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  1. Darren Landrum says:

    The first thing I’m wondering is, if the fidelity could be improved by elevating the magnet off of the cardboard a bit to center it in the coil. This could be done with a round of foam, or something similar, with a diameter slightly smaller than the magnet. It’s a thought, anyway.

  2. 09jkitchen says:

    what do you think the minumum voltage for this to work is?

  3. Anonymous says:

    I could be wrong, but i think it’s possible to seriously damage your amplifier hardware if the speaker impedance is too low. Its like running a wire over a 9-v battery — too small a load results in lots of power lost as heat. It should probably be emphasized that the coil should read at least 6-8 ohms on your meter to be absolutely sure you won’t damage anything.

    Less than 8 ohms is probably okay, since resistance is only half of the impedance equation, but since its difficult to measure the reactance of a coil over the audible spectrum without expensive equipment, its better to be safe than sorry.