Basic Microphone Question

CClub wrote on 1/30/2009, 1:08 PM
[I used to have a great microphone article I downloaded comparing different types of mics and their uses, but I can't locate it, so if anyone has a good link, let me know. ]

Here's the question: I purchased two Rode Stereomics several years ago, and they're great within a couple feet. Beyond that, not that great. I thought when I bought them that they were shotgun mics of the variety that would capture sound nicely that was a bit away... not so. I'm looking to purchase two mics to feed audio into 2 V1U's when taping an A Cappella concert (where the singers would be about 12-15' away from the mics). Last year I bought a Sony D50, which worked great (it contains 2 condenser mics, which apparently record distant vocals better than the Stereomic "shotgun" variety). But I'd also like two mics for the Right and Left positioning that I can feed the audio right into the V1U. Any suggestions? Clarification: I'm not looking to spend more than $300 or so for each.

Comments

farss wrote on 1/30/2009, 1:31 PM
Seeing as how you're already using Rode mics the NT3 could be a good choice or if you'd prefer a lower noise floor then the NT1A would suit although it's a large mic.

Having mics physically apart for recording stereo can be very problematic due to problems of phase cancellation in a mono mix. Also you can leave a hole in the middle. Generally you want a stereo mic of some sort in the middle augmented with side mics to cover the edges of the choir. If your side mics are more that 3 times the distance between the centre mic and the middle of the choir you should be OK.
Less is always more in my opinion when recording these kinds of works.


Bob.

[edit] Just to give you some more pointers.

You can use two or three mics in a variety of configurationsto create a "stereo" recording. Common techniques are the Decca Tree, ORTF, MS and X-Y. There's more of course, a quick Google will have you swamped with information. I'd ignore the esoteric arguments about each, just so long as you understand the issues of each technique. Best position for recording natural is over the conductor's head. He is in charge of the 'mix'.
If you want a simple X-Y mic Rode have the NT4. Again placement is important. If you can think about buying a good mic stand made for this work. Manly make one that'll get you up high but heavy and expensive. There's much cheaper units made in Italy or a decent C Stand can be used.
newhope wrote on 1/30/2009, 1:51 PM
Great answer Bob!!!
richard-amirault wrote on 1/30/2009, 5:31 PM
I'm looking to purchase two mics to feed audio into 2 V1U's when taping an A Cappella concert (where the singers would be about 12-15' away from the mics).

12 to 15 ft away? What about double system sound? Are they using a sound system? Can you get a feed off the mixing board? If you can't get a feed, can you put your own mics on stage?

I've never done this type of shoot, but I'd worry about getting the amplified house sound mixed in with my camcorder mics at that distance.
Grazie wrote on 1/31/2009, 1:29 AM
http://www.hhb.co.uk/hhb/global/press_word_docs/RODE%20Stereo%20VideoMic%20Review.pdf . .and as if by magic here IS a review I did for the Rode Stereo Mic. And a little about ORTFs and Squids and things!![/link]

Also an interview I did with Peter (owner of Rode) Freedman. Copy of this PDF used with kind permission of "FOCUS" magazine!

Yeah, I know, I'm without shame . . .

Grazie


John_Cline wrote on 1/31/2009, 1:39 AM
CClub,

I'm curious what you consider to be "not that great" about the Rode mics? There is no microphone that will make a sound source appear closer than the microphones were to begin with.

12-15 feet is quite a distance.As was already pointed out by others in this thread, if you really need to be that far away, then having the correct stereo configuration and position for the microphones will make all the difference in the world.
Grazie wrote on 1/31/2009, 1:41 AM
You are correct John. I "walk" the plot, and then some, trying for that sweet spot.

Grazie
JohnnyRoy wrote on 1/31/2009, 7:37 AM
I agree with brighterside to go for the house sound mix. If you don't have a field recorder, get one. If you shoot lot of live performances, you won't know how you lived without it once you do. I've got a Marantz PMD660 but they just came out with the PMD661 to replace it and it looks really nice.

