I was hoping some one could help me with a calculation. I am an engineer in another dicipline who has been trying to stitch together formulas from many sources to try to solve what I would have thought to be a basic problem. That is:

How many turns are required for a single layer air-gap-coil of 4"diameter and 4" length to provide 8 ohms impedence at 80hz.

The length of the coil can be varied 25% either way if that helps.

I kept coming up with approx 1 turn, but thought this must surely be wrong.

Any help would be appreciated.

-Scott Hooper