Questions about Panasonic WM-60 mic

[mr_push_pull]

Hi all

Yesterday I ordered a couple of Monacor MCE-2000 capsules (Panasonic WM-60AT equivalent) from local representative. Of course these will be used for loudspeaker measurement.
I've done my homework and asked dr. Google, but having never worked with an electret mic before I have some things left to clarify. Those being:

1. I see the term "battery box" being mentioned often. What is it and when/how should it be used? Is it a box with a battery put near the mic that provides power to it instead of using phantom (remote) powering?

2. From what I understand, using a higher voltage (close to spec'd maximum of 10V) gives better results (in terms of clipping?). Do I still need to do this if I'm using the Linkwitz mod for the capsule?

3. Which is the best of wiring the mic? Is running a long cable (balanced) from mic to preamp OK, or should I put the preamp very close to the mic (not recommended because of reflection problems)?

4. Which preamp shoud I use? This will be connected to line-in of my soundcard. There are a couple of schematics by Rod Elliott, there is the Mitey Mike 2/3, and other numerous ones I've found on the web. I'd like to build the best one for the purpose (SNR, bandwidth, adjustable gain, etc). If someone had tried one of these (preffereably the ones mentioned above, but not necessarily) please give some opinions.

Thank you.


PS: please don't recommend me to buy a Behringer mic and/or preamp, it defeats the (my) purpose

[Centauri]

This is how I did it.

http://www.users.bigpond.net.au/ggoo...i/diy/mic.html

Cheers
Graeme

[jomor]

A phantom power comes from ac-dc transformation thus it contains some noise, even if its regulated.

In such critical and sensitive applications like a measurement microphone preamp, it is wiser to use a battery for power supply.

the pre amp should be placed close to the mic, so the signal which will travel through the cable from the mic to the sound card will be stronger compared to the signal between the capsule and the preamp, thus less sensitive to noise interference.

[Mendelt]

A phantom power comes from ac-dc transformation thus it contains some noise, even if its regulated.

Any noise from a decent phantom supply is far below the noise floor of any wm-60'ish capsule. So I don't think that will be a problem.

I used this circuit to power my linkwitz modded wm-60 (actually 61's but they're about the same) http://scotthelmke.com/phantom-power-2.jpg

If you want to use batteries there are lot's of examples on linkwitz's site.
http://www.linkwitzlab.com/sys_test.htm#Mic
He uses 9v batteries to power the microphones.

[soongsc]

Originally posted by Centauri
This is how I did it.

http://www.users.bigpond.net.au/ggoo...i/diy/mic.html

Cheers
Graeme

That's a nice setup.

[Svante]

Originally posted by jomor
A phantom power comes from ac-dc transformation thus it contains some noise, even if its regulated.

In such critical and sensitive applications like a measurement microphone preamp, it is wiser to use a battery for power supply.

the pre amp should be placed close to the mic, so the signal which will travel through the cable from the mic to the sound card will be stronger compared to the signal between the capsule and the preamp, thus less sensitive to noise interference.

I'd say that a good phantom power is far better than batteries. Maybe not in terms of noise, but because batteries always run out when you need them most. If you want absolute calibration, poor batteries can lower the output voltage and introduce a hard-to-notice error in the level, and possibly distortion if the batteries are nearly dead.

Batteries are a pain.

[soongsc]

Originally posted by mr_push_pull
Hi all

Yesterday I ordered a couple of Monacor MCE-2000 capsules (Panasonic WM-60AT equivalent) from local representative. Of course these will be used for loudspeaker measurement.
I've done my homework and asked dr. Google, but having never worked with an electret mic before I have some things left to clarify. Those being:

1. I see the term "battery box" being mentioned often. What is it and when/how should it be used? Is it a box with a battery put near the mic that provides power to it instead of using phantom (remote) powering?

2. From what I understand, using a higher voltage (close to spec'd maximum of 10V) gives better results (in terms of clipping?). Do I still need to do this if I'm using the Linkwitz mod for the capsule?

3. Which is the best of wiring the mic? Is running a long cable (balanced) from mic to preamp OK, or should I put the preamp very close to the mic (not recommended because of reflection problems)?

4. Which preamp shoud I use? This will be connected to line-in of my soundcard. There are a couple of schematics by Rod Elliott, there is the Mitey Mike 2/3, and other numerous ones I've found on the web. I'd like to build the best one for the purpose (SNR, bandwidth, adjustable gain, etc). If someone had tried one of these (preffereably the ones mentioned above, but not necessarily) please give some opinions.

Thank you.


PS: please don't recommend me to buy a Behringer mic and/or preamp, it defeats the (my) purpose

1. The batery box provides the phantom power.

2. The Linkwitz site still uses 9V with the modified cap. I think this already brings you close to the limit of most opamps in terms of clipping, but you might want to find out yourself. More than 9V might not be necessary unless you really are missing that little bit. For test purposes, you may not need that much.

3. If you put the amp clost to the mike right at the end of the wand, you can cover it up to reduce reflections with the mic stand, you also reduce wire capacitance this way.

4. The Wallin II amp sold at Madaboutsound seems to work well. If course the setup with the circuit in an old commercial mic chassis will resuce reflections further if you like to do your own boards.