At 7:13 AM +0000 8/14/09, Raimund Specht wrote:
>
>Hi Vicky,
>
>So, it seems that the higher self noise level at SENSE LOW and 16
>bit is still sufficiently low for these microphones.
Hi Raimund and Vicki--
The gestalt or overall impression of the Telinga->LS-10 recordings
made with these enlightened gain settings seems to be fine for
Vicki's applications. One would think that the LS-10's input noise
should be low enough for recording events like the Red Wattlebirds
(as indicated by the ability to use the lower gain setting and
assuming the gain levels in the RWB.LS10_TEL vs SD_SASS file was not
appreciably changed).
Before we can reach the conclusion. "that the higher self noise level
at SENSE LOW and 16 bit is still sufficiently low for these
microphones," I think Vicki would have to use the ideal record gain
settings for the LS-10 and make recordings in a quiet room using both
the SASS [10 dB(A) self noise] and her Telinga [higher self-noise].
If the LS-10's pre is sufficiently quiet, there should be a very
audible noise jump when going from SASS to Telinga. Might be wise to
include other mics in the test too.
Even with the mixed mic/recorder samples, when I listen to clips from
the quieter sections of the RWB.LS10_TEL vs SD_SASS. mp3 file, I'm
detecting what could be an increase in noise >500 Hz with the LS-10.
There's a consistent, jumbled, uneven quality to the ambience or
background presence in both recordings that's making the judgement
more difficult.
I don't think we have evidence that the LS-10 is a good fit for
recording ambience in quiet locations with a rig like the MKH-10/SASS
recording ambience as yet. Maybe, by using this ideal record gain
setting, one can record at 24 bits and boost the results in post to
get low(er) noise performance. I fear this technique will not be able
to get around the LS-10's audible noise under 500Hz, but a test will
shed more light on the possibilities.
Of course, Vicki can take her SD722 into the field to record ambience
in quiet locations with the SASS. The comparison test I'm suggesting
would only apply to those who are looking at an LS-10 to use for
similar situations and she might have better things to do! :-)
Should you be curious about this comparison, Vicki, be sure to make
the takes long so you can choose the quietest moment from each. Post
the original clips, no changes applied. Rob D.
>
>I think that the problem with the lower LEVEL control settings on
>the LS-10 (and other similar recorders) is that it is a simple
>potentiometer (a voltage divider) that attenuates the output signal
>of the first preamplifier stage before the signal is further
>amplified and fed into the A/D converter. In other words, it is not
>appropriate to first attenuate the input signal and then amplify it
>again (by using the HIGH SENSE setting).
>
>For the same reason, it is not a good idea to activate the
>attenuation pad on the microphone or the recorder while turning up
>the gain on the recorder at the same time.
>
>Cheers,
>Raimund
>
>Vicki Powys wrote:
>>
>> Raimund, Klas and all,
>>
>> I just compared 16 and 24 bit noise-wise in a quiet room, and I could
>> hear no difference in noise between them. However there is a big
>> difference (as mentioned previously) between high sense 2 and low
>> sense 10, the latter being MUCH quieter. I hear this difference for
>> both the Telinga stereo mic and the ME66.
>>
>> Conclusion: I will stick with low sense 10 as my default setting for
>> LS-10 with external mics, and stick with 16 bit. Unless I am working
>> with a difficult bird with soft calls (e.g. Regent Honeyeater) where
>> my default settings would be high sense 5, 16 bit.
>>
>> cheers,
>>
>> Vicki
>>
>> PS Klas, I am listening to all my tests through headphones.
>>
>>
>>
>>
>> On 13/08/2009, at 5:22 PM, Raimund Specht wrote:
>>
>> > Hi Vicky,
>> >
>> > I can confirm your observations regarding the noise levels on the
>> > different SENSE HIGH / LOW settings on the LS-10. The input noise
> > > levels I measured are as follows (see also
><http://www.avisoft.com/>http://www.avisoft.com/
>> > recordertests.htm):
>> >
>> > SENSE HIGH, LEVEL 10 (16 or 24 bit):
>> > -122dBu(A) -119dBu(unweighted)
>> >
>> > SENSE HIGH, LEVEL 2 (16 or 24 bit):
>> > -103dBu(A) -100dBu(unweighted)
>> >
>> > SENSE LOW, LEVEL 10 (24 bit):
>> > -121dBu(A) -118dBu(unweighted)
>> >
>> > SENSE LOW, LEVEL 10 (16 bit):
>> > -113dBu(A) -110dBu(unweighted)
>> >
>> > Note that both the SENSE HIGH, LEVEL 2 and SENSE LOW, LEVEL 10
>> > settings provide the same input clipping level of -30 dBu.
>> >
>> > So, the bottom line is that one should better not use the SENSE
>> > HIGH setting for recording louder sounds that require to turn down
>> > the LEVEL setting. Instead one should use SENSE LOW, LEVEL 10 at 24
>> > bit resolution.
>> >
>> > Regards,
>> > Raimund
>> >
>> >
>> >
>> >
>> >
>> > --- In
>><naturerecordists%40yahoogroups.com>
>>vickipowys
>> > <vickipowys@> wrote:
>> >
>> >> Re self noise, I don't think I AM hearing Telinga self noise.
>> >> Someone contacted me off-group to query my setting of low sensitivity
>> >> 10 (rather than say, high sensitivity 3). There has been a previous
>> >> discussion on naturerecordists re this. Using add on mics, including
>> >> the Telinga and a Sennheiser ME66, I find that there is more fizz
>> >> when using high sensitivity. Note that this applies to add on mics
>> >> and not just the LS-10 inbuilt mics.
>> >>
>> >> I did a test this morning, using a metronome on front verandah rail
>> >> (quiet, rural background), standing back 5 metres, with settings on
>> >> LS 10 at high sens. 2.5 versus low sens. 10. At these settings the
>> >> ticking levels of the metronome matched exactly. With both the
>> >> Telinga mic (used open) and the ME66, there was more fizz with the
>> >> high sensitivity setting, and when I later boosted the low sens
>> >> recordings by 6 dB, the fizz level still did not equal the high sens.
>> >> fizz.
>> >
>> >
>> >
>> > ------------------------------------
>> >
>> > "While a picture is worth a thousand words, a
>> > sound is worth a thousand pictures." R. Murray Schafer via Bernie
>> > Krause
>> > Yahoo! Groups Links
>> >
>> >
>> >
>>
>
>
>
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