I'm looking at getting a Velleman microphone kit. It has two external pick ups routed to a headphone jack. I have a J2P and already have a couple fans mounted, which makes it difficult to hear. Positioning the pick ups is going to be a custom alteration for the kit, bit it's within my skill set.
There's the previously mentioned uproar, which is similar to the kit I'm looking at.
Right now, I'm not using anything to enhance hearing. Sound is muffled bit discernible without my fans running, but when they are on, I can't hear a thing. I use the fans sparingly for that reason.