I would also be careful using shotguns for stereo recording. As Bob pointed out, it's easy to leave a whole in the middle and because shotguns have such a precise pickup pattern they may be hard to aim. I would use a uni-directional cardioid mic that has a wider pattern.

~jr
Jay Gladwell wrote on 1/31/2009, 9:10 AM

Shotgun mics are not like telephoto lenses. They do not reach out and draw distant sounds closer.

This seems to be a major misconception with many folks.


CClub wrote on 1/31/2009, 11:21 AM
Thanks for all the feedback. I’ll take a close look at the Rode NT3’s and 4’s; thanks for the recommendation. To answer a couple questions: 1) There is no sound system at this location. 2) My comment about the Rode Stereomics wasn’t based on their overall quality (in other situations, they’ve done great)… the comment was only regarding their ability to capture sound from the distance I mentioned. I recorded the concert last year, and I put the two Stereomics on C stands, each approx 12-15 feet in front of the A Cappella group, approx 20 feet apart, at eye level at slight angles facing toward the group. I ran the signal directly into separate V1U’s. I also have a Sony D50 audio recorder, which I placed in the center between the two Stereomics, also about 12-15 feet away from the group. Even though the D50 had a central location vs. the Stereomics on the sides, it wasn’t even close regarding the volume and quality that the Stereomics captured versus the D50. The configuration/positioning issues aside for the moment (I have a LOT to learn about microphone configuration), the Stereomics just couldn’t pick up the voices from that distance and they sounded VERY echoey, while the D50 recording sounded phenomenal. I couldn't even use the Stereomic audio and just went with the D50 track.

I’ve recorded several other interviews, and if the Stereomic was within a few feet, it sounds great, whereas even In the D50 manual, it even recommends placing the recorder/mics about 6-10 feet away from the sound source.

That’s why I was asking if anyone has a link to a summary of the specific purposes for the various types of mics. The D50 internal mics are listed as being of the “electret condenser” variety, and that type of mic must just be able to pick up this type/distance of recording better than a shotgun mic. I do understand that shotgun mics don’t work like the parabolic mics (although I admit I originally thought they did!). It may be as JohnnyRoy stated above that a different type of mic other than a shotgun mic (e.g., a uni-directional cardioid mic) would be the direction to go.
rs170a wrote on 1/31/2009, 11:51 AM
That’s why I was asking if anyone has a link to a summary of the specific purposes for the various types of mics.

CClub, have a look at the Transom.org site.
I know they have at least two different mic shootouts as well as several other related articles that should be of some help to you.

Mike
richard-amirault wrote on 1/31/2009, 12:21 PM
1) There is no sound system at this location.

In that case I would try to put mics on stage with the group. Put them where the house sound system would have put thiers.

The difference in sound from 12-15 ft vs 2-3 ft is amazing.
farss wrote on 1/31/2009, 12:38 PM
Just so you don't get too confused there's two aspects to the "types" of microphones. One is how the microphone converts air pressure into an electrical signal. Common types are ribbon, condensor and dynamic. Condensor mics come in two flavours, externally polarised and pre-polarised. The former require power, the later don't unless they include amplification.
Common types of acoustic characteristics are omni, cardioid, hypercardioid and figure 8. You can see the acoustic properties of a microphone by looking at the polar response diagrams however for the full 'picture' you need to look at how the mic 'hears' sounds over the range of frequencies. In theory at least any one of the ways of turning sound into an electric signal can be used to create any pickup pattern. The pickup pattern is mostly determined by the mechanical design of the microphone although a more expensive technique is to use an array of small microphones. Sanken's high end 'shotgun' microphones use up to 10 microphone elements, other manufacturers also offer quite expensive microphones like this. These are mostly used for recording location sound however their high cost sure limits their appeal.

