Im kinda new here, been lurking off an on thru the years, finnaly decided to take the plunge and make an account, I have been a stereo nut for years and thinking about some diy speakers, I definately want full range, every x-over I have had just kills my music, doesn't matter if it's Bach or Marilyn Manson, if theres a crossover, its dead, however every full range speaker I have tried has been lively and musical, even the cheap dual cones from wally world sound better than my pioneer or JBL "multi element screech boxes" however my current KLH speakers with 4" dual cones sound just incredible! those are so good I even use them on my keyboards the piano is wonderful thru them
. I want to know if there is any sound quality differences or advantages to using field coils. I have never used them but have been doing a lot of reading about them and I am very intrigued by the technology. What has been your experiences with field coils vs permanent magnets? I want to build me some OB's with large full ranges, shouldn't be too hard considering my crappy woodworking skills. I am already well studied on full range drivers, I am just curious about these mysterious field coil drivers, there isn't a whole lot of info out there on them. what info I do find just makes me more curious. I know they were used in a lot of OLD radios, and now they seem to be making a come back in the hi-fi world. I am also a musician and looking for anything to create new sounds
. my musical tastes are mainly classical music and goth/darkwave/death rock and metal. most of the time I just listen to classical and compose/arrange some too. I play pretty much anything with a keyboard on it.
any good sources of CHEAP tube amps or tube amp kits would be appreciated too. time to kick the transistor habit too.. LOL
. I want to know if there is any sound quality differences or advantages to using field coils. I have never used them but have been doing a lot of reading about them and I am very intrigued by the technology. What has been your experiences with field coils vs permanent magnets? I want to build me some OB's with large full ranges, shouldn't be too hard considering my crappy woodworking skills. I am already well studied on full range drivers, I am just curious about these mysterious field coil drivers, there isn't a whole lot of info out there on them. what info I do find just makes me more curious. I know they were used in a lot of OLD radios, and now they seem to be making a come back in the hi-fi world. I am also a musician and looking for anything to create new sounds. my musical tastes are mainly classical music and goth/darkwave/death rock and metal. most of the time I just listen to classical and compose/arrange some too. I play pretty much anything with a keyboard on it. any good sources of CHEAP tube amps or tube amp kits would be appreciated too. time to kick the transistor habit too.. LOL
No one has really looked into why some prefer field coils. One *thought* is that back emf has less effect on magnetic field integrity and therefor is more accurate under normal operation.
As to the sound - that depends *far* more on the driver than just the motor itself when comparing identical motor parameters.
The fact is that there aren't that many field-coils available, and all are generally much more expensive than *most* other (somewhat) similar offerings. In fact, I don't know of *any* cheap field-coil full range drivers.
Perhaps the Supravox 165EXC is the least expensive driver (..at around 700 US each).
Despite this (the very knowledgeable) Thorsten has heard permanent magnet versions from Supravox AND the field-coils, and believes the field-coils are in another "league", and others have only confirmed their happiness (..usually regarding the use of the more expensive 215 EXC.)
There are a few cheap tube amps, and even a few cheap tube kits.. NONE that are particularly good IMO.
One decent *design* that is relatively in-expensive is:
New 2A3
An amplifier that compared well to that designer's 845 SE tube amp is from this Co. though not tube, but isn't terribly costly:
NewClassD Amplifiers
2008 - Class D Amplifier comparasion test
As to the sound - that depends *far* more on the driver than just the motor itself when comparing identical motor parameters.
The fact is that there aren't that many field-coils available, and all are generally much more expensive than *most* other (somewhat) similar offerings. In fact, I don't know of *any* cheap field-coil full range drivers.
Perhaps the Supravox 165EXC is the least expensive driver (..at around 700 US each).
Despite this (the very knowledgeable) Thorsten has heard permanent magnet versions from Supravox AND the field-coils, and believes the field-coils are in another "league", and others have only confirmed their happiness (..usually regarding the use of the more expensive 215 EXC.)
There are a few cheap tube amps, and even a few cheap tube kits.. NONE that are particularly good IMO.
One decent *design* that is relatively in-expensive is:
New 2A3
An amplifier that compared well to that designer's 845 SE tube amp is from this Co. though not tube, but isn't terribly costly:
NewClassD Amplifiers
2008 - Class D Amplifier comparasion test
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that tube amp looks interesting and am thinking of that one seriously, but I will never use a class D amp, have tried them, killed all reception on my ham radio, cant have that. however the class D amps I used were dirt cheap, so probably badly filtered switching circuits. I just moved so none of my radios are set up, just my receiver, FR speakers and keyboard. probably wont set up the ham radio anyway, apartment = no antennas . The class D amps I did use had a sound very close to a tube amp, I just might try one if I can find a GOOD one that has addressed the RFI issue. the last one I had even killed my FM tuner, the locals didn't even get thru that mess but CD's did sound AMAZING!! That info on the field coils is all I was able to find on the net, I have got an itch to try some but the few I have found are rediculasly expensive. I found some info about being able to adjust the q and sensitivity with a field coil for musician applications. that's got me realy itchin to try some. I wonder if making my own would be a possibility???? I know enough about speakers and acoustics that it probably wouldn't be too hard to build my own driver from scratch. or at least modify one. Building an amp, thats no problem, I have built a few in the past, even ham radios.. from scratch.
