"Except that it is not 'impedance' compensation" should have read been read ""Except that it is not about 'impedance' compensation".
But then again, the context had already made that clear.
Nobody is saying this is not impedance compensation. But the "gotcha" tactics are not about science either.
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But then again, the context had already made that clear.
Nobody is saying this is not impedance compensation. But the "gotcha" tactics are not about science either.
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It would be interesting to see measurements of the current and voltage at the voice coil compared to the amplifier terminals with and without the impedance compensation.
The above remains all wrong, the current equalized is that going into the "box" which includes the shunt networks where of course a good deal of the current goes.
True, but...
Thinking about current control would induce re-thinking completely Xovers: these are defined to share incoming voltage to 2 or more "ways" (according frequency spans) working in parallel== no influence of one way onto what others "see".
One couldn't keep the ways working in parallel paths if the loudspeaker is current-fed.
The "ways" must therefore work series-wired, OR bi/tri-amping would be necessary.
This is simply based on the fact that we couldn't get each speaker way keeping a constant impedance throughout the whole frequency range, SO there will be cross-coupling between the ways IF a voltage-designed Xover is current-fed.
That is just part of a much larger picture. For example, with the driver used in the Elsinores, connected directly to the amplifier, has a 5mm gap and the total length of VC 16mm. In Xmax terms that is 6.5mm and max linear travel is 11mm peak-to-peak. But do the maths, the whole of the current is seen by the total length of VC, but only 31.3% of the voltage is seen by the part of the VC that is in the gap. That means, if the VC has an Re of near 6 Ohm, then if it was a single layer, the amplifier would see 2R resistance before the gap. But since it is two-layer (VC has to go in and then out, so the number of layers will always be an even number), then it is about 1R DC resistance before it gets to the gap.
Most the the VC inductance is inside the gap, very little outside it. The BL factor is only inside the gap. That means that near 69% of the DC resistance of the VC is outside the gap.
That scenario makes the idea that an amplifier is acting as a voltage source questionable. The first thing the amplifier sees is a chunk of DC resistance - hidden in plain sight!
Can you see that?
What I am trying to illustrate is that there is a much bigger picture going on, and that it is finally getting some attention. The amplifier may well be a voltage source, but when connected to an overhung VC it is not acting as a voltage source in the sense that popular folklore presents it. The overhung VC shows that something else is hiding in plain sight.
The undehung VC is different? Actually it isn't, it is just the underhung VC makes it so damn obvious. In fact the amplifier sees the total resistance and not part of it. It's just that it is a little bit harder to explain with underhang VC.
I hope you make the mental effort, please, to take the above in and make some sense of it. This is about getting the science right.
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Could you show us measurements of that too, please. I'm not sure I understand how it makes a difference whether the resistance is in the gap, just outside the gap or through an actual resistor connected to the speaker.
What measurement is that?
That in the driver I mentioned that only 31.3% of the voltage of the amplifier appears inside the gap? That is not a measurement, that is a basic calculation.
BINGO!
But read my post again because you haven't quite understood it.
It doesn't matter whether Re is in the gap or not, I thought I made that clear already.
The simple point I was making is that there is a fake claim out there being repeated over and over again. There is no such a thing as "voltage drive."
It's just not obvious unless you examine what an overhung VC really is, that it shows in 'plain sight' that the first thing the amplifier sees in a chunk of resistance before it gets to the gap. It acts like a wire-wound-resistor.
But as I said, these facts are only presented so as to debunk "voltage-drive" with any speaker, whether or not the Re is in the gap at all.
So that leaves the current of the amplifier as the only force that causes sound. Force = BLi.
Ergo, we are listening to the current of the amplifier, not its voltage!
I was making a point, so did you get it. Other intelligent people I have pointed this out to, did in fact get it.
As for the other matter...
Asking for measurements? Very reluctant to do so based on previous experience. I need to make the case on a subject that is so wide-ranging that tit-for-tat ego driven online discussions makes it impossible to find a rational way forward.
So I am using the traditional method, writing it all out, and with LOTS of measurements, then get it peer reviewed, then the physics will be checked by actual working scientists with an interest in loudspeakers, one of them was a designer with a major loudspeaker company. Both are physicists. If it does not pass, then nobody will see it and that will be it. OTOH, I am quite confident that it will work out, and if corrections are needed, the will be made. This will be all about the science!
PS: There is such a thing as "voltage-drive" when it comes to electrostatic loudspeakers. I have to state this or somebody will say "you forgot about electrostatic speakers" and no I did not. I am wisening up, the tit-for-tat exponents are everywhere!
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I don't feel there's anything to be gained by questioning my intelligence. Why would you do that?Joe Rasmussen said:
The fact remains that current does not work this way. It does not encounter one thing at a time.
It's the current flowing through the voice coil that makes it move. That's why I'd like to see a measurement at the voice coil, you've shown it at the amplifier but it's not the same, unless you drive the speaker directly.
Sigh. You took me out of context, such a thing was not meant to be implied.
Once again, you simply missed the point. Others have gotten the point, but that was part of a conversation, but clearly I am failing to do it in this medium.
Maybe if you read my original post again, you might see it? I am not questioning anybody's intelligence, OK?
Yes, I know that "current does not work this way" and did not say it did.
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"Ergo, we are listening to the current of the amplifier, not its voltage!"
Does anybody read my posts?
I am not dissatisfied by what people might say about my posts, but I am dissatisfied by the fact that nobody even tries to understand them.
So, either somebody makes a comment on them that makes sense, or don't expect a response from me. OK?
So let us take a break here, unless that comment is forthcoming. I am not asking for much.
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"Ergo, we are listening to the current of the amplifier, not its voltage!"
Does anybody read my posts?
I am not dissatisfied by what people might say about my posts, but I am dissatisfied by the fact that nobody even tries to understand them.
So, either somebody makes a comment on them that makes sense, or don't expect a response from me. OK?
So let us take a break here, unless that comment is forthcoming. I am not asking for much.
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Perhaps you could be more clear. I understand that your speakers present a benign load to almost any amplifier due to the impedance compensation. That is a good idea. Can you explain how the impedance compensation controls the current through the voice coil?
For sure!
Joe, your posts are clear and the fact that the sound we hear is produced by the current flowing into the VC -and only that- (no voltage stories here) has been said, explained and agreed a number of times already by several different people, was it just considering this thread...
IMO you should join to your explanations a picture of how the gap, VC and (moreover!) the magnetic field is oriented inside the gap.
from this, what you mean would become enlighted.
One thing though:
I didn't open any speaker during the last 40 years or so, but in my mind, the VC should be immersed into the gap, NOT extending outside of it on any side...unless the manufacturer is aiming at something else I'm not aware of.😕