Reconstructing a microphone

[polar]

Hello everyone. I got a Sound Professionals SP-SPSM1 Single Point Stereo microphone from http://www.minidisco.com/sp-spsm1.html, and it woudlnt record in stereo. Well, it would, but one channel was MUCH louder than the other one.

I got upset, thinking it was a loose connection, and took it apart a while ago. Well, i found all the parts (except for the base), and was wondering where i would solder what, and if there is a way i can test the microphones themselves.

here are some pics:

http://img359.imageshack.us/my.php?image=dscn21084uw.jpg

(1)

http://img359.imageshack.us/my.php?image=dscn21042zm.jpg

(2)

Picture 1 is a picture of the parts that i have.

Picture 2 is of "the connector"

Notice on one of the microphones, the wire is off, and is soldered into the connector.

Does anyone know where i would put the other wires, what type of solder to use, and where to get a similar type of wire?

thanks if anyone can help!

[greenmachine]

Connect it like that and try again if it works before assembling it:

[attachmentid=548][attachmentid=549]

Any standard solder and any thin cable should work - if you plan to use longer cables, use screened ones. Be careful not to overheat the capsules, it could damage the diaphragm and / or FET. If it works and you plan to assemble it as a T-mic again, use a greater distance between the elements, something like 6-7". Omnidirectional microphones need a certain distance in between to get an adequate stereo separation as they're non-directional.

[polar]

Connect it like that and try again if it works before assembling it:

[attachmentid=548][attachmentid=549]

Any standard solder and any thin cable should work - if you plan to use longer cables, use screened ones. Be careful not to overheat the capsules, it could damage the diaphragm and / or FET. If it works and you plan to assemble it as a T-mic again, use a greater distance between the elements, something like 6-7". Omniaural microphones need a certain distance in between to get an adequate stereo separation as they're non-directional.

←

Thanks a bunch! I was planning on using the same distance wire, but the thing that concerns me is the stereo separation. With the current distance (approx 1.25"), would it sound quite a bit like mono? 6-7" seems to be a bit to large. Do you think it could have been the initial design that caused me to take it apart? it sounded 99% mono, you could hear something in the other channel @ about 1/100th the volume of the other speaker upon playback of recordings with that microphone.

Also, the current wire appears to have fiberglass in with the wires- any particular reason? And should the mic capsules be "cool" enough if i perform a quick operation? or would they require addational cooling/heatsinking?

Thanks again!

[greenmachine]

Plastic / fiberglass in the wires is used to make them more flexible so that they don't break easily when regularly bent - useful for longer, often carelessly handled equipment like headphones, wired microphones, etc. - not really necessary here. If you are careful to keep soldering times short enough, no additional cooling would be required. Try not to exceed about 3 seconds continuously. If you need longer for one capsule, wait a few seconds and cool it down meanwhile by blowing against it before you continue soldering. But before making great plans about the distance and final assembly, you should really reconnect them and try if you still have that unusual channel difference. If it's still there, you need to get properly working capsules first.

[polar]

Alright, i re-constructed the microphone, alothough it required some modifications. I'm wondering now where i could get something like the screen they use on microphone capsules? The microphones are somewhat loose, and have a tendancy to push "out", and i was going to put some screen over both of the sides of the "T"

[greenmachine]

Or you could wrap some tape around the capsules until they fit in tightly. I still think you won't get happy with 1.25" distance though.

[polar]

All i really wanted the microphone for was to record lectures. I tested it, and it seems to work okay for that purpose. I cant take the microphone all the way out, because the wires are not that long- i tried to wrap the microphones in tape AFTER i soldered them in. I didnt try before because i used an aligator clip as a heat sink. I guess i'm

happy with the final result. It was a real pain to solder, though.

I'll post pictures of it a bit later, as i'm going back to new york soon, and my brother wants to use my microphone for when he goes out of town, and is mailing it back. I'll also make a recording of tv, or something.