double bass passive quadruple piezo pickup with low pass filter and volume controle
double bass cardioid microphone + quadruple piezo with preamp and tone control
cello cardioid microphone + piezo with preamp and volume control
violin and viola omnidirectional microphone + double piezo with preamp and volume control
violin and viola passive double piezo pickup with low pass filter
cello passive double piezo pickup with low pass filter