Does a pickup microphone work in space (vacuum)?

Question

Of course in space there is no sound transmitted via air, so there is no air-borne sound, but there is structure borne sound. This sound can be recorded with a pickup microphone, but do pickup microphones need air to work as well?

Considering that a pickup is really just recording the surface waves, but if it is mounted on the same surface with the same vibrations, it in theory should measure nothing, correct? My assumption is that pickups measure the difference between the air damped surrounding and the material itself, so it should not work in vaccum as there is nothing to damp against.

The other theory I have is that it depends on the mounting of the microphone. So if I fully connect it in a sphere around a certain point, it would measure the surface wave within this mounting area, but wouldn't that limit the measurement to sound waves smaller than the mounting area (higher frequencies)?

Answer 1

A contact microphone is basically an accelerometer. It does not require any air for its operation.

Answer 2

if it is mounted on the same surface with the same vibrations, it in theory should measure nothing.

When sound waves propagate through solid material, it's not just the whole rigid object shaking back and forth: It's waves of strain.

Those strain waves will pass through a contact microphone that is attached to some small area of the surface. It will work better still if it can be wedged in between two different parts of some flexible structure:

_{(source: kksound.com)}

^{Piezo pickup wedged into the bridge of a string bass (double bass)}

Answer 3

Pickups, like the ones used in guitars, are not strictly microphones. They work on a similar principle, but are coupled in some way to the object producing the vibration. I'm not sure exactly what kind of pickup you are thinking of, but I'm aware of two primary kinds:

1. Magnetic Pickup
2. Piezo Pickup

In the case of the first, the magnetic field inside the pickup will oscillate along with the (guitar) string's vibration; this causes an electric current which can be transmitted to a speaker. Magnetic fields can propagate through space without any air.

In the case of the second, the vibrations are carried through solid material (again, not air) into the magnet/coil pair which produces the electrical current. This will also work in a vacuum.