I think the posting may have been mine. I have a pair of KM184s and have used one strung between the legs of the bridge - it worked OK for low volume gigs, but at higher levels was prone to feedback. I also have a KM185 which I also used in a similar manner - this worked better, but still tends to feed back at high levels. The foam mount behind the tail-piece, was just a convenient way of mounting the mic quickly, as I found that setting up and adjusting the rubber-bands was too fiddly in a live situation, especially if the lights were dimmed. The KM185 would also work very well on a stand with the mic pointing at the bridge, but then I'd have to be constantly aware of keeping the bass in the "sweet-spot", especially with a hypercardioid, so it's much easier to have the mic mounted on the bass (one disadvantage of having it pointing up is that it tends to pick up any noises or comments I might make, although I tend not be a "grunter"
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As for the results, I find that if it's a quiet gig (just guitar & bass, say) I can easily play without the amp - if there's a sax or piano and drums, then I might have to have the amp on low, and I now use the KM185 behind the tailpiece - the sound is my bass, but louder. If I'm playing with a larger group where there may be even more sound (horn section, or big-band) then I use the Fishman Full-Circle, which I've found is least susceptible to feed-back, but doesn't sound as good as just using the mic.
I've also played at gigs where there's been a sound system, and I found that using just the mic through the board, so that the bass was amplified through the main system, and not bothering with my stage amp - that seemed to work extremely well - people commented on how nice the bass sounded, and everyone in the band could hear it clearly even though I wasn't using a stage amp.
For recording, where you have total control of the environment, I think using a good mic beats using any pickup any day (IMNSOH)
Hope this helps -
- Wil
