Mic position in relationship to to resonators

Hello all,

I think the subject title of this post pretty much explains it all.  I am just wondering, for a 4.3 marimba using two mics to cover the full range, and 1 mic for the vibes, where I should place the mic in relationship to the resonators.

A bit of info I'd like to share....I did a lot of experimenting this summer with creating my own suspension or shock mounting for our mics, built out of PVC, rubber bands, and zip ties; and the results have been stunning.  ZERO frame noise, and just an over all better clarity and depth of sound.  I'll post some pics soon...I thought it was going to look tacky, but after painting them black, you don't even notice them...

RM
Just saw this on Sweetwater and thought it was worth a mention. It's a universal shock mount.

http://www.sweetwater.com/store/detail/SSM1
I agree with you Jim!  This has turned out so much greater than I imagined when I first made the post.  I used a similar design to rhythmaniacs photos, but with a yamaha multi clamp, ABS 2'' PVS ABS pipe, and a flexible (small) goose neckish pipe line that I believe is used for gas lines or something.  I'll post pics later tonight.  It costs a total of $10 from start to finish. 
This is a cool topic. It's fun to see the ingenuity of people here, and I'm sure others reading from the sidelines will find lots of useful info in these ideas!
Check this mic suspension tutorial.  I like this set up, too.  [url=http://www.wiremonkey.com/diy_shock_1.htm]http://www.wiremonkey.com/diy_shock_1.htm
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RM
Thank you all for your insightful answers.  I have a lot of experimenting to do over the next couple of weeks.  Rhythmaniacs, I sent you an email with a couple of questions about the mic set up in your pics...I really dig that system!  Hope to hear from you soon.

Sincerely,
RM
Acoustically, I think the best mic position would be overhead. Placing mics overhead comes with a number of challenges (large mounting device, possible interference with cymbals and other accessory instruments, more exposure to wind, susceptibility to damage, etc.). Placing mics under the keys near the tops of the resonators allows them to be secured in a position that is relatively safe in a world where these instruments are rolled over bumpy terrain on a weekly basis. For making a recording I doubt this mic position would be suitable, but it's close enough to work for sound reinforcement purposes.

The biggest problem I find with suspending mics under the keys near the tops of the resonators is that certain keys are closer to the mics than others, which can lead to uneven sound distribution. Lowering the mics helps alleviate the problem, but the lower they go the more susceptible they are to getting kicked, picking up wind noise, and being too far from the resonator openings. There's a sweet spot in there somewhere, but I don't know exactly where.
Another thing to consider, as I was having this conversation with forum member Joe a week or two ago - are your resonators open or closed?  And how would that play into mic-ing.  Would you go closer to the bars then?
Great system gots2drum!

I just wanted to share another possible shock mounting system that can be created. The difference is that these can actually be mounted onto a goose neck if so inclined. I took the design and made it meet my specs. When I marched in the Boston Crusaders front ensemble in 07, they worked very well.
Thanks for the advice on mic positioning guys!  I'll post some pic this coming Monday or Tuesday, of the pvc shock mounting.  I am in the process of painting the pvc to blend in with the look of each instrument.  Until I post those pics, I'll share the first design concept.  They should be attached to this message.  Please remember that this was my first attempt.  The only thing I know for sure is that it eliminated our frame noise DRAMATICALLY!  It is VERY simple to do, and cost about $1.50. 


I just came across this system by Randall May [url=http://www.randallmay.com/marimba_miking_system.php]http://www.randallmay.com/marimba_miking_system.php[/url]

Where can I find some pricing info on this product?  I have been searching online and cannot find them anywhere with a price quote.  This is a very cool design, and I would love to integrate it into our miking system this year.  Anyone know where I can find and purchase this item?  Thanks in advance for your help!

Sincerely,
Ricky Morrow

I'd like to see those shock mounts. Our frame noise is getting too noisy!

I think the main thing to consider is that you have to have the mic far enough away so that it's pick up range covers the whole instrument (or only half on the marimbas since you have 2 mics). Try to locate the graph associated with your microphone, usually provided on a piece of paper or available on the internet and it will show you the pickup pattern of your particular mic. I also know that higher frequencies are more directional than lower frequencies. In other words, to get a good high end marimba sound, you need to point the mic most directly at the high end. The low frequencies are less directional and the mic can pick them up from the side usually as well as in front. Keep in mind that the attack sound of a bar is a high frequency so if you aim the mic off axis on any certain bar, you will lose the attack sound a bit. Finally, there is this thing called the proximity effect that basically says the bass sound level increases exponentially as it gets closer to the mic and vice versa. I am still messing around with my mic set up, but I hope this gives you something to work with.
As a non-audio engineer, I've usually subscribed to the idea that you'll get better sound the closer you place the mic toward the resonator opening. But I'm not as certain about that now. Getting the mics too close to the bars may lend itself to more attack sound that you don't want. When I was at Cavaliers, we had great results by placing the mics beneath the instruments about midway from the top of the instrument to the ground. They were basically secured to the horizontal support , and it worked well.

It sounds like you've put some good ingenuity to use for your shock mounts. Cool! When you get the chance, it'd be great if you could post them for others to check out. Thanks for sharing your experience!
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