You are correct, L will be a function of velocity. Nice work.
Jn
Ps more specifically, L is a function of rate of change of flux when exclusion occurs.
Jn
Ps more specifically, L is a function of rate of change of flux when exclusion occurs.
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Are you telling me I have been trying to do this for a year if not longer and have finally succeeded?
No, I am not telling you that you have been trying for a year if not longer... 😀
That long? Guess I've been out of the loop for a while.
A model is only good if it can predict. I've been detailing the tests I do and plan, fundamental tests eliminating as many confounders as possible. With luck, perhaps everybody here can chip in on what tests and setups are useful to try. Detailing design and setup so that you could try your model would be a good thing.
I've been spending my exercise time working out a magnetic design to level inductance without the dissipation of a shorting ring, as well as enhancing BL linearity. Getting the magnetics to cleanly run well above 20khz is a no brainer, the former two issues require elegance.
I was thinking also about tailoring BL(x) to counter suspension compliance, but quickly realized that as a huge mistake.
Jn
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Thank you, John.
It is very effective, too. Especially, for bass. Maybe JN will find a way to lower distortion over all.
-Richard
I actually tried to model it the first time you mentioned it in one of the Blowtorch threads which was probably several years ago.
The problem is the current version doesn't pass conservation of energy. Something about the way I'm modulating L (as in F=BLi where L is length) causes it to go overunity.
Don't forget that any mechanisms currently used (on purpose or not) to lower inductance, also dissipate energy. Pole tips. faceplate, shorting ring. I don't think we're into vc wire proximity effects yet.
Honestly, I am still amazed that nobody has thought to put an EDM slit in the faceplate from gap to outer edge..duh.single turn short??
That's probably patentable..😎
Jn
talk to mfr of speakers or of the parts and get NDA and a royalty fee agreement. cash out is good too. 🙂
-RNM
Use a driver with a properly designed motor.
All Acoustic Elegance drivers 12" and above do 50Hz at 100dB with less than 1% distortion, sometimes a lot less. They also do multi tone IMD at levels better than many amplifiers. Proper motor design. The owner of AE used to contribute here at DIYA and was a very knowledgeable and helpful guy.
I haven't got time to dig through them but there are a variety of dist measurements here.
Driver Measurements - drivervault
Go to 12" and 15" section, note in particular AE 12" and 15" IMD measurements.
Pretty darn good.
T
For typical economical speakers the front plate is typically riveted to the basket, and the rest of the magnet assy glued to the front plate. It does not take genius to understand that reducing the glue bonding area is prone to failure. You could remove the magnet assy and slice the front plate to gauge if there is useful advantage in segmented front plate but production version would require significant redesign.
JC did not insult you or your work, however you repeatedly go out of your way to insult and denigrate him. "nobody knows anything but me" schtick ???......this is exactly how you are writing yourself up and repeatedly so, perhaps all those magnetic fields are effecting your thought processes. JN perhaps you ought to proof read your submissions and edit out the self ego content before posting, this would help to make this thread a better discussion forum.
BS, you made no offer except to meet.
JN, we are all for your researches, but keep your comments to the subject at hand and not about yourself or others please.
Dan.
Unfortunately while the addition of the current sense resistor helps acoustic distortion, it has a side effect of slight increase on THD of the amp which most probably deters acceptance by amp designers. Does not help conventional marketing strategy.
WRT single turn short of face plate, yes, this works for you not against. I depends whether VC is under hung or over hung. AE drivers offer *additional face plate slugs of aluminium (apollo upgrade) where you propose to put the slit, to*reduce distortion even further.
Maybe you could speak to AE's owner WRT this. I'm sure they have measurements with / without Apollo upgrade. WRT EDM slit, be it wire cutting or spark eroding, too slow for any production process that needs to be cheap. Even water jetting would be quicker.
T
This is not "my" issue but room modes and reflections issue encountered by anyone with audio system in a room. DRC and Rephase allow for reducing peaks of FR at just one specific point of the room. Filling of holes of the FR is impossible due to added unwanted Q/resonances. Equalization alone, made by equalizer, does not help to solve room modes issue and rather worsens the situation. However, though DRC + Rephase help to improve FR, they do not help in distortion measurements. I assume you know this well - or - do you have your own set of measurements to publish that would show the opposite?
What has deterred is they dont know about it. With appropriate amp design the change is imperceptibly small. Barely move the needle. But the speaker distortion has been lowered is so much greater affect that cannot be missed in listening as cleaner and more accurate sound. .
-RNM
That is good to know. At what cost? I was commenting on the data just shown from a measured driver. One which cost $200 USD. Another low distortion well designed speaker for bass is used in the JBL M2 speakers -- the ones I own. However, the tests for the AE drivers are up close and low power. It is small signal distortion. The JBL are low distortion at high power inputs as well
If there is a way that average person and what they can afford can get better sound thru cost effective but better driver design and/or a simple amp mod, then there is where the money is at.
THx-RNMarsh
You confuse cause and effect. And you ignore history.
Jn
Water jet is perfect, or even just a saw blade. I was thinking minimal kerf, but really, it doesn't have to be .004 inches wide. What is a reasonable water jet kerf?
Everybody has been concentrating on how to fiix inductance issues using dissipative mechanisms.
Shorting rings, especially around the pole piece, have time constants determined by it's intrinsic L and R, which determine the break frequency. Above that freq, it does reduce VC L but increases effective VC R.
Note: most people are happy using the ring as an inductor when invoking Faraday's law of induction to create ring emf, but then consider the ring as a resistor carrying the resultant current. However, induction is a two way street, the emf is driving an inductive ring. Below break, nothing much happens, above there is bucking flux.
Fixing the magnetics is a more subtle thing. I was thinking that AE is trying to fight current climb as the L lowers in forward motion by increasing braking drag. My breakfast coffee guess.
Jn
An NDA on something that was posted on a forum visited by people on every continent is probably a moot point.
Jn
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