Fine test, Gianni!
Happy about EM23. 7 db more noise than NT1A would be around 14 db, which is=
expected.
I'm surprised about the Sennheiser, though. I thought they would have an
even fight with the EM23.
Both my NT1A are now malfunctioning. They make low frequent noise and even=
popcorn noise. I am 99% sure it's the polarizing voltage leaking between
membrane and electrode, cause of micro-dirt and moist. When warm and dry
they work fine.
Klas.
At 21:28 2005-10-18, you wrote:
>Hi all,
> I tried to figure out how different mics could behave with the
>MT2496 and the Mic2496 while recording in a quiet environment. My
>target was to understand more of the relationships among sensitivity,
>self noise and mic preamplifier noise.
>
>Here the equipment I used:
>
>MAUDIO MT2496 --> 2GBCF
>CoreSound Mic2496 --SPDIF--> MAUDIO MT2496 --> 2GB CF
>CoreSound Mic2496 --TosLink--> CoreSound PDAudio CF --> iPaq 3870 --> 2GB =
CF
>MOTU Traveler --> FireWire --> Laptop
>
>Microphones:
>
>SONY ECM957 (stereo)
>AKG SE300+CK98 (short shotgun)
>AKG 451EB+CK8 (short shotgun bought 15 years ago)
>Sennheiser K6+ME66 (short shotgun bought 10 years ago)
>Rode NT1A
>Telinga EM23
>
>I used 96K and 24 bits; due to time constraints I did not test all
>combinations and permutations; after few tests I focused on comparing
>the Rode NT1 / EM23 / AKG SE300 and the MT2496 vs the Mic2496.
>
>I worked in a very quiet room at night. A piezo beeper at 3m distance
>in front of the mics was recorded to roughly calibrate levels in post
>processing (it makes "bips" and not noise). The Mic2496 was set for
>max gain to get the "bips" at about -15 dB with the loudest mics; the
>MT2496 was set to High gain position and Max level position (I
>avoided to use the digital boost available in the menu' Settings).
>
>
>The most interesting results I got are that the Mic2496 offers
>greater gain and less noise than the MT2496.
>By recording with the Rode I got 16 dB more on the "bips" and 8 dB
>less noise with the Mic2496 than with the MT2496.
>I got the same numbers by recording with the AKG SE300+CK98 (same
>sensitivity as the Rode).
>
>It is now interesting to look at the numbers with a different perspective:
>
>The MT2496 noise masks the noise differences of all the mics I
>tested!! A Rode NT1, the quietest mic, appears as noisy as the AKG
>SE300 and the SONY MS957, that are the noisiest mic!
>
>Thus, to evaluate the real mics noise I used the Mic2496 digitally
>connected to the PDAudio system based on an old iPaq (the MT2496
>could be used for digital recording as well) or the MOTU.
>After adjusting the "bips" levels in post processing (normalization)
>I can compile the following list of microphones ordered according to
>their noise floor (electronic hiss, above 1 kHz), or, to be more
>correct, to the Signal to Noise ratio they can offer if connected to
>a quiet preamplifier (I don't consider here the directional
>characteristics nor the tonal quality nor frequency response):
>
>Rode NT1 (the quietest)
>Telinga EM23
>Sennheiser K6+ME66
>AKG 451EB+CK8
>AKG SE300+CK98
>SONY MS957
>
>The disappointing result here is that the AKG SE300+CK98 has a noise
>floor 15-16 dB higher than the Rode NT1A noise floor (they have the
>same sensitivity and thus the noise floor comparison has not been
>affected by the normalization) but its noise was completely masked by
>the MT2496 noise and low gain.
>
>The EM23 is 4-5dB more sensitive than the Rode but after
>normalization it is 7-8dB noisier.
>The least sensitive microphone is the SONY MS957: 15dB less than the
>Rode; after normalization it is 17-18dB noisier than the Rode and
>only 2-3 dB noisier than the AKG SE300. In the SONY the R channel is
>noisier than the L; the L is flat but the R increases at high
>frequency up to 6dB more.
>
>These results are the combination of self-noise and sensitivity on a
>specific preamplifier whose noise floor is lower than the self-noise
>of the microphones, but of course the quietest microphone could have
>been affected in some way by the preamplifier noise. Also, the least
>sensitive microphones (the SONY) could have been affected by the
>preamplifier noise pumped up in the post-processing amplification.
>
>The results on the Rode and AKG have been also confirmed by
>connecting them to the MOTU Traveler: the Rode noise was 15 dB lower
>the AKG, but the test was disturbed by the fan of the laptop.
>
>The comparison among the Mic2496 and the MOTU is interesting too, but
>not definitive because of the fan of the laptop.
>The MOTU was set to 48dB gain for both the Rode and the AKG. By
>comparing the Rode recording, the bips were 12 dB higher on the MOTU
>than on the Mic2496, and the noise was 6-7dB higher on the MOTU than
>on the Mic2496. Thus the MOTU allowed a Signal to Noise Ratio 5-6dB
>better than the Mic2496.
>
>I hope these preliminary information are useful to understand a bit
>more how different combinations of hardware behave and may fit
>different requirements.
>
>Sooner or later I hope to be able to repeat the tests with more
>accuracy and more devices to compare,
>Gianni
>--------------------------------------------------------------
>Gianni Pavan
>Email
>Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
>Universita' degli Studi di Pavia
>Via Taramelli 24, 27100 PAVIA, ITALIA
>Tel +39-0382-987874
>Fax +39-02-700-32921
>Web http://www.unipv.it/cibra
>
>
>--
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>
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email:
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