Question about Neodymium drivers

[Rolling Thunder]

Not necessarily

I guess I assumed that Neo is like Corinthian leather...if it has it, you will hear about it. It seems, to me at least, like a strong selling point.

 

[beans-on-toast]

Rather than a permanent magnet, would a rotating magnetic flux around a speaker improve the sound? Did the old AC field coil speakers sound better?

Interesting question. My dad had a radio with a field coil speaker. That type of design was a good idea in the era when noone had figured out how to make permanent magnets, but once alnico came in, they disappeared pretty quickly. Why? A few things:

1) The magnetic structure, plus the weight of the coil, made them pretty heavy.

2) They did tend to hum - the filtering required to make them stop doing that adds a lot of cost to the amplifier driving them.

3) They add heat - in the area of the voice coil, which means they decrease the signal power you can out through the thing before it overheats.

4) They cost quite a bit more, given the complexity of the things needed to make them work. Making the customer pay more for a product that doesn't work as well is not a good long term strategy.

The post was intended to be tongue in cheek. It’s an interesting subject though.

Some speaker field coils were also used as a filter choke in the power supply. There were also humbucking windings to reduce hum. Old radios with 15” field coil speakers sounded quite good.

 

[BlueTalon]

I have 2 cabs that I love, one is a Barefaced and I know it's not a Neo but it's super light...

Do you know that? I have a Barefaced cab, and I don't recall anything specifically mentioned about the type of magnet on the driver.

The barefaced 12XN550 driver has a neodymium magnet.

That's what I thought, but I don't remember seeing anything definitive.

 

[gtirard]

Do you know that? I have a Barefaced cab, and I don't recall anything specifically mentioned about the type of magnet on the driver.

They don't mention anything on their website, but I saw this on the official thread. It seems that 10" driver are not Neo, and 12" drivers are Neo.

[EDIT] But we don't really care, do we? From what I understand of the super comments we had here, thank you all of you, knowing if a driver is neo or not will not tell anything, it all depens on the design. A driver may sound good or crap, Neo or not.

 

[Rip Van Dan]

I'm confused about Neodymium drivers:

• Some people say the only way to make a lightweight cab is to use Neodymium drivers.
• A few people say that Neodymium sound crap.
• A lot of manufacturers don't say if the drivers they use in their cabs are Neodymium or not.

I have 2 cabs that I love, one is a Barefaced and I know it's not a Neo but it's super light, the other is a GR Bass and they don't say if it's a Neo or not, but it is also super light and it sound great.

So my questions are:
"Only Neo cabs can be light" Is there such a law?
What are the tonal drawback of Neo cabs?

I hope these questions are not as stupid and sterile as the class D related discussions…

And maybe it has been discussed already, sorry if I missed it…

I remember the first time David Nordschow offered Neo speakers in some of his Eden cabs. When he first brought out his DNS cabs with his new company DNA in 2010, they were an option on all of his cabs. David has always designed his own speakers and he said the challenges with them were to get the same sound out of them as out of the ceramic mag speakers and to get a long life out of them. He said the Neodymium magnets wore out from use (magnets became weaker) sooner than on the ceramic speakers. Neo's had been out for a few years before he come up with ones that he liked and got similar life expectancy out of.

I actually have Neo speakers in my Eden EX-112 cabs. They are pretty inexpensive cabs by comparison to Eden's top of the line D-series speakers which sell for around $875. The EX-112's are only $269 and the first night I played a gig at a small venue with one of them, I was so pleased with their sound I decided I was going to get a second one and use two at medium-sized venues. Again, these are David-designed speakers and not some off the shelf speakers but they really sound great to me. Maybe not as great as the D112XST speakers, but there's sure not $600 difference in the sound between them.

So yeah there is a difference in the sound, but nothing that a good designer can't deal with. I'd be surprised if most of the Neo's out now days aren't good sounding and long-lasting speakers. Was different when they were first being introduced. Now virtually everyone makes or has made them. David stopped offering NEO speakers on his DNA cabs because they just got prohibitively expensive. Said he would make them again when the neodymium came down in price some more. Originally they were more expensive, but not a lot more. Later on they became quite a bit more expensive. Then I believe they came down a bit from their peak. I know the DNS-210 cab that I would have been about $100 more expensive with the Neo speakers in it. So another $50 per speaker for the Neo's. I don't know how much difference there is now.