Well ill be back tomorrow, probably with a few OB questiunes, im starting to fade, its time for bed..
good night!
P.S. those class D amps are TINY!!! I cant see how it's possible to get hundreds of watts out of those without frying them??? those numbers cant be right??? if they are, that's shocking. mine was bigger than that and a measly lil 10w.. and it did run HOT. Thats got me looking into class D amplifiers now.. I know practically nothing about them, But I can build old school anolog..LOL
. The class D amps I did use had a sound very close to a tube amp, I just might try one if I can find a GOOD one that has addressed the RFI issue. the last one I had even killed my FM tuner, the locals didn't even get thru that mess but CD's did sound AMAZING!! That info on the field coils is all I was able to find on the net, I have got an itch to try some but the few I have found are rediculasly expensive. I found some info about being able to adjust the q and sensitivity with a field coil for musician applications. that's got me realy itchin to try some. I wonder if making my own would be a possibility???? I know enough about speakers and acoustics that it probably wouldn't be too hard to build my own driver from scratch. or at least modify one. Building an amp, thats no problem, I have built a few in the past, even ham radios.. from scratch. Well ill be back tomorrow, probably with a few OB questiunes, im starting to fade, its time for bed..
good night!
P.S. those class D amps are TINY!!! I cant see how it's possible to get hundreds of watts out of those without frying them
??? those numbers cant be right??? if they are, that's shocking. mine was bigger than that and a measly lil 10w.. and it did run HOT. Thats got me looking into class D amplifiers now.. I know practically nothing about them, But I can build old school anolog..LOLYou may also want to do some reading about Alnico speakers. I will leave the search
for you but it seems that speakers built with Alnico magnets sound better like field
coil speakers sound better. It is too bad that Alnico and field coils are so expensive.
It's so much cheaper to use a 40oz ceramic magnet than an oz or two of Alnico.
for you but it seems that speakers built with Alnico magnets sound better like field
coil speakers sound better. It is too bad that Alnico and field coils are so expensive.
It's so much cheaper to use a 40oz ceramic magnet than an oz or two of Alnico.
Ok I tried this from my phone but that didn't work.... opera mini and bolt (phone browsers) both suck at forums... I hate the blackberry browser because its soooooo slow... painfully slow.
Back on topic, I have used alnico speakers in the past and loved them, its amazing how big a difference changing the magnet metal can make. my experiance with both alnico and neodymium is that they are much fuller and open than the usual ceramic magnets. Im still trying to figure out why, its just a magnet??? they do the same thing: concentrate all there magnetic energy to the coil gap. I no longer have my old alnico's I had to sell them to survive since I had been in a bad relationship and was kicked out to the street, all my hifi stuff went bye bye. I cried over the tube amps I built.. Now things are better and im getting back into hifi currently with some cheap but surprisingly good full range speakers, and a low end pioneer receiver from a yard sale. I WILL get another pair of alnico full ranges if it kills me.. maybe even neodymium.. Why are alnico magnets so expensive?
Im going to check out ebay for some more of those vintage goodmans FR's...
I'm also going to try to find some old 6x9 dual cone car speakers for some OB experiments since there cheap and basically made for OB then if I want to go that route I'll get something better, thinking maybe 2 per baffle wired in series to get 8 ohms so my receiver don't fuss or burn.
anybody used these:
Kenwood - KFC-6950S
or
Pioneer USA - TS-694P - 6
How is the mid range on those? treble harsh or smooth? I had some OLD kenwoods simular to those about 12 yrs ago and they were very good in a sealed box, never tried them OB so I wonder if those new ones are an improvement or a step back. I have never used any pioneer car speakers for anything so dont know a lot about them, but the paper cones on the pioneer might be a plus over the hard heavy rigid poly cones on the kenwood for bringing out some detail.
Any other recomendations for just cheap OB experiments? I dont want to put a lot of money into it unless I know for sure I want to stick with OB.
Back on topic, I have used alnico speakers in the past and loved them, its amazing how big a difference changing the magnet metal can make. my experiance with both alnico and neodymium is that they are much fuller and open than the usual ceramic magnets. Im still trying to figure out why, its just a magnet??? they do the same thing: concentrate all there magnetic energy to the coil gap. I no longer have my old alnico's I had to sell them to survive since I had been in a bad relationship and was kicked out to the street, all my hifi stuff went bye bye. I cried over the tube amps I built.. Now things are better and im getting back into hifi currently with some cheap but surprisingly good full range speakers, and a low end pioneer receiver from a yard sale. I WILL get another pair of alnico full ranges if it kills me.. maybe even neodymium.. Why are alnico magnets so expensive?
