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Different Binding Posts - is it audible?

ctrl

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#1
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:
1600360087907.png


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.
1600360315367.png



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)
1600360661166.png

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.
1600360702390.png

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.
1600360768906.png

BP-Screws: 0.009-0.005 = 0.004 Ohm
1600360806787.png

BP-Nails: 0.01-0.005 = 0.005 Ohm
1600360861976.png

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
1600361129135.png

BP-Clamps: 0.09 - 0.06 = 0.03 Ohm
1600361161896.png

BP-Luster: 0.07 - 0.06 = 0.01 Ohm
1600361185612.png

BP-Screws: 0.07 - 0.06 = 0.01 Ohm
1600361218905.png

BP-Nails: 0.09 - 0.06 = 0.03 Ohm
1600361252186.png

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.
1600361757302.png


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?".

1600371229015.png 1600373612154.png
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.

1600394614291.png


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):

1600395508503.png


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.
 
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tw99

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#2
Some people will still say "Look there's a huge difference in the last graph" while ignoring the scale!
Actually is your experiment even repeatable given the tiny differences, which could possibly be within the bounds of measurement error?
 
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ctrl

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Thread Starter #3
Some people will still say "Look there's a huge difference in the last graph" while ignoring the scale!
Unfortunately, there is no cure for deliberate ignorance ;)

Actually is your experiment even repeatable given the tiny differences, which could possibly be within the bounds of measurement error?
As I said in the first post, the tendency is repeatable, but not the absolute values, because the resistive changes are too tiny, the setup for each measurement takes a relatively long time and there are four contact points per measurement.
The luster terminal always cuts best, the BP with the nails at worst. The other two BPs are in between.
 

Mnyb

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#4
Thakyou again , for bashing in open doors :) ie what should be obvius to all off us but arent , but you go the extra length of proving it .

Ive had rhodium plated spade lugs and expensive wbt conectors et all in my previus life as a card carrying audiophool . I think my audiophile card is revoked nowadays o_O
 
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ctrl

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Thread Starter #5
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.

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


I think the binding post degrades the quality of signal and sound very much because the post is made of one of larger metal in the signal chain. If a speaker cable from an amp is directly connected to speaker's internal wire, the signal will be purer.
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:
yesterday I replaced my binding posts on my rogue audio m150 monos with the highly regarded wbt nextgen copper binding posts and yes there was more detail,but it was also thin and not as harmonic and rich, and not as open sounding as before... well crap. is this another case of [ it needs 256 and a half hours of break in and then it will sound great!] or what?
https://forum.audiogon.com/discussions/binding-post-break-in


This is truly pure audiophile high-end porn:
Product description:
...
The conventional “classic” connectors are almost always made of brass or brass
sheet. They certainly fulfill their tasks, however not precisely enough.

- The massive connector body works unavoidably as a mass storage,
i.e. it creates a kind of “capacitor effect” and
- the greater and heavier the terminal, the greater the eddy current.

Both problems create clearly audible distortions of a non-linear kind and are as is generally known non-correctable. Those who attach great importance to “high-end” will have to deal with solving this problem.
...

The result of the innovative construction is just the ideal connector with considerably audible3 sound improvement: ...
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 ;)
 

Mnyb

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#6
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 ;)
Actually the opposite, you prove than even any armchair scientists could bust this without breaking a sweat.

I could even deduct the result from my EE training without any measurement ;)

But as I myself belonged to the other side for many years , logic does not apply at all . I can not explain my mental state back then.

Minimum of lazy thought that anyone can do “ what could the underlying mechanisms bee if a 3cm rod of very conducting metal has a sound” that should set off a mental alarm that it is perceptive faculties that are the culprit nothing electrical at all.
 

anmpr1

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#7
I want a secure connection. Not so much for 'sound' issues, but simply for system integrity. A locking post (such as the SpeakON) is preferred. Expand-o-matic locking banana plugs are a good choice. Simple screw down spade lugs, or wire through the hole are last on my list.
 
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ctrl

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Thread Starter #8
But as I myself belonged to the other side for many years , logic does not apply at all . I can not explain my mental state back then.
When something is exclusive, expensive and has a "good story" (space research, Nano-XY, Platinum-XY, surface creeping current inductance-free vibration dampers, ...), we usually associate better with it.
This principle is simply transferred to BP, capacitors and resistors. Therefore, a perhaps minimal improvement always turns into a "sound explosion", an extreme sound improvement or something incomparably good sounding. And the more often we are told this or read it in forums, the more credible the story becomes.

I want a secure connection. Not so much for 'sound' issues, but simply for system integrity. A locking post (such as the SpeakON) is preferred. Expand-o-matic locking banana plugs are a good choice. Simple screw down spade lugs, or wire through the hole are last on my list.
I have no problem with that at all. If someone simply finds certain BPs beautiful and buys them because of that, no problem.

However, if something is supposed to lead to considerable sound improvements of loudspeakers, proof must be provided.
 

RayDunzl

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#10
I'm satisfied with the binding posts I have.

On the amps, nice things that can be had tightened and will hold most any size spade:

1600450853122.png


Whip out the 13mm wrench for the speakers:

1600450989261.png


Mine don't have the hole for banana plugs.
 

Hipper

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#11
I want a secure connection. Not so much for 'sound' issues, but simply for system integrity. A locking post (such as the SpeakON) is preferred. Expand-o-matic locking banana plugs are a good choice. Simple screw down spade lugs, or wire through the hole are last on my list.
From what I can gather this thread is about binding posts from the point of view of the speaker maker.

