Klas
How are you Mic picking noise from pre-amp noise?
Klas Strandberg wrote:
> A Telinga microphone boosts sensitivity and low noise. It sacrifices high
> sound pressure level and in one case (stereo DATmic) also linearity.
>
> Other mic's don't do that. Therefore, if you want to combine "the Telinga
> qualities" with high sound pressure level and linearity, - you are
> stuck in
> the Sennheiser MKH system. There is no way around this problem.
>
> I don't know about the Rode mic's, except that they are made by a
> Swede who
> emigrated to Australia and sold here, too, in shops for musical
> instruments
> and vocals.
>
> What I know about microphone tests is that is is soooo easy to make
> errors.
> Even the most careful tests which I (and J=F6rgen) have made, have
> proved to
> be wrong after a few days only. It is like you have to "get acquainted"
> with a certain microphone over a long time before you can judge about
> it. I
> have listened to mic noise one evening and judged it as okay, next day I
> find it too high... And vice versa!
> And most of the tests which I do have to be repeated over and over again.
> Only when I get the same result at least five, six times - then I am
> pleased with the reliability.
>
> I can only claim two things:
>
> If you hear microphone noise, then you cannot lower this noise by using a
> preamplifier. It is there, and all you can do is amplify it.
> If you hear MD / DAT amplifier noise, you have the wrong microphone for
> nature sound recording. Or - rare - you have a very, very bad microphone
> preamp, must worse than any common MD mic input.
>
> I tested again today: Used a 10 mm PIP electret and a EM23PIP into
> different Sharp MD's which I have + the Edirol R1. The noise I could hear
> came from the microphone FET and not from the MD / Edirol mic input amp.
>
> A preamp into the line inputs will only amplify this FET noise.
>
> I don't deny that others have other experiences, but I can't explain it.
>
> When reading data sheets with noise figures and frequency curves, don't
> forget that those figures were measured with a brand new microphone,
> inside, room-temperature and a suitable humidity. Age, low temp, impact
> from use in humid areas, dust and bacteria (even fungus!) will affect
> those
> figures by many db.
>
> Klas.
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> At 20:07 2005-05-09, you wrote:
> >Hi Klas-- I apologize for my error. Were you able to download the
> >test? There's a noticeable increase in noise with the NT-4 that I'd
> >like to hear your thoughts about. The MP2 preamp does seem to lower
> >the noise with the NT-4 and the curious thing is the NT3 and Nt4 both
> >have very similar self noise (16 and 17dBA) and exact sensitivity
> >specs (12dBA). I can email it to you too, its 2.3 mb. Rob D.
> >
> >At 6:47 PM +0200 5/9/05, Klas Strandberg wrote:
> > >At 23:55 2005-05-04, you wrote:
> > >>I went down to fix dinner and realized that my logic is wrong about
> > >>being able to deduce any Mic Pre noise figure from the test. Sorry.
> > >>With the NT3, if the noise through the HiMD mic pre and the
> > >>workaround MP-2 is the same, what we're hearing is likely the noise
> > >>just from the NT-3.,..I have to go back to making dinner, but why
> > >>does the NT-4 through the workaround MP2 have less noise? Where would
> > >>the noise be coming if not from the HiMD mic pre? Rob D
> > >
> > >
> > >How wonderful isn't it with people who has such a free-running
> brain that
> > >it realized a previous error while fixing dinner....
> > >
> > >I still don't know for sure what is right and wrong in this topic,
> but I
> > >hope that my brain will solve it while making dinner next time. Have t=
o
> > >wash my car tomorrow. Perhaps then...?
> > >
> > >Until then I repeat: If you hear noise, you can never lower this
> noise by
> > >using a preamp.
> > >
> > >Klas.
> > >
> > >
> > >
> > >
> > >>Rob D: wrote and realized soon afterwards,..
> > >>
> > >> >
> > >> >
> > >> >At 12:22 PM +0200 4/21/05, Klas Strandberg wrote:
> > >> >> >Since the 957 already terminated in an 1/8th mini jack,
> and uses
> > >> >>>plug-in power? Or maybe it's battery operated? I'm not sure
> how much
> > >> >>>you'd gain by adding a preamp. I think we're mainly referring to
> > >> >>>phantom powered mics using external preamps. That being said,
> I know
> > >> >>>often the minidisc mic input isn't the cleanest, and if you
> can go in
> > >> >>>line level, you'll bypass some of the noise.
> > >> >>
> > >> >>
> > >> >>I clam that that statement is common but wrong.
> > >> >>Give me some proof!
> > >> >>
> > >> >>Klas.