 

[agedhorse]

Neo magnets “wearing out” was a myth based on some very old magnetic material that was never used in production loudspeakers as far as I know.

I am not aware of any Neo motors wearing out in the last 20 years, at least from any major supplier.

 

[retslock]

It’s a magnet. It doesn’t have a sound unless you hit it with something.

 

[tom-g]

They don't mention anything on their website, but I saw this on the official thread. It seems that 10" driver are not Neo, and 12" drivers are Neo.

[EDIT] But we don't really care, do we? From what I understand of the super comments we had here, thank you all of you, knowing if a driver is neo or not will not tell anything, it all depens on the design. A driver may sound good or crap, Neo or not.

10" is ceramic mentioned here [Invalid or Expired Link Removed]
12" is neo mentioned here Barefaced Bass - 12XN550 - pushing the boundaries of driver design

 

[Rabidhamster]

Rather than a permanent magnet, would a rotating magnetic flux around a speaker improve the sound? Did the old AC field coil speakers sound better?

Interesting question. My dad had a radio with a field coil speaker. That type of design was a good idea in the era when noone had figured out how to make permanent magnets, but once alnico came in, they disappeared pretty quickly. Why? A few things:

1) The magnetic structure, plus the weight of the coil, made them pretty heavy.

2) They did tend to hum - the filtering required to make them stop doing that adds a lot of cost to the amplifier driving them.

3) They add heat - in the area of the voice coil, which means they decrease the signal power you can out through the thing before it overheats.

4) They cost quite a bit more, given the complexity of the things needed to make them work. Making the customer pay more for a product that doesn't work as well is not a good long term strategy.

Field coil Jensen speakers sounded completely amazing, only downside is they blow easily. Not for bass though, just like everything of the era.

 

[Al Kraft]

As best I recall rare earth magnets like neodymium do need to have a bit more attention paid to thermal management than ceramic or ALNICO magnets. They have a lower Curie temperature and tend to begin losing some strength at lower temperatures than other magnet materials. Also, as best I recall we're not talking about properly designed and conservatively rated speakers (i.e. with some safety margin) operating in temperature ranges where heat would typically be a performance or longevity issue.

My understanding from the literature is that the biggest advantage of Neodymium for speaker design is the trade space/design options it opens up in speaker motor architecture. The converse is that the biggest downside would be poor performance from not understanding what the different material properties require a designer to consider (e.g.. using a ceramic/ALNICO motor design and simply substituting neodymium for the ceramic/ALNICO magnet).

 

[agedhorse]

The Neo “alloys” used in speaker motors are plenty high for the application. These alloys are also used in electric vehicle motors and other high temperature components.

 

[beans-on-toast]

Comments from a manufacturer that caters to motor and wind turbine customers. They briefly mention care and handling. Of course it depends on the application.

Do neodymium magnets wear out? - Neo Magnets

I once saw a figure estimating the life of a neo speaker, it was 20 years to life depending on how it was used. Probably no different than a ceramic magnet speaker. If a neo speaker magnet looses a small amount of it’s charge over time, it isn’t a big deal relative to the soft parts life of the speaker’s components. Besides, most speaker magnets can be re-gaussed. Some service centers do this when re-coning speakers.

I worry more about Alnico speakers driven hard.

 

[agedhorse]

Comments from a manufacturer that caters to motor and wind turbine customers. They briefly mention care and handling. Of course it depends on the application.

Do neodymium magnets wear out? - Neo Magnets

I once saw a figure estimating the life of a neo speaker, it was 20 years to life depending on how it was used. Probably no different than a ceramic magnet speaker. If a neo speaker magnet looses a small amount of it’s charge over time, it isn’t a big deal relative to the soft parts life of the speaker’s components. Besides, most speaker magnets can be re-gaussed. Some service centers do this when re-coning speakers.

I worry more about Alnico speakers driven hard.

