I've been using the 'uncalibrated' ECM8000. I've also read somewhere that this mic has some HF problem, or the likes...
However, using it with RTA function of the same brand DEQ2496, flat is flat to my ears. And it's also capable of pointing out those problems in FR which are pretty much consistent with my hearing. (or maybe we adpated to each other?)
I know this is not objective at all and very rough. It's good enough for me, though.
However, using it with RTA function of the same brand DEQ2496, flat is flat to my ears. And it's also capable of pointing out those problems in FR which are pretty much consistent with my hearing. (or maybe we adpated to each other?)
I know this is not objective at all and very rough. It's good enough for me, though.
Fine.
...
It means you send your scientific instrument out to a certified laboratory, and they make the necessary adjustments to bring it into conformity with a specification. They usually affix a label or provide a document certifying compliance and indicating when you should pay them to do it again....
Only some instruments get treated like that, mics not being one of them.
The mic ships with data describing how it deviates from a standard. The measurement software uses the supplied data to calibrate its input to that standard or another one. Until that process is accomplished, the mic is not "calibrated." It never is, actually; the concept relates instead to the status of the measurement system using it.
A calibrated mic is one which comes with traceable certification of performance in conformity with a standard....
A calibrated mic is one which comes with traceable certification of performance in conformity with a standard....
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This is ideal, i.e., for professional applications. In the DIY world I'd say that it is perfectly OK for a mic to be calibrated against another calibrated mic. The risk here is, of course, that of uncertainty and - most importantly - the method used. There are levels of calibration: primary, secondary, tertiary... with accuracy, certainty and repeatability substantially decreasing with every successive step away from the accredited standard.
My Behringer mic is calibrated by the "Ai No Kea"* method.
The mic is supposed to have a bump at the top if used at 0 degs. It is a free field mic meant for room correction. Not meant to be used straight on.
So just buy one that has been measured and graphed, or use one of the many files that are on the web. They aren't that far off!
*Hawaiian for "I No Care." I have far better things to worry about than if my DIY measurements of my DIY speakers are 1dB off in part of the range. Brah, Ai No Kea!
The mic is supposed to have a bump at the top if used at 0 degs. It is a free field mic meant for room correction. Not meant to be used straight on.
So just buy one that has been measured and graphed, or use one of the many files that are on the web. They aren't that far off!
*Hawaiian for "I No Care." I have far better things to worry about than if my DIY measurements of my DIY speakers are 1dB off in part of the range. Brah, Ai No Kea!
When NIST 'calibrates' a mic (starting at about $6K), they measure its frequency response and voltage sensitivity. They'll measure other stuff for an extra charge. They don't 'certify' it to meet any standards, they just give you the numbers, guaranteeing them to be within so many dB at the frequencies measured. What you do with the numbers is up to you. If that definition of 'calibrate' is good enough for NIST, it's good enough for me.
http://ts.nist.gov/MeasurementServices/Calibrations/acoustic.cfm
Man, I can't believe we're getting this sidetracked over the calibration of a $50 mic. If the included curve isn't good enough for your needs, spend another $40-50 and send it to Kim or Herb for an independent calibration.
http://ts.nist.gov/MeasurementServices/Calibrations/acoustic.cfm
Man, I can't believe we're getting this sidetracked over the calibration of a $50 mic. If the included curve isn't good enough for your needs, spend another $40-50 and send it to Kim or Herb for an independent calibration.
You got it. I don't know what mic you have (EDIT - I see you have the ECM8000, so the following is true), but most mics based on electret capsules show a peak somewhere in the high treble, from 2-5dB. I agree with your's and panomaniac's take on things, close is good enough for our purposes, particularly with errors in the high treble. But I like the added security of knowing more accurately than is probably necessary (plus my mic had a broad .75dB dip in the midrange, which is probably significant). Its good to know the LF roll off if your working in the mid to low bass too.
Catapult, although some parts of this thread were less than enlightening, the calibration is the significant aspect of the PE mic - I though a mic at this price would preclude some of the excuses and encourage people to be more substantive with the work they share here. Anyway, I still think it is a great idea and value. (BTW, I sent my mic to Kim
)Right....
Ok, then, I don't know if my mic is that one out of 40 (according to ZilchLab), or my ears also have a "rising response". When I EQ it flat all the way up to 20kHz by the RTA, it's too bright, already! But it should be rolling off in reality, no? Hmmm....
