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Different Binding Posts - is it audible?

somebodyelse

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Crimps have actual research behind them (this being a random example). The principle of the gas-tight contact area is long established for reliable connections, and doesn't require fancy materials or plating. Even well designed screw terminals have that as a goal - Neutrik show it in their speakon docs with a section through the screw terminal. While you're looking at their documentation you can check out the specified contact resistance, 0.003 Ohms or less. It's a properly engineered connector at a sensible price, and the pro audio world adopted it for good reasons. I wish more hifi manufacturers would use them.
 

waynel

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The influence of BP on the sound of loudspeakers has often been controversially discussed. It even goes so far that individual voices describe the influence of binding posts as immense and recommend only very high-quality BPs - That made me curious.

Of course it is not possible for me to test "all" binding posts (BP). Therefore I compare binding posts that are generally considered the "worst" ones (on planet earth) and evaluate their possible influence on the sound of loudspeakers.

This way, everyone can decide for himself whether it is worth spending ten or hundert times the price for high-end binding posts, the effect of which is then at best between the results of the worst binding posts and the measurements without binding post - apart from aesthetic differences.

The compared binding posts (BP) are shown here:
View attachment 83367

BP-No: Without bindig post, serves as baseline. Here only the influence of 0.3m, OFC, 2.5mm² speaker cable is measured.
The measurements of the other BP also use 0.3m of the same speaker cable. The resistance value of the loudspeaker cable can then be subtracted from the BP measurements.

BP-Clamps: Probably the cheapest commonly used type of BP. Great care must be taken to ensure that the clamps are used correctly. The speaker cables must be inserted deep enough to touch the rear panel of the terminal - this is how at least the BP I use works. Personally, I would not use this binding post, as my tests often required several attempts to fix the speaker cable ends correctly.

BP-Luster: I often use luster terminals because I regularly make changes to loudspeakers.
Disadvantage, the screws of the luster terminals must be, after some time, tightened at least once to guarantee a faultless connection.

BP-Screws: These BPs are likely to be used very frequently. The nuts on the screw were adjusted to correspond to a cabinet wall thickness of approximately 21mm (0.83''). If banana plugs are not used, the speaker cable ends must be checked for tightness after some time.

BP-Nails: The secret formula for this BP was found during renovation works of our house, whose foundation walls date back to the 14-15th century.
As you can see on the photo, other adventurers had to pay with their lives to get the secret formula. Before the "Copernican Revolution", people knew just how to make a good binding post.
View attachment 83368



Why were the cable ends soldered?
With bare speaker cable ends the measured resistances are slightly worse and not as consistent. Therefore all cable ends were soldered.



1. LCR-Meter Comparison

In the first comparison the resistance values of the individual binding posts are simply measured with 0.3m loudspeaker cable.

After deducting the value for 0.3m loudspeaker cable we get a first indication of the influence of the BP on the overall performance of the loudspeaker.

Please note that the given absolute resistance values still have error tolerances which are not given here.

BP-No: 0.005 Ohm (0.3m speaker cable)
View attachment 83370

BP-Clamps: 0.012-0.005 = 0.007 Ohm
Since further cable transitions were necessary for this measurement (see picture above), the comparison is not quite fair - for the further measurements this disadvantage will no longer exist.
View attachment 83371

BP-Luster: 0.012-0.005 = 0.007 Ohm
Since further cable transitions were necessary for this measurement (see picture above), the comparison is not quite fair - for the further measurements this disadvantage will no longer exist.
View attachment 83372

BP-Screws: 0.009-0.005 = 0.004 Ohm
View attachment 83373

BP-Nails: 0.01-0.005 = 0.005 Ohm
View attachment 83374

But this is only half the truth, since the LCR meter only measures at a fixed frequency (in this case it was 1kHz), we do not yet know how the resistance values change over the entire audible range.

Cheap BP are supposed to have a negative influence on the high frequency reproduction, that has to be clarified.



2. Impedance measurement with Arta-Limp

The Arta-Limp software can also function as an LCR meter. For this purpose, the impedance of the component against the frequency is measured.

When measuring the impedance of a resistor, which corresponds to our BP, Arta-Limp calculates the resistive and inductive part (at a given frequency).
The inductive part is shown in a phase >0° in the measurement diagram (less than 0° phase would indicate a capacitive behavior or a bad calibration in this case).

In the diagrams (except BP-No) the impedance of the BP-No is shown as an additional yellow curve.

