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What's the deal with microphones?

Blumlein 88

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Here is an overlay of 3 omni microphones. Blue is the Umik 1. Red is a CAD M179 in omni mode. It has 1.2 inch diaphragms I think. An LDC in any case. The green trace is an Avantone CK-1 omni pencil condenser. I think .5 inch diaphragm. I applied calibration curves to all. The Avantone and CAD I created the cal curves from overly smooth looking frequency response curves. There are a few areas they differ, but I'm surprised how they mostly are pretty close to the same. I'm using 1/6th smoothing for the display. Each grid line is 1 db in this. case.

I think it is safe to say using the published curves as cal files any of these omnis would not lead you terribly astray for measuring in room response of speakers. Most especially in regard to woofers down below 200 hz. I was measuring the same speaker from the same mic location to do this. While I was careful I know the positioning of the mic diaphragm is no better than nearest 1/4 inch. I'd expect some considerable portion of the variance at the higher frequencies is due to less than perfect positioning.

1630015392890.png


Same graph as above only at 1/12th smoothing.
1630015819783.png


Here is psychoacoustic smoothing in REW>
1630016015420.png
 
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earlevel

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Pardon me if I'm a little skeptical of the "EQ a cheap mic, no need to buy and expensive one" idea (I know most people here aren't saying that). Like EQ cheap headphones, or "no reason to buy Genelecs, etc, just EQ some cheap ones to sound like Genelecs". :D

(A reminder, my point of view is singing, not VO, so more demanding—far greater pitch and loudness difference, often accompanied by varying the distance to the mic.)

But some of the virtual mics are tantalizing. The Townsend Labs seems to be the best, but it clearly starts with a premium mic. But the Slate seems to be useful, the demos of changing mics after recording are pretty striking. If nothing else, they help people who want to defer their decision, and have the option of changing their mind again down the road, when another virtual mic choice grows on them.

And yes the room is very important, but I'll add that just how important does depends on the mic. A "decent" sounding room should be adequate for an SM7B, but may be your downfall with an LCD (especially something like a Chandler REDD, which many feel sound best backed off a foot or two). SM7B is forgiving enough that a number of singers use it specifically so that can track in the control room (Chris Martin, for instance, whose mainstay was otherwise a C414...though last I knew he switched to a Soyuz 017 Tube, which is quite sensitive). But a small, untreated, boxy room is going to sound like crap with any mic. One of my pet peeves, going way back, is hearing a commercial on the radio where I can picture the guy sitting in front of a flat table with a mic on it, in an empty hundred-sq-ft room. Yuck.
 
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617

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Pardon me if I'm a little skeptical of the "EQ a cheap mic, no need to buy and expensive one" idea (I know most people here aren't saying that). Like EQ cheap headphones, or "no reason to buy Genelecs, etc, just EQ some cheap ones to sound like Genelecs". :D

(A reminder, my point of view is singing, not VO, so more demanding—far greater pitch and loudness difference, often accompanied by varying the distance to the mic.)

But some of the virtual mics are tantalizing. The Townsend Labs seems to be the best, but it clearly starts with a premium mic. But the Slate seems to be useful, the demos of changing mics after recording are pretty striking. If nothing else, they help people who want to defer their decision, and have the option of changing their mind again down the road, when another virtual mic choice grows on them.

And yes the room is very important, but I'll add that just how important does depends on the mic. A "decent" sounding room should be adequate for an SM7B, but may be your downfall with an LCD (especially something like a Chandler REDD, which many feel sound best backed off a foot or two). SM7B is forgiving enough that a number of singers use it specifically so that can track in the control room (Chris Martin, for instance, whose mainstay was otherwise a C414...though last I knew he switched to a Soyuz 017 Tube, which is quite sensitive). But a small, untreated, boxy room is going to sound like crap with any mic. One of my pet peeves, going way back, is hearing a commercial on the radio where I can picture the guy sitting in front of a flat table with a mic on it, in an empty hundred-sq-ft room. Yuck.

I don't think anyone is arguing mics can be equalized to sound alike (although mics that can mimic directional characteristics can get as close as you want). My point in comparing mic responses is to collect some data points on why mics sound different despite having largely linear responses.

The recording 'industry' is somehow even more prone to superstition and myth than audiophilia, but looking at the mic responses is proving to be interesting.