> > >> >>
> > >> >
> > >>
> >=20=20
> >m("sbcglobal.net/vwp2?.to","//f2.pg.briefcase.yahoo.com/bc/rob_danielson");=">http:=
k
> > >>=20
> =3DbcmKTRVBNxZgHObW&.dir=3D/Tests&.dnm=3DCompareMiniDiscMicPreNoise.mov&.=
src=3Dbc
> > >> >
> > >> >Right-click on the paper-looking document and select, "Download
> > >> >linked files as,.." option.
> > >> >
> > >> >I've uploaded the above 2.3 mb QuickTime movie that compares the
> > >> >resultant noise from Rode Nt3 and Nt4 mics using a HiMD mic input
> > >> >jack and the same mics routed through a Sound Devces MP-2 outboard
> > >> >preamplifier into the HiMD's line input. The recordings were
> made at
> > >> >16/44.1; the QuickTime movie has an IMA:4 compressed sound track s=
o
> > >> >that more people can download it. Again, these tests are for quiet
> > >> >location recording situations where high gain is more likely to be
> > >> >used. The files are well saturated and loud, be sure to adjust
> > >> >playback volume to a comfortable level
> > >> >
> > >> >To my ears, the NT3 presents a fairly close match between internal
> > >> >and external preamp noise which suggests to me that an "effective
> > >> >self-noise" rating for the NH-900 HiMD recorder's mic pre _with
> this
> > >> >particular mic_ is in the ballpark of 16 dBA. [The self noise
> > >> >equivalent for the MP-2 (with some conservative assumption
> involved)
> > >> >is in the area of 5dBA, so its very unlikely to be adding noise.]
> > >> >
> > >> >I say only for "this particular mic" because, as we found before,
> > >> >sensitivity (output) and other factors come into play. You will
> note
> > >> >that I had to boost the playback level of the NT4's recording
> 14dB to
> > >> >match the playback level of the NT3's recording. Even though both
> > >> >mics have very close self noise specs (16dBA for the NT4 and 17dBA
> > >> >for the NT3), the noise component in the NT-4's recording is also
> > >> >increased 14dB to match playback leve with the NT3's. The additio=
n
> > >> >of noise from the HiMD mic pre can be confirmed by looking at
> the NT4
> > >> >signal routed through the MP2 where we hear less noise than
> that from
> > >> >the recording where the NT4 is connected to the HiMD recorder's mi=
c
> > > > >pre.
> > >> >
> > >> >The NT3's recording (apparently taking advantage of effective
> higher
> > >> >output) exhibits about the same noise as the recording made
> when the
> > >> >NT3 routed through the MP2. This suggests to me that a HiMD mic
> > >> >preamp is more likely to introduce significant noise when the
> record
> > >> >level is high and the mic does not have high output. This is
> > >> >consistent with our theory of why the Shure 183 performed well
> with
> > >> >22.5dBA noise in the prior test with its high sensitivity of 42
> mv/Pa.
> > >> >
> > >> >So, there is no simple way to put MD mic preamp noise into a
> general
> > >> >"effective self noise" number because performance is the result of
> > >> >speciifc mic-preamp combinations. If you need further proof of
> this
> > >> >phenomenon, according to Rode, the NT3 and the NT4 have equal
> > >> >sensitivity (12 mv/Pa). Their output impedance is also matched at
> > >> >200 ohms.
> > >> >
> > >> >I tested the mics from the first test again and I feel the
> results of
> > >> >the first test are very reliable. That's is available as a small
> > >> >.mov now:
> > >> >
> > >> >http://www.micbooster.com/movies/TransMic&PreTestSor3_IMA.mov
> <http://www.micbooster.com/movies/TransMic&PreTestSor3_IMA.mov>
> > >> >
> > >> >People commented on the appreciable leap in quality that happened
> > >> >with the NT1A/Mp2 in the first test so I'm testing some higher end
> > >> >mic-pre combos. Rob D.
> > >> >
> > >> >
> > >> >
> > >> >
> > >> >
> > >> >
> > >> >
> > >> >"Microphones are not ears,
> > >> >Loudspeakers are not birds,
> > >> >A listening room is not nature."
> > >> >Klas Strandberg
> > >> >Yahoo! Groups Links
> > >> >
> > >> >
> > >> >
> > >> >
> > >>
> > >>
> > >>--
> > >>Rob Danielson
> > >>Film Department
> > >>University of Wisconsin-Milwaukee
> > >>
> > >>
> > >>
> > >>"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:
> > >
> > >
> > >
> > >
> > >
> > >
> > >"Microphones are not ears,
> > >Loudspeakers are not birds,
> > >A listening room is not nature."
> > >Klas Strandberg
> > >Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
> >
> >--
> >Rob Danielson
> >Film Department
> >University of Wisconsin-Milwaukee
> >
> >
> >
> >"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:
>
>
>
>
>
> "Microphones are not ears,
> Loudspeakers are not birds,
> A listening room is not nature."
> Klas Strandberg
>
>
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>
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