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  #1  
Old 11-18-2008, 07:58 PM
Solo Solo is offline
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Default Ultimate Microphone Project

After searching for a ultimate dual source setup, I decided to build my own system. Problem? I am not quite sure what I am doing... :-) Here's my progress so far, and I need some help from anyone who's handy with electronics.





I have a very nice podium mic made by electro voice (Polar Choice 18) lying around. Just for fun, I stuck the thing into my guitar sound hall and started experimenting with my PA system. I was quite shocked at its performance. The feature I like the most is that there's a switch on the mic that gives me 4 different polar patterns. 3 directional and 1 omni. As in the picture at the bottom, I liked the hyper cardioid pattern the most pleasing but the other two cardioid were bad either. I cranked it up and started strumming and picking and I couldn't get it to feedback until gain was so high that it was clipping.

So here's what I am thinking of doing. I want to purchase D-Tar wavelength pickup and add this microphone as a second source and run it through Highlander PAMDI via a stereo cable. This will give me two separate channels with individual eq before summing the channels together. So this afternoon, I strip the casing off the unit and took the guts out of this $350 microphone.



As you can see there are two electret condensers in two opposite directions. The bottom electret is the one that gives different polar patters I believe.

Now here's the question!
Do I just solder the condenser element straight to the second source of the D-Tar endpin jack? Or do I still need the preamp from the microphone? I assume I will need the preamp to get the proper power and also various polar patterns.

How would I go about the wiring? Obviously, there are two wires for each electret. One for hot and another for ground. If I were to use the entire components including the preamp, then, I would have the option to choose from the 4 patterns. In that case, I still have three wires coming out of the preamp. Black for ground, but with red and white, I am not sure how I can attach them to the wavelength endpin.





My PAMDI can send power through the ring section of the cable. But, I understand DTAR preamp will also provide power from its 18V supply. This mic requires 12-15V so I think it should work.

Love to hear your thoughts and input. I would hate to find out that I just gutted this $350 microphone for nothing.

Last edited by Solo; 11-18-2008 at 08:04 PM.
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Old 11-19-2008, 02:26 AM
derek2400 derek2400 is offline
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OOHHHHHHH!!!!!! Can`t wait to see how this goes down!!!! Wish I knew what to tell ya. Very interesting though! Good luck.
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Old 11-19-2008, 05:22 AM
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Bob Womack Bob Womack is offline
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Two questions:
1. Does the E-V mic require P48 phantom? If so, you are going to need a source.
2. Do you know whether the case of the mic supplied any form of an acoustic phase shift that was used in the pattern?

Have fun!

Bob
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Old 11-19-2008, 08:46 AM
Solo Solo is offline
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Quote:
Originally Posted by Bob Womack View Post
Two questions:
1. Does the E-V mic require P48 phantom? If so, you are going to need a source.
2. Do you know whether the case of the mic supplied any form of an acoustic phase shift that was used in the pattern?

Have fun!

Bob
Hi, Bob,
Yes, the mic requires power, but, it can run on 12V. The spec says 12-52VDC, and the EV people confirmed it can run on 9V battery or the power provided by Highlander preamp.

As for the phase shift, I am not sure. I just removed the casing, and there was no wiring attached to the case.

I am trying to understand how I can attach the three wires to the stereo endpin jack which seems to have only 2 available attachments. I found out that AKG C416 has the similar configuration, so it must be possible.

Ted
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Old 11-19-2008, 09:17 AM
ronmac ronmac is offline
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Ted,

Bob is referring to the impact the body has on the frequency response, pickup pattern and phase relationships of the two mics. This an inherent part of the microphone design, so don't be too surprised if it doesn't sound like it used to, although it still may be perfectly OK for your purpose.

The red wire is the "hot", the black and white are "ground" and "cold" and can be joined together for your application.

Rane Note 131, no longer on their web site, was a great primer on how to wire various mics to be used with the AP13 acoustic preamp (two wire mic input with 6v or 15v T power). If you need a copy send me a PM with an email address and I will send it to you.
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Old 11-19-2008, 09:38 AM
Solo Solo is offline
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Thanks Ron, for clarifying what Bob meant. I am not sure how the mic will perform without the case, but am hoping it wouldn't change the tone drastically. I pm'd you for the wiring info from Rane. Thanks once again.

ted
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Old 11-19-2008, 10:44 AM
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Quote:
Originally Posted by ronmac View Post
...Bob is referring to the impact the body has on the frequency response, pickup pattern and phase relationships of the two mics. This an inherent part of the microphone design...
Hi ronmac...
Exactly right. The two capsules mounted back to back and the housing are used to create the different patterns.

Perhaps the capsules could be mounted inside a well fitting plastic tube (or metal) which would reproduce the mic housing that used to enclose them.

Open like this they might even be able to accomplish a figure-8 pattern (which comes from throwing back-to-back capsules out of phase).
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Old 01-10-2010, 10:10 AM
BuleriaChk BuleriaChk is offline
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How about using a cheap Radio Shack electret mic? Has anyone simply put one of those on a putty ring to imitate the Dyna-G? Maybe put it in a pillbox to avoid ambient sound?

They are under $4, and the frequency response is way overkill.

Or the mics in a Zoom H4?

Hey, I just started thinking about it this morning, and it is still only 9 am...
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Old 01-10-2010, 10:43 AM
sdelsolray sdelsolray is offline
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Quote:
Originally Posted by Solo View Post
Hi, Bob,
Yes, the mic requires power, but, it can run on 12V. The spec says 12-52VDC, and the EV people confirmed it can run on 9V battery or the power provided by Highlander preamp.

As for the phase shift, I am not sure. I just removed the casing, and there was no wiring attached to the case.

I am trying to understand how I can attach the three wires to the stereo endpin jack which seems to have only 2 available attachments. I found out that AKG C416 has the similar configuration, so it must be possible.

Ted
That mic uses balanced phantom power (+ and - legs running on the hot and cold wires). The Highlander provides unbalanced phantom power (i.e., "T" or "bias" power; + and - legs running on the hot and ground wires). If you short the cold to ground on the mic wiring and run directly to the Highlander, that should work. There may be other solutions.

A bigger issue, though, is the two capsule config. You will need to run that EV mic preamp with the capsules.
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Old 01-10-2010, 10:11 PM
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Interesting --- If you can get the dual electret capsules operating in a differential noise cancelling mode and get one element real close to the soundboard/bridgeplate you may be able to scoop the yet to be released L.R. Baggs Anthem system.
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