two vocal mics going into two amps via a little mixer,
Two amps? Are you referring to GUITAR AMPS? Or a stereo amp or what? If you are using guitar amps, usually, the signal from a mixer is LINE LEVEL, which when fed to a HI IMPEDENCE level input on a guitar amp will overdrive the amp very easily, to the point it is difficult to adjust minute volume differences.
so I tried turning an amp into the wall/away from the mics, but still can't get much volume without the squealing.
First off, IF these are indeed guitar amps, the circuitry and speaker is designed for reproducing a range of frequencies specific to guitars. They do not work well for PA amps.
Furthermore, IF these amps have OPEN backs, it won't matter which direction the speaker faces.
My next plan off attack is to put one amp in the closet (with some padding around it) and the other near the opposite corner (again with padding because I know corners are bad) with the microphones going into the amp furthest from each.
Brilliant. First you amplify a signal in a small room to the point of feedback and then put the speaker in a closet.
ummm, what part of this am I missing. The point is, IF you are trying to amplify vocals in a "small room" to compete with electronic instruments or drums, you have a problem. The higher the volume of the band, the more difficult it becomes to match the vocal volume to it. Especially if you are using guitar amps...which you may also be using at the same time for the instrument.
There is a simple solution. Since this is practice, I suggest using your mixer to drive a HEADPHONE DISTRIBUTION AMP, and have each musician wear headphones. This isolates the sound of the vocals from the mics, and as the mics are picking up the whole room, will pick up drums and amplified instruments. Some guitar amps have a LINE LEVEL output to feed a mixer as well, so you can adjust the levels in the headphones. Bass guitars can be fed direct to the mixer if it has HI IMPEDENCE inputs. Or simply use a Direct box to match the output of a guitar/bass to a LOW IMPEDENCE mic input on the mixer. As far as drums are concerned, I've played with drummers under these circumstances who use ELECTRONIC drum pads and they sounded great. For guitarists, running direct to a mixer is usually a problem, as they can't get the tone. There are all kinds of devices to put between the guitar and the mixer to get incredible guitar sounds.
No matter what, this problem has plagued ROCK bands for centurys.
Playing at concert level in a small room and trying to make vocals cut through is difficult under the best of conditions, and impossible under some conditions....like using guitar amps for a PA.
BTW, have you ever noticed the musicians in large venue concerts wearing EAR BUDS. I wonder why?(take a guess)