Thanks for responding, Macrojack, and fully disclosing your affiliation with Zu. I was pretty rough on you there, but now I can see that there are two sides to it.
In my opinion the readers have a right to judge for themselves whether or not an affiliation matters, or is merely theoretical. Some will misjudge you out of an innate prejudice against anyone who believes in a product enough to be officially affiliated with it, but methinks it best to err on the side of disclosure. Of course, memakes not the rules.
To answer your first question, yes - a field-coil driver uses an electromagnet rather than a permanent magnet, typically connected to a battery or a power supply. I've been told the theoretical advantage is that a battery or power supply's voltage is more constant than is the flux of a permanent magnet (even an Alnico one) under dynamic conditions, but don't know whether that's really true. One very cool thing about an electromagnet is that you can vary the strength of the magnet (and thereby the Qes, and thereby the frequency response) by adjusting the voltage applied to the field coil. You can tailor the driver's characteristics to the enclosure, to a certain extent.
To answer your second question - I think you did great!
Duke
In my opinion the readers have a right to judge for themselves whether or not an affiliation matters, or is merely theoretical. Some will misjudge you out of an innate prejudice against anyone who believes in a product enough to be officially affiliated with it, but methinks it best to err on the side of disclosure. Of course, memakes not the rules.
To answer your first question, yes - a field-coil driver uses an electromagnet rather than a permanent magnet, typically connected to a battery or a power supply. I've been told the theoretical advantage is that a battery or power supply's voltage is more constant than is the flux of a permanent magnet (even an Alnico one) under dynamic conditions, but don't know whether that's really true. One very cool thing about an electromagnet is that you can vary the strength of the magnet (and thereby the Qes, and thereby the frequency response) by adjusting the voltage applied to the field coil. You can tailor the driver's characteristics to the enclosure, to a certain extent.
To answer your second question - I think you did great!
Duke