replace a permanent magnet with a field coil and changes little in most cases worsens the flow.
to have advantages over permanent magnets must do it in order to saturate the core and this is not copying the driver gets some western electric.
transform the field coil woofer without using hbc or modifying the core (material, shape, length) is useless if no one can say is a field coil.
post screens of flowcharts, designs or characteristics of the cores of the solenoids would regurgitate the various vendors smears field coil.
everything is already written for 50 years and everything is available online.
to have advantages over permanent magnets must do it in order to saturate the core and this is not copying the driver gets some western electric.
transform the field coil woofer without using hbc or modifying the core (material, shape, length) is useless if no one can say is a field coil.
post screens of flowcharts, designs or characteristics of the cores of the solenoids would regurgitate the various vendors smears field coil.
everything is already written for 50 years and everything is available online.
Hi David,
I agree with you, you touched a "dangerous" subject.
I reply in a simple way: to my ears field coil sounds better. With identical flux in the gap.
Why? I don't know, I can do assumptions. But I don't think we can find many objectives.
But I repeat that to my ears it works very well. As already told here, the power supply is very very critical! This could be the bottlenek.
A "standard" magnet is more practical.
When I studied electronic engineering I did learn that we have to look at the real world and then we can try to understand how it works, not the opposite.
All the best
Fabio
I agree with you, you touched a "dangerous" subject.
I reply in a simple way: to my ears field coil sounds better. With identical flux in the gap.
Why? I don't know, I can do assumptions. But I don't think we can find many objectives.
But I repeat that to my ears it works very well. As already told here, the power supply is very very critical! This could be the bottlenek.
A "standard" magnet is more practical.
When I studied electronic engineering I did learn that we have to look at the real world and then we can try to understand how it works, not the opposite.
All the best
Fabio
At voice coil gap, flux density can be same (to some point) for ceramic magnet, Alnico, Rare earth or field coil.
Magnetic circuit material can be inexpensive iron, high purity iron, or exotic material, permendur.
We can set to same flux density with different combination at “static” condition. However, they produce VERY different sound at dynamic condition.
As for Feastrex drivers, NF5ex (field coil) has far better three dimensional image and ambience than NF5 (alnoco). This is similar to the difference between transformer core material.
Cheers,
Kenji
Magnetic circuit material can be inexpensive iron, high purity iron, or exotic material, permendur.
We can set to same flux density with different combination at “static” condition. However, they produce VERY different sound at dynamic condition.
As for Feastrex drivers, NF5ex (field coil) has far better three dimensional image and ambience than NF5 (alnoco). This is similar to the difference between transformer core material.
Cheers,
Kenji
No, audiofilofine, you leave because you are using a wrong language with wrong behaviour.
I'm not a seller of such devices. I'm not a modifiers of "stereo bebbons". I don't sell trinkets.
This is another mistake from your side.
Your behaviour is a perfect example of italian blogs/forums, so it's clear why I don't read them anymore.
Has anyone interesting links on such modifications? I mean from magnet to field coils.
Fabio
I'm not a seller of such devices. I'm not a modifiers of "stereo bebbons". I don't sell trinkets.
This is another mistake from your side.
Your behaviour is a perfect example of italian blogs/forums, so it's clear why I don't read them anymore.
Has anyone interesting links on such modifications? I mean from magnet to field coils.
Fabio
As I wrote, this is not clear to me. I can try to give you answers, but I have no evidence, just clues. I simply say that for the same flux in the gap the sound is different. And it's enough for most...
I know a manufacturer (C.A.R horns) who started to make FC drivers using available donors and custom parts and was earlier using TAD drivers almost exlusively. I didn't like his TAD versions , because they were little too aggresive. Field coils are opposite, too soft. I know Shindo does Altec conversion but I read that it's not a simple magnet system swap and the resulting drivers sound nothing like the originals. And ,like with everything Shindo it's all very secret
We can get much better permeability with Field coil magnetic circuit.
Other beauty for multi speaker system (2 way, 3 way etc):
We can make woofer faster by increasing voltage and tweeter slower by reducing voltage. For example, by increasing voltage fieldcoiled-515, you can make it like GOTO alnico drivers, or standard altec 515E by reducing voltage.
