This project originated when our band, The Horseshoe Crabs, realized that we would like to have a bass drum. After a little internet research, I found that several people have made foot drums from fruit crates or other wood boxes with microphones built into them. I already had eighteen four inch CTS drivers that I removed from a pair of Bose 901 speakers I found at the local transfer station several years ago. The 901 wood cabinets were in very poor condition and the drivers were the only thing worth saving. I built a wood box with 3/4 inch pine wood for the bottom and sides and a 1/4 inch plywood top. I mounted one of the 901 speakers inside the box. The box is sealed like an "acoustic suspension" speaker. I plugged the speaker into an amplifier input and found that the drum worked but the pitch was too high to sound like a bass drum. However, after epoxying a large steel washer to the speaker cone, I was able to lower the resonance of the system into the "bass drum" range. Here is the foot drum viewed from the bottom:
Recently, I decided to add a handle and paint the sides. I did not paint the top and bottom so as not to interfere with the sound. Here is a picture taken while the black paint was drying:
Foot Drum - New Paint
Here is the foot drum with the handle installed.
Foot Drum - Handle Installed
I must say a few words in praise of the quality of the four inch CTS speaker driver found in the Bose 901. This foot drum has been in use for about four years now. I have seventeen more of the CTS speakers from the 901 and I always knew I would be able to replace the foot drum speaker in the event that it succumbed to the beat imposed upon it during gigs. However, the speaker is still working fine. Kudos to Bose for sourcing such a robust little woofer. The foot drum sounds great too!