I do agree that the room (and, you know, performance) are really important. I actually got a sm57 and tried the trick where you equalize it to sound like a sm7b. It works really well, to my ears, as it should given they share the same capsule.
 

earlevel

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I don't think anyone is arguing mics can be equalized to sound alike (although mics that can mimic directional characteristics can get as close as you want). My point in comparing mic responses is to collect some data points on why mics sound different despite having largely linear responses.

Although he didn't say it to that extent, I was referring to AnalogSteph's comment earlier about cheap mics that he felt had the essential character of expensive ones. At least, he showed one that was pretty far from my current mic, but somewhat similar shape, and I assume he meant it was within EQ'ing of it, taking into account other comments.

The recording 'industry' is somehow even more prone to superstition and myth than audiophilia, but looking at the mic responses is proving to be interesting.

I do agree that the room (and, you know, performance) are really important. I actually got a sm57 and tried the trick where you equalize it to sound like a sm7b. It works really well, to my ears, as it should given they share the same capsule.
Interesting that you tried the EQ trick. They aren't the same capsule, but are related:

ARE THE SM7 AND SM57 IDENTICAL?

QUESTION
Is it true that both the SM7 (all versions) and the SM57/58 employ the same capsule, hence sound very similar?

ANSWER
The SM7, the SM57, and the SM58 are all based on the Unidyne III capsule design. The SM7 capsule is not identical to the SM57 or SM58, but it is similar. The SM7 also has a larger acoustical chamber behind the mic element, and this extends the low frequency response.
 

Pluto

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The single most important factor in getting a great sounding, clean VO track…

…use a decent pop shield and set it up so your artiste works the shield from about 4-6 inches. The shield itself should be about 3" from the mic. The output of a mic varies as a square-law to the distance of the sound source and one of the biggest errors is to let the artiste get too close*. By encouraging the talent to work a little further away than you might think ideal, you keep the levels more consistent and, therefore, more controllable. People like to embrace the microphone, which is nothing but trouble. Letting them embrace the shield instead of the mic satisfies the human need while minimizing problems for the recording.

The point here is this: if you assume that the natural movement of the artiste while performing (and some are far more mobile than others) is, say, four inches, the resultant change in mic output is far smaller if the mean distance is 10" than, for instance, 3".

Oh, and shields sound a lot better than any foam windshield as they deal very effectively with LF blasts while letting all the HF through.

Your pop shield can easily be home-made but for maximum effectiveness, a ring that supports two layers of the shield fabric, separated by about half an inch, is perfect.

That's today's free pro tip. Any more you'll have to pay for ;)

*If you have a good compressor and a front end that will handle the level, you might get away with it but many setups will not be able to cope sufficiently well.
 
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earlevel

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Your pop shield can easily be home-made but for maximum effectiveness, a ring that supports two layers of the shield fabric, separated by about half an inch, is perfect.
Not that I'm an authority on pop screens, I spent years without one, but some years ago (6-8?) I bought a mudguard (backsplash) and a pop screen. As an (electrical) engineer, it bugged me that at some point fabric impedes way too much (denim fabric, lol), while superfine, low-mass, and loose not enough. There is mass causing damping, and a pop screen has to err on the side of stopping pops, by deflecting with a combination of mass, tightness and flexibility of the stretch, and the thread and hole size—and one layer or two. The mesh type (I bought Stedman XL) makes more sense to me.

To be clear, I'm not saying a fabric pop screen will not do the job without degrading the sound, I'm saying the other type makes more sense to me, and I went that way.

And it works really well. The area of the holes is roughly equivalent to the area of metal mesh, you can see straight through. But when you put your hand on the other side, you can feel that the puffs of any plosives aren't simply diffused, the bulk of the force it directed downward at a 45-ish degree angle, because the mesh is made by twisting the metal grid lines at an angle. You can blow straight in and feel the bulk of the force dive steeply and under the mic. Even blowing hard, there's only a slight gentle waft of air hitting your hand in front of the mic. I don't feel the screen is altering the sound at all—no scientific tests—but it effectively kills plosives.

And you're not going to tear a metal screen, would need considerable abuse to damage in any way, and they can be easily cleaned (and little need to). The Stedman XL has a ring around it, you're not going to bend it with mishandling, but they have a cheaper one without the ring.

XL+label.jpg
 

Pluto

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I'm sure plenty of manufacturers have found ways of elevating this simple $3 concept to the $80 level, but that's audio for you. While it's probable that all the verbiage about “large louvered openings to deflect the air bursts away from the microphone” is sort-of right, the best material I have found is to commandeer sheer tights when they have outlived their primary purpose. Stretch the material to the point where the center can move about .5cm. The last part is important as it's that movement which absorbs the energy in LF blasts, while the HF seems to get through unchanged.

