'Matched' mics?

[suprstar]

What exactly does that mean? Does it just mean you got 2 of the same model of mics from the same mfr lot? Or do they go thru some analysis and/or modification to make sure the freq response is closer than 2 random mics of the same model?

[AndrewClaycomb]

They are matched very closely in frequency response and dbl sensitivity.

[suprstar]

More closely than 2 random mics of the same model? Does that mean someone tried out 20 mics and hand picks 2 that are the most closely matched? How much variation is there among different mics of the same model?

[hairylarry]

suprstar,

For instance and RE15 is supposed to be stereo matched with another RE15. This is not true of the identical RE10 model.

I believe any RE55 omni is matched with another RE55.

Some mics show more variance and must be matched to avoid excessive variance from the left and the right.

Stereo recordings can be made with unmatched mics and even with mics that are not the same model. You do have to be careful though.

For instance if the right mic has a stronger upper midrange and you record a sax player going from a low register to a high register the sax may shift right as the frequency moves into the strength of the right mic.

I think when mics are advertised as a matched pair that would imply some post quality control selection was taking place.

Thanks,

Hairy Larry

[antichef]

Yeah - Shure SM81s are supposed to all be matched, and this has been true of the ones I have (even though they're from very different vintages) -- not so much on other mics. If they're "factory matched", then I suppose the manufacturer did some testing. Certainly there are some folks on this board who could talk about this in a more first hand kind of way.

I've got two mics with consecutive serial numbers, but haven't tested to see whether they match - I didn't buy them that way. I suppose that mics made in the same "batch" would less likely to undergo conditions that would force them to not match, but I've seen nothing to say that either a) they have to made at the same to in order to match (and the SM81 thing contradicts this) or b) that being made at the same time makes them more likely to match.

I frequently use pairs of mics (same model) for stereo recording that I know are not perfectly matched, and it doesn't seem to matter that much for what I'm doing.

[pohaku]

Originally Posted by suprstar

More closely than 2 random mics of the same model? Does that mean someone tried out 20 mics and hand picks 2 that are the most closely matched? How much variation is there among different mics of the same model?

Generally mics that are sold as matched pairs have been specially selected and matched for frequency response and sensitivity. It involves more than picking two random mics or selecting sequential serial numbers. You typically pay more for a pair of matched mics than two singles. Some companies, Neumann and AT come to mind, don't sell matched pairs, claiming that their manufacturing tolerances are so tight that any two mics of the same model are matched.

Depending on the company, there can be quite a bit of variation between different mics of the same model. Oktava comes to mind. For example, the EV RE-10 is an RE-15 that didn't meet spec. Still a good mic and perfectly usable, but it didn't meet the specific response and/or sensitivity parameters EV requires for the RE-15. So EV sold them as different models. (I have both mics and mine do sound different). Doesn't mean that you can't find two unmatched mics of the same model that sound pretty close, just that there is a greater likelihood that they won't. Lots of folks here have winnowed through the Oktava bin at GC to try and find a pair of mics that match (or are close enonough). The trick in doing that is you are usually just doing it by listening, rather than also having a frequency plot for each mic.

[XLR]

Here's my experience... based on four pairs of small diaphragm condensers I've used for stereo-configuration recording (I've used others too but these come to mind).

Two of the pairs were matched in some way. Of those, one pair was matched by simply being consecutive serial numbers from a manufacturer with very high quality control (Schoeps). The mic's sound exactly the same.

My other matched pair (Naiant) was tested, if I remember correctly, by sensitivity. They also sound identical to my ear.

My two unmatched pairs are MXL 603s and Shure BG 4.0. With each of those, the two mic's have noticealby different levels and freq response. The levels are easy to compensate for with preamp gain and with the freq response difference they're still perfectly good for things like A-B close mic'ing of an instrument as for that mic's don't need to be matched.

[suprstar]

Cool, thanks all!

[mshilarious]

It's going to vary a lot by manufacturer, but a matched pair should at a minimum be matched for frequency response and sensitivity. You could also look at off-axis response and distortion if you wanted to get really crazy, but the variation there is quite a lot less noticeable.

One thing to consider if you are buying a matched pair second-hand is the care & feeding of the mics. The SM81 is a good example; it's been in production for 30 years and many have been used live. Accumulated grime might throw off the sensitivity of the mic, even if it is still otherwise OK, and that would prevent a match with every other SM81 in the world. Heck, I even brought an SM81 back from dead after it had been dropped in the toilet (not my mic, and I didn't dunk it either!), but I guarantee you it was never gonna match another SM81 on the planet, unless . . .

[Ritzy]

Originally Posted by mshilarious

Heck, I even brought an SM81 back from dead after it had been dropped in the toilet (not my mic, and I didn't dunk it either!), but I guarantee you it was never gonna match another SM81 on the planet, unless . . .

What was the person recording for that to have happened?

[dgatwood]

Originally Posted by mshilarious

Heck, I even brought an SM81 back from dead after it had been dropped in the toilet (not my mic, and I didn't dunk it either!), but I guarantee you it was never gonna match another SM81 on the planet, unless . . .

Sounds like a good idea to me. Might help make the mic sound a little less cold and sterile....

[suprstar]

Originally Posted by mshilarious

Heck, I even brought an SM81 back from dead after it had been dropped in the toilet (not my mic, and I didn't dunk it either!), but I guarantee you it was never gonna match another SM81 on the planet, unless . . .

lol, I guess you have a good excuse if your tracks sound like shit!

[antichef]

Originally Posted by mshilarious

unless . . .

And there are still a lot of variables to consider for mic #2 - water temperature, diet of the technician, etc. - complicated.