Topic: How do I know if two electret caps are matched?

[lordbelial]

Well, that's my doubt.

How can I know if two different same branded elecret caps are matched?

What kind of measure do I have to do?

Thnks!

[Roving Sign]

I think "matched" implies some science has been applied and some serious measurement gear used...but I think you can use some "rough science" - try some white noise on your stereo and swap elements (use same mic body if you can) - I dont think you can truly "match" elements this way - but you can get an idea if there is some serious differences in output or sonic character...

[F.O.Bean]

i have a multimeter that can detect caps and see what they emasure, its a cheapie, so id but out a digital multimeter

[sml42]

What I would do... first make yourself a test tone that you can play back over your loudspeakers. Hook up a pair of caps (left, right) right next to each other and directly in front of one loudspeaker, start your recording device and then play the test tone. Take your recording (you only need a few seconds) and visually inspect the waveform (left channel vs. right channel), that should give you a fair idea of how closely matched the two caps are.

(actually it's not quite what I'd do... I'd play back the test tone and look at the output from the caps directly on my 'scope... of course this method requires access to a 'scope )

[OOK]

Being matched is more than just output volume.  It also means in terms of frequency response.  For that you need a realtime analyzer that measure FRq. resp.   When each mic is made no two capsules are exactly identical.  there are small variation.  Now a days quality control is much tighter but there is deviation.  Companies that truly match mics neuman, AKG, MBHO, Schoep all  use various analyzer that measure the above info.  They then match up mics within 1 - 3 % tolerances and call them matched, then assign consecutive serial numbers, package and sell.

[stober]

I noticed a U.S schoeps edition set of cmc6 with the mk4's once were the certificate of matching had serial numbers of the caps were like 10 serial numbers apart example (15432 and 15442) and it was a matched set . My dpa's are matched and have consective serial numbers.anybody?

[MattD]

What I would do... first make yourself a test tone that you can play back over your loudspeakers. Hook up a pair of caps (left, right) right next to each other and directly in front of one loudspeaker, start your recording device and then play the test tone. Take your recording (you only need a few seconds) and visually inspect the waveform (left channel vs. right channel), that should give you a fair idea of how closely matched the two caps are.

Sans oscilloscope, that's a pretty good idea. I'd use an FFT to do the comparison, though and visually compare that. I think some software packages allow you to put L/R FFTs on the same plot. I bet there's something out there that could even perform a difference operation on the two.

[TNJazz]

Consecutive serials does not necessarily mean they are matched.  Matching can be done after the fact as well, so you could always buy two singles with varying serials and have them matched later on down the line...