| How to connect and use the
QM12 Quad
microphone: You will need a good mixing board with balanced inputs and 48V phantom, preferably with the EQ disabled and with a phase reverse button. If it doesn't have a phase reverse button you will have to use an adaptor cable to reverse the phase. (XLR: pin1-pin1, pin2-pin3, pin3-pin2). If all 4 cartridges are recorded to seperate tracks, experimentation with different pickup patterns is possible without having to re-record to try different techniques. Mono patterns. Cardioid: Since the QM12 is built of four completely identical cardioid cartridges, picking up cardioid is just a matter of connecting one of the four cartridges (see number on XLR fan-out) to the mixer. Omni: Cartridge "1" (front) and "3"(back) are connected to the mixing board and mixed together in at equal levels, resulting in an even omni pickup. By lowering the level of the back channel it is possible to adjust the directionality and go from omni to cardioid, without steps. Figure eight: The same procedure as "omni". The difference is that to achieve figure eight, the back channel is phase reversed (with the mixing board phase-reverse button or using an adaptor cable). By lowering the level of the back channel it is possible to adjust the directionality and go from cardoid to super-cardioid to figure eight, without steps. Both channels used should, to begin with, have the same gain. Stereo patterns. X/Y: Cartridge 1 is pointed 45 degrees to the left with cartridge 2 pointed 45 degrees to the right. "1" is panned left and "2" is panned right. This usually gives a very faithful reproduction of the recording event, with a natural balance of direct and ambient sound and good stereo separation and stable center image. It is also very easy to set up, just point and record. Sound coming from behind the mic is damped. Wide X/Y (stereo omni): If cartridge membranes 3 and 4 are mixed in (1+4 panned left and 2+3 panned right) with equal levels, the result is an X/Y that has no backwards damping at all. This can be very useable when sound sources are spread out all around the microphone. It also returns more ambience, but too much in some situations. By lowering the level of the back channels it is possible to go from wide X/Y to X/Y without steps. Blumlein (crossed figure eight): Two figure eights set up in a cross. Membrane "1" front (in phase) is mixed with "3" back (phase reversed) to make the left channel. The right channel is built of membrane "2" front (in phase) and "4" back (phase reversed). All channel levels should be equal to begin with. This technique will, with some experimentation and planning, give a reproduction with a very convincing, exploding stereo image with very good stereo separation. (Sound sources very far out on the sides can in some situations sound slightly out of phase.) By lowering the level of the back channels it is possible to go from Blumlein to X/Y without steps. M/S (Middle/side): Is built of one cartridge (cardioid) picking up straight forward ("middle") and a crossed figure eight ("side") picking up mainly left and right (only a little center). Membrane 1 is used as center and is pointed and panned center. The figure eight is built of "2" and "4". The easiest way to describe and connect it is using four more channels on the mixer, totally five. Two of these four channels are panned right and two panned left. Split cables may be needed. Right: "2" is connected to one of the two "right" channels in phase while 4 is connected phase-reversed to the other "right" channel. Left: "2" is connected to one of the two "left" channels phase-reversed while 4 is connected in phase to the other "left" channel. You now have four channels on the mixer, carrying the stereo information and one channel carrying the center/"middle" information. All channels mixed in a equal proportions results in a stereo image similar to the X/Y technique. By changing the level of all the four channels carrying the stereo information, it is possible to adjust the wideness of the stereo image from mono (no "side" level at all) over to "normal" (equal "side"/"middle" levels) over to "wide" (by exaggerating the "side" level). Suggestion for the mono and stereo alternatives: If the signal coming from behind is of ambient nature it can sometimes sound better with some experimentation, for example, if the room sounds boomy it can sometimes sound clearer if low end is filtered out slightly from the back membranes using a soft shelving filter (low Q and low phase distortion). Quad pattern (and surround): Each membrane is connected to one of four channels ("1" left, "2" right, "3" right back, "4" left back) and will pick up real Quadraphonic-sound with real, explosive depth in all directions. This results in the same exact definition of L-R placement as X/Y stereo recordings, with the additional sensation of real depth and distance from all locations around the mic. |
