Overview:
This project is intended to try and help with the problem of the exaggerated high frequency (HF) response found in many - otherwise excellent - cheap Chinese condenser microphone capsules.
THIS article from Michael Joly helps to explain why the problem exists.
Where the microphones are being used to record, applying frequency response corrections in DAW software during editing is a pretty standard approach.
If however real time correction is required (for podcasting, broadcasting etc) the problem can be more challenging...
( There's a direct link to the project prototype band pass filter schematic... HERE )
Adding low pass filters to the internal microphone electronics is often suggested as a possible solution for this problem, but these simple passive filters can often remove too much overall HF content, rather than just the specific band(s) of frequencies that are causing the problem.
In addition, adding passive resistors into the signal path - especially before the mic preamp - can introduce extra noise into the system.
This project suggests adding active filters into the signal path at line level via the 'TRS insert jack' of an audio interface - or mic channel strip....
The images on the right here suggest how such individual filters might look, although - as you can see - the prototypes were constructed very much with economy in mind for these initial experiments!
This approach may offer a way for more complex - and hopefully more accurate? - frequency response correction can be introduced into the signal path - in real time - without adding any significant extra noise in the process...
Click on any of the 3 page buttons at the top (or bottom) of this page for details of some initial ideas on how suitable EQ modules might be constructed...
