tell you is if I think the person is a complete idiot.

 

[Benedict_Arnold]

Most of those "brass" jumpers are probably brass or cadmium plated steel.

And since iron and steel have six times the resistivity of copper, not to mention the phase changes caused by the different reactances... From there on it gets really testical...

[/quote]

These cable type threads always end up talking b####x! Got my granny to knit some speaker jumpers. Maybe she used too heavy a gauge as the sound became all woolly. Removed them again and it was like a veil had lifted.

FWIW I just pass the cable through the low connector, de-nuding enough cable for it to clamp down and terminate it on the high connector. Something about using one continuous piece of wire makes sense to me. It doesn't really sound a world different to other configurations.

[/quote]

Aristotle is supposed to have said "The more you know, the more you know you don't know." The flip side of that is that "the less you know, the less you don't know what you don't know". Therefore Just because YOU don't understand something doesn't make it ball-cocks.

My degree is in mechanical engineering, but it included enough electrical engineering, and my experience with 30 years designing and spec-ing subsea power cables in umbilicals, has taught me there's a darned sight more to cable design than simply the cross sectional area, DC-resistivity and length. Stuff like the capacitance of the cables, the dilectric coefficients of the insulators, how the impedance varies not only with current, but also the temperature of the cable, the frequency of the signal, etc. Our cable engineers go to great lengths (cough) to ensure that signals actually make it to the ends of these very long (30+mile) cables, and don't fizzle out half-way along (that's called attenuation by the way).

Let's start with a simple DC circuit, like, say, a bicycle light. A battery operated device where a DC current goes through an incandescent bulb, which, one it gets to a constant temperature, has a static, Ohms Law only resistance. If we neglect the drop in battery output over a short time period, there is no alternating or dymanic element to the voltage, and therefore the current is constant. Therefore the reactive elements of the conductors and the bulb don't come into play.

In a speaker circuit, however, the signal is dynamic. It rises and falls according to the volume, and it's frequency varies according to the notes being played. Therefore the cable's impedance rather than its resistance comes into play and that can and does affect how quickly different frequencies make it along a cable. All conductors have both a resistive (static or DC if you like) element and a reactive (or AC if you like) element that adds up to the total impedance (rather than basic Ohm's Law resistance) of the cable. Impedance is usually expressed as the square root of the sum of the resistive element squared and the reactive element squared (a bit like Pythagorus).

Now, comparing a cable to a brass (or steel or chewing gum for that matter) jumper, it should be bleeing obvious that a collection of, a PAIR of say 39 copper strands, helically would together, then wrapped in a poly-something-or-other insulating layer, then bunched under an outer sheath over that, looks a lot like a lot like a capacitor (two conductors separated by an insulating material), whereas two metal stips in isolation look a lot more like very simple 1-turn or zero-turn coils. In a capacitor the current leads the voltage by 90 degrees (or a quarter cycle if you like). In a coil, the current lags the voltage by the same 90 degrees. So now you've gone from a situation where the current, which was leading the voltage in the cable, now gets forced to lag the voltage in the jumper. This introduces a phase shift and that's why jumpers often make the sound, erm, sound, so naff.

 

[andyjm]

Aristotle is supposed to have said "The more you know, the more you know you don't know." The flip side of that is that "the less you know, the less you don't know what you don't know". Therefore Just because YOU don't understand something doesn't make it ball-cocks.

My degree is in mechanical engineering, but it included enough electrical engineering, and my experience with 30 years designing and spec-ing subsea power cables in umbilicals, has taught me there's a darned sight more to cable design than simply the cross sectional area, DC-resistivity and length. Stuff like the capacitance of the cables, the dilectric coefficients of the insulators, how the impedance varies not only with current, but also the temperature of the cable, the frequency of the signal, etc. Our cable engineers go to great lengths (cough) to ensure that signals actually make it to the ends of these very long (30+mile) cables, and don't fizzle out half-way along (that's called attenuation by the way).

Let's start with a simple DC circuit, like, say, a bicycle light. A battery operated device where a DC current goes through an incandescent bulb, which, one it gets to a constant temperature, has a static, Ohms Law only resistance. If we neglect the drop in battery output over a short time period, there is no alternating or dymanic element to the voltage, and therefore the current is constant. Therefore the reactive elements of the conductors and the bulb don't come into play.

In a speaker circuit, however, the signal is dynamic. It rises and falls according to the volume, and it's frequency varies according to the notes being played. Therefore the cable's impedance rather than its resistance comes into play and that can and does affect how quickly different frequencies make it along a cable. All conductors have both a resistive (static or DC if you like) element and a reactive (or AC if you like) element that adds up to the total impedance (rather than basic Ohm's Law resistance) of the cable. Impedance is usually expressed as the square root of the sum of the resistive element squared and the reactive element squared (a bit like Pythagorus).

