Hi Jatinder --
I enjoy this community of recordists who want to
help each other become more and more confident
about our goals. Boiling it down to lists could
stunt our growth. There are too many options, too
many combinations and "noise as voltage levels"
are nothing like a definitive experience like
plugging in a mic and turning up the gain. The
best way I know to become confident is to compare
mics, lots of them, both expensive and cheap.
But I assume you need at least one mic to start
with! :-)
Feel free to contact me off-list at
<> and remind me again what
recorder and interests you have. (Or better yet,
your budget before you buy the recorder ;-) ).
Rob D.
At 9:18 AM -0700 4/1/08, Jatinder Singh wrote:
>Hello All pros,
>I have been following the discussion on Mic.
>recorder combinations, but have been able to
>digest only a little bit of it - being a novice.
>I was wondering if the likes of Rob, Raimund and
>others would be kind enough to develop a list of
>mic and recorder combinations in increasing
>order of quality and price so that novices can
>then take a look at it and depending on their
>budget and purpose pick a combination. I know it
>is going to involve a bit of work, but it will
>be a blessing for novices and newcomers like me
>and help us to invest our money in the right
>place. Also, recommendations on sound analysis
>software will be welcomed.
>Thank you all
>Jatinder
>
>Rob Danielson
><<type%40uwm.edu>> wrote: At
>7:55 AM +0000 3/31/08, Raimund Specht wrote:
>>Hi Rob,
>>
>>It is probably quite difficult for a layman to fully understand these
>>things.
>
>Yes, it is and I appreciate you taking your time
>to provide such a thorough explanation. The
>ramifications are important even if one does not
>understand the different measurement methods
>involved.
>
>I, for one, will stick with using dB(A)
>self-noise numbers when drafting lists of mics to
>study for certain applications. Sensitivity seems
>to become much more of a factor with noisier,
>lower-gain mic preamps. The rule of thumb of
>avoiding those under 10 mV/Pa for nature
>recording holds up pretty well.
>
>Rane Notes 148 Table 3 can provide some crucial
>insights about the role of pre noise. Ironically,
>it might be most useful if one is trying to find
>the specs for mics to use with a recorder that is
>not ideally suited for nature recording.
>
>Otherwise, after using Table 3 to "see" how
>limited mic options become with noisier pres, the
>simple lesson is to invest in a recorder with a
>low noise mic pre. Your pdf is another very good
>graphic representation:
><http://www.avisoft.com/test/noisefloors.pdf>http://www.avisoft.com/test/n=
oisefloors.pdf
>
>As long as people tend to buy recorders before
>starting to think about micing and mcs, I guess
>we'll need to keep pursuing convincing models of
>explanation.
>
>Thanks again,
>Rob D.
>
>>
>>
>>Rob D. wrote:
>>
>>> It seems the intended use of Table 3
>>><<http://rane.com/note148.html>http://rane.com/note148.html><http://rane=
.com/note148.html>http://rane.com/note148.html
>>>is
>>> for determining whether the noise output of a preamp is at least 10dB
>>> lower than the noise output of the mics. It creates dBu, A-weighted.
>>> equivalents for the mics and your A-weighted, EIN measurements on
>>>
>>><<http://www.avisoft.com/recordertests.htm>http://www.avisoft.com/record=
ertests.htm><http://www.avisoft.com/recordertests.htm>http://www.avisoft.co=
m/recordertests.htm
>>>plug in with no additional
>>> adjustment.
>>
>>Yes, this table is intended for comparing the absolute noise voltage
>>levels of the microphones and preamplifiers.
>>
>>> My question is whether it is appropriate to use Rane Table 3 to
>>> compare fully adjusted noise output between mics? When I try to do
>>> this, it seems I should interpret higher negative values as lower
>>> effective noise output, like preamp numbers. For example, a Rode
>>> NT1-A (5.5 dB(A) and 25mV/Pa) computes to -117.5 dBu and a MKH-20 (10
> >> dB(A) and 25mV/Pa) computes to -113.5 dBu (all numbers are
>>> A-weighted). Assuming all noise is equal for the moment, and 1 dB is
>>> the smallest unit of difference that one can hear, the table suggests
>>> the MKH-20 has about 4 audible increases or "steps" in noise above
>>> the noise produced by the Rode NT1-A. For this example, the Table
>>> seems to be in agreement with my experience with higher negative
>>> numbers resulting is less, cumulative noise output.
>>
>>Yes, this is true if you are looking at the absolute noise VOLTAGE
>>levels. Because these two microphones have the same sensitivity of
>>25mV/Pa, the absolute noise floor difference (expressed in dBu or =B5V)
>>equals to the difference of the equivalent SPL noise levels (expressed
>>in dBA). So it is important to know that the noise voltages on this
>>table don't tell anything about the noise floor that you finally hear
>>in your recording.
>>
>>> Table 3 computed mic comparisons, however, that come out contrary to
>>> experience.
>>
>>Note that this does not work for microphones that have different
>>sensitivities. This is the reason why one must use the dB(A)
>>specifications to compare the equivalent sound pressure noise levels
>>of different mics.
>>
>>> Are you using Table 3 to compare noise output between mics?
>>No.
>>
>>> Are you
>>> saying that the Table 3 grid numbers are not really noise output
>>> equivalents between mics and pres-- that mics compute to "noise
>>> voltage floor" numbers where lower negative numbers effectively mean
>>> less noise output?
>>
>>Yes, but a lower negative dBu number does not always mean that the
>>specific mic is less noisy! If this mic also had a lower sensitivity,
>>you had to turn up the gain on your recorder to compensate for the
>>lower sensitivity and this would also amplify the audible noise floor.
>>
>>[I'm going on your example, "The 20 mV/Pa model
>> > provides a noise voltage floor of -112 dBu. The 50 mV/Pa model
>>> produces a higher absolute noise voltage of -104 dBu. The 50 mV/Pa
>>> model could just be interpreted as a 20 mV/Pa microphone with an
>>> additional ("zero noise") 8 dB preamplifier."] I can see how -104 dBu
>>> is -8dB hotter than -112 dBu, but I thought that Table 3 attempts to
>>> show equivalent noise output, apples and apples, for all mics and all
>>> pres.
>>
>>Yes, the table compares the absolute noise VOLTAGES (and not the
>>equivalent sound pressure noise levels). This is necessary because the
>>preamplifier noise can only be described by the absolute noise voltages.
>>
>>Regards,
>>Raimund
>>
>>
>
>--
>
>
>
>
>
>
>---------------------------------
>You rock. That's why Blockbuster's offering you
>one month of Blockbuster Total Access, No Cost.
>
>
>
--
|