Test: Mod vs NoMod

A project log for Mini Shotgun Mic

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

MengaMenga 06/01/2018 at 07:310 Comments

Today I repeat the test usign a the same circuit preamp and just switching capsules, the modded and the original.

I use this circuit:

Resultado de imagen para electret preampAt 3V. Curious thing, the modded capsule is less sensitive than the original one, also it picked alot of line noise (50hz), might be a shaving acting as an antenna or something.

The capsules were tested at 10cm of a speaker, at 0° (on axis) and at 90° (off axis) with a 500hz tone.
I also compared an Audiotechnica AT897 (Condenser hipercardioid) and a Shure 8800 (dinamic, cardioid) at 30cm of the speaker.

(Warning: ugly circuites ahead)

The results were measured usign Audacity, by duplicating the track and usign the tool "Contrast" on the Analize menu. This tool allows to compare two selections on different tracks and calculate the RMS.

In this test no filtering to isolate the 500hz tone were applied.

Now the Audiotechnica AT897

Shows -10.3dB off Axis

Shure 8800

Showed -1.4dB off axis

I'd like other people trying this mod and testing it, so we can compare results.

Also i will try to find bigger capsules to see how they behave, mostly because i think such a small capsule would't be apropiate for a shotgun mic.

Or maybe build my own capsule