BP-No: 0.06 Ohm
View attachment 83377

BP-Clamps: 0.09 - 0.06 = 0.03 Ohm
View attachment 83378

BP-Luster: 0.07 - 0.06 = 0.01 Ohm
View attachment 83379

BP-Screws: 0.07 - 0.06 = 0.01 Ohm
View attachment 83380

BP-Nails: 0.09 - 0.06 = 0.03 Ohm
View attachment 83381

If all impedance measurements are ploted in one diagram, it can be seen that the resistive part of all binding post is, as expected, close to zero ohms, the inductive part shown as phase angle differs more clearly.
View attachment 83382

The two different measurement methods clearly show that binding posts have an influence, albeit small, on the overall impedance of the loudspeaker.

Does this lead to an audible influence on the sound of the loudspeaker? This will be clarified in the next section.



3. Impact on frequency response

In the last part we will look at the effects of BP on the frequency response. For this the same test setup is used as in my posts on "Capacitor upgrade in crossover - Is it audible?" and "Replace resistor by low-inductance resistor - Is it audible?".

View attachment 83389 View attachment 83393
The test signal is fed to the tweeter via 5m loudspeaker cable. A simple crossover circuit protects the tweeter from damage and serves to create a realistic test environment.
The binding post to be tested is then placed between the crossover and the connecting cable, just like you do with a real loudspeaker.

The result should not surprise anyone. The effect of the different BP on the frequency response is negligible.

View attachment 83469

Who is familiar with my other posts, knows what will follow.
To make sure I'm not bullshitting you, the measurements are normalized to the frequency response of the BP-No, smoothed with 1/3 dB/oct and displayed with a 0.01 dB scale (only the frequency range down to -10dB of maximum sound pressure is displayed):

View attachment 83470

Please do not regard the results presented here as absolute. I have had series of measurements where, for example, the BP-Screws were closer to our baseline BP-No (the measurement without a binding post) than shown above.

But the tendency was always similar, best results were always achieved by the luster terminal and the highest sound pressure reduction (greatest resistance effect) was caused by using fu... nails as binding post.

When using reasonable binding posts (therefore no nails), their effect on the frequency response is still well below 0.1dB according to my measurements and thus inaudible.
(If the loudspeaker cables were soldered to the nails instead of attaching them with crocodile clips as here in the test, their use as BP should also cause frequency response changes well below 0.1dB)

Before this is mentioned, also other measurements like distortions, decay,... no effect can be determined.



4. Conclusion

Had long considered whether I should write anything at all to binding posts, since common sense tells you that the impact should be minimal.

But after reading in forums over and over again and being told in YouTube videos how dramatic the effects of high-end BP are on the sound of loudspeakers, I had no choice.

When using quite "normal, reasonable" binding posts, the effects on the sound of the speaker is inaudible. Important are of course cleanly processed solder joints and firmly seated contacts when using banana plugs.
Then the resistance of the binding post should be below/around 0.01 Ohm. If you extend your loudspeaker cable by one meter, you will cause a greater effect than using normal binding posts.

Here is another comparison. In almost all crossovers a resistor in series to the tweeter is used (as part of a voltage divider) - usually with values around 1-3 Ohm.
Their tolerances are often around 2% for MOX resistors, but for other resistors it can be 5-10%.
Even if only a 1 Ohm resistor is used, the tolerances are in absolute terms with +- 0.02 Ohm to +-0.1 Ohm significantly higher than the resistance caused by binding posts.
In measuring the AHB2 Amir found a measurable (no claim of audible) difference in distortion bewteen the Speakon connectors (better) and binding posts (worst), that's why Benchmark recommends locking bananas at the speaker ends.
 

Gringoaudio1

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A popular Speaker kit seller and YouTube speaker upgrade personality says the binding posts on my Sonus Faber speakers are shit because they mildy attract a magnet. The only scientific justification for this line of thought that I can think of is that they perhaps act as inductors?? How else could they affect the sound other than to filter out certain frequencies? The tiny amount of inductance they would provided might filter out something way higher than audible frequencies. But how would they actually even be inductive? Really they are a small link in the audio chain that happens to be mildy infused with a bit of iron.
 

Doodski

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A popular Speaker kit seller and YouTube speaker upgrade personality says the binding posts on my Sonus Faber speakers are shit because they mildy attract a magnet. The only scientific justification for this line of thought that I can think of is that they perhaps act as inductors?? How else could they affect the sound other than to filter out certain frequencies? The tiny amount of inductance they would provided might filter out something way higher than audible frequencies. But how would they actually even be inductive? Really they are a small link in the audio chain that happens to be mildy infused with a bit of iron.
They are not inductive in any sense of the application and may have some ferrous properties making them attracted to a magnet. As long as they have a good contact with the speaker wire termination you are all set.
 
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ctrl

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Another thread was about the influence of terminal connectors (for example cheap banana plugs) on distortion of hi-fi equipment with extremely low distortion and that small effects can be observed there.

PIM (passive intermodulation) was mentioned as a possible explanation for the phenomenon - please see "passive inermodulation causes" and on the nonlinear analysis of PIM.

