Topic: how do they match mics?

[guysonic]

One technique I find most useful in matching mics (this is done here for matching DSM mics) is to apply pink noise to two closely positioned mics at >1 meter distance from a speaker. 

Amplify the output of the two mics and invert the signal to one of the mic channels, then sum the two channels to mono and observe the spectrum graph of this mono signal.

If the two mics are perfectly identical over the pink noise frequency, then a straight line results when viewed on a spectrum graph display.  Where the sum of two mic signals (one channel inverted) are not an identical match, the summed output appears as a deviation from a straight line over the test frequencies.

If one mic has higher output than its mate, then a straight line still occurs if mics have perfect "bandwidth over frequency match," but the straight line will have some value other than 0 db indicating amount of overall output sensitivity mis-match.  This sensitivity mis-match is quite OK when known and can easily be corrected with simple level adjustment of recorded channels in post edit process.

While omni mics need not be rotated for doing a test like this, directional type mics should be rotated 30, 90, 180 degrees to observe any change in off-axis response match existing.

[Giant_Rick]

That's a very interesting thread, goes straight to my Favorites on Google Chrome!

I have two questions.

1. Is there an equivalent of the 'PAZ Analyzer' for Audacity? Or may I just use EAC (after making a mono track of the stereo one -- what does 'invert' mean, why do I have to do this and is there a way to do this with Audacity?)?

2. Can soldering have any effects on the capsules?
I've ordered some Panasonic WM61-A to make a small set, but I'm afraid that the soldering operation can be harmful. Obiviously I'll touche the mike the least time I can with the soldering tip.

Thanks!

[bucsab12]

2. Can soldering have any effects on the capsules?
I've ordered some Panasonic WM61-A to make a small set, but I'm afraid that the soldering operation can be harmful. Obiviously I'll touche the mike the least time I can with the soldering tip.

This may sound like a stupid comment but make sure that you use some sort of heat sink for the capsule when you are soldering the wire to it.

I have used these small "crocodile" connectors (I am not sure if that is the correct term in English, please excuse me) when I soldered the capsule to the cable and it worked great. The capsule stayed at the same temperature, maybe a little hotter.

One time, when I forgot to use the crocodile connector, the capsule became very hot after touching it for only about 2 seconds with the soldering iron...

[Giant_Rick]

This may sound like a stupid comment but make sure that you use some sort of heat sink for the capsule when you are soldering the wire to it.

I have used these small "crocodile" connectors (I am not sure if that is the correct term in English, please excuse me) when I soldered the capsule to the cable and it worked great. The capsule stayed at the same temperature, maybe a little hotter.

One time, when I forgot to use the crocodile connector, the capsule became very hot after touching it for only about 2 seconds with the soldering iron...

I have some iron alligator clips that helped me last time I made a work with two cheap and crappy capsules.
They didn't have any solder on.

Do the WM61 come from some solder on, and do I have not to use any other solder but the one there's already on?

[Giant_Rick]

They do have solder on their pads, but I always freshen it with a tiny dab of mine.

I'll do the same.
Thanks for replying!