Mic sensetivity and rejection of unwanted noise

P

Petrus

Well-known member
Every now and then I read a response here on the audio forum which states: " with a less sensetive mic you get less unwanted sounds", or something to that effect. This makes no sense to me.

As I see it, the loudness ratio of wanted sound (talent speaking etc.) and the unwanted background noice (aircon, traffic etc.) is fixed in each case and the mic can not make a difference. Of course I am talking about mics with the same pickup patterns!!! I assume with both types of mic we want the talent's voice at the same recording level. So, if we use a less sensentive mic we just have to crank up tha gain on the mixer, with more sensetive mic the gain is lower. In both cases the dB difference between the wanted and unwanted sound is exactly the same.

Is there some secret to this that I am not aware of, or do these people just mean that with an unsensetive mic the ambient noise is covered by the mic's self noise and can thus not be heard. Or do they just record at lower level and kid themselves? I would rather take the ambient noise than the mic noise...
 
i think it mostly written by not educated people - completly bull
usially for dialog you want something more sencitive then 10mv for 94 spl not to cranl the preamps to its limits - of course for loud efects or close up micking you like less sencitive not to overload the inputs . have nothing with regection or ratio with unwonted sounds .
 
" with a less sensetive mic you get less unwanted sounds"
Click to expand...

if you are refferring to me, then thats a total misquote. the mic has no idea what sound is 'unwanted' but if you know the traffic is x yards away then you can make a decision on which mic will reject it the most.

why do we not use a dynamic vocal mic on a boom? because it wont pick up any decent sound unless you are right up close to it. its less sensitive. hence why it is good in a live environment because it will be less prone to feedback. thats why less sensitive mics dont overload when you record fireworks and gunshots etc.

its not just the gain that is different between a dynamic cardioid and a consenser cardioid, its also the dynamic range.
 
scenario: you are, say, in a factory where there is effectively a signal/noise ratio less than 1 (the singal less than the noise) . you need to record a voice and you have two mics to choose from. a long shotgun and a commentators lip mic.

what do you choose? and why?
 
bad comparation - the shotgun mic is directional in its hight fq and almost omny in it low end while the distance from the capsule is going to be 6 times more then the colles .
better comporation would be mkh 50 from 2 inches- i bet you will never go back to calls ( ribon - half of figure of 8).
and by the way the ratio doesnt change if you are using dynamics or condencers - the dynamic usially just handle better close micking but then not every one use dpa - right ?
gunshots - try dpas
 
You must log in or register to reply here.
Back
Top