As well as learning about microphones, in fact I'd say before learning about microphone it is very important to understand the nature of sound. Although like light it is a "wave" it reflects much, much better than light. Much of what we and a microphone hear is reflected not direct sound. In a venue such as a church with hard surfaces this is very important. As you place any microphone closer to a sound source it hears more of the direct and less of the reflected sound. In a large traditional church you can understand how important where you put the microphone is, as Grazie said walking the floor listening for the sweet spot is very important unless you plan to close mic the performers. Doing that though takes them "out" of the church. You may prefer that sound or you may wish to capture the natural sound of them singing in that space. These are the creative choices you make.

Bob.
craftech wrote on 1/31/2009, 4:04 PM
You might try the following references:

Mix Magazine Microphone Tips

Sound on Sound and their technique articles

John
John_Cline wrote on 1/31/2009, 4:46 PM
"Condensor mics come in two flavours, externally polarised and pre-polarised. The former require power, the later don't unless they include amplification."

All condensor mics require some sort of power.

Most all externally polarized mics and some pre-polarized (electret) mics require external +48v phantom power. Some pre-polarized mics can be run off of a battery and some can be run off either phantom power or a battery.
farss wrote on 1/31/2009, 5:15 PM
You are indeed correct. I was thinking purely about the mic element.
I think some of the very small lapel mics move the preamp to an external unit. Regardless, the signal from the mic element is so small and high impedance that some form of powered amplification will be required.

Some of the externally polarized mics such as the Rode NT3 and NT4 can be run from a 9V battery inside the mic which should make them attractive for those with a camera without phantom power. The NT4 comes with a lead with a 3.5mm plug as well.

Bob.
John_Cline wrote on 1/31/2009, 8:07 PM
The power is required to drive the active impedance converter. This circuit is usually a J-FET or a tube.

Rode makes some very nice microphones. I have a matched pair of Rode NT5 "true condenser" externally biased microphones and they sound spectacular. The NT4 is basically a pair of the NT5 capsules in a fixed 90 degree X/Y configuration.
farss wrote on 1/31/2009, 8:40 PM
I would have bought a pair of NT5s however a NT4 came up on eBay at a price I couldn't resist.
Hint, if you're selling your kit on eBay don't get your Dad to do it while you're overseas :)

I've become a bit of a microphone junkie. 3x NT1As, 3x NT3s, 1x NT4, 1x NT6, 1x CS-1, several boundary mics of dubious manufacture, CMS-10 (borrowed). Looking for a mic that goes below 20Hz (that I can afford) and I need a couple of drum mics. Nearly bought a set of DPA IMK4061 instrument mics. Also thinking about the A&H ZED R16 mixer to replace my Edirol R-4. The R16 can be used for the house mix plus I can record all inputs independantly into Vegas on a lappy.
Most of this is for recording my Bengali friend's musical performances, their sound guys are always short of mics and the house mix is always mono and doesn't do them justice. No money in this but heaps of fun amongst the chaos.

Bob.
craftech wrote on 2/1/2009, 3:56 AM
Nearly bought a set of DPA IMK4061 instrument mics.
============
That's the one I was thinking of and couldn't remember - DPA

When I posted the two microphone info sites above there was one more I couldn't think of that would be good for CClub to read. It was the Microphone University section at DPA Microphones.

John
musicvid10 wrote on 2/1/2009, 8:41 AM
Many times mics on stands are impractical because of visual or coverage concerns.
Shotguns on or off camera are generally a poor substitute because for all kinds of considerations.
If I have the time and the venue's cooperation, I'll hang between 2-5 choir mics (Pro-45) running through a portable mixer.
When that's not practical, I have a couple of PCC floor mics that are easy to set up and do the job nicely.
Other approaches are a field recorder like the H4 or even some strategically placed wireless mics, or any of the above in combination.
Getting mics for choir applications close enough for good sound but still retaining full coverage requires planning and preparation. On-camera solutions are generally the least effective.