I tend to tune my system slightly roll off (again, seen by the RTA) towards the top 2 octaves to get a more natural and easygoing sound. So now it's rolled off and rolled off again !?
And, if the Eminence specs are fair, then I probably got 106~108db/w in the midband of my system! (The tweeter is rated 105dB/w and the mid is several dB higher. Both are not attenuated. )
Interesting, and also confusing...
Ok, then, I don't know if my mic is that one out of 40 (according to ZilchLab), or my ears also have a "rising response". When I EQ it flat all the way up to 20kHz by the RTA, it's too bright, already! But it should be rolling off in reality, no? Hmmm....
I tend to tune my system slightly roll off (again, seen by the RTA) towards the top 2 octaves to get a more natural and easygoing sound. So now it's rolled off and rolled off again !?
And, if the Eminence specs are fair, then I probably got 106~108db/w in the midband of my system!
(The tweeter is rated 105dB/w and the mid is several dB higher. Both are not attenuated. )Interesting, and also confusing...
That happens all the time when mixing for concert crowds. The sound check settings will be dramatically different from the settings that account for human bodies absorbing audio - assuming the performer(s) can attract a crowd.
CLS, how old is your Behringer? They used to be quite flat until Panasonic discontinued the WM-60 capsule. The replacement WM-61 has the rising HF response and Behringer apparently didn't change the electronics to compensate. From the Dayton curves I've seen so far, it looks like PE had Superlux include a bit of EQ to flatten the HF.
Hi,
I don't remember when I bought the mic & EQ. It's been quite a while, maybe 10 years...
As to the AutoEQ function, I remember the adjustments were quite large (over +/- 8~10dB or so at some points) in my previous uses. Maybe it'd be better now with my dipole bass in new place.... And I had a feeling that the 1/3 Oct. bands seemed too rough for those really problematic zones. I also tend to like sounds with overall less EQ adjustments, especially on the + side.
For solving those really painful 'problems', I like to use the 'Feedback Destroyer' function which are very narrow and deep notch filters. With helps from these very narrow notches (usually 2~3 points), the EQ adjustments can be reduced significantly. I like the overall sound by this way.
I don't remember when I bought the mic & EQ. It's been quite a while, maybe 10 years...
As to the AutoEQ function, I remember the adjustments were quite large (over +/- 8~10dB or so at some points) in my previous uses. Maybe it'd be better now with my dipole bass in new place.... And I had a feeling that the 1/3 Oct. bands seemed too rough for those really problematic zones. I also tend to like sounds with overall less EQ adjustments, especially on the + side.
For solving those really painful 'problems', I like to use the 'Feedback Destroyer' function which are very narrow and deep notch filters. With helps from these very narrow notches (usually 2~3 points), the EQ adjustments can be reduced significantly. I like the overall sound by this way.
That's part of the answer. The ear includes vast amounts of processing the brain does to fix on sound from the forward hemisphere, which means microphones pick up sound quite differently from how humans perceive it. Try taping the output from these mikes at the same time as you listen to music - I think you'll be amazed at how terrible the tape sounds. It's not the microphone's fault, it's doing exactly what it was designed to do: pick up sounds from all directions, including sound the ear normally ignores.
Now, speakers get more directional in the highs so room energy diminishes the further up you go, but the ear doesn't pick that up as dullness because the Haas precedence effect makes sure direct sound is perceived over the various reflections. Meanwhile, the mike's response curve knows nothing about Haas precedence, so EQing flat means the on-axis curve rises with frequency to the extent the speaker beams and room surfaces absorb highs over lows. EQing for perceived flatness actually means the room curve picked up by an omni microphone should roll off in the top end.
The -1 db/octave rolloff is an approximation which seems to work well for most rooms, so that's why many RTA/EQ combos include it as an option.
I have EQ'ed a couple systems years ago with my old RS SPL meter. I would use pink noise and set flat according to the SPL meter up to ~2-3kHz or so, and then just go by ear after that. It usually worked pretty well.
A friend had one of those BSR EQ's from DAK with the RTA and pink noise generator and I EQ'ed my speakers flat with that - the only recording that sounded better was Rush 'Fly by Night' - everything else was extremely bright and had lots of glare.
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