The Black Hole......

At what Frequency?

I guess that we all know that
Ohms law is not
V=I*R
But: U=I*Z
Where Z=R+X and Xl=jwL and Xc=1/jwC

I guess that everybody here knows what "w" and "j" are as well.

Stein

Ohm law is none of the above. Ohm law is a "material law" and is not part of the fundamental Maxwell equations; it's J=Sigma*E and degenerates to the common simplified electro kinetic law I=U/R if and only if a) J vector is collinear to the E vector, b) Sigma=1/R=S/(Ro*L) (a scalar) and c) E=-grad(V)= DeltaV (1-Dimensional potential), so all together J=DeltaV/(S*(Ro*L)) or I=DeltaV/R, otherwise said the current is the ratio between the voltage drop and the resistance.

An even more general Ohm law is J=Sigma*(E+VxB) where all J, E, V (speed) and B are vectors and x is the common vector product. VxB is the Lorentz force, which is zero in a frame referential at rest. This Ohm law formal definition appears as natural, after reducing the magnetic field to an electric field in a moving frame, per the Maxwell electrodynamics model.

Nitpicking after a couple of Belgian Trippel beers, sorry 🙂. As I said, leave Ohm out of this stupid thread.
 
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Seems he took a stable amplifier output current to mean stable current through the driver which can no longer be true once a parallel equalizing network is in place. Seems funny he so much wants to belong to a current-drive crowd considering all the problems associated with it.

Please!

I DO NOT BELONG TO THE CURRENT-DRIVE MOB!

That proves you are not listening to what I am saying, please. I thought I had made it very clear that I don't want the problems of current-drive (how LOUD! do I have to holler this?)

Basically I am talking about fixing the problems of voltage sources.

Actually, there is no such thing as voltage-drive because the Re of the driver prevents it (but 'current-drive' is a technically proper phrase). But they are still voltage sources even if they can't achieve voltage-drive. They cannot control the current, only the voltage.

The more recent research tells us that leads to problems using voltage sources because it cannot directly control the current that flows through the voice coil. If the current deviates under load due to the driver, that becomes distortion. The distortion of the driver is now compounded by distortion from the amplifier even if this is -80dB (0.01%) seventh harmonic showing up in the critical midband where it is not masked. The fundamental might be around 300 Hertz, but the problems show up around 2KHz. Any cone displacement away from its centre rest position and it has to reproduce 2KHz along with low notes, the characteristics of the current of the amplifier has changed. Very small amounts of distortion can ruin the sound in a negative way. This is where the Purifi drivers excel:

994171d1635731341-black-hole-purifi-inductance-gif


This is a remarkable achievement and this result will give you lower distortion of current-drive when using a voltage source.

THAT is what I am talking about!

So figure out WHY those distortions are suppressed by current-drive and then find ways to get that current distortion suppressed when using voltage sources.

Cheers, Joe
 
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Ohm law
Nitpicking after a couple of Belgian Trippel beers, sorry 🙂. As I said, leave Ohm out of this stupid thread.

That is perfectly ok, enjoy your beer.

Belgian tripple beer is one of my favorite beers.
If you visit the "old town" in Brussels there are an endles number of resturants/pubs that has a huge beer menue and all the different beers has their own type of glass.

When it comes to Ohms law, it was not me that introduced it in this thread. I simply told the person that he could not use a simlified version only meant for DC.
What I have put up is exactly Ohms law.
If you follow what I'm writing and put in "j" and "w", I think that we agree.

Stein
 
First it was the word 'fix' and that word got weaponised by Bill.

The word 'fix' means 'a solution' and Bill is the only one allowed to use it? This is ridiculous.

Now it it the word 'mob' and what does that mean? It's another word for 'crowd' and now the rabble wants to weaponise that as well.

Boys, grow up!

.
 
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I think the others should jump into a lake and cool off. I am just fine! Life's better now than it has been for a long time. There are people here who have egos much bigger than I will ever have and I thank God for that!

You are not fixin’ a damn thing. You are only exposing your ignorance in the very basic electricity, at what used to be high school level.

You want an education, watch this video and tell me that you understand it, then be honest and come back here and answer truthfully just how much you did, and then I might take you seriously - here is a chance to get an education:

LIVE! with PURIFI Co-Founder Lars Risbo! - YouTube

Are you humbled now?

I was!!!

.
 
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I don't want the problems of current-drive
Your solution has merit with no relation to current drive. Your continual mention of current drive associates your solution to the problems.
... a similar condition to current drive, where the benefit is stable current = stable force...
That is why I said that the statement quoted above is wrong. Condition of current through the driver with a parallel equalizing network is not similar to current drive.
I am sorry you don't seem to understand how this works.
Seems you know how your solution works but chose your words very poorly to form a coherent explanation regular down to earth people can grasp.
 
So what happens when you take an ordinary driver and simply arrange for it to not have any excursion - or at least an amount that would take a micrometer to measure? Cross over before the frequency that demands excursion to another unit.

So most listeners arent graced with the latitude of using 18" drivers; a much smaller unit is necessary and that means multiple mm of excursion; like 15, vs 2...

Most amplifiers are two channel. Same idea; most arent having the latitude of separate amp outputs for each driver- where current modulations of the amplifier signal by the speaker are isolated between high and low drivers.

If the hf driver doesnt move much and the lf driver doesnt move much - and the two are on isolated voltage sources - is this a way of paring down the issue? As impractical as it is?

So what's going on with HiZ drive for the case when the driver cone isnt really displacing at all? "But we need to sell speakers where the cone displaces a lot on the low frequencies" Yes, I know that and I know why - just curious about this other, albeit fringe condition.
 
Your solution has merit with no relation to current drive. Your continual mention of current drive associates your solution to the problems.

That is why I said that the statement quoted above is wrong. Condition of current through the driver with a parallel equalizing network is not similar to current drive.

Seems you know how your solution works but chose your words very poorly to form a coherent explanation regular down to earth people can grasp.

Now we are down to semantics. Sigh.

No, I have no interest in current-drive and any nuanced thinking is getting over some people's heads either because that is their limit and others because they choose to. There are plenty of people who understand it and they now outnumber any who is here!

Do you believe that if a driver responds on the current side and cause the amplifier to deviate, that this is a problem? Current-drive to me is a mere thought experiment because that cannot happen with a current source because the amplifier controls the current, in effect at any moment in time, the current source is a current regulator.

Follow?

If you do, then you should also be able to fill in the rest. I certainly don't consider you an idiot and I know you should be able to.

OK?

I am trying to sound friendly.
 
Joe,
Let me try to give you my 2 penny advice in order to stop those endless series of postings, leading to nothing but turning in vicious or in this case porous circles.

This is how the drill should work:
1: Formulate the problem(s) you see with existing solutions and how you think you can improve on that.
2: Create models of both versions, as is and modified.
3: Build a real life test setup for both models to verify that your theory holds
4: Publish in detail the measured test results for both versions when goal(s) achieved.
5: Try to formulate the impact and the general applicability of your findings.

That's it, that may prevent you from sending people into the water for cooling down, calling them wolves or whatever else irrational and irritated behaviour.
Looking forward to it.

Hans
 
So what happens when you take an ordinary driver and simply arrange for it to not have any excursion - or at least an amount that would take a micrometer to measure? Cross over before the frequency that demands excursion to another unit.

No motion, no sound. No excursion, no bass. Most designs are 2-Way and they are the worst in this respect. This is where a 3-Way should have an advantage, but basically, you get the point, more so than others here, but then again they are not even trying. They can't even get their hands on a pair of 8 Ohm resistors and do the simplest experiment that anybody has ever done.