That's interesting Greg. With my Olympus LS10, when I use it with a
really long lead to my bedside table (recording at night) I find that
I can get a very slight hum (in both channels) when my hand is on top
of the recorder, waiting to press the record button. When I take my
hand away, the hum stops. The hum was worse with a lightweight
cable, but much improved with a heavier well-shielded cable.
The hum doesn't happen with a 2 metre lead that runs to my SASS Lite
(with 2 EM172 capsules per channel). In any case, I usually just
hang the recorder on the tripod and walk away, so as not to pick up
breathing, shuffling feet, etc. My default setting is Low 10 which
rarely clips.
cheers,
Vicki
On 12/03/2012, at 11:49 AM, Gregory O'Drobinak wrote:
> Well, after all of this discussion and Peter's observation about
> the noise
> essentially going away when the M10 is 1.5 m away, it reminded me
> of my own bad
> ex[erience at Seney last year.
>
> I set up my M10 in a waterproof case for an overnight drop and left
> it. I was
> pressed for time (and by hoards of mosquitos!), so I didn't take
> the time to do
> a headphone check before I left it. The next day I found that my
> recording had
> been ruined by a 'whiney' sound and I noticed that the shielded mic
> cable had
> been pulled across the front of the display. The noise. of course,
> cvame form
> the display refresh of the M10.
>
> ****The Sony M10's display is quite evil when it comes to
> generating electrical
> noise!!
>
> Do not have the M10 anywhere near your mics and keep your mic cable
> extended
> straight out & directly away form the mic jack.
>
>
> Then don't attempt to hold the M10 with any part of your hand near
> the display.
> If you have to handle it at all while recording, hold it from
> underneath with
> your hand only touching the lower half of the metal case.
>
> I have run into this problem with many different mics, piezo
> pickups, geophones,
> etc., and it doesn't matter whether they are PIP'ed or not.
>
> The basic problem is that Sony completely botched the sheilding for
> that display
> (the backlight doesn't matter, it's the digital refresh) and when
> you crank up
> the gain for low-level signals, the display noise couples into the
> input.
>
> Sorry I didn't think of this earlier, but now you know. Many other
> recorders
> have the same effect when touching the display, etc., but the Sony
> M10 is
> definitely the worst.
>
> Take care,
>
> Greg
>
>
>
>
> ________________________________
> From: Raimund <>
> To:
> Sent: Sun, March 11, 2012 7:32:30 PM
> Subject: [Nature Recordists] Re: Initial SASS test shows bands of
> harmonics
>
>
> Peter, you wrote:
>
>> The clipped noise is from me handling the array as I wrap the
>> towel over it.
>
> I just listened to your recording again. I can indeed hear the
> (acoustic) noise
> caused by the towel. But there is also another clipped noise at 6.4
> and 6.9 sec
> that has a different quality, which is alslo visible on the waveform.
>
>
> I guess that this crackling noise is caused by poor electrical
> contact between
> the TRS plug and the mic input socket, which is a common problem
> with PIP
> microphones.
>
>
> As far as I know, it is caused by the DC current that flows through
> the
> connectors. Such a poor electrical contact can then also increase
> the overall
> source impedance and so reduce the immunity against electromagnetic
> interferences. That would be at least a consitent theory for the
> sudden start of
> the interferences at that point in time.
>
> Regards,
> Raimund
>
>
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