Hi
Thanks for the link!
Yes I undestand that using faraday rings has basically the same effect as using a magnetic material that resists better to flux modulation by VC currents (ALNICO in this example). Both attempts result in lower 2nd harmonics.
On the other hand, lowering 3rd harmonics as claimed by the ATC construction is even more desirable and this isn't outlined here in comparison. Or did I miss the point?
Greetings
Michael
Thanks for the link!
Yes I undestand that using faraday rings has basically the same effect as using a magnetic material that resists better to flux modulation by VC currents (ALNICO in this example). Both attempts result in lower 2nd harmonics.
On the other hand, lowering 3rd harmonics as claimed by the ATC construction is even more desirable and this isn't outlined here in comparison. Or did I miss the point?
Greetings
Michael
Hi
almost anything about faraday rings is also outlined at:
http://www.diyaudio.com/forums/show...2247&highlight=
"http://www.diyaudio.com/forums/showthread.php?s=&threadid=62247&highlight="
Please note that faraday rings basically lower 2nd harmonics. This isn't always your desire.
Especially not if 3rd or higher order harmonics become dominant that way.
What I am curious about is why ALNICO is rated so high and if probably hysteresis has more to do with it than resistance to flux modulation, though this should show up at distortion graphs as well.
Most interesting I find any technique that lowers odd order harmonics - as the SL for example.
greetings
Michael
almost anything about faraday rings is also outlined at:
http://www.diyaudio.com/forums/show...2247&highlight=
"http://www.diyaudio.com/forums/showthread.php?s=&threadid=62247&highlight="
Please note that faraday rings basically lower 2nd harmonics. This isn't always your desire.
Especially not if 3rd or higher order harmonics become dominant that way.
What I am curious about is why ALNICO is rated so high and if probably hysteresis has more to do with it than resistance to flux modulation, though this should show up at distortion graphs as well.
Most interesting I find any technique that lowers odd order harmonics - as the SL for example.
greetings
Michael
mige0 said:
You're absolutely right. Volterra filters can sort out second-order distortion a lot more easily than third-order, and higher order corrections need astonishing amounts of computation. Some of the newer techniques such as XBL2 reduce second and third order products at the expense of increasing higher order terms, so those drivers won't be as amenable to DSP distortion reduction.
Faraday rings around the base of the pole piece fight 2nd harmonic distortion by reducing the degree to which the voice coil field pushes the virtual center of the B field down the pole.
A faraday shield all the way through the gap can be even more effective because it both anchors the B field and reduces the penetration of the VC field into the pole, especially at higher frequencies, thereby also reducing 3rd harmonic distortion. The VC field's interaction with steel's nonlinear BH curve is otherwise a prime source of 3rd harmonic.
As already mentioned, ATC's SLMM material (powdered iron in a nonconductive binder matrix, as far as I can tell) is a completely different approach to the problem. In addition to raising inductance by suppressing eddy currents, it may offer a more linear BH curve than steel. I haven't studied it out, so I'm taking a few guesses here.
As technology marches on, it seems to me that we're going to have to start reducing steel's role in loudspeaker motors if we want to keep pushing down HD numbers.
It takes some imagination to picture a motor without steel, but there are some nifty ways to do it.
A faraday shield all the way through the gap can be even more effective because it both anchors the B field and reduces the penetration of the VC field into the pole, especially at higher frequencies, thereby also reducing 3rd harmonic distortion. The VC field's interaction with steel's nonlinear BH curve is otherwise a prime source of 3rd harmonic.
As already mentioned, ATC's SLMM material (powdered iron in a nonconductive binder matrix, as far as I can tell) is a completely different approach to the problem. In addition to raising inductance by suppressing eddy currents, it may offer a more linear BH curve than steel. I haven't studied it out, so I'm taking a few guesses here.
As technology marches on, it seems to me that we're going to have to start reducing steel's role in loudspeaker motors if we want to keep pushing down HD numbers.
It takes some imagination to picture a motor without steel, but there are some nifty ways to do it.
I was buying some pro sound drivers a couple of years ago and while researching I noticed that every Neo driver (compression drivers, mids, woofers - all of them) in Beyma's line-up had substantially higher levels of H2 and H3 than their top line ferrite products. This was taken directly from their own product literature. Anomaly?
KBK said:A well designed field coil driver makes all of this discussion get up and go away.
Think abut that for a few minutes.
Considering that Arnold magnetics is adding a surcharge on cobalt and nickle, I will not surprised that speaker designers will be moving forward and advancing to using field coils once again.
This isn't directly apropos of recent comments, but I wanted to mention that I just replaced the 2220J's in my Iron Lawbreakers with freshly reconed and remagnetized 2220B's (courtesy of GPA) and am noticing a very significant improvement in inner detail through the lows and lower mids, also matching these characteristics of the HF 288G's quite a bit better. As a result, the sound stage has also become deeper and more coherent throughout the speakers' bandpass with better articulation of small musical details.
Compared to the 2220Bs, the 2220Js sounded a tad hashier, masking subtle inner detail. Since I'm not going to push the 2220B's with more than a few watts average or dropkick the speakers around town in this application, I have no concerns regarding alnico 'demagnetization'.
Compared to the 2220Bs, the 2220Js sounded a tad hashier, masking subtle inner detail. Since I'm not going to push the 2220B's with more than a few watts average or dropkick the speakers around town in this application, I have no concerns regarding alnico 'demagnetization'.
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