In the first post I had written that all the usual analyses show no significant differences between the different BP:
Before this is mentioned, also other measurements like distortions, decay,... no effect can be determined.

But it is always better if everyone can decide for themselves on the basis of measurements. Therefore, in the following a few distortion measurements of BP.
I will try to cover the most extreme cases. As the "best" possible binding post, a luster terminal (BP-Luster) is used because correctly executed, the cable ends touch each and as "worst case" simply iron nails were used as BP (BP-Nails) - more details, see first post. All other BPs, in terms of distortion performance, should be between these two extremes.

Test Setup
A simple crossover protects a tweeter whose signal is recorded by a microphone in the near field.
The test signal is routed through the different BP.
test-setup_small.jpg

The measurements are reliable in the range 2-30kHz. Outside these ranges, the sound pressure drops too quickly to be reliable.
1614085337482.png

First, a comparison of harmonic distortions when using BP-Luster and BP-Nails, as expected there are no differences there:
BP-Luster 1614085774978.png BP-Nails 1614085801324.png


So, now the crucial measurement. Is there an increase in inter-modulation distortion (IMD) when using cheap, simple binding posts?

1614087571194.png


In the meaningful range 2-30kHz the IMD are practically congruent. If you are petty, you could state a touch better results for the BP-Luster.
But the minor differences are on average -75dB (110dB - 35dB) below the test tones.

The sound pressure range for IMD, where minor differences can be seen, is on average -75dB (110dB - 35dB) below the test tones. The IMD in question is therefore in the range of 0.02%.
It would be very difficult for most of us to hear a difference if it were "only" 0.03%.

That means for all "real" BP it should not make any difference at all which one is used.
 

Wes

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What is the maximum current in any home speaker on high volume bass ?

After establishing that, run that amperage thru the test sequence above and compare.


A second factor is the susceptibility of each bind post design to corrosion.
 
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ctrl

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What is the maximum current in any home speaker on high volume bass ?

After establishing that, run that amperage thru the test sequence above and compare.

No idea up to what sound pressure most people listen to music.
Therefore, I simply set 16V@1kHz sine as the volume. At a distance of 2m, pink noise is already damn loud.

I don't know what you're expecting, but the IMD of the tweeter will naturally increase significantly at this voltage, masking any possible minimal influence of the BPs.

1614110919061.png


Even at 16V voltage, no influence of different BP can be seen.

But maybe a "bad" BP raises the noise floor considerably? Therefore, I made another measurement with 16V.
A 2.5kHz sine tone was played and recorded with the spectrum analyzer.

1614111253291.png


The high sound pressure level naturally produces decent harmonic distortions of any order (2nd - 15th).
But both the amount of harmonic distortion and the amount of noise floor do not change when comparing the two BPs.
 

Wes

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my point is that contact area for higher current flow matters in some speakers, and may not be adequately assessed
 
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ctrl

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my point is that contact area for higher current flow matters in some speakers, and may not be adequately assessed
If this were a serious problem, every passive loudspeaker would have considerable problems, because every crossover has quite a few transition points with a small contact area.

Quoting myself:
It is important that the contact surface during the transition is as "good/big" as possible. But even there you shouldn't go crazy, since there are several material transition points of components in every crossover and their contact area is very small.
index.php

The wire diameter for components is usually <1mm. Anyone can easily estimate how small the contact area of a component in the circuit board of a crossover is. Of these material transitions, there are usually four to eight in the tweeter section of the crossover in series with the tweeter (1-2 resistors plus 1-2 capacitors). In addition, there are the material transitions of the components connected in parallel.
 

kevin1969

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Here are a few examples of what we should actually hear or not hear when using different BP.
Of course, as always, the statements are without any verification by measurement.


Source: https://www.audiocircle.com/index.php?topic=137288.0



Source: https://forum.audiogon.com/discussions/no-binding-post-a-good-idea


Here is a really funny post, I am not sure if it were meant seriously:

https://forum.audiogon.com/discussions/binding-post-break-in


This is truly pure audiophile high-end porn:

https://www.wbt.de/english/products/a/Detailansicht/Artikel/nextgenTM-pole-terminal-2.html


On the other hand, a few measurements of an armchair measurement "scientist" (as I was recently called) have no chance. As always, if a manufacturer is convinced of his product, he is welcome to send me something to measure and compare ;)

I'm gonna upgrade to Brushed Nickel binding posts. There's a lot of "evidence" that it makes the music sound more modern and contemporary.
 

Wes

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you think the jaws on the BP have a larger contact area than the internal solder joints for crossovers?

or did you measure them?
 

