Recording an Orchestra Rehearsal in a Small Room

[chris319]

The other day I recorded a youth symphony rehearsal in a small room (classroom size, about 20' x 30') and the result was just awful. It lacked all sparkle and brilliance. I used a pair of modified MXL 990s in an ORTF configuration. The acoustics of the room were quite live to begin with -- linoleum tile floor, no treatment anywhere -- but became less live when people came in. There were tympani which sounded awful and the cellos sounded bad. It sounded like it was recorded in the 1940s with tube equipment and ribbon mics. Due to the size of the room there was no place to put the ORTF pair except behind the conductor and that put them in front of a row of cupboard doors, so I'm thinking reflections from these cupboard doors had an adverse effect.

There is no requirement that the recording be stereo -- monaural is perfectly fine as it is only a rehearsal. Any ideas? Close micing is not really an option. I've got a PZM mic on order and was going to experiment with affixing it to those cupboard doors and hopefully eliminate one source of reflection. Any other ideas?

[NorseHorse]

Hey Chris! Glad to have you. Would you like to post a sample of what the first recording sounded like? That might give us an idea of where to go from there.

Also, what are yours goals? Are you trying to make it more spacious?

Originally Posted by chris319

It sounded like it was recorded in the 1940s with tube equipment and ribbon mics.

If you pretend you meant it, you might get a great reputation as the guy with that "vintage" sound!

[Corran]

Yeah, a lot of people are looking for that sound...maybe you've got a winner!

Anyway, I've been recording rehearsals recently with a band I'm working with using their equipment. It's in a slightly larger room but has some similarities - for one we use ORTF right in front of the whiteboard so that might have some similar acoustic properties to the cabinets. Have you tried moving the mics up? We are blessed with good ceiling height - how is the ceiling in your room? I'd try getting the mics higher and then maybe facing them down towards the group, to get a little more "space" in a small room.

Once in a really bad room I had two mics facing each other about 30 feet apart, straddling the group. It actually sounded good (compared to the other options in that room at least). That might be another option to try.

I have been lucky to work in relatively okay rooms, nothings horrid like yours might be. This is all guesswork based on some of my observations, so take it with a grain of salt. Let us know what happens though.

[chris319]

Here is a link to a highly-compressed mp4 mono file of the entire rehearsal:

www.miclisteningroom.org/MSLMYSO/MSLMYSO_3-2-09.mp4

and a FLAC excerpt:

www.miclisteningroom.org/MSLMYSO/YSO.flac

It is a youth symphony orchestra, mostly high school age. The playing is what it is. The (non-tympani) percussionist was a professional musician and quite good. At about 23 minutes into the mp4 file there is a featured violinist who stood up and was playing a lot closer to my left-channel mic.

It sounds muddy to me overall. I want it to sound brighter, with more sparkle. I was using a new mixer which it occurs to me I should benchmark. I'll be surprised if there is a major problem with it. During the recording I was sitting stage right of the orchestra, monitoring on cans. Needless to say I did not get a look at the room until I showed up with my gear.

[chris319]

I have thought about hanging a single mic overhead (remember, it's OK if it's mono) but then I would have six reflective surfaces instead of five with the PZM, at least that's my thinking. OTOH if I used a cardioid there would be some attenuation of five of those surfaces (all except the floor) and I would even have some distance from the floor.

The ceiling is sloped, made of wood, and there are fluorescent light fixtures above. They are exposed fixtures, not the flush-mount false-ceiling type.

I have also thought about a cardioid on a low stand in front of the conductor, pointing up. With a sloped ceiling the sound is being reflected away from my mic, so I might want the most cancellation in the direction of the floor.

One luxury I have is that I can record two channels, one with the PZM and one with an alternate setup, for comparison.

[chris319]

No ideas?

[Audiop]

I would hesitate to use PZM mic's in a small room due to the pronounced eigentones that terminates at the boundaries of the room.

Mission impossible I'd say! :-(


/Peter

[mixedupsteve]

Hi Chris,
There is something very basic wrong with the recording. Have you used these mics before? What is your chain? Were you getting normal output from the mics?

[chris319]

Originally Posted by mixedupsteve

There is something very basic wrong with the recording. Have you used these mics before? What is your chain? Were you getting normal output from the mics?

This is my first experience ever recording music. Fortunately the stakes were low. I've used the 990s on speech before. The audio chain was MXL 990 to Peavey PV6 to Fostex FR-2LE.

Peavey.com :: PV Series

Welcome to Fostex USA

I hadn't used the Peavey before but at the last minute the conductor informed me there would be a soloist so I came prepared to spot mic a soloist with a third mic, which it turns out I didn't do).

I need to benchmark the Peavey.

[chris319]

OK, benchmarked the chain (sans mics) using RMAA. Other than about 1 dB rolloff at 20 kHz there were no surprises. THD was .0056%.

One of the two mics used can be heard here:

http://www.miclisteningroom.org/FLAC...0_Cap_Mod.flac

[mixedupsteve]

Can you post a .wav or MP3?

[chris319]

Originally Posted by mixedupsteve

Can you post a .wav or MP3?

Here ya go:

http://www.miclisteningroom.org/MSLMYSO/YSO.wav

Do you have trouble playing back mp4 or FLAC? Winamp will do both.

[NorseHorse]

Listening now...

Listen to the first general crescendo. There is a weird high metallic sound.

So I guess that comment doesn't help much, but maybe someone else will recognize it.

