The D-112 will work fine but I bet you'll end up drastically cutting lows and boosting mids at mixdown.
I think the 421-II is a much better choice for micing bass cabs. It also has the advantage of being a world class mic for guitar cabs, drums (including kick), many vocalist and just about anything else you'll ever want to mic.
If you can hunt down one of the older (used) Sennheiser 421u5 models in nice shape, they're even better than the new ones and usually cost much-much less. (I own three 421u5's and one of the newer 421-II models)
There's also some older versions of the 421 that are very desirable.
Here's some 421u5 info:
http://www.google.com/search?hl=en&r...421+u5&spell=1
If you run across a deal on a nice used Sennheiser 441, grab it, there even better.
441 info:
http://www.google.com/search?sourcei...Sennheiser+441
