Why don't you use the search function or Google?
Most major PA driver makers have mids and woofers- efficient too:
Eminence, PAudio, Beyma, B&C come to mind
Most all PA driver makers have a horn driver or various that use neo.
dome or cone midranges?
Morel ,Seas. HiVi
OK you didn't ask about tweeters, but
Audax, Peerless, Scanspeak, Morel ,Seas. HiVi
have neo
All those new ribbon tweeters from China- I think they use neo
as well ase Bohlender Graebener
Most major PA driver makers have mids and woofers- efficient too:
Eminence, PAudio, Beyma, B&C come to mind
Most all PA driver makers have a horn driver or various that use neo.
dome or cone midranges?
Morel ,Seas. HiVi
OK you didn't ask about tweeters, but
Audax, Peerless, Scanspeak, Morel ,Seas. HiVi
have neo
All those new ribbon tweeters from China- I think they use neo
as well ase Bohlender Graebener
Bill Fitzpatrick said:
There's a misconception that the type of magnet affects the sound quality. It's not true. And while Neodymium magnets are more powerfull by weight, they are typically smaller, so any gained efficiency disappears.
About the only thing Neodymiums have going for them is small cross section, which means a smaller reflection back into the rear cone. Even the benefits from that are over rated.
Alnico does not sound any better either. Flux is flux. All that matters is how it's used in a motor design.
(All IMHO)
Re: Re: Re: If neodymium is all that great . . .
Sometimes I habitually add an IMHO to the end of my posts as a sort of disclaimer or flame retardant suit. It's a little less aggressive than strutting around and forcing facts down people's throats.
Additionally, stating what I think are facts tends to lead me down the long road of trying to prove myself to people who are unwilling to listen. I don't have the time or patience for that. So... everything I say is an opinion.
I've read many claims also. To answer your original inquiry, The reason you don't see many woofers with neo magnets is because the manufacturers know that this is not a financially advantageous area to spend money in, at least with traditional motor design. There is no substantial gain except for having the buzzword "Neodymium" on the product. There's more performance gain in spending money on better cone forming equipment or machining of steel motor parts, cone materials, frame aerodynamics, coil former materials, adhesives or the R&D of the aforementioned parts. I feel inclined to add another IMHO here.
Bill Fitzpatrick said:
Sometimes I habitually add an IMHO to the end of my posts as a sort of disclaimer or flame retardant suit. It's a little less aggressive than strutting around and forcing facts down people's throats.
Additionally, stating what I think are facts tends to lead me down the long road of trying to prove myself to people who are unwilling to listen. I don't have the time or patience for that. So... everything I say is an opinion.I've read many claims also. To answer your original inquiry, The reason you don't see many woofers with neo magnets is because the manufacturers know that this is not a financially advantageous area to spend money in, at least with traditional motor design. There is no substantial gain except for having the buzzword "Neodymium" on the product. There's more performance gain in spending money on better cone forming equipment or machining of steel motor parts, cone materials, frame aerodynamics, coil former materials, adhesives or the R&D of the aforementioned parts. I feel inclined to add another IMHO here.
Just the other night I was reading a paper (which I stupidly failed to bookmark) by an individual who seems to know what he's talking about. Come to think of it, it may have been a link on the Linkwitz site.
He performed a number of test with a variety of listeners comparing ceramic and neodymium magnets on otherwise identical drivers. His focus was on how the ceramic magnet was the lesser performing in terms of how the driver handled the steep fronts of transient information. He talked much about the inability to evaluate equipment given that the speakers used to do so are so inadequate in terms of resolution and that the inadequacies could be partly addressed by using neodymium magnets. He also went on to say that the importance of "time alignment" had been unfairly minimized because of old school ideas. There was also some discussion on how the ear handles transient information.
I'm going to try to find that paper again.
I'll be back.
