Eminence Flux Density Modulation

[Steve Conner]

This is an advertorial pure and simple. Mr. Coil is the guy from Fluxtone Speakers, he is here to push his product, so he's not interested in an unbiased technical discussion about it. Of course it's awesome! He sells it! He even produced a happy customer. (Yes, I checked that they have different IP addresses.)

I just want to make sure that is clear, same as those full-page ads in magazines are required to say "Advertisement" somewhere, in case they get mistaken for the equally mindless, biased pap that fills the rest of the magazine. So yes, I am challenging you at a personal level, Mr. Fluxtone.

I think the Fluxtone thing is a perfectly good idea, just overkill for my personal needs. I already know how to make amps that sound perfectly good at a whole range of volumes, using ordinary speakers. And, I have a guitar cabinet with ports, but I must admit they only really do anything when I play bass through it. Really heavy, distorted metal guitar tones have subharmonic content that the ports will boost, and I imagine this is why Randall used to put them on the Warhead stack. But I don't play that kind of stuff so much nowadays. A regular sized tube power amp struggles with it too.

Also, welcome back to the forum KG!

[Mr.coil]

Actually I wadded in here to challenge someone who was going off about how a FluxTone product could not possible work as stated. It turned out that that person was "quoting" someone else. So I apologized to him.

I am not in here to sell my product...but I will defend it's claims.

Sometimes I show little patience for ignorance, and I apologize for that as well.

After meeting with a "Marketing Professional", several years ago, I was told that my product will be hard to market, because it actually works. At first I thought he was full of s...! But slowly I have come to understand what he meant. Everyone is used to being lied to.

MC

[Chuck H]

Well Steve try to understand that this particular forum isn't your average group. As I said before we will often break things down just for the sake of discussion. Most of the claims as to why your system is flawed are based in accurate electronic principals. That doesn't mean your system doesn't work. I've heard the clips and read many reviews and "I" believe that you have refined the concept to the point where any percieved differences are so small as to be ignored. Great job. But the system and what at face value would seem to be obvious flaws is still going to be discussed. It's just what we do. In the end most (like myself) will come out of this with a better understanding of what you do and where the advantages to such a system can benefit the cause of making our amps louder or quieter at will. This is a good thing.

On the other hand any lack of grace on your part is very likely to be met with technical opposition and a "prove it" attitude. This is just as much about debate and win as anything else. It doesn't mean that your product doesn't work. It means you pissed someone off enough to make them say 'here are the technical reasons why your product doesn't work, give me the tecnical reasons why it does'. If you can't provide these technical reasons then the opposition "wins". It still doesn't mean your product doesn't work.

At the very least what you can take from this thread is areas to test to generate figures that disprove nay sayers as well as a good understanding of what kind of opposition and interaction you'll be dealing with elsewhere. Believe me, if you can stand here you can stand anywhere. But it's going to take grace and figures. If you don't have the technical prowess or figures to show why your product works so well then you need to be graceful about it. To stand up defiantly and say 'your all full of it. Just listen and you'll hear that it works.' won't do at that point, because that's no longer the point. It still doesn't mean that your product doesn't work, or even that that anyone here believes it doesn't. It means you've been called on the carpet for whatever your attitude and position in the debate. As you have seen a mis step after that can be pounced on like weakness. There is a lot of discussion here that can potentially help you or at least prepare you. Grace is still very important. As in 'Well I can't say I'm as studied or that I have tested the parameters being argued because the product sounds so good I haven't had to.' That kind of humility takes nothing away from your product and diffuses the argument.

[loudthud]

Doesn't the TS theory dictate that cone excursion is reduced in the octave (or more) above and below the cabinet tuning frequency? Then there is the effect a tuned cabinet has on the impedance vs frequency curve and how it interacts with a tube amp at clipping. It's hard for me to imagine these things don't have an effect on tone. Can anyone describe an experiment to demonstrate the effect or lack thereof ?

