The under appreciated impedance curve
I do think that the community at large does not appreciate how much we can learn.I second that. That doesn't mean to be an accusation of anyone in particular.More more it's talked about, the more they'll make a effort to at least try understand them. For those how wish to understand impedance/-phase graphs using Ken Kantor's easy simulated speaker loading. https://www.stereophile.com/reference/60/index.html https://www.stereophile.com/content/measuring-loudspeakers-part-one-page-6 Cheers George |
Bruce Thigpen stated in his discussion on the design of his magnetic-planar driver, the Linear Field Transducer (LFT), that he could make it with any nominal impedance he chose. Bruce says he chose 4 ohms for the LFT-3, LFT-4, and LFT-6 so as to enable the power amp driving them to provide them with as much power as they are capable of producing (assuming the amp is solid state, of course. SS amps produce more power into lower impedances than into higher. Most tube amps are the opposite.). He doesn’t say why he chose 8 ohms for the LFT-8 (and improved incarnation the -8a and current -8b), but by virtue of it being a nominal 8 ohm speaker, the LFT-8/a/b is more suitable for use with a tube amp than are the magnetic-planar driver 4 ohm Magnepans. By the way, if bi-amped, the LFT-8b’s magnetic-planar midrange driver and ribbon tweeter themselves presents an almost purely resistive 11 ohm load to the power amp, and are therefore an excellent candidate for use with a tube design. |
that he could make it with any nominal impedance he chose. This is true for all cones as well. Off the shelf components are often available at different impedance for exactly the same reasons. Lower impedance = more current = more force against the magnetic field. However, I have in fact seen Focal create a crossover deliberately to burn power. It had 80 W worth of resistors that didn't need to be there. |
