Electrostatic Field Meter Used
Simco
Magnetic Field

A typical loudspeaker magnet can have a magnetic field strength ranging from around 5,000 to 10,000 gauss, depending on the speaker size and quality, with higher-end speakers potentially reaching even higher values; this is often measured in terms of flux density, which is typically expressed in Tesla (where 1 Tesla equals 10,000 Gauss).
Composed
of Aluminum, Nickel and Cobalt, JBL was the industry leader in
introducing this strong permanent high power alloy in professional
speaker systems. Alnico magnets produce magnetic field strength at their poles as high as 1500 gauss (0.15 tesla), or about 3000 times the strength of Earth's magnetic field.
Electromagnetic Field
Nuclear Radiation