Sounds like fun, especially with that potentially nice sounding room.
Assuming the players are good and the room sounds nice here’s what I would do:
Imagine a circle on the stage or a nice sounding spot in the room. The circle will have a radius of about 4-5 feet.
Set-up the drums so that the batter side of the kick is tangent to the circle and faces the center of the circle. In other words, the BD is just inside the circle. If possible place 3-4 foot tall gobos on either side of the drums (this is no big deal but nice if you can).
Now place the guitar and bass on opposite sides of the drums about 2-3 feet to either side with the front of the amps also tangent to this imagined circle. Think of the amps as being just outside the circle facing the center, one to the drummer's left and the other to the right.
The center of your circle is ground zero. On that spot, place a coincident (whatever coincident type you like) pair in omni mode (second best is figure of 8, third best is cardioid) so that their height is about 1 inch above the bass drum hoop (but still 4-5 feet away from the drums). If you were to draw a line from the “center” of the drum set to ground zero, it should bisect the angle between your mics (i.e. mics are not pointing directly at drums). One mic should point directly at the guitar amp (elevate the amp if needed) and the other at the bass amp. Choose mics that capture low end well and are detailed.
Now place a cardioid or hyper cardioid mic above the drummer. Rather than pointing it stright down, angle it lisghtly toward the center of the circle, pointig at the spot where the beater hits the BD. This mic must be in phase with the other 2 mics:
-all 3 mics equidistant from the “center” of the drum set.
-The phase setting on the OH preamp should be the opposite of the GZ premps.
The guit and bass amps should be in the null of the OH mic. Gobos help with this but are not necessary. What is the “center” of a drum set? In this case I would consider it the spot where the beater hits the BD head.
Once these 3 mics are set-up, record the drummer hitting a few very staccato and loud snare and BD hits (not together). Check your DAW for phase:
-zoom in on the tracks and make sure the waves start at the same time
-make sure the sound waves are moveing in the same direction.
Then adjust the position of the OH mic as needed. During mixing use the OH track to fill in the gaps your ears may hear from the ground zero mics. The drums should sound nice in the GZ mics but may lack some definition. A touch of compression will help this as well (but save that for mixing).
Place the keyboard amp opposite the drums pointed at ground zero. The XY mics will capture the keys. Move the amp for balance. If the amp is stereo, all the better! Just make sure the stereo field of the amp is centered with that of the GZ mics. Close mic this amp just in case. If your ground zero mics are figure-of-8 then you shouldn’t need another mic for the keys. If they are omni you probably will. If they are cardioid place the keyboard amp in the null of the GZ mics and close-mic it.
You can put the trumpet player wherever you want, close miced. Just make sure the other sound sources are in this mic’s null. The best place should be between the keys and the bass amp facing ground zero with a cardioid mic facing out from the middle of your imagined circle.
One alternative is to swap the bass amp position with the drum set's position. One of the GZ mics should point at the drums and the other at the guitar amp (after all, you are simply swapping the bass and the drums) and the bass right down the middle. This may allow you to get rid of the OH mic. In this case I would place the trumpet between the keys and guitar.
Place a flanked stereo pair in the room.
Don't use the NT4
as your ground zero mic. I like those but they exhibite a pronounced proximity effect and will sound thin in this role.
5-7 mics and it should sound awesome! Post a sound bite when you get a chance.