> I'd be interested to see if the boost switch increases the noise
> along with the HF.
Yes it does.
Vicki
On 20/01/2012, at 4:06 PM, doctorobotnik wrote:
> Dan
>
> I don't remember the source of my opinion on this, but I've always
> had it in mind that the MKHs have their noise spectrum 'shifted'
> upwards so that there is less audible noise in the very noticeable
> 3-5kHz range.
>
> For this reason, and despite their excellent HF response, I've
> always discounted them as good mics to record extreme HF for
> pitching down in post because all that noise will be transposed
> into the audible bands along with the signal.
>
> I'd be interested to see if the boost switch increases the noise
> along with the HF.
>
>
> Ben
>
> --- In Dan Dugan <> wrote:
>>
>> A few weeks ago someone, I think it was David Brinicombe,
>> mentioned observing HF noise in Sennheiser MKH 20 microphones.
>> I've noticed it too, when looking at a spectrogram of a quiet
>> environment.
>>
>> This morning we did a comparison of a 3032 next to an MKH 20 on
>> the carpet of an interior room, covered with some blankets. The
>> diffuse-field HF boost switch was in the flat position. I used the
>> preamps in a Sound Devices 744T. I posted an expanded-scale
>> picture of the resulting spectrum at:
>>
>> http://www.dandugan.com/downloads/Nature_Sounds_Photos/
>> AT3032_v._MKH_20_noise_via_744T_preamps.png
>>
>> Red is Sennheiser, green is Audio-Technica. The down-sloping curve
>> on the left is obviously ambient noise. I tried to match the
>> levels at around 500 Hz. I believe that above 1K we are probably
>> seeing mic self-noise plus preamp noise. The "hiss" from the MKH
>> 20 is obvious. I put hiss in quotes because I can't hear this
>> noise at all. It isn't trivial however. I see that up-sloping top
>> end in recordings from quiet locations.
>>
>> The tonal artifacts in the 3032's spectrum, especially in the
>> range 400-1KHz are curious. They could be from the mic or the
>> preamp, not investigated yet.
>>
>> My first guess is that the MKH 20 might be equalized in its
>> electronics to compensate for a naturally rolling-off HF response
>> of the capsule.
>>
>> -Dan
>>
>
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