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[Helge A Bentsen]

I'm not sure I understand; in my mind, if a microphone isn't "low-frequency capable" then it's probably not a very good measurement mic.

-Russ

Omni measurement mics have a better low-end response than directional mics, especially over distance. The proximity effect work both ways, you gain low end as you move closer and loose low end as you move away.
It's a myth that you need a directional mic or a large capsule to capture low-end.
My measurement mics can handle 159dB SPL peak. Enough to stick them pretty close to any large array of subwoofers without any issues 
A omni lav is actually a pretty good choice for recording low end (if it can handle the SPL).

[Tim Weaver]

I'm not sure I understand; in my mind, if a microphone isn't "low-frequency capable" then it's probably not a very good measurement mic.

-Russ

The 635A or any measurement mic is capable of picking up low freqs just fine. But large diaphragms (like a kick drum mic) do it a little better is all. In my mind having a seperate LF mic that can be tweaked and then blended in would be the way to go. Keep the natural unmodified sound from the omni mics and add in some boom from the Large Diaphragm mic. A D112 or a D6 or even something like an AT4040 or similar LD Condensor. 

[Russell Ault]

The 635A or any measurement mic is capable of picking up low freqs just fine. But large diaphragms (like a kick drum mic) do it a little better is all. {...}

I'm sorry Tim, I still don't understand. The measurement mic that Jason linked to (as one example) is only +/- 1 dB down to about 12Hz. How much better does low frequency response get?

(The 635A is another matter; it's specified frequency range is actually pretty small by modern standards.)

-Russ

[Tim Weaver]

I'm sorry Tim, I still don't understand. The measurement mic that Jason linked to (as one example) is only +/- 1 dB down to about 12Hz. How much better does low frequency response get?

(The 635A is another matter; it's specified frequency range is actually pretty small by modern standards.)

-Russ

Ok. Forget that I said "low frequency capable". It's just semantics.

Yes, absolutely a measurement mic would be just fine at recording LF.


I was specifically trying to offer a different path. A pair of extremely rugged omni dynamics (635a) which DO exhibit some LF rolloff, then supplemment that with some type of mic that will capture very low frequencies quite easily. Like a kick drum mic (which would not be flat response) or a large diaphragm condensor, or even a single measurement mic. Either way this more fragile microphone could be placed further away and protected.

[Jason Glass]

I'm sorry Tim, I still don't understand. The measurement mic that Jason linked to (as one example) is only +/- 1 dB down to about 12Hz. How much better does low frequency response get?

(The 635A is another matter; it's specified frequency range is actually pretty small by modern standards.)

-Russ

Yup.  All of this^.  Two EMX-7150 at head height, spaced  to taste.  Beautifully simple.  Or one at head height, close-arrayed with a pair of high-SPL cardioid SDC's in X-Y stereo config for ambience, preferably with extreme HPF and LPF to maintain cracking center-image transients in the final mix, all while maintaining minimal phase cancellations and maximal mono summing compatibility.  Getting creative, my nutty mind drifts to one central mono EMX-7150 mixed with a distant ORTF pair for stereo ambience, also with band pass EQ.

FWIW IMHO, in far field applications, priority of transient impact to the listener is inversely proportional to the diameter of the diaphragm.  Yes, LDC can enhance impact when close miking a source on-axis (kick drum is the prime example).  But wide-soundstage reproduction of distant concussions in outdoor open spaces is a whole other world of complexity where IMHO, the smaller the diaphragm, the better, for concussive punch and especially crack.  Explosive shells are not only generating sound waves, they're also delivering shock waves.  Shock waves, and convincingly reproducing them them with hardware that cannot generate them, are a distinct subset of physics and Audio Engineering.

UNLESS your budget allows for tools of this caliber.  https://www.manley.com/legacy/refsgold  Then just stick the thing up on a stand and enjoy whatever it delivers.     It may or may not be accurate, but it will sound great.

[Chris Grimshaw]

The 635A or any measurement mic is capable of picking up low freqs just fine. But large diaphragms (like a kick drum mic) do it a little better is all. In my mind having a seperate LF mic that can be tweaked and then blended in would be the way to go. Keep the natural unmodified sound from the omni mics and add in some boom from the Large Diaphragm mic. A D112 or a D6 or even something like an AT4040 or similar LD Condensor.

At close distances, you'll get the proximity effect boost in the low end, particularly in the 50-120Hz range.
A decent measurement mic will be flat to 10Hz (or below), even at larger distances.

I'm afraid I don't see the application for a D112 or whatever in this use case.

Chris

[Tim Weaver]

It's so he can record and process the LF differently.


To Have a different option.


Will 2 measurement mics work? Yes. Absolutely.

Will 3 mics work? Yes. Absolutely.


Will 35 mics work spread out around the display? Yes. Absolutely.






It's all about options. For me, if I'm recording this for maybe youtube, or whatever medium for an advertisement or something, I would insist on having a seperate, mono source specifically for the low frequency content which I could limit, eq, and mix in to the (probably) untouched stereo track. This makes a world of difference on the end product where the listener will probably be watching this on an iphone or similar.

If the final product is just for OP to listen to on his high-end headphones with a decent front end, then sure. By all means, record a pristine and untouched pair of omni condensers and leave it alone.

[Russell Ault]

{...} Getting creative, my nutty mind drifts to one central mono EMX-7150 mixed with a distant ORTF pair for stereo ambience, also with band pass EQ. {...}

For many years the top choir recording engineer in the area used a standard C414 ORTF pair augmented with wider-spaced pair of factory-matched omnis (also hard-panned) all on the same tree, with the balance between the two pairs adjusted to taste based on the repertoire and the acoustics of the space (typically churches with pleasing-but-significant RT60s).

It's so he can record and process the LF differently. {...}

I must still be missing something; why can't you do this with just two mics? Break out each mic's LF, sum to mono (or pick one and discard the other; the only significant difference that's likely between the two will be timing, which won't be missed but likely will cause summing problems), then process to taste. I'm sure there are plug-ins out there that will do this automatically, but it wouldn't be hard to achieve with some basic crossover filters, either.

-Russ

[Jeff Lelko]

I really appreciate all the great discussion here.  There are definitely several factors and approaches to consider! 

I'm intrigued by the measurement mic approach.  One of the uTestMics for setting up an Audio Tools measurement rig has been on my casual wishlist for a while now, seeing as it's something I'd like to learn more about.  It looks like that mic hits all the specs minus having only a 108 dBA performance range.  I take it that's a deal-breaker for reliable use in close proximity to concussions?

That aside, I think the bottom line for me is that I'm looking for something simple and easy to just go place and forget.  Since in all of these cases my focus is on pyro and not audio, I want to adhere to the "KISS" philosophy and not over-complicate things as much as possible.  Maybe that'll change if I ever get paid to provide exquisite recordings of my firework audio, but until then I'm just looking for something simple but better than the GoPro mics that have reached their limit.  Thanks again!

[Chris Hindle]

I really appreciate all the great discussion here.  There are definitely several factors and approaches to consider! 

Since in all of these cases my focus is on pyro and not audio

It's SACRILEGE to talk like that around here........
You should know better....   
Chris.

[ProSoundWeb Community]