Im going to check out ebay for some more of those vintage goodmans FR's...
I'm also going to try to find some old 6x9 dual cone car speakers for some OB experiments since there cheap and basically made for OB then if I want to go that route I'll get something better, thinking maybe 2 per baffle wired in series to get 8 ohms so my receiver don't fuss or burn.
anybody used these:
Kenwood - KFC-6950S
or
Pioneer USA - TS-694P - 6
How is the mid range on those? treble harsh or smooth? I had some OLD kenwoods simular to those about 12 yrs ago and they were very good in a sealed box, never tried them OB so I wonder if those new ones are an improvement or a step back. I have never used any pioneer car speakers for anything so dont know a lot about them, but the paper cones on the pioneer might be a plus over the hard heavy rigid poly cones on the kenwood for bringing out some detail.
Any other recomendations for just cheap OB experiments? I dont want to put a lot of money into it unless I know for sure I want to stick with OB.
One word - Cobalt. It's not exactly the most common material & is nowadays incredibly expensive i believe.
Interesting thread so far
Although alnicol is expensive it isn't near as expensive as the platium cobalt magnets.
I believe the strongest magnets available use about 50% platium and 50% cobalt. I doubt anyone will use that for a speaker magnet. This material is used to form a verry verry thin film on hard drives.
I believe the strongest magnets available use about 50% platium and 50% cobalt. I doubt anyone will use that for a speaker magnet. This material is used to form a verry verry thin film on hard drives.
Eh? Sorry Nick, please check these metal prices
Cobalt per lb
Nickel per lb
As you can see Cobalt is a damn sight more expensive
Also there is no price for a truckload of Cobalt, but there is with Nickel.If it was all about flux density, neodymium would rule the roost. It seems neo is used more for light weight than sound quality.
One thing that interests me, is the effect of the field coil voltage.
I have heard it said that the vintage high voltage field coils (100v - 200V) sound better that moder low voltage coils. Does anyone know why this might be so?
The only thing I could think of was that voltage ripple might have less impact.
I have heard it said that the vintage high voltage field coils (100v - 200V) sound better that moder low voltage coils. Does anyone know why this might be so?
The only thing I could think of was that voltage ripple might have less impact.
I've heard a number of low voltage versions, (Mostly vintage RCA cinema sound drivers, both woofers and horn midranges) and with modern power supplies ripple is not going to be an issue. The 13.8V coil because the current is on the order of 1.5A or so uses a larger diameter wire whereas the higher voltage coil would use a smaller wire theoretically filling more of the winding window which for a given power level might imply slightly more ampere/turns in a given electro-magnet, and hence a slightly stronger field? OR not?
Something else to think about from an electrical perspective is that the voice coil/field coil looks like a something close to a shorted transformer to the ac signal driving the VC. So I am wondering if audio intermodulation of the power supply driving the field coil might be audible. This is purely conjectural, but my suspicion is you would want a supply as close to a perfect voltage source as you could manage. This might be less of an issue with high voltage field coils due to the implied transformation ratios between the VC and field coil.
Eventually I hope to experiment with field coils, I should be able to make small ones here in my machine shop, however I have to find suitable driver candidates for conversion. The Altec drivers that are commonly converted are beyond expensive even before the conversion kit is installed..
Note that this is all conjectural on my part and I could be quite mistaken in a number of areas. I hope to learn by doing, but would love to hear from people who actually know what they are talking about..
Alnico 5 is the alloy probably most commonly used in speaker driver magnets, here is its chemical composition:
Iron is quite cheap, so you can see quite clearly that the primary and completely dominant contributor to the high cost of AlNiCo is as has been pointed out in several previous posts : Cobalt.
My references from here: Permanent Magnet Company, Inc.
- AL: 8 %
- Ni: 14%
- Co: 24%
- Cu: 3%
- Fe: 51%
Iron is quite cheap, so you can see quite clearly that the primary and completely dominant contributor to the high cost of AlNiCo is as has been pointed out in several previous posts : Cobalt.
My references from here: Permanent Magnet Company, Inc.
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Actually NEO is used in some fairly expensive high performance drivers including some very well regarded FR drivers from Tang Band. See the links below:
Tang Band W8-1772 8" Neodymium Full Range Driver http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-893
Disclosure: I'm thinking I might use the W8-1772 in another FR project at some point down the road.
Tang Band W8-1808 8" Neodymium Full Range Driver http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-894
Neo also sees application in some very high power subwoofer applications and there are also a number of high end speaker systems that use NEO. I would consider it to be a high quality choice where the goal is increased flux density rather than lower weight.
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Obviously I meant of Alnico formulations, not in general because clearly ferrite magnets are most commonly employed even in some quite expensive drivers.
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