Mics and Preamps.....Guitars and Guitar amps...

[TalismanRich]

Does the sensitivity really have anything to do with the ability of the mic to pick up a differential in sound level? What you are dealing with is how much you need to amplify the signal when it reaches the preamp to reach a set level (say 0 dB). But it really shouldn't change the differential between loud and quiet sounds. Turn down the preamp gain by 15mV and that 23mV/1 Pascal pressure mic should be the same as an 8mV/Pa. That's why they put 10dB pads on a mic. The difference isn't due to the inability of the capsule to react to the pressure change and if it's the same capsule the actual output voltage of the capsule should be exactly the same. It's in the different gain structure of the amplifier circuit in the microphone itself. Unless you are overloading the amplifier circuit (or overloading the preamp down the path) it really shouldn't matter.

You don't set your input level the same for all microphones. Especially within the same type of mic, what you would gain by having a higher mic output voltage would be less preamp induced noise. Of course that also depends on how quiet the microphone's amplifying circuit is. A noisy circuit pumping out lots of volume doesn't help.

Comparing a dynamic vs condenser might change things, as the inertia of a dynamic mic's diaphragm with the coils could be higher than that of a 32mm condenser capsule. I would think that would show up in transient response, and it might mean that below a certain level, a quiet sound may lack the necessary energy to even move the diaphragm. It would be a bit like the difference between moving a 15" woofer cone vs a lightweight tweeter element.

I've seen several studies where they have shown that the idea that a low output dynamic is better for a noisy room is completely wrong once the levels are equalized. If a low output SM7b makes you eat the mic, then the lack of room noise isn't due to the mic, it's due to you being so much closer to the diaphragm that the relative level hitting it is different.

 

[CoolCat]

I think I will. why not? at that price too. C114 is around 13mvpa, that seems to work in this studio/closet/w blankets and pillows. 13 +/- sensitivity tends to work fine with the interface preamps which I like having the option, though I have 5qty outboard preamps for now too.

Coming from your "AKG414 positive" comments...seems the C114 is thumbs up!..., thanks for mentioning it....

 

[CoolCat]

Does the sensitivity really have anything to do with the ability of the mic to pick up a differential in sound level? What you are dealing with is how much you need to amplify the signal when it reaches the preamp to reach a set level (say 0 dB). But it really shouldn't change the differential between loud and quiet sounds. Turn down the preamp gain by 15mV and that 23mV/1 Pascal pressure mic should be the same as an 8mV/Pa. That's why they put 10dB pads on a mic. The difference isn't due to the inability of the capsule to react to the pressure change and if it's the same capsule the actual output voltage of the capsule should be exactly the same. It's in the different gain structure of the amplifier circuit in the microphone itself. Unless you are overloading the amplifier circuit (or overloading the preamp down the path) it really shouldn't matter.

You don't set your input level the same for all microphones. Especially within the same type of mic, what you would gain by having a higher mic output voltage would be less preamp induced noise. Of course that also depends on how quiet the microphone's amplifying circuit is. A noisy circuit pumping out lots of volume doesn't help.

Comparing a dynamic vs condenser might change things, as the inertia of a dynamic mic's diaphragm with the coils could be higher than that of a 32mm condenser capsule. I would think that would show up in transient response, and it might mean that below a certain level, a quiet sound may lack the necessary energy to even move the diaphragm. It would be a bit like the difference between moving a 15" woofer cone vs a lightweight tweeter element.

I think it has more to do with up close, and really up close ... ...in comparison to a mic that can record further away and can "hear" sounds better and captures them. Theres some term called "reach" too. and "hotter" mics.As the KlausNeumann explains its the FET that overloads on higher sensitive circuits (the FET) more easily than a lower sensitive circuit, the trade off is noise level specs vs headroom, something like that. In my dumbed down laymens terms its "hearing" analogy, some mics hear really really well, very sensitive and others dont hear as well, less sensitive.

But getting up too close to the FET circuits , or overloading the higher sense can cause distortion to the FET circuit thats then transferred to the preamp.

Going dynamic seems the most common, but the "in between" middle might be a lower sense LDC?

 

[TalismanRich]

Maybe you can overload an FET, but there are mics that can handle 140 or 150dB. That is VERY loud. We're talking gunshot, or jet engine loud. If your vocals are 140+ dB you're really wailing. The P420 is supposed to be able to handle 155dB, and I'm guessing that is using the 20dB pad.

Mics are rated in mV/Pa. 1 Pascal in air is about 94dB. 155dB would be 1124Pa. In terms of voltages, 20dB is 10x the voltage, if I remember my calculations. 40db is 100x, so 134dB without the pad would be 2.8v which isn't anything outlandish. Conversely, engaging the 20dB pad, would drop the 28mV to about 2.8mV/Pa which is similar to what I get with my Sennheiser e935 dynamic.

I'm sure Klaus is very knowledgeable about the mics, and theoretically, I'm sure he's right, but I wonder how many people actually actually run into overloading the FET. Drum are some of the louder instruments and they are generally in 110 to 120dB range unless you are really hitting hard.

 

[CoolCat]

Its above my head in engineering and all the distortions or overloading, proximity.of the circuits.
"why are there various sensitivities of microphones?"
Tensions of the capsule mylar and the deposition thickness...and age of gunk on the capsule...

Im going to get my SM7b (1.2mvpa) and the P420 (28mvpa) and revisit this, MXL V67G is 15mvpa.

here's Neumann site...

Why Sensitivity Varies:

• High-SPL Applications (Lower Sensitivity): Dynamic microphones have lower sensitivity, making them ideal for loud sound sources (e.g., guitar cabinets, drums) without distorting or overloading the preamplifier.
• Quiet Sound Sources (Higher Sensitivity): Condenser microphones often feature high sensitivity to capture subtle details and quiet sounds (e.g., acoustic instruments, vocals), providing a stronger signal.
• Background Noise Rejection: Low-sensitivity mics are often preferred in untreated rooms or live environments because they require higher SPL to produce a strong signal, inherently picking up less background noise.
• Distance to Source: High-sensitivity shotgun microphones are designed for broadcast and film to maintain a usable signal when the subject is far away.