From the perspective that the OP was looking for a mic under $200, and doing a quick google search, the D112 seemed to be the mic that fit the cost parameters, and provided some adequate ability to reproduce bass guitar. I have used SM57's when I was a kid (no offense meant, I just haven't ever HAD to use a 57 on a bass since the 80's) and once I had the good fortune of using an RE20, I bought one and never looked back.
I did however, put that mic to the side and primarily use DI's because the sound guys I used after the 80's didn't really know what to do with a mic'd signal. And also because my tonal tastes moved away from being a T-Bird/Ampeg type hard rock bassist into being a cleaner solid state tone guy. I no longer wanted the tube grind unless I wanted to call it up for a song.
At that time, I did play for a living and immediately after giving up the playing road as a means of full time employment, got into pro audio contracting industry as a system designer and lead technician working my way to being the GM at my current company. IMLTHO, I would not use a 57 for live bass, I would use a DI. Maybe you want that ratty tone because it's what you like, OK, who am I to tell you how to translate what's in your head. I also only use my RE20 in a studio situation anymore. As mentioned the knowledge level and experience level of the majority of the live FOH guys I have worked with since the mid-90's has dropped like a rock, so I prefer controlling what the audience hears (besides the mostly 80HZ and freqs below that the FOH guy is using).
So my answer to this thread would be....If you can't afford a good mic but like the non-hifi bass sound, a 57 would work. If you prefer the cleaner hifi bass tone and can't afford a good mic, buy a DI. If you play in a modern metal or modern punk band, buy the 57, who in those venues might ever notice the difference. If you are playing fusion, country, jazz, pop, gospel, or just love that Level 42/Marcus Miller/Tal W type tone, go with a nice mic or a nice DI, but a 57 probably is not your better choice over a DI. But...if I couldn't afford a good mic, and did not already have a spare SM57 laying in the bottom of my mic bag....I would not go out and buy one. I would buy a nice passive DI box (made by a company that does not begin with "B"), and save the other $50 to $75 bucks in the bank until I could afford a better quality mic for your bass rig such as an RE20.
Make sense? I know there are plenty of guys out there that can't seem/don't know to get anything out of the AKG D112, so they might as well just use a 57, I'm good with that. I do own an RE20, s obviously no issue there, but I couldn't find a used one for under $200 and I could find a D112.
I've also had lengthy diatribes on other threads that if you can't afford an RE20, I would only use a DI. And I would certainly rather use a non-"B" made DI than a 57 until I could afford a good bass mic, so please save you gas from driving to MA and just drop the $30 on a Rapco DB-1 until then.
But I also understand Malumutes frustrated postured response. Some of us that do this, even though we don't pay for a living anymore, we've been to places, done some gigs...that 95% of the guys here will never get to experience. We offer our truly learned knowledge to assist those not in the know. Some of us are at times, blunter and more sarcastic than we need to be. It truly amazes our sense of "if you're going to do it...do it right" approach to our music, that you guys don't spend what we do on our gear. You'll buy a nice bass and rig, but when it comes time to drop money on the rest of the weakest link in the signal chain, many wimp out and aren't going to invest that kind of money. Maybe you thought you needed a new GPS for your boat, wanted to put some pinstripes on your pickup or tats on your ass...whatever. For the more impassioned players, we invest in the best we can lay our hands on.
That said....do I make more money when I use an RE20 instead of my DI...F*ck No! Do I make more money using my DI instead of an SM57...no again, it has nothing to do with the sound of my bass, it has everything to do with the band I'm playing in and the music we play. The many many 1,000's I am lucky enough to play for every year couldn't care less about my/your bass sound as long as it doesn't suck. They really just want to hear me/us sing and shake my/our ass.
I searched for one for a while for a decently priced used RE20 before buying my Heil PR40. It's pretty darn close to the RE20 and has served me well, plus it's not as bulky as the RE20 and fits on my short stand better for mic'ing my cab live.
