Eminence Flux Density Modulation

[wizard333]

Waitaminnut................

Did I see you say that for guitar frequencies, size of cab doesn't matter, just open vs. closed back??

[Mr.coil]

ok

[J M Fahey]

Thanks Steve, it's very kind of you.
Unfortunately we live some 8000 miles from each other, but if I am ever within a 300 mile radius, I'll make a detour and visit the factory.
Good luck.

[Mr.coil]

JM,

If you would like to test one of our speakers, we would be happy to send one out to you for a while.

MC

[J M Fahey]

Hi Steve ... congratulations !!!
Wish you a ton of good luck with this.
I've read it quickly because it's 2:30 AM here, I have to wake up early tomorrow (in 4 or 5 hours) but didn't want to sleep before congratulating you.
Hope all goes smoothly with Mr Kim.
I'll re-read 10 times (no kidding) the claims, because they are the ones which make or break a patent.
I loved the legalese; unfortunately it's needed and then some.
Good luck.

[Mr.coil]

JM,....Let me know if this works.....

1) Go to United States Patent & Trademark Office

2) Then enter the application number in the field provided: 11768484

And from there, the Image File Wrapper tab will have links to particular documents, and in addition, there are other tabs that are self explanatory.

[Mr.coil]

thanks
MC

[kg]

um...

ok.

good luck with your product!

[Mr.coil]

No, actually the tones that FluxTone preserves are the ones created by two magnetic devices strapped together in an unavoidable battle of wills.

As soon as you put a resistor, or any power eating device, in between them you break that bond and the tones are never generated.

The tones that we are talking about are created when the output tubes are asked to make a sign wave larger than they can, this stress is exacerbated in the output "transformer-voice-coil" marriage. The tubes and transformer says "do this", the speaker says "I can not", there are ensuing back EMF's, round and round we go...and wallah! Tone is born, that is to say frequencies are created in that circuit that did not come out of your guitar. Those frequencies will not be born in a amp that has no "tube driven output transformer". And they will not be born until the output stage is clipped, and they will not be born if there is a resister in between the output transformer and the voice coil.

That's why most people say "Well that Master volume control turns down the amp alright, but it killed the tone". That is because those type of attenuators allow for PRE-AMP tube clipping, and the output stage merely re-amps that sound. That is a different tone than an output stage being over-driven.

I am not saying FluxTone is the cure all for everything...90-some% of all players are completely satisfied with pedals and the like...as they should be...they are inexpensive and lightweight! But there are those who can hear the difference and have wanted a solution for quite sometime. When those players finally hear what we have done....They are very grateful.

Thanks
MC

[kg]

Wow, Here is my attempt at Grace:

We are comparing attenuating methods...So all of the following have no effect on the comparisons.

(how do you get around the lack of speaker cone breakup?

"speaker cone breakup" only comes into play when you drive the cone too far...we are limiting the cone movement in all these tests.... Via resistive methods, Eminence methods, FluxTone methods, over driving the pre-amp tube methods, limiting the B+ to the final methods, or re-amping with an inductive load. If part of "your tone" is derived from over-driving the X-max on your speaker....then the only way to attenuate that is a closet with a microphone. What this thread is about is, preserving those tones created by over-driving the output stage of a TUBE amp., while reducing the SPL in the room.

cabinet resonances?tube microphony?the change of amplifier load? i assume you've heard of fletcher-munson...)

All of the above is the same for all other measurements. That is to they are all identical for these tests.



MC

ahh.

so when you mean "no coloring of the tone" you really mean "less coloring of the tone."

i fail to see a substantial difference in weakening the motor strength via physical vs. electrical means. ultimately the only thing that matters is the number of lines of flux traversing the voice coil and the amount of current flowing through that coil. whether you reduce the flux or you reduce the current, the exact same effect can be achieved.

the more i think about it the more i have my doubts that weakening the speaker motor strength necessarily accomplishes a different final tone vs. a well tweaked/custom LCR attenuator. weakening the speaker motor is probably easier to implement with less iterations of testing component values and topology.

i will readily admit the method is "sexier" since it is not commonly used, and will likely enjoy great success as a result.

[Mr.coil]

Wow, Here is my attempt at Grace:

We are comparing attenuating methods...So all of the following have no effect on the comparisons.

(how do you get around the lack of speaker cone breakup?

