I understand the Math of complex numbers and I understand the Physics of impedance and I can do an AC analysis of an RLC circuit. If I were you, I could show people (if I want to) what I'm talking about and everyone will understand. But it doesn't seem so with your case, Joe? What is going on? Look at Bob, poor him he's so confused. And I'm genuinely confused too in a different way. Tell me honestly, what do you think, how hard it would be for me to understand your theory? I have engineering background with IQ in genius level. Okay, I'm not an EE, but why you cannot have an agreement with the experts here?
My confusion is different with Bob's confusion. The way you express this, Joe, as if there is something 'big' or 'new' or 'hidden' or 'rocket science' or something else behind this that people don't yet understand. And I don't know what I'm missing
Usually I don't care about things like this. I tend to see good things in people but things just didn't add up nicely. I mean, Psychologically
Giving lectures, tours, and talks to the general public, middle school kids through post doc, into faculty and significantly higher, I am used to dealing with dialog the full range of understanding of the topic I teach.
As a result, it is trivial to spot those who think they understand when they don't, yet insist they know more than world leading researchers.
This discussion is no different here.
Everybody seems to be frustrated with Joe, but we've no control on his level of understanding.
I personally decide which erroneous statements to correct of his only if I think it will help others.
Silence is not agreement. Giggles do not go through the keyboard.
Life is too short to try and hold the horse's mouth in the water.
Jn
As a result, it is trivial to spot those who think they understand when they don't, yet insist they know more than world leading researchers.
This discussion is no different here.
Everybody seems to be frustrated with Joe, but we've no control on his level of understanding.
I personally decide which erroneous statements to correct of his only if I think it will help others.
Silence is not agreement. Giggles do not go through the keyboard.
Life is too short to try and hold the horse's mouth in the water.
Jn
Look at Bob, poor him he's so confused. And I'm genuinely confused too in a different way.
No pity please, I’m perfectly content in my confusion......I can discern subtle differences in sound that would leave most of you phoning Oticon.
I learn from y’alls genius head butting sessions
Merriam-Webster defines reactive load as "a load which is carried by an alternating current generating station or system in which the current and voltage are out of phase and which is measured in volt-amperes or kilovolt-amperes". So yes, there is a reactive load, and your question is quite revealing of your unwillingness to abide by terminology used by us commoners.
Abide...or understand.
Voltage driven, reactive current. Current driven, reactive voltage.
Norton, thevenin... Those who learned this understand.
It gets far more interesting when the load iron is driven heavily into saturation, into the 4 to 6 tesla range. As we charge the inductance, the iron loses control of the fields, and the inductance drops by half. When a 70 Henry magnet is running a kilo amp, the caution barriers really creep outward.
Speakers do this as well, but both as a consequence of total flux and position/velocity modulation. Something no network can fix.
Ah, ps. Thinking that the force equation is the bomb is foolhardy. B is dependent on current, velocity and position...L is dependent on position, current, and velocity.
Jn
Last edited:
Thanks Dan,
Took a couple measurements with and without the Boucherot and what’s happening I believe is the hp lowered by just enough to put me back in the spike I had @ 1800hz and also it’s as if there’s a lp pass @ around 16khz. Which lowers fr incrementally all the way down to 8khz, At least that’s what the fr shows. Which all coincides with subjective observation.
I’m still gonna play around with it but I think it might fall under my ‘less is more’ philosophy.
Doesn’t phase distortion from the speakers and xo ultimately affect the current phase? Isn’t that what joes trying to alleviate?
Did you notice what they are saying: Now something is reactive when there is no current? I must have entered Lah-Lah land.
The point is actually simple enough, the amp can only control the voltage, it cannot control the current. This is beyond debate. The driver is a current device. Despite showing measurements earlier, which they completely ignored, showed conclusively the acoustic output of the driver is directly related to the current in the voice coil. This is beyond debate - it is proof. Does proof not matter to them?
If we put a current sense resistor in series, like 0R1 value, then ideally the voltage across the current sense resistor should mimic the voltage of the amplifier. If they are not identical, then which of the two does the driver reproduce. This is a serious question. That earlier measurement showed absolutely conclusively that it is the current.
What if there is more distortion on the current that is not on the voltage side, then you have to ask, what is causing it. I will tell you, measurements have been done confirming this: More distortion on the current side compared to the voltage side.
I have played this scenario to many people and many times and it is not rocket science to figure out. The Re of the driver, that is definitely not reactive, this is beyond debate. Also the current going through Re does not modify the current of the amplifier. We usually have an Re of 6 Ohm (8 Ohm driver), but what we observed is that at any other frequency other than DC, the impedance is always above 6R and hence we have to examine what causes the impedance to go up in value.
It is caused by back-EMF, across most of the bandwidth of the driver, it is inductive back-EMF. At LF peak it is motional back-EMF. The driver cone pushes against obstructions of the driver's own construction, all kinds of reflections. Even neighboring drivers covering the same frequencies, all cause these to make the driver into a messy microphone. Hence we have microphonic back-EMF.
