The Rode NT5's cardioid pattern will reject sound coming from the rear, which can be useful in live recording situations.
I have been planning to record an upcoming choir concert with a centred ORTF stereo pair of Rode NT5 cardioids. It's a 30-person choir and the location is a 900-year-old Danish stone church. The problem is, the choir director won't let me put a mic stand in the middle of the centre aisle because it is narrow, the church will be crowded and she has to go back and forth to play the organ in the back of the church for several numbers. However, most songs will be a cappella.
There's nothing suitable to hang the mics from, and I only have ordinary K&M mic stands, with small booms. Since the choir is in the front, and the organ is in the back, I figure a good solution is use to a spaced pair of omni condensers, such as AT3032s, on stands on each side of the aisle, a couple of metres back from the choir (about the third pew).
As an alternative, I did find a short gooseneck section to put at the end of the boom and attach to an ORTF stereo bar. If I can tilt the boom a bit out toward the middle I will still be able to bend the gooseneck up so the bar is level. This is my first choir recording, and I haven't bought the AT3032s yet, so I'd really appreciate any advice or suggestions, on mic placement (height and distance from choir) and choice of mics.
SOS Forum Post
Technical Editor Hugh Robjohns replies: A stone church is likely to be very reverberant so I would think spaced omnis would produce a very 'swimmy' sound, and your only way of balancing the choir against the organ would involve moving the mics up or down the church, which doesn't sound like it will be a popular or easy thing to do.
I'd stick with the original idea of ORTF NT5s for the choir, as their cardioid polar patterns will tend to reject the direct organ sound coming from behind them and thus give you more control over the choir-to-organ balance. I would then rig a second mic or pair of mics specifically to capture the organ. Cardioids facing the organ would tend to reject the direct choir sound and thus give more control again, although a fairly close pair of omnidirectional mics would give a big organ sound and lots of spacious reverb which might work well. In all likelihood, the organ mics will have to be on very high stands to get a good balance of all the pipe sounds.
As for mounting the choir mics, I'd be very wary of using a gooseneck as they tend to droop, and the last thing you need halfway through a recording is for the mics to end up pointing downwards at the end of a sagging gooseneck!
You don't necessarily have to use a single stand in the centre of the aisle for ORTF miking — you could use two separate stands, one either side, with their boom arms stretched over the top like an arch. Mount one mic on each stand and position as required. There is no law to say the two ORTF mics have to be mounted on the same bit of metal. As long as you are careful to get their relative spacing and angles right (see the diagram on the facing page) you'll get exactly the same results from two mics placed on separate stands.
If your existing stands aren't big enough to accommodate this (or if the idea of two stands doesn't appeal), then it might be better to invest in a single big stand with a long boom instead. Place the stand safely to the side of the aisle, and extend the boom arm over to place the mics in the centre above everyone's heads. When using any stand with an outstretched boom arm, always make sure that one of the stand's legs is extended directly below the boom arm, to ensure that there is no risk of toppling.
I use heavy-duty K&M tall stands with long boom arms for this kind of job, as they are very stable and thus safer, as well as more versatile to use. The legs of these stands do splay rather wide wide, though, and although this is what makes them very stable it can present a trip hazard. I use stripy black and yellow 'hazard' tape to make the legs of the stands more visible, and it's also a good idea to try to tape or rope off the area around the stand whenever possible.
With either of these 'up and over' approaches, just make sure that you tighten the boom arm clamps well. If there is any possible danger that a collapsing mic stand might hit someone, I usually also use a length of chain or rope attached to the counter weight end of the boom arm and fixed to the base of the stand to ensure that the boom arm can't swing down and hit anyone accidentally.
In terms of positioning for the ORTF pair for the choir, I'd suggest starting at about three metres back and the same height if you can, and then adjust as necessary. With small-diaphragm condensers it won't make a huge difference whether the mics are perfectly horizontal or pointing slightly down, although the associated tonal changes would be far more obvious with large-diaphragm condensers.
Remember that the audience will soak up some of the reverb, so don't worry if the rehearsal sounds slightly (and I do mean only slightly) too wet. Of course, it is fairly easy to add additional reverb later if the recording ends up a little too dry, but the reverse is impossible, so it's best to err on the side of miking too close rather than too far away.