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Re: ME67 handling noise samples uploaded

Subject: Re: ME67 handling noise samples uploaded
From: "Mitch" wa1ykn
Date: Sat Nov 6, 2010 12:38 pm ((PDT))

--- In  "stwebvanuatu" <> =
wrote:
>
> Hello again,
>
> Thanks for the many useful responses to my handling noise problem. I have=
 now uploaded some files to this group. I didn't make a folder and you'll h=
ave to scroll down to find them in the list (which is alphabetical):
>
> noise1gain10, noise2gain10hpf, noise3gain5 were all recorded indoors
> recording1 is a field recording with maximum gain. The mic was in the sam=
e shock mount. I braced my arm against a tree to try and stabilise the mic.
> recording2 is another field recording, but this time I am trying to hold =
the mic steady at maximum gain.
>
> Are these normal noise responses? Even the one at 50% gain?
>
> What I'm thinking now is, like someone had commented, the ME67 is too 'ho=
t'. It's very sensitive, particularly towards low frequencies and it's fron=
t heavy and makes hard work for the shock mount. I think it may be rather i=
mpractical for a walkabout mic?
>
> I checked the noise spectrum in the top three files and the peaks are rat=
her consistent. The highest frequency noise peak was 40 Hz.
>
> I previously used an Audiotechnica 835b mic, which was good enough , unti=
l I dropped it in a creek! I started out holding the AT835b in my hand, wit=
h the HPF on to reduce handling noise. I later put it in a shockmount and w=
as getting clean recordings with the HPF off. That's why I was surprised wh=
en I experienced handling noise problems with the ME67, right from the star=
t. I wish that I could borrow another Sennheiser to compare with mine, with=
 the same shock mount and recorder.
>
> Sennheiser ME67 sensitivity =3D 50 mV ~ -26 dB
> AT835b sensitivity =3D 11.2 mV ~ -39 dB
>
> Stephen.
>

Stephen,

After listening to your test recordings and viewing each as a sonogram, I'm=
 suspicious that you may have the wrong type of mic cable.  I have found th=
at many dealers that sell the Sennheiser ME series microphones for use with=
 a PCM recorder with a un balanced input, i.e. 3.5mm TRS jack, recomend and=
 sell the buyer a mic cable with a built in balanced to unbalanced transfor=
mer.  While this would appear to be technically correct, in my opinion and =
practice, this type of cable when used with the LS-11 and PCM-M10 recorders=
, provides too much signal driving the recorder into saturation. A sonogram=
 of your first sample recording shows this is what is happening.

What I use is a Hosa Technologies XVM105F cable.  This is a simple cable, d=
irect wired from the XLR female pin 2 to both the tip and ring of the 3.5mm=
 TRS plug with no balanced to unbalanced device involved. The reason for th=
is is that the ME67/K6 operates in both balanced and unbalanced modes witho=
ut any balanced interface device being required. Part of this is in the fac=
t the ME67/K6 microphone is a very high output mic at 50mv/P and accounts f=
or the 3 db loss of an unbalanced connection with barely detectable loss of=
 audio... The K6 power/interface module is designed to run in unbalanced mo=
de simply by connecting pins 1 & 3 of the XLR connector together. This is a=
ccomplished in the Hosa Technologies XVM series cables as they are designed=
 and made.

After listening to your sample/test recordings, I took my LS-11 with the ME=
67/K6 microphone on pistol grip out in the yard and made a sample recording=
 at max gain for the sake of comparison.

You can listen to that recording here:

http://dc235.4shared.com/download/PJr0rUlE/LS110159LS.mp3

At 18 seconds, you will hear a clunk, I hit my jacket with the back of the =
ME67 mic connector against my jacket, and in one or more places I stopped t=
he recorder momentarily as a car drove up the street past my place. Besides=
 the crow flying past a couple hundred yards away, You will also hear a whi=
stle blow and people yelling at a soccer game about 1/4 mile up the street =
from my place.

I think the biggest issue you are having is dealing with the high gain/outp=
ut of the mic into the recorder, using and and trusting what the record lev=
el indicator is telling you will help...

One other comment, I always use the mic's HP filter when outdoors, there is=
 an amazing amount of random low frequency sound in nature and it carries a=
 very long way. We do not hear it as well with our human ears as compared t=
o when using a very sensitive microphone.

Hope this helps...









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