Playing With SM81s

[BenFranske]

So I'm really more of a live engineer and system designer but for my own interest and edification I'm interested in playing with some acoustic recording. Specifically I have some personal interest in doing some choral, piano, classic guitar and organ recordings. I picked up a pair of SM81s, high stands and a stereo bar. I also have a Presonus Saffire Pro 26io and an Echo Layla 24.

I'd like to do some experimentation with different recording setups: ORTF, NOS, XY, etc. Eventually I'll probably get some additional condensers with figure 8 (for M-S) and some omnis for spaced pair but that's at least a few months away. We'll see how I do with the 81s first.

I have a couple of questions. First, any suggestions for things to try (which sound both good and bad! so I can hear what some of the effects of bad micing are) with the 81s and sources like choral, piano, classic guitar and organ recordings? If you can suggest what I listen for in a given configuration all the better.

Secondly, one of my first personal projects to play with is likely to involve pipe organ recording. Based on what I've read it's probably more ideal to do this with a spaced pair of LDC omnis because of low end roll off on SDCs but what I have is the 81s (which seem not to have a low end roll off as bad as some other SDCs). I also have a Heil PR40 dynamic which has fairly good frequency response and which I've been quite happily using for some voice recording for some time. My thought and question is what would happen if I supplemented an ORTF SM81 pair with the PR40 in the middle (and center panned)? I could low pass the PR40 as well to help preserve the stereo image coming from the ORTF pair. Is this just nuts? Phasing issues? Has anyone done much acoustical recording with a PR40?

I appreciate any thoughts anyone might share? If I had another $700-$800 for recording mics in a few months any suggestions/rationale?

Thanks!

[chris319]

First consider your acoustical environment. I got burned by bad room acoustics, which you can read about in the thread about recording an orchestra in a small room. Fortunately the stakes were low and no damage done.

<old geezer mode>
You know, these Guitar Center kids fret about the nuances of this preamp or that, but let them set up in an unknown, unseen room and improvise solutions to problems. That'll teach those young whippersnappers a thing or two.
</old geezer mode>

[jnorman]

first, LDCs are generally dual diaphragm pressure gradient mics, and thus still exhibit proximity effect. to acheive full bass response at a distance requires a true pressure omni, generally all SDCs (the only exception that comes to mind are the large capsule DPA omnis). so, yes for organ you would prefer a spaced pair of true pressure omnis. but a good ORTF pair can do almost anything pretty well, and the sm81s should be just fine. omnis can be a little harder to work with, unless you know your space well.

it is fairly easy to experiment and hear the (huge) difference that distance can make in mic placement - it can be much harder to hone in on that perfect mic placement, but ORTF is very forgiving and will give you pretty good results if you are in the ball park. XY has its place for good mono compatibility, but ORTF ALWAYS sounds better (IMHO). NOS and DIN are slight variations on ORTF and can used to good effect depending on the size of the group you are recording and the distance you are working from.

good luck and have fun.

[fifthcircle]

SM81 mics were the first mics that I ever owned when I was a student. I used them for *everything* that I recorded. (really no choice- it was all I had) I got to the point where I could make them work for just about anything. As a student I was recording numerous solo recitals (all instruments) and large ensembles. I learned to make them work for each... Probably 95% of the time I was in some sort of an ORTF pairing with them.

The SM81 is a fine mic, but is rather colored off axis. Means that while the mic has some interesting "meat" in the mid range, it was difficult to get it to sound great in a lot of rooms. Today, they have been sent to my live sound kit and they work fine there- although they are usually close enough to the source that I don't have to worry too much about the off-axis issues.

--Ben