SK10 is a free audio plugin that simulates a sub-kick microphone. A sub-kick mic is essentially a speaker converted into a microphone. Thanks to its diameter it captures a lot of low end and it’s a perfect fit along your regular kick mic for boosting the low frequencies.
Formats:
VST
Audio Units (AU)
AAX
https://www.wavesfactory.com/free-audio-plugins/sk10/