I very much doubt you'll hear any difference between your Stedman Proscreen XL and my old pair of tights. Perhaps I could write a PhD on the question of determining the optimal denier density.
 

earlevel

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I'm sure plenty of manufacturers have found ways of elevating this simple $3 concept to the $80 level, but that's audio for you. While it's probable that all the verbiage about “large louvered openings to deflect the air bursts away from the microphone” is sort-of right, the best material I have found is to commandeer sheer tights when they have outlived their primary purpose. Stretch the material to the point where the center can move about .5cm. The last part is important as it's that movement which absorbs the energy in LF blasts, while the HF seems to get through unchanged.

I very much doubt you'll hear any difference between your Stedman Proscreen XL and my old pair of tights. Perhaps I could write a PhD on the question of determining the optimal denier density.
You can keep (and repeatedly look at) your old pair of tights ;-)

$69 and I put it on, done, it looks good, in my mind it makes more sense. And I don't own tights, old or new, I don't need to make a frame (uh, coat hanger? or you have more sophisticated free stuff hanging about?) and figure out how to attach it—a "$3 concept" is not $3 without having the right free stuff on hand and your time. I've got a big fat knob to unscrew it and attach it to another mic and stand in seconds, it's got a nice flexible yet sturdy gooseneck. I can afford $69 for that.
 

Watsonian

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I want to record some voice-over stuff, and I have an inexpensive condenser mic. I was not really happy with the sound I was getting, so I started doing some EQ and looking at other microphones that people rave about...and I just don't understand what they're talking about.

Doesn't EQ account for 90% of a microphone's sound?

When it comes to buying most microphones, you're essentially buying a baked in EQ sound.

EQ for microphones is generally used to tame any defects of the room, instrument or voice and to make things work in a music mix not to make one microphone sound like another.

Unless there's something drastically "wrong", or you're looking for a specific effect, it's better to go easy on the EQ. Note that wrong is a very broad term, it depends on your taste, not anyone else's.

It seems to me that the source proximity and proportion of room noise is vastly more important than the actual microphone.

In a reverberant room, or on stage, proximity to the microphone will minimise extraneous noise and reverberation. It doesn't cut it out completely though and the closer you are to - most - microphones the greater the bass boost you'll get.

Shouldn’t all cardioid 1" units have the same basic pattern?

Yes and no. If all 1" units were made exactly the same way, they'd sound close but even microphones of the same model generally have to be matched (as pairs) for stereo recordings.

With condenser mics, you get centre and edge terminated designs, square diaphragms, single and double diaphragm and then the shape of the head basket comes into play as well. Long story short: it's best to audition a microphone, if you can.

Expensive, beautiful sounding mics? What’s up with that?

Some expensive microphones will work with your voice, some will hate you and the feeling will be mutual!

Expensive mics such as (say) the AKG C12 can record your voice, the rumble of the washing machine and your neighbour talking outside. Bonus! Well, maybe not. It's why a lot of the more expensive microphones only live in well treated recording studios.

My large diaphragm condenser has a sort of pleasant thickness to it, and produces a nice loud signal, but my tiny instrument type omni condensers (made by Niaint) and my speaker measurement microphone sound far truer to life.

Large diaphragm microphones generally colour the recorded sound more, so people buy ‘em for that exact purpose. As said at the top, you’re essentially buying a baked in EQ curve with most mics.

Small diaphragm mics are very honest and realistic and, as such, are most often used on instruments. You can use them for voice but don’t expect them to lie about the quality of your voice!

There are also ribbon mics - if you like pleasant, smooth, thick and somewhat rolled off at the top end. Modern ribbon mics are a galaxy away from vintage mics, in terms of performance, so don't write them off as an option. Just be aware that they're more delicate than the average mic.

Finally - never look at a microphone’s stated frequency response and assume anything! Try it (if you can) and then make up your mind.

Here’s the frequency response of the AEA KU5A and, to be honest it looks like a disaster area. It ain’t - it's a fabulous microphone.

Best thing you can do is work with what you've got, work out what kind of mic type you like and then see what works with your voice, instrument, room and general approach to life. There are very few absolute rules when it comes to microphone use.


Screenshot 2021-09-12 at 18.26.38.png
 
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