Funny story: A well know player in Dallas had a stereo Rivera amp, 120W per side, played through a pair of sealed 4x12 cabinets loaded with EVM12Ls. He actually only owned 7 speakers and borrowed one from is girl friends' monitor cab. She found out about it and had me remove it before the gig without telling him. The sound man, not realizing the speaker was missing, mic'd the hole with the vacant speaker. Nobody noticed! About half way through the set I told the sound man, he moved the mic and told the guitar player that the speaker sounded funny.

[Mr.coil]

Thank you,

MC

[walkman]

Hi Stephen,

You've got that all wrong

He even produced a happy customer. (Yes, I checked that they have different IP addresses.)

JoeM started the topic and i chipped in as i actually have some fluxtones. Ive no association with Mr coil whatsoever

( I don't know of anyone else who has them , but there are more fluxtone models available now then when i got mine so i assume people are buying them; In part i decided to buy mine when i did as I though this might be the sort of think that pops up and then goes out of business before you eventually get around to buying some kit.)

What I wanted to know, was whether the comment that i had read on another forum , had some basis. Mr Fahey kindly responded , though I either misunderstood his answer or he missed my point..... anyway Mr Coil moved away somewhat from the marking vibe and i did appreciate that.

Its been a bit of a bun fight since then regarding ported speaker cabs..... not really on topic but then so what.

I'd be happy to have a fuller understanding of how the fluxtones work , and was a little disappointed myself, at the lack of info and the vibe
but no so off put that i was not willing to give them a try.

Sure this is a place where people will get tested , but also judged as chuck H says on how they conduct themselves.

Walkman

[J M Fahey]

Hi everybody.
Yes, I'm addressing no one in particular, this is a general comment and might be posted here as in any other topic:
If somebody, someday, feels tired/bored/unexcited/pissed with this Forum, I suggest he visits some others, to see what happens in them.
As a free sample, I suggest reading (as much as you can stand it, no obligation whatsoever) some posts from the comments Forum in well known (and that's an understatement) Harmony Central.
Here a guy shows his product, a very well made tube amplifier, "boutique type" but series produced in a small factory.
Amps actually look well made, use "mojo" parts such as Wima capacitors, V30 speakers, show good looking PCBs, clean layout , etc. *but* he is Chinese, doesn't master English , chose "Wang" as the trademark (it means "Powerful General" or something like that in Chinese) *and* showed great sensitivity to (admittedly bad taste) jokes:
Virgin Show Of "Wangs" Amplifier under "BIYANG" brand
Mind you, this is a supposedly "adult" Forum, meaning over-18s ; can't even imagine the same in one chock full of under-18, know-it-all kids, the ones who only watch "Beavis and Butthead" and used to watch "South Park" up to 1 or 2 years ago.

[kg]

Kg .... what makes you an expert besides that you DIY ? ive seen your site , you appear to be a self proclaimed expert. You appear to be shouting or perhaps a little put off by someone with different ideas from yours

the only thing that puts me off is bullshit.

i have NOTHING to say about whether or not flux-tones work, or whether they are worth the investment.

i have EVERYTHING to say about whether or not a ported guitar speaker cabinet is useless, or whether or not an open backed cabinet is actually properly thought of as a poorly aligned vented cab. that's not an "idea" that differs from mine.. it's an idea that differs from the body of established engineering on acoustic physics.

these comments have NOTHING to do with slandering or attacking someone's product or character.

<big snip>

Walkman

the kg of over a decade ago is the same kg. hence the "lifetime member" under my screen name.

as you can see for yourself i found the idea to be intriguing and meritorious back then, as i do now!

however, if people cannot discern the specific points of an argument and rebut them (or accept them), what can i say?

[walkman]

Hi kg,

It was your use of CAPITALS , and aggressive tone, on point that was off topic to the main course of the thread, that made me wonder where your coming from? So please take my directness in questioning your experience in that light. It might be better to start a different post on that topic and present a outline of the terms of that new debate.

walkman

[Mr.coil]

Can anyone shed some light...as to why players prefer the non-vibrato channel on a 18 watt Marshall amp?

[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!

[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

[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 !!!

[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."

[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