Now, comparing a cable to a brass (or steel or chewing gum for that matter) jumper, it should be bleeing obvious that a collection of, a PAIR of say 39 copper strands, helically would together, then wrapped in a poly-something-or-other insulating layer, then bunched under an outer sheath over that, looks a lot like a lot like a capacitor (two conductors separated by an insulating material), whereas two metal stips in isolation look a lot more like very simple 1-turn or zero-turn coils. In a capacitor the current leads the voltage by 90 degrees (or a quarter cycle if you like). In a coil, the current lags the voltage by the same 90 degrees. So now you've gone from a situation where the current, which was leading the voltage in the cable, now gets forced to lag the voltage in the jumper. This introduces a phase shift and that's why jumpers often make the sound, erm, sound, so naff.

Benedict,

Rather like going to the doctor with a serious diagnosis you found on the internet only to be told you have a common cold, a little knowledge can be a dangerous thing.

All components (including cable) have capacitiance, inductance and resistance in varying amounts. The important question is whether it matters in the circuit in question.

In a typical loudspeaker circuit, with a very low output impedance source (the amp), a very low input impedance sink (the speaker) and at baseband audio frequencies, the only cable parameter that really makes any difference is the cable resistance.

This wouldn't be the case at RF, nor would it be the case for long cables, but for the few metres of cable draped around your living room, resistance is pretty much the whole story.

I am afraid your phase shift example is well wide of the mark. You have neglected the very low impedance of the overall circuit, the relatively low frequencies involved (baseband audio) and also the the tiny changes in capacitance and inductance that replacing a jumper with a cable will make.

Take it from me, you just have a common cold.

 

[nopiano]

Aristotle is supposed to have said "The more you know, the more you know you don't know." The flip side of that is that "the less you know, the less you don't know what you don't know". Therefore Just because YOU don't understand something doesn't make it ball-cocks.

My degree is in mechanical engineering, but it included enough electrical engineering, and my experience with 30 years designing and spec-ing subsea power cables in umbilicals, has taught me there's a darned sight more to cable design than simply the cross sectional area, DC-resistivity and length. Stuff like the capacitance of the cables, the dilectric coefficients of the insulators, how the impedance varies not only with current, but also the temperature of the cable, the frequency of the signal, etc. Our cable engineers go to great lengths (cough) to ensure that signals actually make it to the ends of these very long (30+mile) cables, and don't fizzle out half-way along (that's called attenuation by the way).

Let's start with a simple DC circuit, like, say, a bicycle light. A battery operated device where a DC current goes through an incandescent bulb, which, one it gets to a constant temperature, has a static, Ohms Law only resistance. If we neglect the drop in battery output over a short time period, there is no alternating or dymanic element to the voltage, and therefore the current is constant. Therefore the reactive elements of the conductors and the bulb don't come into play.

In a speaker circuit, however, the signal is dynamic. It rises and falls according to the volume, and it's frequency varies according to the notes being played. Therefore the cable's impedance rather than its resistance comes into play and that can and does affect how quickly different frequencies make it along a cable. All conductors have both a resistive (static or DC if you like) element and a reactive (or AC if you like) element that adds up to the total impedance (rather than basic Ohm's Law resistance) of the cable. Impedance is usually expressed as the square root of the sum of the resistive element squared and the reactive element squared (a bit like Pythagorus).

Now, comparing a cable to a brass (or steel or chewing gum for that matter) jumper, it should be bleeing obvious that a collection of, a PAIR of say 39 copper strands, helically would together, then wrapped in a poly-something-or-other insulating layer, then bunched under an outer sheath over that, looks a lot like a lot like a capacitor (two conductors separated by an insulating material), whereas two metal stips in isolation look a lot more like very simple 1-turn or zero-turn coils. In a capacitor the current leads the voltage by 90 degrees (or a quarter cycle if you like). In a coil, the current lags the voltage by the same 90 degrees. So now you've gone from a situation where the current, which was leading the voltage in the cable, now gets forced to lag the voltage in the jumper. This introduces a phase shift and that's why jumpers often make the sound, erm, sound, so naff.

Benedict,

Rather like going to the doctor with a serious diagnosis you found on the internet only to be told you have a common cold, a little knowledge can be a dangerous thing.

All components (including cable) have capacitiance, inductance and resistance in varying amounts. The important question is whether it matters in the circuit in question.

In a typical loudspeaker circuit, with a very low output impedance source (the amp), a very low input impedance sink (the speaker) and at baseband audio frequencies, the only cable parameter that really makes any difference is the cable resistance.