OK. Two minutes searching and here I am again with the link. It's the first link "Putting The Science Back In Loudspeakers." It's a pdf.
http://www.linkwitzlab.com/links.htm
He performed a number of test with a variety of listeners comparing ceramic and neodymium magnets on otherwise identical drivers. His focus was on how the ceramic magnet was the lesser performing in terms of how the driver handled the steep fronts of transient information. He talked much about the inability to evaluate equipment given that the speakers used to do so are so inadequate in terms of resolution and that the inadequacies could be partly addressed by using neodymium magnets. He also went on to say that the importance of "time alignment" had been unfairly minimized because of old school ideas. There was also some discussion on how the ear handles transient information.
I'm going to try to find that paper again.
I'll be back.
OK. Two minutes searching and here I am again with the link. It's the first link "Putting The Science Back In Loudspeakers." It's a pdf.
http://www.linkwitzlab.com/links.htm
Hey there guys.
First of all I will say that I don't know an awfull lot about magnets, however, I have read that some magnets (Neobodenum included I think) suffer less from Barkhausen Noise than others.
Barkhausen Noise was discovered by Professor Heinrich Georg Barkhausen in 1919. It seems that in the case of loudspeakers that Barkhausen Noise describes how the voice coil jumps from one magnetic domain to another as the voice coil moves through the magnetic gap. Here are a couple of links that I attained from a quick google search.
http://www.stresstech.fi/products?id=85&c=1&l=1&parent=1&s=2
http://physics.queensu.ca/~lynann/mbnoise.html
I don't know if it's true, but I remember reading from somewhere that because of the discret steps in the magnetic feild of ceramic magnets they aparently can't even achieve 16 bit sound quality.
Interesting that, isn't it?
I hope someone more knowlegable than me can add to/clarify or maybe even correct what I have said.
First of all I will say that I don't know an awfull lot about magnets, however, I have read that some magnets (Neobodenum included I think) suffer less from Barkhausen Noise than others.
Barkhausen Noise was discovered by Professor Heinrich Georg Barkhausen in 1919. It seems that in the case of loudspeakers that Barkhausen Noise describes how the voice coil jumps from one magnetic domain to another as the voice coil moves through the magnetic gap. Here are a couple of links that I attained from a quick google search.
http://www.stresstech.fi/products?id=85&c=1&l=1&parent=1&s=2
http://physics.queensu.ca/~lynann/mbnoise.html
I don't know if it's true, but I remember reading from somewhere that because of the discret steps in the magnetic feild of ceramic magnets they aparently can't even achieve 16 bit sound quality.
Interesting that, isn't it?
I hope someone more knowlegable than me can add to/clarify or maybe even correct what I have said.
I quoted that paper recently on these forums, and I find it very interesting. To attempt an answer to the original question, I would assume you need the highest resolution in the tweeter department with concurrent low excursion. Here, discrete steps would harm the most. And you do find neodymium mostly in tweeters and fullrange drivers.
Maybe you simply don't need it for the degree of precision required for the woofer frequency and excursion range.
Maybe you simply don't need it for the degree of precision required for the woofer frequency and excursion range.
As far as I remember John once wrote in "Sound On sound" that these magnets make the most difference in midranges and tweeters.
The Manger BTW uses rare-earth magnets in the better versions.
I think Alnico has the same advantages over ceramic magnets that Neodymium has. This is one of the reasons why old Alnico drivers are that sought-after.
Regards
Charles
The Manger BTW uses rare-earth magnets in the better versions.
I think Alnico has the same advantages over ceramic magnets that Neodymium has. This is one of the reasons why old Alnico drivers are that sought-after.
Regards
Charles
Its funny reading that paper and then Hartmann paper..
Sure, the gist of the Watkinson paper holds true - but some of the science behind it is blatently "lax" when compared to the Hartmann paper, and even sometimes misleading..
Watkins should have just kept it at: "recording studios need better equipment to hear deficiencies with playback".
As to "why" neo, well I don't think its a matter of the material per se, but instead of field intensity vs. crystalline structure. Commonly higher gauss can be achieved with neo vs. ceramic. Additionally, the crystalline structure of neo vs. ceramic is typically superior - i.e smaller and more uniform. (Perhaps an appropriate analogy would be the difference between void free plywood and normal plywood for cabinet use, the former sounds better than the latter because it suffer's fewer resonances because of its more uniform density). This isn't to say that neo IS inherently superior to a ceramic base, but that it USUALLY is superior.
