How Matched Should a Matched Pair Be?

R

Relakst

New member
I just received my new "matched singles" set of small diaphragm mics. Strangely, there were no graphs included to show what criteria was used to match them. Curiosity got the best of me so I set them up last night right next to each other like a double barrelled shotgun.

After recording my acoustic guitar I was able to hear slight tonal differences between the two. They are supposedly matched to within 1db of each other.

So, is it normal to be able to hear slight differences in matched singles?
 
If you can hear a difference then it's quite possible that they are not matched to within 1 dB of each other, unless you have golden enough ears to hear a 1 dB differnce at those frequencies where that variation is present. Consider also that the two mics, even when placed side by side, will pick things up with slight difference.
 
Lets pretend for a minute that I DO have golden ears and I CAN hear 1db difference in frequencies. In the larger scheme of things, or more specifically, in an actual stereo recording process, is there any real reason for having spent any time at all asking the original question ie caring about slight tonal differences?

I think I am beginning to "hear" the answer to my own question... I mean one mic might catch different reflections than the other mic because of room placement, room treatment, furniture, direction, distance etc. They could be absolute clones and still "hear" differently.

I guess I won't sweat the small stuff. They do have a great overall sound. And the brand name of the mics is
 
Yikes

1) Set up a mic stand
2) Place mic "A" in stand
3) Beam white noise at it and record it
4) Place mic "B" in same stand, same place
5) Beam same white noise at it and record it to track 2
6) Do a frequency graph of mic "A"
7) Do a frequency graph of mic "B"
8) Compare
 
Well, sounds easy enough. All I need is white noise and a frequency grapher. I have Sonar 4. I'll see what tools I haven't explored yet in that program.
 
White Noise - how about turning the volume up on your TV on an untuned channel?

Would that be sufficiently noisy enough? Now you just need software to graph it - should be easy to find something on the web ?
 
i have a good frequency plugin that i use to check levels of things that includes timed amounts, waterfall and many others that i use all the time in sonar 4. it's a vst plugin.

next time i'm at the studio i'll let you know as it's very free.
 
Quick and dirty: reverse the phase on one of the mics, and judge how matched they are on the degree of cancellation.
 
Brilliant! I assume this will work on all frequencies. I always thought this was more of a bass thing but, really, if one mic is exactly the opposite of the other then there should be no sound, theoretically. Correct?
 
So many variables... so little time. The Peluso CEMC6s sound great. I think I'll just take a pill and relaks.
 
Spotting

Reversing the phase on one of the mics will only be completely accurate if both of the mics are in the exact same spot.
 
Relakst said:
I just received my new "matched singles" set of small diaphragm mics. Strangely, there were no graphs included to show what criteria was used to match them. Curiosity got the best of me so I set them up last night right next to each other like a double barrelled shotgun.

After recording my acoustic guitar I was able to hear slight tonal differences between the two. They are supposedly matched to within 1db of each other.

So, is it normal to be able to hear slight differences in matched singles?
Click to expand...
Having a near-perfectly matched pair is only important, IMO, if they're going to be used as a true stereo pair such as XY or ORTF, at least a few feet from the source - so they are able pick up the L/R soundstage accurately. It's a whole different thing when recording sources up close, especially at two different mic locations, and matching isn't really an issue there, IMO.

With the test you did, depending on where the mic's were, having them side by side could give a different sound from each even if they were a carefully matched pair. For instance, if placed in the common neck/body joint position a few inches away, one inch left or right can make a big difference in tone. I'm not sure what the blocking effect of having another mic's body in parallel might have on the sound, but that might be an issue also, as the guitar produces a diffuse soundfield, so different aspects of the tone are coming from different directions when close mic'ing. If your mic's were 2-3 ft away, I don't think the shotgun-barrel positioning would really matter.

Mic pairs that I own tend to vary more in output level than spectrum response – more so with less expensive mic's, and that's not really a big deal. I just mark them and adjust preamp gain.

Tim
 
The only problem with these mics was ME not knowing what to expect from a matched pair.

Timothy, your response satisfies me such that I will just enjoy my Pelusos. Also, I did contact SoundPure and received the info I wanted from John Peluso himself! A class act to say the least. Highly recommended!
 
northsiderap said:
Reversing the phase on one of the mics will only be completely accurate if both of the mics are in the exact same spot.
Click to expand...

That is true. I would use a straight mic stand, with a spring-loaded clip, so the mics could be easily swapped out without drama.
 
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