[rumleymusic]

I know what is wrong with it! It is a youth orchestra recorded in a tiny room.

There is nothing wrong with the recording equipment that I notice. Sure the mics could be a little higher up because all you hear is strings (angle is important when you are using a stereo pair on a large group), but that is what it will sound like when you record against a wall in a poor acoustic space. You can't expect a quality sound in under those conditions.

[TheRealRoach]

Originally Posted by rumleymusic

I know what is wrong with it! It is a youth orchestra recorded in a tiny room.

I agree. That's just what orchestra's sound like in rehearsal room. I rehearsed as part of an orchestra for many years in a rehearsal room very similar to the one you described and that's what it sounded like.

On a side note: I just did a recording a couple weeks ago in an 800 seat theatre, properly designed/treated. A close pair a few feet above the conductors head, ORTF, and an M/S setup in the middle of the seating, about 50' back. Killer!

The ORTF above conductors head should work really well. With any orchestral recording though you are totally dependent on the quality of the room. In the case of my gig a couple weeks ago it made my job REALLY easy.

[NorseHorse]

Originally Posted by rumleymusic

I know what is wrong with it! It is a youth orchestra recorded in a tiny room.

No, that is not the problem.

I've done a number of recordings with 990s in small rooms, including classrooms, and they don't sound like that AT ALL. MixedUpSteve is correct in saying there is something wrong with the chain. Power problems? Encoding problems? Damaged mics? 22kHz sample rate? I don't recognize the sound, but I'm hoping someone else will.

[chris319]

I've done a number of recordings with 990s in small rooms, including classrooms, and they don't sound like that AT ALL.

How were your 990s configued?

It was recorded at 44.1/24. Granted, having them in front of those cupboards doesn't help, but perhaps one or both of my 990s goes wacky at the high SPL the orchestra was playing at? This would be very difficult to track down being on cans in the same room as the orch. I have many other mics I could try.

It would sound more coherent if they were playing closer to the actual notes they were supposed to play, I'll give you that.

Listening now...

Listen to the first general crescendo. There is a weird high metallic sound.

Were you listening to the mp4, the FLAC or the wav file?

[NorseHorse]

.mp4 - didn't check the others.

All recordings below were with a pair of MXL 990s and a Tascam DP-01FX. Don't remember the configurations. These are meant as encouragement and also to demonstrate that there might be something wrong with the chain.

[chris319]

If there were something wrong with the chain, I would think it would show up in the RMAA frequency response curve.

How were the room acoustics in these recordings?

If you're listening to the mp4 you might be hearing compression artifacts. But it's still a bad recording. Give the FLAC a listen.

I assume your 990s have the stock ceramic capacitors and have not been modified?

Next time I might try an RE27 as an experiment.

[NorseHorse]

Room is maybe 20 x 40. I was micing within 1-2 feet on the Alina Harway sample, clarinet sample, and five/six feet on the Poppadom. Reverb added in post.

Stock 990s.

[chris319]

Room is maybe 20 x 40.

Right, but how was it treated? Carpeting on the floor? What kind of walls and ceiling?

[NorseHorse]

Carpeting mostly, padded seats. Nothing special about the walls/ceiling, untreated.

Your should be able to get much better results with your 990s and the Fostex, even if recording in a 15x15 box full of musicians. (Which I did once and the recording was used as a backing track for a musical at the NYC Fringe Festival. Sounded fine.) The producer has the recordings though; I was just donating my time / gear for the tracking portion.

[chris319]

Carpeting and padded seats are more absorptive than linoleum tile and metal folding chairs. I still think I'm fighting room acoustics.

[NorseHorse]

Yes, you are fighting room acoustics some, but that doesn't account for the "vintage" sound you described. Sorry I can't offer any more insight into the problem. Hopefully someone else will chime in.

[rumleymusic]

Oh come on, I doubt there is nothing wrong with the equipment.

Since the file is mono, that could explain a little of the "vintage" sound. If it was recorded in OTRF and then summed to mono that could explain a little of the "phaseyness".

Combine that with a bad room and you got yourself a bad recording.

[chris319]

The right channel sounds just a bit better than the left, but it could just as easily be the result of acoustics as the functionality of the mic.

[chris319]

NorseHorse -

Here are instructions for replacing the ceramic capacitors in an MXL 990. If you are interested I'll dig up the part numbers for you. You can hear the difference by listening to the modded and unmodded mics here:

Mic Table

Gus' MXL 603s mod - Pictures/Part numbers -thanks Flatpicker

[NorseHorse]

Originally Posted by rumleymusic

If it was recorded in OTRF and then summed to mono that could explain a little of the "phaseyness".

Good point.

Originally Posted by chris319

Here are instructions for replacing the ceramic capacitors in an MXL 990.

Cool pictures. I sold my beloved 990s two weeks ago though... growing pains.

[mixedupsteve]

Originally Posted by NorseHorse

Room is maybe 20 x 40. I was micing within 1-2 feet on the Alina Harway sample, clarinet sample, and five/six feet on the Poppadom. Reverb added in post.

Stock 990s.

Where were the mics located on that close miced piano piece? I like it!

[mixedupsteve]

Originally Posted by chris319

The right channel sounds just a bit better than the left, but it could just as easily be the result of acoustics as the functionality of the mic.

I haven't done the math but it would seem to me that OFTF in a small room like this would result in your mics pointing at the side walls. If so, you would get a lot of cancellation right at the mic location. The wave sounds better so I guess your mics are OK.