Other beauty for multi speaker system (2 way, 3 way etc):
We can make woofer faster by increasing voltage and tweeter slower by reducing voltage. For example, by increasing voltage fieldcoiled-515, you can make it like GOTO alnico drivers, or standard altec 515E by reducing voltage.
The difference between the different magnetic materials and FC is in the shape of the BL curves... other than that, flux is flux.
The other variables include the possible difference in the pole structures that carry the flux to the gap. Also when converting an existing driver to FC, there is going to be some change in the air volume and physical layout inside the driver for a compression driver or large alnico magnet cone driver, or the obvious addition to the rear of a driver for a ferrite or neo type motor assembly.
And, of course, when you change the juice going to the FC itself you can alter both the sensitivity and also the Qe quite a bit...
As far as winding a FC, well it is a basic electromagnet. The same equations apply as well the same techniques. Fat wire for low voltage high current, thin wire for high voltage low current...
The only other factor could be the number of paralleled coils in the coil pack and the way that the winding is done physically...
But of course I have never made a FC myself...
Maybe I should?
Hmmm... adds another line to the already long list.
_-_-bear
The other variables include the possible difference in the pole structures that carry the flux to the gap. Also when converting an existing driver to FC, there is going to be some change in the air volume and physical layout inside the driver for a compression driver or large alnico magnet cone driver, or the obvious addition to the rear of a driver for a ferrite or neo type motor assembly.
And, of course, when you change the juice going to the FC itself you can alter both the sensitivity and also the Qe quite a bit...
As far as winding a FC, well it is a basic electromagnet. The same equations apply as well the same techniques. Fat wire for low voltage high current, thin wire for high voltage low current...
The only other factor could be the number of paralleled coils in the coil pack and the way that the winding is done physically...
But of course I have never made a FC myself...
Maybe I should?
Hmmm... adds another line to the already long list.
_-_-bear
Last edited:
Let me repeat that with identical flux (measured) and iron (not special exotic materials) FC sounds better.
For example, a 515 has much better mid frequency, and of course a richer bass response (more harmonics). Tha better mid is the key, to me.
Fabio
Why of course? Not that abvious. Many people don't think so (they never tried).
I continue to read that flux is flux...
What do you mean with that? Maybe I did not understand...
Fabio
Sorry if my sarcasm was to subtle. I really don't believe that field coils are special at all and would expect you to take some steps to prove it rather than mearly offer "I heard it".
If you have two structures where they both have the same total flux in the gap, both have the same fringing flux (not the case where the amount of iron saturation is different) and both have equally solid operating points (free from being driven around by an applied AC voice coil signal), then I think you will have a very hard time convincing a person who understands magnetics that one will "sound" different than the other.
We live in an age in this hobby where everybody claims to hear "dramatic" differences between units with the most trivial technical differences. There also is great nostalgia for any obsolete technology (tubes, LPs, mono, old horns, open back, etc (and I myself enjoy LPs and tubes)), so it is no wonder that we will now add field coils to the list of things that were better than what they make today.
What does that say about all those stupid engineers that abandoned field coils in the 40's and 50's as soon as Alnico 5 came along?
It is not enough to assert that something sounds better. Prove it.
David
If you have two structures where they both have the same total flux in the gap, both have the same fringing flux (not the case where the amount of iron saturation is different) and both have equally solid operating points (free from being driven around by an applied AC voice coil signal), then I think you will have a very hard time convincing a person who understands magnetics that one will "sound" different than the other.
We live in an age in this hobby where everybody claims to hear "dramatic" differences between units with the most trivial technical differences. There also is great nostalgia for any obsolete technology (tubes, LPs, mono, old horns, open back, etc (and I myself enjoy LPs and tubes)), so it is no wonder that we will now add field coils to the list of things that were better than what they make today.
What does that say about all those stupid engineers that abandoned field coils in the 40's and 50's as soon as Alnico 5 came along?
It is not enough to assert that something sounds better. Prove it.
David
Why man never went back to the moon after 1972?!
The technology was already here. Maybe the only reason was the price.
A good reason (consequence) to make and build a good sound is to master the manufacture process/chain from start to the end (client). And it doesn't matter how many units you build if you have the same quality control in all of them.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.