From the MAKE Flickr pool
Member Aud1073cH writes -

My DIY low frequency speaker microphone, inspired by the Yamaha Subkick. I feel this one is much better with a dual coil woofer allowing for coil selection, damping, and input modes. Also has its own DI circuit for use as a DI and speaker, and a balanced output. Pad, phase flip, and ground lift included.

He’s also created an instructable for the project. Nice remake!

SPKR MiK on Flickr -Link

SPKR MiK on Instructables -Link

Subkick on Yamaha.com -Link