As to the original question, well consider that with any magnet the higher in gauss you go - the greater the cost. Most manufacturers rarely see the need for a magnet above 1.2 gauss, and conventional ceramics are quite capable of providing this high a figure - so why spend more? (..or so they believe - i.e. they don't look at crystalline structure OR they feel the cost benefit is so marginal as to be unimportant). The only time they seem to look at neo is for a weight savings, not for sound quality (though they often harp endlessly on this in their advertising whether or not the driver actually benefits sonically from the use of the neo).
As to benefiting from its use sonically, that is derived both from the previously mentioned properties of gauss and crystalline structure - but also field uniformity as a measure of the length of the voice coil and magnet size. As to the first and second properties - time domain performace is key (..VERY short time durations). As the wavelength gets longer this become "less" perceptable (more because a driver needed to produce lower freq.s has characteristics that are at-odds with short time duration attributes - like increased mass and excursion).
As to the third, this has to do with the "poles" or ends of the voice coil, the neo magnet typicallly is more focused with less "over-field" than a ceramic version - or with a field that is stonger at the voice-coil's ends. This results in a "throw" that is more uniform in acceleration at the driver's excursion apex. (note though that this can be engineered "around" with a ceramic magnet - or done poorly with a neo magnet.) Here again longer wavelengths will not benefit anywhere near as much as shorter wavelengths for the same reason as in the first two properties. (And note that this property is particularly important with ribbons where lax deceleration at the apex isn't an option and where minute over-excursion as a result of "over-field" will often result in damaging the driver.)
The final property "magnet size" will simply allow for better engineering of the driver - with particular emphasis on venting. For example venting a large driver is usually fairly easy to do. Venting a smaller driver (i.e. a tweeter) is more difficult because of the increased size of the magnet and the required frame for that magnet. (again though, like the third property - this can be engineered "around" with a ceramic magnet - or done poorly with a neo magnet.)
All of the above (especially when factoring in price) relegate the use of neo magnets to higher freq. drivers, specialty drivers (like Lowthers), or drivers where weight is a factor (i.e. pro touring gear).
Sure, the gist of the Watkinson paper holds true - but some of the science behind it is blatently "lax" when compared to the Hartmann paper, and even sometimes misleading..
Watkins should have just kept it at: "recording studios need better equipment to hear deficiencies with playback".
As to "why" neo, well I don't think its a matter of the material per se, but instead of field intensity vs. crystalline structure. Commonly higher gauss can be achieved with neo vs. ceramic. Additionally, the crystalline structure of neo vs. ceramic is typically superior - i.e smaller and more uniform. (Perhaps an appropriate analogy would be the difference between void free plywood and normal plywood for cabinet use, the former sounds better than the latter because it suffer's fewer resonances because of its more uniform density). This isn't to say that neo IS inherently superior to a ceramic base, but that it USUALLY is superior.
As to the original question, well consider that with any magnet the higher in gauss you go - the greater the cost. Most manufacturers rarely see the need for a magnet above 1.2 gauss, and conventional ceramics are quite capable of providing this high a figure - so why spend more? (..or so they believe - i.e. they don't look at crystalline structure OR they feel the cost benefit is so marginal as to be unimportant). The only time they seem to look at neo is for a weight savings, not for sound quality (though they often harp endlessly on this in their advertising whether or not the driver actually benefits sonically from the use of the neo).
As to benefiting from its use sonically, that is derived both from the previously mentioned properties of gauss and crystalline structure - but also field uniformity as a measure of the length of the voice coil and magnet size. As to the first and second properties - time domain performace is key (..VERY short time durations). As the wavelength gets longer this become "less" perceptable (more because a driver needed to produce lower freq.s has characteristics that are at-odds with short time duration attributes - like increased mass and excursion).
