How to make an inexpensive microphone capable of picking up low frequencies that doubles as a speaker and direct box.
The large diaphragm of this microphone will pick up more of the low frequencies when recording a kick drum or bass guitar.
Sound recording engineers have been using this trick for years, and Yamaha has also made a commercial speaker microphone called the SubKick, that usually retails for around USD$300.
I was able to build this mic for under $20 by “scrounging” various parts out of old junk. Even if you need to buy all the components, you should be able to build this mic for a fraction of the price of the retail version.
This design goes slightly beyond the SubKick, as far as electronics are concerned, with a dual coil design, and internal direct injection (DI) box.