I would be interested in guidance on BP use for the consumer comparing the usual types of connections - spades, bananas, bare wire, bare wire screwed to spades or bananas. As anmpr1 suggests, perhaps this is more about system integrity then sound.

For some reason I've always liked the idea of spades. I too have nuts on my speakers (so enabling tightening with a spanner) but only hand tightening nuts on the amp. I have to check them regularly for tightness.

Also I've always been a bit concerned that positive and negative spades coming loose could electrically connect and lead to to some damage - is that possible? I use a bit of insulation tape to try and prevent them touching.
 

Wombat

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#12
I want a secure connection. Not so much for 'sound' issues, but simply for system integrity. A locking post (such as the SpeakON) is preferred. Expand-o-matic locking banana plugs are a good choice. Simple screw down spade lugs, or wire through the hole are last on my list.
If it puts you at peace. :)

Domestic hifi connections are under almost zero stress, unlike gear that is in harsh environments or regularly connected/disconnected. Your last two options have been used successfully for decades, even in dank/smoky bars and the like.
 
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anmpr1

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#13
If it puts you at peace. :)

Domestic hifi connections are under almost zero stress, unlike gear that is in harsh environments or regularly connected/disconnected. Your last two options have been used successfully for decades, even in dank/smoky bars and the like.
You'd think so. But I've found loose terminals over time. Why? Maybe after a period the hand tightened torque simply loosens. Also, oxidation on bare wires. I don't know if the latter means anything from a signal transfer standpoint.

The worst were the old screw spade lug strips you'd find on tube gear from the '50s and '60s. Trying to get a tight connection with those was always impossible. The first thing I did when mod time came was to change those for binding posts.

The idea of a 'sonic' improvement with different wire/posts is, for me, a stretch. Locking terminations are, however, a big improvement in hi-fi. I attribute that to Mark Levinson. Of course he was talking interconnects, but he was the first man I recall who decided that standard RCA terminals were junk, and had to go--on consumer gear. I think that idea eventually morphed into the now common XLR plugs you see on most gear.

terminal.jpg
 

Hipper

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#14
Another question is contact cleaner/enhancer like Deoxit. Is it really good practice to disconnect, 'clean' and then reconnect every so often - a year perhaps?
 

somebodyelse

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Another question is contact cleaner/enhancer like Deoxit. Is it really good practice to disconnect, 'clean' and then reconnect every so often - a year perhaps?
If you find that necessary there's an argument to be made that you're using the wrong connector for the job. Unfortunately history and fashion have lumbered hifi with a number of less-than-great connectors, so it's a solid maybe.
 

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I was hoping that somewhere someone would know if research had been done on the various aspects of using speaker binding posts. Imagine someone is entering the world of Hi-Fi and wants to know what the best solution is.

The questions I would have are, in regard to the sound (signal transfer) and security:

1. Which connectors/binding posts are best.
2. Do they need regular checks and maintenance, including the likes of using Deoxit.

It's a confusing situation when you look into it. We read about the metal used for the connection (both plated and pure, including smoothness so maximum contact, corrosion and its prevention), security (can it easily come loose, risks of the two terminals touching as I described above for spades). Some claim soldering directly to binding posts is best. It would seem obvious that some sort of pinned type connection (similar to XLR) might be best. Is it?

As an example, I got an amp with some modern apparently well designed binding posts, yet my spade speaker cables could not be attached to them securely no matter how much I tried to tighten them. They could far too easily slip out. The BP were made by CHK and had some plastic sleeves which made it very difficult to connect. I also noticed my spades had dimples on them and that combined with this piece of plastic may have been the cause of the inability to secure the spades properly.
 
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ctrl

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Thread Starter #18
...in regard to the sound (signal transfer) and security
1. Which connectors/binding posts are best.
In terms of sound quality, the binding post material plays practically no role. As my measurements show. Even when using iron nails, whose specific resistance is about five times greater than that of copper, as binding posts no difference should be audible.
The resistance that 0.05m iron nail with 12mm² cross-sectional area represents is simply too low to play a role (should be in the range 10e-4 Ohm).

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.
1600765647210.png

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.

2. Do they need regular checks and maintenance, including the likes of using Deoxit.
Soldered cable ends need no maintenance ;)
With screw connections it is useful to check the screw connection after the first screwing after a certain time (because soldered cable ends deform a little bit).
 

somebodyelse

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#19
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.
I don't think I'd emphasize big in this context - as you've pointed out, 'big enough' is actually quite small. 'Finger tight' is the most you can get with many binding posts, limiting clamping force, so a smaller (but still big enough) contact area has a better chance of a high contact pressure to make a good gas-tight contact. Then again I don't have any research to back up my hypothesis, while you've been doing actual tests ;)
 

AnalogSteph

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#20
I don't think I'd emphasize big in this context - as you've pointed out, 'big enough' is actually quite small. 'Finger tight' is the most you can get with many binding posts, limiting clamping force, so a smaller (but still big enough) contact area has a better chance of a high contact pressure to make a good gas-tight contact. Then again I don't have any research to back up my hypothesis, while you've been doing actual tests ;)
The popularity of crimp connectors demonstrates that you're not the first one to think this way. Also, WAGO clamps easily beat lusters (which, btw, are named like that because they were traditionally used to connect chandeliers and other lighting equipment running on mains voltage - they are definitely not optimized for applications requiring the lowest of contact resistance long-term).
 
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