As to the third, this has to do with the "poles" or ends of the voice coil, the neo magnet typicallly is more focused with less "over-field" than a ceramic version - or with a field that is stonger at the voice-coil's ends. This results in a "throw" that is more uniform in acceleration at the driver's excursion apex. (note though that this can be engineered "around" with a ceramic magnet - or done poorly with a neo magnet.) Here again longer wavelengths will not benefit anywhere near as much as shorter wavelengths for the same reason as in the first two properties. (And note that this property is particularly important with ribbons where lax deceleration at the apex isn't an option and where minute over-excursion as a result of "over-field" will often result in damaging the driver.)
The final property "magnet size" will simply allow for better engineering of the driver - with particular emphasis on venting. For example venting a large driver is usually fairly easy to do. Venting a smaller driver (i.e. a tweeter) is more difficult because of the increased size of the magnet and the required frame for that magnet. (again though, like the third property - this can be engineered "around" with a ceramic magnet - or done poorly with a neo magnet.)
All of the above (especially when factoring in price) relegate the use of neo magnets to higher freq. drivers, specialty drivers (like Lowthers), or drivers where weight is a factor (i.e. pro touring gear).
False (not just IMHO
).Tho I don't think there is much benefit in using neodymium in any other application than PA.
A good performing 15" bassdriver will be around 10 kg (22 pound) and a good 18" around 13 kg (28,5 pound).
With neodymium a 15" would be around 4 kg (8,5 pound) and a 18" around 6,5 kg (14 pound), sometimes even less.
For PA that's just about the difference that will make it easy to carry all those cabinets around or not. At home you wont have to move it and extra weight could actually be seen as a benefit here.
A second thing that can be seen is that some PA neodymiumdrivers get a "little extra package" in getting Qts below or around 0.2 with a substantial Xmax and still weigh less than a conventional driver.
Espescially 18Sound, BMS and P-Audio (AFAIK) have neodymiumdrivers ranging from subwoofer to mid and high.
Some negative pointouts about neodymium is that it supposed to loose magnetstrenght over time, by severe shock and heat. Last is the reason neodymium drivers almost ever have big coolingribs mounted on the magnet.
Mvg Johan
Rademakers said:False (not just IMHO
Tho I don't think there is much benefit in using neodymium in any other application than PA.
True, that's why I qualified my statements with "Traditional motor design".
Note that I was just refering to woofers. Neo tweeters are a dime a dozen, since they allow frames and overall designs to be smaller and cheaper. It's a different balance of costs in that case. Neo tweeters do not perform as well because they have limited rear chambers. (or none at all) This pushes the Fs and Qts up and increases non-linear distortion and energy storage on the low end.
BTW, the Seas Neo magnet W15CH01 does not perform as well as the W15CY001. The neo version actually has higher distortion, though it's completely attributed to motor design rather than magnet material. On the bright side, the magnet is less likely to fall off if the speaker is dropped.
One of the speaker designs that makes good use of Neodymium is the larger Aura NRT motor woofers. These are a completely non-traditional underhung design however. Very low distortion. Also, expensive to manufacture. They own a patent on it, which is why you will only see it used there.
Allow me to add my 2 cents as a MSEE, as I've seen this discussion raised in the past before, as with every new technology or material introduced. Many uneducated fools (no pun intended) throw an orgasmic fit when they read about some exotic new material used in a loudspeaker/amplifier/disc cleaner solution/etc. without ever second guessing what is really going on.
I catagorize these people in the same category as those that use just two 470uF/63v capacitors in a 400-watts amp and omit all other caps, including those in the zobel or input filter because they subscribe to the true audiophile - less-is-more - approach. These are the same people that run pure silver cables, 24K gold plated spikes and use battery operated pre-amps or buy $5K line conditioners and swear by the $50 cinch plugs they just installed as it improves their mids and treble significantly.
