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Re: Good mics, medium mics, the best mics - what's the difference o

Subject: Re: Good mics, medium mics, the best mics - what's the difference o
From: rock_scallop
Date: Tue Jun 17, 2014 12:18 pm ((PDT))
Hi David,=0D
>My Sennheiser MKH416's have an HF noise level which is usually drowned by =
 natural hiss from wind on leaves and a distant stream, but the pile of =0D
 bedclothes test reveals an HF tip-up which is close to where the thermal =
 noise of air would be. One day I will prove this by putting it Into a =0D
Looking at the MKH416 product sheet, the frequency plot shows a boost in th=
e higher frequencies. It could be what you think you are hearing as thermal=
 noise of air is just the amplification of those frequencies.=0D
 >We've got such a rule, the sound level from a single source drops 6dB eve=
ry =0D
 time you double the distance, plus some other factors like HF sound =0D
 absorption. If you can get closer to a wildlife sound source, you can alwa=
ys =0D
 improve the signal to background-plus-mic noise ratio. =0D
Yes I know, that 5dB rule is what I was referring to. What I was wondering =
is could the 6dB rule mic also be applied to mic-self noise? For instance i=
f one compared side by a mice with 10dB self-noise and one with 14dB self-n=
oise, might that translate to the 10dB mic recording lowest level sounds at=
 twice the distance as the 14dB?=0D
 >Whose definition of "self noise" would you use? To have any meaning, this=
 has to be an "equivalent self noise" in other words the acoustic noise lev=
el =0D
 in Phons which would give the same noise level as the mic itself, in other=
 words a sound which would raise the total mic noise level by 3dB. =0D
I would just use dB A-weighted, as that is the most common format.  I know =
you do not like it, but I think trying to convert everything to Phons would=
 just add unnecessary complexity. =0D
Regarding the rest of your reply, I agree that a manufactures specs cannot =
always be taken as accurate. That is one of the reasons I follow this group=
 - to get recommendations on equipment by others who have tested it out.  T=
hat said, when I bought my Rode NT1-A mics years ago, it was just on the se=
lf-noise spec alone, because I was not a member of this group yet, and had =
no one to turn to for equipment advice.  In that regard, I was lucky becaus=
e it turned out to be a great mic for me.=0D
John Hartog=0D

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