Recording advice

general questions, comments and ideas about recording, audio, music, etc.
Locked
Jeremiah Cymerman
audio school graduate
Posts: 11
Joined: Fri Apr 16, 2004 9:19 am
Location: New York City

Recording advice

Post by Jeremiah Cymerman » Thu Jan 20, 2005 9:47 am

What do you guys think?
I am going to be doing a live recording of a concert with an 18 piece band. The musicians will be set up in an ascending half-circle, three rows deep, with a conductor in the middle. The music is very experimental and will feature one of just about every instrument you can think of except for a vocalist. There wil be a lot of dynamic range. To record this I will be using a Digi 002R, running Pro Tools 6.2 on my Powerbook, which means that I will have 8 ins, only 4 of which provide phantom power. I want a very well balanced sound, where every instrument can be heard clearly. What advice do you guys have as far as creative recording, practical, etc? Any suggestions would be greatly appreciated.
Best
Jeremiah
"I am as empty as a Fart"- the Great Went

kayagum
ghost haunting audio students
Posts: 3490
Joined: Wed May 07, 2003 11:11 pm
Location: Saint Paul, MN

Re: Recording advice

Post by kayagum » Thu Jan 20, 2005 10:05 am

Search on any of these terms:

coincident
ORTF
Decca
Blumlein
location
stereo
XY*
orchestra
"a capella"
strings

User avatar
joelpatterson
carpal tunnel
Posts: 1732
Joined: Tue Jun 10, 2003 5:20 pm
Location: Albany, New York

Re: Recording advice

Post by joelpatterson » Thu Jan 20, 2005 10:12 am

This means 4 mics, so to speak?

I'd plan on two sets of stereo, one set more or less behind the conductor's head, another set a little further back, a little higher up, a little wider apart.

Hopefully you'll get a chance for a soundcheck, ask for the loudest blast you'll ever hear. A stereo compressor on each "set" might be a good idea.

If you've pre's and all for the other four inputs, I'd just go ahead and surround the group as feasibly as possible. In big groups, I like to think of everything as a gigantic drum kit and mic accordingly. Good luck, experimental is good.
Mountaintop Studios
~The Peak of Perfection~
Petersburgh NY 12138

mountaintop@taconic.net

LittleDogAudio
pluggin' in mics
Posts: 33
Joined: Fri Jan 14, 2005 11:51 am
Location: Cleveland, Oh
Contact:

Re: Recording advice

Post by LittleDogAudio » Thu Jan 20, 2005 10:23 am

I would set-up 2 stereo pair.

Both would be very close to the conductor's position.
Using matched-pairs.
One set being XY and the other Spaced pair.

During sound-check listen to which pair sounds the best and take the other pair out into the hall/room as room/ambience mics.

Chris
Little Dog Audio
Oh Joy, Oh Joy-More Gear!!!

User avatar
andyg666
re-cappin' neve
Posts: 669
Joined: Tue Jun 17, 2003 9:25 am
Location: Witchtown, MA
Contact:

Re: Recording advice

Post by andyg666 » Thu Jan 20, 2005 10:31 am

with only 4 mics, you won't be able to spot mic any of the instruments, so if they don't play with balanced dynamics, you're not going to be able to do much about it. i would think that they conductor and the musicians would be sensitive to their dynamics and trying hard not to bury the queiter instruments when it's their time to shine...

what mics do you have to choose from?

Professor
ghost haunting audio students
Posts: 3307
Joined: Wed May 07, 2003 2:11 pm
Location: I have arrived... but where the hell am I?

Re: Recording advice

Post by Professor » Thu Jan 20, 2005 11:46 am

Three rows of six musicians sounds like a narrow but deep stage arrangement. The stereo pair plus omni 'outriggers' that has been mentioned above is more for a very wide ensemble like a 50-piece orchestra. And an XY mic pair over the conductor's head would yield a rather narrow stereo image, especially of the more distant back row.