Because I'm an EE I believe in the laws of physics, and subscribe to Thevenin and Kirchoff and all other laws that apply, if it can't be measured, or be theoretically proven I dismiss it as magic, or worse; nonsense and marketing babble. So what about those magnets? I'm with Zaph if he states that a good motor design works well regardless of magnet material used. Neodymium isn't a miracle material, much like paper cones still haven't been replaced by plastic or fibre cones like kevlar or carbon as many said they would.
Neodymium works well where you're bound by space contraints, or when you positively need to ensure a certain amount of flux is reached that you can't get to with conventional materials. At the end of the day neodymium is expensive, and thus isn't used for woofers and midranges that much. Maybe a 10" woofer with 100dB sensitivity sounds appealing to you, the manufacturer just looks at if from a cost-vs-performance point of view and decides it just isn't worth it, not even for high-end applications.
A properly designed motor and voice coil will not sound better when you substitute ceramics for neodymium, it will however end up being more efficient. Whether a higher efficiency equals better, or more accurate reproduction is an entirely different story. Claims that neodymium driven tweeters or midranges sound better than those using ceramics can only be subscribed to higher sensitivity, hence more revealing, or simply better engineering on the part of the neodymium drivers.
At the end of the day it is the question whether the manufacturer has done his homework; it is just as feasible to design and manufacture a utterly shite neodymium tweeter or midrange as a truely orgasmic paper cone woofer using a ceramic magnet. The higher theoretical magnetic flux enabled by neodymium isn't a cure for soddy engineering.
There's a reason why some loudspeakers, amplifiers and other equipment continue to offer outstanding performance even when compared to their state-of-the-art successors. It usually isn't in the materials, but the slow process of painstakingly improving upon small details of an already good design. Good engineering is what makes a masterpiece, not the materials used, these are just the ingredients, it is the recipe and the cook's cooking skills that make a wonderful cake.
Just my 2 cents really.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
I catagorize these people in the same category as those that use just two 470uF/63v capacitors in a 400-watts amp and omit all other caps, including those in the zobel or input filter because they subscribe to the true audiophile - less-is-more - approach. These are the same people that run pure silver cables, 24K gold plated spikes and use battery operated pre-amps or buy $5K line conditioners and swear by the $50 cinch plugs they just installed as it improves their mids and treble significantly.
Because I'm an EE I believe in the laws of physics, and subscribe to Thevenin and Kirchoff and all other laws that apply, if it can't be measured, or be theoretically proven I dismiss it as magic, or worse; nonsense and marketing babble. So what about those magnets? I'm with Zaph if he states that a good motor design works well regardless of magnet material used. Neodymium isn't a miracle material, much like paper cones still haven't been replaced by plastic or fibre cones like kevlar or carbon as many said they would.
Neodymium works well where you're bound by space contraints, or when you positively need to ensure a certain amount of flux is reached that you can't get to with conventional materials. At the end of the day neodymium is expensive, and thus isn't used for woofers and midranges that much. Maybe a 10" woofer with 100dB sensitivity sounds appealing to you, the manufacturer just looks at if from a cost-vs-performance point of view and decides it just isn't worth it, not even for high-end applications.
A properly designed motor and voice coil will not sound better when you substitute ceramics for neodymium, it will however end up being more efficient. Whether a higher efficiency equals better, or more accurate reproduction is an entirely different story. Claims that neodymium driven tweeters or midranges sound better than those using ceramics can only be subscribed to higher sensitivity, hence more revealing, or simply better engineering on the part of the neodymium drivers.
At the end of the day it is the question whether the manufacturer has done his homework; it is just as feasible to design and manufacture a utterly shite neodymium tweeter or midrange as a truely orgasmic paper cone woofer using a ceramic magnet. The higher theoretical magnetic flux enabled by neodymium isn't a cure for soddy engineering.
There's a reason why some loudspeakers, amplifiers and other equipment continue to offer outstanding performance even when compared to their state-of-the-art successors. It usually isn't in the materials, but the slow process of painstakingly improving upon small details of an already good design. Good engineering is what makes a masterpiece, not the materials used, these are just the ingredients, it is the recipe and the cook's cooking skills that make a wonderful cake.
Just my 2 cents really.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
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