Rode NT5 and ORTF or AB Stereo?

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CJ-Mich

New member
First off, I apologize if this is way too basic for what looks like some very educated audio experts here but I've been hunting, reading, and searching like crazy for what I hope is an easy question:

I am looking to record some high school band and orchestra performances at a local high school auditorium. I am doing this not as a professional or in the hopes of making any money, just trying to get a decent recording of these great musicians.

I know my set up is barely a step up from someone with a minidisc recorder and a few mics hidden in their hat but here it is:

Marantz PMD670 recorder, mic stand with a boom and gooseneck and a plate to mount two mics, and a pair of Rode NT5 mics.

I have read the Stereo Techniques section at DPA's website and have decided that the ORTF or AB Stereo setup is what I think I need. I will be behind the conductor about 10-15 feet and I can get the mic's about 6' above the stage height (9' from the seating area). The band takes up about 75% of the stage, if not all of it.

It seems to me that the ORTF at 110 degrees apart is a bit excessive. Almost as if the mics will be pointing at the walls and not the band. Since I am trying to minimize noise from the audience, wouldn't something like 70 or 80 degrees be better?

With the A-B set up it seems like the opposite is true. The mics are pointed right at the conductor, with the players on the outside edges being too far away.

My first inclination is to use the A-B setup, but instead of 0 degrees between them, open them up to about 30 degrees. I'm no expert, but I do like good music. How critical is the placement in this scenario?

Again, I understand this is about as basic as it gets, but it seems like most of my searches has resulted in things that go way over my head. Any help for a struggling dad would be greatly appreciated.
 
I'm no expert on this type of recording but I think it would just be easier to go with the ORTF setup, for the A-B setup Omnis are the prefered mic, I think...
 
yes, the ORTF is the way I would record this same situation.

Now, the 110 degree number is supposedly mimics the behavior of the human ear but there is a more important consideration in setting the actual angle.

You need to get even response.

Not every cardoid pattern is equally 'wide'. If the cardoid pattern of your microphone is 'wider' than average then the degree of separation should be more than 110 degrees. If the cardoid pattern is 'narrower' you would want a narrower angle. If you narrow the angle just because it 'seems' right then the instruments in the center of the band will be picked up too strongly by both mics and overemphasized in the recording.

The easiest thing to do is to do a test.

Set up your microphones at what you think is going to be the right angle. Have a single musician play a note at a constant volume as they move at a constant radius from far right to far left.

Then get an idea of the total volume by merging the two stereo tracks into a mono track.

You should see close to a constant amplitude of the wave form as they go from right to left. If it is louder when they are in the middle then you need to have the spacing be wider. If it is weaker in the middle then you need to have the spacing be narrower.

Because most cardoids will need to have a fairly wide spread in an ORTF I try to have the mic stand be as close as possible, i.e. right behind the conductor, and as high as possible, i.e. roughly half the distance to the back row and pointed directly at the back row. Thus the first row of players are closer to the mic but somewhat off-axis.
 
Either technique should work, as will a spaced stereo pair. Not to worry. The mics aren't laser beams, the pickup pattern is more like a cone that gets wider the farther away the mic is from the source. With any stereo mic'ing technique, whether spaced, coincedent, near-coincedent, ortf, or MS, the technique depends on the pickup fields of the mics overlapping. At say, 20-30', the mics are going to pick up a whole lot of stuff that they are not pointed directly at. Think of them as the two eyes of a binocular, which overlap to create one image that comes into focus at the right distance. Don't worry that the mics have to be pointed straight on to some specific part of the source. Just put them up and listen. I'd start with X-Y, then try a spaced pair, listen and compare.-Richie
 
CJ-Mich,

I do a few of these type of recording a month and here is what I use and how I use it.

My little portable recording system is as follows.

I have everything mounted in a little light weight plastic SKB rack with a Furman PL-Plus power conditioner mounted in the top space. Next is the DBX 1066 dual compressor/limiter/gate, then a Symetrix 302 dual microphone preamplifier, and I'm recording to a Tascam CD-RW700 CD recorder. This (and a pair of Sony MDR-7506 headphones) all fits nicely in the SKB rack and it also has room for the extra cables in the back of the rack.

Most of the time I use one mic stand with a boom arm and stereo bar and mount two Shure SM81's in an X/Y manner on it... and position the stand right behind the conductor with the mikes above him.

What really makes this little portable recording system great is, 1) It sounds great. 2) The whole system can fit in a small car. 3) The whole system can be loaded in or out of an event in just one trip. 4) System setup time in only few minutes.

Or sometimes I'll AB two mikes if I have time and get a sound check and etc.

Checkout these links.
http://www.shure.com/pdf/booklets/mics_for_music_studio.pdf
http://www.lcc.gatech.edu/gallery/radio-idt/digaudio/placement.html
Also do a Google search... there is a lots a good stuff about this on the web.
 
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I record our local symphony

I use the ORTF method with small condensers and it sounds great. If you watch the video to Diana Kralls live from Paris concert you will see an ORTF pair over the top of the conductor.

When I record, my mics are 9' up and 4' to 6' behind the conductor depending on the orchestral setup.
 
The ORTF is great if you have room for it. The X-Y is good only if everyone is well trained and you don't have an out of balance section of show offs. One other option is the Decca Tree using 3 figure 8 patterned mics. Using ORTF, X-Y and Spaced Pair all work differently depending on the room and the type of Mic's. Ive had good results recently in using spaced pair combined with a LDC in the middle. Experiment to see which one works for the room. I did a choir this year and used an X-Y with 2 SDC and it was not very good for the room. Every situation demands its own investigation into what will and what won't work.

SoMm
 
If you look carefully to the DPA site you'll see the NOS placement as well.

ORTF will give you great stereo image, much better than XY imho.

But in smaller rooms with smaller choirs and/or orchestra's you might have a better result with NOS, which is a pair of cardioids at a 90 degree angle and 30 cm between the diaphragms.

Kind of XY with a better stereo image, but still mono compatible.
 
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