The hybrid dipole project requires a small, approximately 4”-5", mid bass driver.  After many tests I’ve narrowed it down to a few contenders.  Here are the test results thus far:

BMS 5S117-8

CSS VWR126X

Eton 3-401 A8/25MG

Motus UH130PW1

Peerless 830992

Peerless 835023

SB Acoustics SB12NRX25-4

SB Acoustics SB12NRXF25-4

Scan Speak 10F/4424G00

Scan Speak 12W/4524G

Seas MCA12RC

Seas W12CY-003

Tang Band W3-1878

Vifa NE123-04