This is an old, but very effective trick for miking kick drums. Take a Yamaha NS10 speaker cone and use that to capture the extra low frequencies of the drum. Without going into too much theory about this, a dynamic microphone and a speaker are essentially the same thing, they are both transducers. They take acoustical energy and convert it into electrical energy or vice versa.
So what you do is take the speaker out of the box, solder a male XLR plug on a short cable to the speaker terminals. Pin 2 goes to (+) and Pin 1 goes to (-) pin 3 is not used. The matter of mounting this speaker to a stand is a different matter, this is the main reason to go buy the Yamaha Subkick microphone, because of it’s great, easy to use mounting system, that and its also more durable likely than the home version. One way to do it is to take a standard mic clip apart and fitting the slotted part securely to the corner mounting holes of the speaker, that is if the speaker you are using has the 4 corners and not just holes drilled just around the cone [square not a circle]. Or you can attach it to a microphone boom or goose-neck permanently.
The output of the subkick is very hot, meaning you are going to have to attenuate the signal for it to be of any use to you. An inline -20dB pad, a pad at the mic pre, or one built into the mic will need to be used. This guy used a 10k Ohm in series with pin 2 and a 1k Ohm resister across pins 1 and 2 to drop the output about 20dB.
Mic placement: These work really well at the edge of the drum parallel to the skin. Try it under a floor tom too.
Why the NS10? Most time you see these in a studio it will be with an NS10 cone, but why? From what I’ve been told it is because there are usually extra NS10s lying around a studio, all studios had NS10s, you could predict how it would sound, and they have a frequency response that works well. Don’t know how much truth there is to that. You can use any speaker you want, it will obviously make a difference in the sound.
Finally, here is a picture I took of one of the two diy subkicks at Metalworks Studios. Note mounting, placement, and inline pad.