Mic Sensitivity

[PHILANDDON]

I was looking at a magazine and it said the way to compare output of various mics was to looking at their sensitivity rating. Is that the same as their maximum SPL? Please advise.

 

[mshilarious]

I was looking at a magazine and it said the way to compare output of various mics was to looking at their sensitivity rating. Is that the same as their maximum SPL? Please advise.

No. The sensitivity is the voltage produced by the mic at a given SPL, usually 94 dB.

 

[PHILANDDON]

So what statistic do I use to compare output/loudness of various mics?

 

[mshilarious]

So what statistic do I use to compare output/loudness of various mics?

That would be the sensitivity.

 

[PHILANDDON]

Thanks. Is that a statistics manufacturers ordinarily give?

 

[mshilarious]

Thanks. Is that a statistics manufacturers ordinarily give?

Almost universally. Just be careful to make sure they are using the same standard. 1 Pa = 94 dB, but sometimes you'll see 0.1 Pa which is 74 dB. Also, usually the output is listed in dBV, but sometimes in voltage (often millivolts, or mV). To convert, use this formula (0dBV = 1V)

dbV = 20 * log ( mV / 1000 )

Then to compare two mics, just take the difference in sensitivity in dBV.

 

[Robert D]

BTW - Max SPL that you mentioned is the measure of the maximum sound pressure level a microphone can can handle without introducing distortion. One measure of a mic's versatility is that it has both good sensitivity and a high max SPL. Another spec to look at is self noise, with a combination of low self noise and good sensitivity delivering the best signal to noise ratio.

-RD

 

[PHILANDDON]

Thanks RD that was very helpful.

 

[mshilarious]

BTW - Max SPL that you mentioned is the measure of the maximum sound pressure level a microphone can can handle without introducing distortion. One measure of a mic's versatility is that it has both good sensitivity and a high max SPL.

I don't agree that equates to versatility. In fact I suspect the correlation is low. What if you had a mic with those specs, but no built-in pad? Its tendency to clip preamps might be considered a lack of versatility, since you'd need an external pad for loud sources.

Also, that would make all condenser mics always more versatile than dynamics, which is certainly not the case.

Another spec to look at is self noise, with a combination of low self noise and good sensitivity delivering the best signal to noise ratio.

Be careful here to compare apples to apples . . . dynamic mics have exceedingly low self-noise but low sensitivity. The SM58 self noise is something like -130dBV, or about 146dB quieter than the SM81, while being around 10dB less sensitive. What does that mean? I have no idea, but I do know that my ears have been tested and my internal self-noise averages about 20dB

 

[Robert D]

I don't agree that equates to versatility. In fact I suspect the correlation is low. What if you had a mic with those specs, but no built-in pad? Its tendency to clip preamps might be considered a lack of versatility, since you'd need an external pad for loud sources.

Also, that would make all condenser mics always more versatile than dynamics, which is certainly not the case.



Be careful here to compare apples to apples . . . dynamic mics have exceedingly low self-noise but low sensitivity. The SM58 self noise is something like -130dBV, or about 146dB quieter than the SM81, while being around 10dB less sensitive. What does that mean? I have no idea, but I do know that my ears have been tested and my internal self-noise averages about 20dB

Of course Dynamics have low self noise.....thay have no active components. Your point is well taken though. Ribbon mics are worthless pieces of junk if you start judjing them by their sensitivity compared to condensers.

As for versatility, I said that's ONE measure. A whole chapter in a book MIGHT cover the subject, I was just commenting on the specs mentioned in the post in broad brush. Within the confines of those numbers, a mic with poor sensitivity and a low tolerance for high SPLs is probably going to be suitable for fewer applications than vice versa.

-RD