The temperatures are much higher than what a speaker sees. The magnet is NOT the gap nor is it all that close to the gap so it's not exposed to the heat that some people seem to think it is. Same for the opposing magnetic field, it takes an awful lot of current through the VC to generate that kind of field and fortunately the wire fails before the magnet. 20 years lifespan is a load of crap, it's ignoring the reality of millions of speakers that are approaching this milestone with no such issues. I would expect that if any reasonable care is used, 40 years would be a reasonable expectation, just like with ceramic magnet motors.

 

[beans-on-toast]

The temperatures are much higher than what a speaker sees. The magnet is NOT the gap nor is it all that close to the gap so it's not exposed to the heat that some people seem to think it is. Same for the opposing magnetic field, it takes an awful lot of current through the VC to generate that kind of field and fortunately the wire fails before the magnet. 20 years lifespan is a load of crap, it's ignoring the reality of millions of speakers that are approaching this milestone with no such issues. I would expect that if any reasonable care is used, 40 years would be a reasonable expectation, just like with ceramic magnet motors.

As you know, demagnetization is performed during some recones to clean the gap of any unwanted (ferrous) material. I never said that the magnet is in the gap.

The 20 year lifespan number that I’ve seen was an estimate in studio pro audio applications. They wanted to assign a number to put customers at ease. Warranties don’t extend that far as far as I’ve seen.

MI applications are different, speakers can last for decades or be cut short depending on abuse. Eminence offers a Seven Year Warranty against manufacturer’s defects. That’s longer than others.

But lifespan and warranties are two different things. Soft part lifespan is more a concern than any magnet.

 

[agedhorse]

Demagnetization is rarely done during a recone, it’s only done when there is a real problem which is uncommon. If there’s that much ferrous debris in the gap, IME it’s junk except for rare cases.

 

[timmus]

I don't want to derail this thread if this post should be somewhere else. I just searched on neo mags and this is where it took me. Mods, please feel free to move this post to a better thread if necessary.

I'm looking to lighten up a 210 cab which is heavy-ish, in and of itself.

The cab is empty at this point but not sure of it's weight. I need to go out to my barn tomorrow, dig it out and weigh it.

It's a Fender BXR 210...I know, not the best in the world but if the 10" neos only add 7 pounds to the total weight, it might be doable.

I found some 16Ω Eminence Basslite neos for $114 that should work.

The BXR is a sealed cab which these are designed for.

I am needing to move this cab around to different venues and my back really isn't up to hoisting my other cabs around so looking for as light as possible.

My wallet also has a say in this matter

 

[agedhorse]

You might find that the limiting factor is the cabinet itself, you might not save much weight.

 

[timmus]

You might find that the limiting factor is the cabinet itself, you might not save much weight.

My thought too. I need to go out there tomorrow, extract it from the pile and weigh it...and it's buried deep...LOL

 

[Marko 1]

I don't want to derail this thread if this post should be somewhere else. I just searched on neo mags and this is where it took me. Mods, please feel free to move this post to a better thread if necessary.

I'm looking to lighten up a 210 cab which is heavy-ish, in and of itself.

The cab is empty at this point but not sure of it's weight. I need to go out to my barn tomorrow, dig it out and weigh it.

It's a Fender BXR 210...I know, not the best in the world but if the 10" neos only add 7 pounds to the total weight, it might be doable.

I found some 16Ω Eminence Basslite neos for $114 that should work.

The BXR is a sealed cab which these are designed for.

I am needing to move this cab around to different venues and my back really isn't up to hoisting my other cabs around so looking for as light as possible.

My wallet also has a say in this matter

What total weight would you find acceptable?

 

[timmus]

What total weight would you find acceptable?

10 pounds...LOL
No seriously, 35-40 pounds or so. My Peavey 210 weighs about 60+ pounds and my 410 is about 75 (or more) pounds.
I am probably looking at fairly extensive back surgery in the next few months and horsing those cabs is a no go for me. I'll be 67 in a few weeks and my back is starting to pay me back for all the crap I've put it through in that 67 years...

I'm not playing in loud bands anymore so I don't need a cab that will be able to handle explosive hard rock any more but I do like smooth. I play five string basses a lot so it has to have a decent low end as well.