Re: A Cab I Can Use for Guitar and Bass?
Fender Bassman cabinet.
Practically, you can use any guitar or bass cabinet with any guitar or bass amp (as long as the impedances are matched) - it's not like your gear will burst into flames. You can blow speakers if you aren't careful, but you can blow guitar speakers with a guitar amp (even if the speaker has a higher power rating than an amp's peak wattage); the claim that bass amps will destroy guitar speakers is a bit exaggerated. The real question is simply what will sound good to you, and that requires experimentation. There isn't really a straight answer.
Things to consider: Many guitar speakers have a frequency range that goes pretty low: about 80 Hz. Yes, The fundamental notes of a bass guitar go much lower than that, but so does a guitar's notes. A guitar tuned to C# standard has a low C#2 which is ~69 Hz - below quite a few guitar speakers' frequency range, yet that doesn't really damage the speakers. There's even people using regular guitar amps with 8 string guitars that can go down to G1 (~49 Hz - bass guitar range) which is well below a guitar speaker's range, yet again that still doesn't necessarily cause problems. Part of the reason there isn't a problem with low guitar tunings through a guitar rig is that guitar amps are designed to inherently cut unwanted frequencies, mainly extreme low frequencies so that they don't even reach the speaker and thus won't damage them. If you run a bass amp through a guitar cabinet - just don't include extreme low frequencies when EQ'ing the amp (sometimes even bass amps will cut these frequencies anyways), get speaker's with a low enough frequency range, or utilize crossover networks to send those frequencies outside a guitar speaker's range to a separate subwoofer. You could just cut anything below 60 Hz with an EQ in a bass amp's effects loop, and you won't have to worry about low frequencies damaging the speakers, and it won't really be detrimental to the tone (those frequencies are much more "felt" more than they are "heard", and are usually cut in a mix anyways to avoid low end build up). Also, keep in mind that it takes more power to amplify low frequencies than say, midrange frequencies. So it'd be a good idea to have speakers that have a high power rating to accomodate a bass amp's inherent higher power capabilities, and lower frequencies won't cause the speaker to distort so early.
It's very doable. The Fender Bassman, while not the best amp for bass, can be used for bass through a guitar cabinet and still sound fine. It's not always an ideal setup but like most things gear related, it's fine if you just shut up and play.