MRC01

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... The wire diameter for components is usually <1mm. Anyone can easily estimate how small the contact area of a component in the circuit board of a crossover is. Of these material transitions, there are usually four to eight in the tweeter section of the crossover in series with the tweeter (1-2 resistors plus 1-2 capacitors). In addition, there are the material transitions of the components connected in parallel.
...
My main concern for binding posts is that they have sufficient contact area, especially if you have low impedance inefficient speakers. What's the point of 12 gauge speaker cable if the binding post gives the equivalent of 20 gauge contact area?

Most of the power/energy is in the bass, so in speaker crossovers, the fact that tweeters have thin wires doesn't seem to establish much. Under demanding conditions (inefficient low impedance speakers at high volume) you may have 10 amps of current flowing through the speaker wire, but the tweeter probably has a 1 amp fuse and does fine.
 

iMickey503

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I wonder how good ethernet connectors are? (RJ45/8P8C) I know the new standard PoE++ can do 100W DC with just 4 pairs, so ny using 8 of them, you could do 200W/DC.
But since A/C is what Audio deals with, I don't see a problem using these as far as I can tell.

I know Danny sells those Tube connectors, and for sure they make a good connection. But at the same time? You could always just hard wire your speakers if you really want to go nuts with it with a few issues to sealing the box etc unless you are doing open baffle speakers.

Steve Meade got some flack over his magnetic speaker connectors for subwoofer boxes, but I think he was using stainless steel Bolts from Home Depot at one point. I'm not really sure would make a difference at such low frequencies as subwoofers. and I think he did an amp dyno test proving that is well but of course you can't really hear the quality difference is when you're pushing about a thousand Watts through it I guess :)
 

MRC01

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... I think he did an amp dyno test proving that is well but of course you can't really hear the quality difference is when you're pushing about a thousand Watts through it I guess :)
You mean like 746 watts is 1 HP, so we could talk about the horsepower of our amps? :cool:
 
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ctrl

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Most of the power/energy is in the bass, so in speaker crossovers, the fact that tweeters have thin wires doesn't seem to establish much. Under demanding conditions (inefficient low impedance speakers at high volume) you may have 10 amps of current flowing through the speaker wire, but the tweeter probably has a 1 amp fuse and does fine.
I can fully agree with your comment. I just want people not to get the wrong idea and think decent binding posts are something like a "bottleneck" for the sound of a loudspeaker - as some "experts" like to portray it.

What is in the crossover of a woofer from a passive speaker?
At least one or two coils. Their wire diameter is usually between 1-2mm. In parallel with it a capacitor, whose wire diameter is <=1mm.
Rarely, one or more capacitors are in series with the woofer.

For the midrange driver of a loudspeaker, there is in any case a capacitor in series with the midrange driver, again with a wire diameter <=1mm.

In industrially manufactured speakers, the crossover components are located on a "real" circuit board. If it is soldered cleanly, there is maybe 2mm of wire in contact with the solder. Which is made of what material? This is true twice for each component.
 
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ctrl

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If it's done well, it can look like this with the lowest possible internal resistance:
Subwoofer X-Over
Thanks for the "detailed" explanation about the picture. Now this is supposed to show me what?
Even with your subwoofer example, there are transition points with small contact areas.
1633587846208.png


Just as there are these transition points in every crossover - most of them in series with the driver. With solder, whose main component is tin and serves as a "connecting medium".

1633588675078.png


In a typical 2-way loudspeaker, without binding posts and driver connections, there are at least 6-10 such transition points in series to the drivers (all in all there are at least 10-14) before we hear the reproduced sound.

This should be kept in mind when it comes to statements like this one, promising that if two transition points are treated specifically, of at least 10-14, a "pretty significant with a level of clarity across the board" change will occur.
The improvement over typical binding post cups is pretty significant with a level of clarity across the board. Even if you are using some of the highest quality binding posts on the market there is still improvement to be had by going to tube connectors.
Source: https://www.audiocircle.com/index.php?topic=137288.0 (emphasis by me)

Please do not misunderstand, of course you need reasonable binding posts, but you should not expect miracles when you "upgrade" there from reasonable ones.

Update: This "reasonable" view is supported by the measurements from lousy to reasonable binding posts compared to the measurements without binding post - shown in post#1.
 
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pogo

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Even with your subwoofer example, there are transition points with small contact areas.
In this case, the contact areas are not small when you realize the real size of these x-over. By parallel connection of many capacitors (reducing the influence of small connecting wire diameters, if you use only one) and large-area conductor paths on the PCB, one has realized a very small internal resistance. This is something you rarely see nowadays.
Depending on the design, the 'sound' is unintentionally or intentionally lost on the signal path.

By the way, you can make the different damping factors of amplifiers audible with such a subwoofer design. From drone to deep blackness, there is something for every taste. I prefer a higher DF, because my room modes are less excited ;)
 
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