I'll assume that you don't have extrenal preamps, so are limited to only 4 condenser mics, and I'll assume that you have access to at least two stereo pairs of condensers.
Start with an ORTF pair of mics (LDCs if you can) as high above the conductor's head as you can get them, and angled downward to 'face' the ensemble. The reason for the height is to try and get closer to the same distance from each instrument. If you are at ear height, you'll get a lot of the conductor's breathing and movement, and you will also be maybe 6-feet from the front row and 12-feet from the back, causing the back row to be half the volume of the front. as you move higher, the distances even out a little better to maybe 10-feet from the front and 15-feet from the back which will even up that volume difference. The reason for the ORTF pair is that ORTF will create a stereo image from the volume differences around the cardioid mics and a timing difference between the mics, delivering a more convincing and active stereo image. XY-pairs only use a volume difference with no timing difference and the image gets narrow very quickly as the pair is backed away from the instruments until you're basically recording dual mono. The image also narrows off-axis so you have to be very careful of what direction the mics are pointing.
That will be your primary pair and may be all that you need in mix down as the conductor will likely feel that the sound from that pair is exactly what the group should sound like, since it is from the perspective of the conductor.
The second pair could be a pair of omni outriggers placed on the same plane as the main pair (lined up across the front of the stage) if the group does end up being a little wider and shallower than I would expect. Omnis naturally sound more distant than cardioids, so they don't have to be further back, and indeed, they should have a similar arrival time to the main pair.
But if the group is deeper, I like to place a second pair directly behind the first row of chairs, pulled high and pointed steeply down to capture the second and third (mostly the third) rows. This pair can be XY to contain any phasing issues better, and would be mixed in very lightly (maybe -15dB relative to the main pair) to bring the back row into balance with the front if necessary. It can also give a tiny bit of extra brilliance and presence to the back row which is helpful in this sort of live recording.

The other four channels should be used as spot mics, whether dynamic or condenser doesn't matter too much, just whatever sounds good on the instruments. What to spot mic, you ask? Anything that is limited in its volume and projection. So no trumpets, or flutes, or even oboes or bassoons. We're talking about marimba, harp, piano (if it's pushed back and off to the side) contra-bass (if there's only one), maybe even violin if there's only one. Anything that strikes you as an important tone color that needs extra help against the other instruments - but remember, you only have 4 channels!
Oh, and if there is a soloist, like a concerto soloist that will be out in front (maybe on the wrong side of the stereo pair, get a spot mice there.
I often will mic timpani if they are pushed way the hell off to the left side of the stage, so I can bring the mic up to maybe -15dB and panned to the right to balance the timps closer to the middle of the image. For timpani I usually do a mono spot with a small condenser about 7-feet above the middle pair of drums. Just be sure to mute that channel in mix down whenever he isn't playing (use the score if needed) to avoid mixing in his tuning changes!

And one quick note on levels. If you can have a sound check, ask for the loudest section of the piece and then pull the levels down to allow maybe 6 or even 10dB of headroom above that - because they will play louder live. Then don't touch the levels no matter how soft they get!
Here's why:
When recording to analog tape, the tape machine is a noisy medium, and probably the noisiest part of the signal chain, so we want the hottest levels going into that medium to get the best signal-to-noise ratio.
With your recording setup, what is the noisiest component?
Wrong, it's not the converters, and neither is it likely the preamps. Maybe the mics if you're on Earthworks or something, but most likely the noisiest component to your recording will be...
The Room.
So, if the room and ventilation and musicians moving and audience are the loudest noise source, it really doesn't matter if you turn up the gain at the preamp or in the box at mix down, the noise is going up with the gain.
So error on the side of too low when tracking because it is far easier to turn up the volume in mixdown than it is to correct a clipped peak from an unexpected trumpet blast.

Hope that helps to get you going.

-Jeremy

LittleDogAudio
pluggin' in mics
Posts: 33
Joined: Fri Jan 14, 2005 11:51 am
Location: Cleveland, Oh
Contact:

Re: Recording advice

Post by LittleDogAudio » Thu Jan 20, 2005 4:22 pm

Awesome reply Jeremy!