They all have one thing in common, all three are voltage sources and cause the amplifier's current to deviate in multiple ways, and of course the current phase angle too, this too is not in sync with the voltage of the amplifier.
The inductive back-EMF is basically explained by Faraday's Law of Induction. If you have microphonic disturbance, then the back-EMF becomes modulated, if a driver has a bad resonance at a particular frequency, then that will definitely disturb the back-EMF.
The result is that the various distortions of the driver will modify/modulate the current of the amplifier. But this is only the start because the driver reproduces the current, there is now this very disturbing thought: How many times does it distort the current of the amplifier, because we have a mechanism that interacts, it constantly feeds back on itself and describes an ongoing event. So we get current that is smeared out and it needs to be looked at more closely by people who take notice and are more clever than I am.
Pavel (PMA) on his website has shown that there is a reduction in current distortion when in current drive versus voltage drive. Under current drive the current phase angle is zero degrees, the back-EMF impedance now only produces voltage and cannot affect the current.
This is why Esa (ETM) who joined in earlier, is promoting current drive. This is the 'feedback' mechanism I believe he was describing, literally "feeding backward and forwards" and a circulating current that affects what the driver does. If only the driver could see what the voltage of the amplifier does, and no problem. Alas, this is not how it is.
Now the usual suspects will come out, make no attempt to even try to understand the above. They will complain about my 'language' and I think that i not valid as plenty of others understand 'plain speak' English.
But no matter.
Last edited:
When you have worked out the difference between a driver on the bench and in a box come back and just maybe the conversation can continue. Otherwise you are starting off yet again in completely the wrong direction.
Yes. It is helpless, here, as protagonists of "open mind ideas" have no knowledge of electrical circuits theory, do not design and build electronics circuits (amplifiers) and do not provide measurements to support their fabricated pseudo-theories. In such case, discussion is impossible and explanations are useless. There is not time enough to spend it in circles of absurd nonsensical debates.
The only effect of the equalizing Zobel is higher level of distortion, though "flatter" with frequency, as I have shown and others have explained.
Who stated that?
This it totally bogus.
A driver will attempt to make it's emf identical to the voltage that is being forced upon it. As such, it can be considered a voltage driven device.
When the speaker is massless and in a vacuum, it will produce the exact voltage on it's terminal as what the amp provides, and there will be no current drawn.
When mass and losses are included...
The emf of the driver will be lowered as it is lagging. As the difference increases, the resistive aspect of the wire, the conversion efficiency, eddy dragging, inductance shift, will all work with the voltage difference such that the current attempts to zero the difference.
The force on the cone is a result of current, but it is easily considered a voltage device. The current drawn is what the device wants in order to try and keep up with the driving voltage.
Class dismissed.
jn
ps. It is sometimes difficult to bring down the level of explanation to that which you may understand, but it is good for me as when I deal with the public, it pays to understand how little they know about what I speak of and figure out how to explain. So I am not wasting my time here.
Last edited:
I could be cute and say something along 'maybe they are not the experts they think they are.'
I have been paying around speakers for 51 years and my Dad before that. My Dad was with Philips in Europe in the 50's and was one of the pioneers of TV with Danish Broadcasting (DR) in 1956b when they started up. He was an EE and recording engineer and in acoustics field too. He also made a number of movies as recording engineer - this was done with a Uher Reporter 4000 portable tape recorder:
"Hamlet at Elsinore" with Christopher Plummer, Michael Caine Donald Sutherland... etc.
YouTube
I have had *real world* experience in audio all my life. I have 'expertise' and experience that many here just don't have. Sorry, but Terry Demol even stated that about me right here about two weeks ago.
So being able to quote EE textbooks verbatim is not me, that is not the milieu I was brought up in. It is very different from theirs and my Masters (clients on a personal level, recording studios and government departments) are the only ones I please. I am also on first name basis with some of the best speaker designers in the world. And they listen because I challenge them and they like it.
What is an expert? Somebody who has made every mistake there is to make in a narrow field of expertise.
I don't mind making mistakes because I just don't have the ego to match those who are here. But I got where I am by just giving things a go, at times asking uncomfortable questions.
Usually I don't care about things like this. I tend to see good things in people but things just didn't add up nicely. I mean, Psychologically
I have actually said pretty much those same words on this threat, maybe less than a week ago. Yep, I agree with that. I have lots of friends and I have a generous nature, I wouldn't be typing this in public if it was not true. It is!
But thanks for the tone, yours is different from the others.
Cheers, Joe
PS: Did you know I was even discouraged to talk about speakers here, I was told this was about amplifiers. Does that not make you wonder how much experience they have with speakers? It's easy to design a speaker, it is damn hard to design a speaker that actually sounds better than just 'good' which is to say average. Oh, my EQ is OK too.
Last edited:
- Status
- Not open for further replies.