This wouldn't be the case at RF, nor would it be the case for long cables, but for the few metres of cable draped around your living room, resistance is pretty much the whole story.

I am afraid your phase shift example is well wide of the mark. You have neglected the very low impedance of the overall circuit, the relatively low frequencies involved (baseband audio) and also the the tiny changes in capacitance and inductance that replacing a jumper with a cable will make.

Take it from me, you just have a common cold.

I appreciate both these insights, and am not equipped to judge between them. But congratulations on being civil and humorous, which makes a pleasant change from the insults and discourtesy that often prevails.

I have previously posted a link to an interesting review by Martin Colloms in HiFi Critic on an ATC speaker. It had similar jumper bars to mine. He detected a problem because it was slightly loose. Replacing the jumpers with wire solved the problem.

The relevant extract is here:-

“ATC’s Ben Lilly explained that the Far East market had demanded fitting tri-wire terminals, which in my view might impair potential performance. The standard electrical connection comprises multiple metal linking straps finished in matt grey plating, which are then daisy-chained. If not carefully and very tightly installed these can make for unreliable connections. I placed one of these strap links on the test bench measuring the contact resistance of an inch strip with pointed probes and even with significant force I obtained varying results in the 0.25ohm range. (The nickel-plated probes that I used, even if lightly touched together, gave a much lower 0.05ohm value on this meter.)
Furthermore, the shoulders of the 4mm apertures on the removable screw caps are sharply radiused, making plug insertion difficult, and a larger spade terminal jaw size is required to clear the oversize posts. If not done up really tightly these connections may be imperfect as even a moderately tight install will result in attenuated or even missing driver outputs (which initially happened during our tests). Finally, the fine knurling on the connectors might be aesthetically pleasing but it means poor finger grip, especially as they are too tightly grouped. Even when well tightened I compared the sound quality before and after substituting wire jumpers: an unmistakable metallic sheen and extra crispness and projection in the high treble was then dispelled, and image depth improved. I make no apology for discarding the supplied hardware and making up a soldered, non-daisy-chained short wire harness to connect everything together. (A dealer should be able to help here.)”

 

[MajorFubar]

There's two different arguments going on here.

One is the Chebby/Nopiano argument that speakers equipped with poorly-designed or inadequate-quality jumpers with dubious electrical characteristics will benefit from having said jumpers replaced with something up to the job, even if that something is just a regular offcut of cable of sufficient gauge. This sounds logical and plausible to me. Even though I can't imagine why a manufacturer would cripple their product in such a way.

Then there's the separate argument that replacing two inches of perfectly adequate wire / jumpers with something just as equally adequate will somehow improve/influence the sound in a perceivable way. I'm sorry but that's just nonsense, no matter how often anyone tries to justify it with technical jargon.

 

[Al ears]

There's two different arguments going on here.

One is the Chebby/Nopiano argument that speakers equipped with poorly-designed or inadequate-quality jumpers with dubious electrical characteristics will benefit from having said jumpers replaced with something up to the job, even if that something is just a regular offcut of cable of sufficient gauge. This sounds logical and plausible to me. Even though I can't imagine why a manufacturer would cripple their product in such a way.

Then there's the separate argument that replacing two inches of perfectly adequate wire / jumpers with something just as equally adequate will somehow improve/influence the sound in a perceivable way. I'm sorry but that's just nonsense, no matter how often anyone tries to justify it with technical jargon.

I would have to agree with your second paragraph. Some time ago I managed to lose a connecting plate from one of my speakers so promptly replace them all with decent quality interconnects from the Chord Company. Was there any easily discernable improvement in the sound produced by said speakers? Um, no......

 

[Muddywaterstones]

Most of those "brass" jumpers are probably brass or cadmium plated steel.

And since iron and steel have six times the resistivity of copper, not to mention the phase changes caused by the different reactances... From there on it gets really testical...

These cable type threads always end up talking b####x! Got my granny to knit some speaker jumpers. Maybe she used too heavy a gauge as the sound became all woolly. Removed them again and it was like a veil had lifted.

FWIW I just pass the cable through the low connector, de-nuding enough cable for it to clamp down and terminate it on the high connector. Something about using one continuous piece of wire makes sense to me. It doesn't really sound a world different to other configurations.

[/quote]

Aristotle is supposed to have said "The more you know, the more you know you don't know." The flip side of that is that "the less you know, the less you don't know what you don't know". Therefore Just because YOU don't understand something doesn't make it ball-cocks.

.

[/quote]

It's not everyday I have Aristotle (maybe that is what Rumsfeld was thinking with his known unknowns etc) quoted in a reply. Consider me honoured.

Just in case there is any confusion, I was not slating your opinion but the general content of these type of threads. However, there are a handful of contributors on both sides of the debate who make it worth wading through.