Your explaination painted the picture perfectly.

Thanks

Chris
Little Dog Audio
Oh Joy, Oh Joy-More Gear!!!

Zoltar
gettin' sounds
Posts: 132
Joined: Thu Jan 13, 2005 10:39 pm
Location: Ontario Canada

Re: Recording advice

Post by Zoltar » Thu Jan 20, 2005 6:14 pm

Thank you for the question and the response. I was put in to a similar situation with a Digi001, but I had preamps, just not enough cables for more than 4 mics. Anyhow, I went with a Spaced LDC pair on the choir, and 2 Small diaphram condensors on the solo piano. It turned out ok, I wish I could have placed mics in the center.

OK, so my question is with stereo pairs, you don't have to worry about phasing as long as the mics are hard panned in the mix, right? I have always suspected this because our ears work this way, but I have never been quite sure.

Thanks

Professor
ghost haunting audio students
Posts: 3307
Joined: Wed May 07, 2003 2:11 pm
Location: I have arrived... but where the hell am I?

Re: Recording advice

Post by Professor » Thu Jan 20, 2005 9:17 pm

Ah, the ever popular confusion over the "3:1 rule" and how the mics in a stereo pair are way too close for the "rule".
First of all, it is not a rule, it is a recommendation.
Second, it is the "greater than three to one recommendation" since 4:1 or 5:1 and so on are even better for reduce phase issues.
And third, it is a RATIO and ratios can be reverse as a '1:3 recommendation'.

An ORTF pair has mics placed 17 centimeters apart. Those mics don't encounter phase problems with the source material that is 12 feet away because the ratio of distances the mics versus the mics to the instruments is up around 1:20. That's why ORTF is a popular technique, you get just enough timing information to get a nicer stereo spread, and the signal can comfortably collapse to mono with little-to-no phase troubles.

Consider how we hear directivity.
We use two cues to locate a sound in space. The obvious one is volume difference - if it's louder on your right side, then the source is probably on your right. The other is the timing (or phase) difference - if it reaches your right ear first, then the source is probably on your right.
Yes, there is also that issue of our brains ignoring duplicate sounds until about 30ms, as a way of ignoring first reflections until they become full on echoes, but that's not so important in this area.
So, we want a volume difference and a timing difference to get the most 'realistic' sense of stereo image.
XY, Blumlein, and Mid/Side microphone arrangements are called 'coincident' microphone techniques because they place the two mics in 'theoretically' the same point in space. At the very least, the two capsules are as close as they can possibly be to the same point in space. This means that all sound from any direction reaches both microphone capsules at the same time, so there is NO timing difference. In an XY pair for example, our only stereo cue is in the volume difference created by the cardioid patterns of the mics which should be 6dB down at 90? off axis, so a sound aiming directly at the left microphone would be 6dB louder in the left than the right. The same scenario in a Blumlein pair would have full volume in the left and nothing in the right, though a sound at the center of the pair would be about 8 or 9 dB down on both sides (depending on the tightness of the fig-8 pattern).
In a spaced omni pair, both microphones 'hear' the same volume in all directions, so there is no volume difference. In this pairing, all of our stereo information is generated by the timing differences between the mics, so logically, the wider the pair, the wider the image.
But in an ORTF or NOS pair, we get both volume difference from the cardioid patterns spread to a wide angle, and a small amount of timing difference from the spacing between the mics.

-Jeremy

Zoltar
gettin' sounds
Posts: 132
Joined: Thu Jan 13, 2005 10:39 pm
Location: Ontario Canada

Re: Recording advice

Post by Zoltar » Thu Jan 20, 2005 9:54 pm

Even more great info, Thanks Jeremy;

What I am gathering is that stereo speakers, headphones, and mono listening are all affected by mic arrangment. Also, tone and character are affected by mic type and placement. so with experience, we learn how to optomize for each situation.

Thanks again.

Locked

Who is online

Users browsing this forum: No registered users and 32 guests