Capsule limitations

A project log for Mini Shotgun Mic

Building a Shotgun Microphone from scratch. From Modifing an electret capsule to building an interference tube.

mengaMenga 05/24/2018 at 02:060 Comments

Besides the unresolved issue with the 48v phantom, i discover that the microphone had very low off-axis attenuation. 

I research the capsule, and apparently it's pressure operated, which means it has a constant internal pressure, and it's the sound wave what changes the outside pressure and moves the membrane.

This is grat for an omni-directional mic, but not for a shotgun.

Shotgun Mics use pressure-gradient capsules. This capsules have vents on both sides (front and rear) to reject sound comming from the sides.

There is an exelent video about it from the EEV blog here:

I dissasemble the capsule to see if can be modified, by making vent holes on the body. The extremly small side of it make it very hard, but not impossible.

The fix plate is drilled so it can be converted to a pressure gradient ( I probably will destroy a few with the drill before i success)