"speaker cone breakup" only comes into play when you drive the cone too far...we are limiting the cone movement in all these tests.... Via resistive methods, Eminence methods, FluxTone methods, over driving the pre-amp tube methods, limiting the B+ to the final methods, or re-amping with an inductive load. If part of "your tone" is derived from over-driving the X-max on your speaker....then the only way to attenuate that is a closet with a microphone. What this thread is about is, preserving those tones created by over-driving the output stage of a TUBE amp., while reducing the SPL in the room.

cabinet resonances?tube microphony?the change of amplifier load? i assume you've heard of fletcher-munson...)

All of the above is the same for all other measurements. That is to they are all identical for these tests.



MC

[kg]

Remember the "FDM" only has 10dB of usable attenuation, with a "manufacture- admitted" coloring of tone.

well, maybe they're just more honest with their marketing?

Where as the FluxTone system has 25dB of change with no coloring of the tone. So this is not apples and apples....Its more like Beef jerky and Steak...lol

how do you get around the lack of speaker cone breakup? cabinet resonances? tube microphony? the change of amplifier load? i assume you've heard of fletcher-munson...

all of these things beg to differ with claims of "no coloring of the tone."

[J M Fahey]

I can confirm that, from a similar machine.
I build my own speakers, and, of course, have to magnetize them.
The magnetizer is just a *big* electromagnet, similar in principle to the one in field coil speakers, although quite a beast, because it must create 5x or 10x the field needed to magnetize a ceramic, which is made of what's called a "hard magnetic " material for good reason. (The technical name would be "high coercivity")
As a comparison, my "small" one needs 16A@full wave rectified 220V ; and the "large" one 42/45A@rectified three phase 380V. Just do the Math
I can't pull the speaker from the small one until after at least 3 seconds, say 5 sec. to be comfortable; and the large one takes from 5 to 8 seconds.
Fact is, there *is* a time constant, RL; similar to the capacitive one, RC, which is the one we see daily in amplifiers.
So I can confirm that current changes slowly, if there is a magnetic circuit involved.
Well, that's the idea behind filter chokes, and in fact field coils were used as filter chokes in early amplifiers (and radios, etc.)
PS: maybe somebody wonders at the monster power I'm talking about, and finds it a typo, specially when compared to the 15W quoted by Fluxtones and similar power used by old Jensens.
Fact is, they have to produce 10000 to 15000 Gauss in a gap that's 1 to 1.5 mm wide; my magnetizers must cover a 150mm gap (6 inches), which's necessary to charge an already built speaker .
Much larger magnetizers used in big factories, can charge the speaker when already in its cardboard shipping box !!!

[Mr.coil]

Oh hey, I could actually shed some light here...

develop a control circuit that modulates it based on signal strength

This will not work...I tried...Why not you ask....Because of the time it takes to build a field and to let it collapse, with a 15 watt power supply, is about 1.5 seconds (because of all the iron)

We found it would take hundreds if not thousands of watts to magnetize and de-magnetize the core parts at your implied rate. (We have charts and detailed files).

At the shows, people inevitably try to use the "foot-controlled amps" that are FluxTone equipped, as a "waa-waa" pedal, they soon find out why FluxTone is more of a "set it to the needs of the song, verse, or venue" and leave it...than an effect.

Of course you can effect changes that are from 10-20 Db shifts in just .25 seconds...But all the way on-- to all the way off....1.5 seconds.

Remember the "FDM" only has 10dB of usable attenuation, with a "manufacture- admitted" coloring of tone. Where as the FluxTone system has 25dB of change with no coloring of the tone. So this is not apples and apples....Its more like Beef jerky and Steak...lol

Now I am starting to sound like an ad...I do not want to...so I will stop here.

MC

[kg]

you'll find i tend to save my capitals from the beginnings of sentences to sprinkle liberally throughout the rest of the post.



back to the topic then:

does anyone have any technical information on EITHER technology?

fundamentally speaking, altering the magnetic field either by physical means (as the FDM solution seems to be) or by electrical means (as the fluxtone seems to be) will net the same result: reduced motor strength.

now, electrical has the benefit of being easily modulated. in fact one could even go so far as to develop a control circuit that modulates it based on signal strength (ie, compression/sag depending on TC). it also seems to have the benefit of being useful in a closed-cabinet scenario.

the benefit of the physical approach is simplicity and robustness. however one needs to have access to the rear of the magnet assembly, which makes an open backed (or a large diameter port) cabinet a necessity. unless you like screwdriving!