I received an Art Phantom II unit and added it to the test. Looks as
though there are two inexpensive portable phantom power supplies ($45
and $70) that work (at least) with NT1-A's to achieve extremely low
noise performance using the standard mic input of a Sony NH-900 HiMD
recorder. The QuickTime movie also shows what one of these portable
phantom units can do for the Rode NT-4.
http://www.uwm.edu/~type/Mic%20Preamps/PortPhantomHiMDReprtv01SorIMA.mov
4.7mb quicktime movie
http://www.uwm.edu/~type/Mic%20Preamps/Rolls_Art_Phantom_HiMD.mp3
mp3 only with three below egments (short break in between)
1) NT1A-s -> 722 (phantom powered from the 722)
2) NT1A's->Rolls PB-224 -> Sony HiMD Mic input gain at "24"
3) NT1A's-> Art Phantom II-> Sony HiMD Mic input gain at "24"
[Tech Note: The Art unit is smaller, handles 12 volt and 28 volt
mics, but it's battery slot is a screw type-- not "easy" to change
batteries at all. The Rolls supplies only 48 volts, has much quicker
battery changing and it comes with an AC wall wart. You also need a
2-XLR (female) ->1/8' stereo mini plug adapter cable which a number
of places like Markertek sell if you'd rather not solder one up from
scratch.]
The addition of the Art Phantom II strengthens suspicions that many
phantom-powerable mics that folks are currently using with consumer
MD/DAT mic inputs could significantly benefit. They're are also about
a dozen ~$100 ea. condenser mics out there with respectable noise and
sensitivity (maybe less than 20dBA self noise and more the 10mv/PA
sensitivity?) that might be fun to test. If you have a pair of such
mics you want me to test, contact me off list. Rob D.
=3D =3D =3D =3D
At 8:27 PM +0200 7/16/05, Klas Strandberg wrote:
>Thanks Rob, yes, I would like to swing a barrel of malt with you even
>though I have not downloaded your files. I don't have quick time, for exam=
ple.
>
>I'll be back here tomorrow or Monday.
>
>I will present some results, too. For the first time ever (??) I can
>display true frequency outdoor measurements of a parabol (telinga) made at
>25 meters under realistic conditions. Curves and pictures.
>It's not much new to discover on these results, but a healthy check up of
>present theory and findings.
>I hope to get the curve pictures tomorrow.
>
>Klas.
>
>At 08:54 2005-07-16, you wrote:
>
>>"The cheapest little chip amp has a better noise
>>performance than the best mic amps 10-15 years
>>ago. You can presume [the mic input] is good,
>>(low noise) enough."
>>
>> -Klas Strandberg 3/25/05
>>
>>5 years ago, on the advice of several pro
>>recordists, I bought a $700 external mic preamp
>>and a $1200 pair of condenser mics and soon
>>joined the chorus citing the consumer MD/DAT mic
>>pre circuit as the weakest link in coaxing low
>>noise performance-- especially using high gain in
>>quiet places. I didn't have any better
>>explanation why the noise dropped so dramatically
>>in my recordings . A couple of years ago, the
>>$200 Rode NT1-A mic appeared with ~6dBA self
>>noise and ~25mv/Pa sensitivity. I bought a pair
>>and became interested in whether one could
>>assemble a much lower cost, low noise
>>mic-pre-recorder system out of the many options
>>out there. I tried several lower cost external
>>mic pres, mods and started running hi gain record
>>tests to pin down the inconsistences I was
>>getting with mics connected to the HiMD mic
>>input. Klas Srandberg took a look at these tests
>>and kept insisting that the mic input circuit was
>>not responsible for the noise. How to test this?
>>Dan Dugan sent me some nice Denecke PS-2 phantom
>>power supplies to try but they created a fizz
>>that I could not eliminate. I ordered parts to
>>build a portable unit using 5 X 9volt batteries
>>based on a schematic drawn up by Klas, when I ran
>>into Paul Dickinson who told me that Ross Corp
>>had just come out with a beefier, battery powered
>>phantom supply for only $70 that I might want to
>>try.
>>
>>http://www.music123.com/Rolls-PB224-Dual--Phantom-Power--Adaptor-i11829.m=
usic?source=3Dfroogle
> >
>>Well, it looks like there could finally be a way
>>to hear/assess the noise floor of the HiMD mic
>>pre.
>>
>>In the test movie, there are four tests, back to
>>back that are so close in performance that you
>>might think there's only one sound sample! Listen
>>carefully, the audio changes occur at the same
>>time as the change in the picture. The gear
>>set-ups compared in the first four tests are:
>>
>>1) NT1A-s Mics->722 Sound Devices Recorder
>>2) Same Mics-> using Rolls PB244 Phantom power
>>supply-> 722 Sound Devices Recorder.
>>3) Same Mics-> Sound Devices MixPre -> Line input Sony HiMD NH900 recorde=
r
>>4) Same Mics-> using Rolls PB244 Phantom power
>>supply-> 3.5mm Mic Input Sony HiMD NH900 recorder
>>
>>The next two tests include familiar
>>PIP-compatible friends-- the Shure 183's and Rode
>>NT-4's for comparison.
>>
>>Finally, I couldn't resist juxtaposing the $2800
>>(1) package with the $700 (4) package.
>>
>>
>>4mb version with compressed sound
>>http://www.uwm.edu/~type/Mic%20Preamps/RollsPB224-%3eHiMDMicPreIMA.mov
>>
>>8.4 mb version - uncompressed sound:
>>http://www.uwm.edu/~type/Mic%20Preamps/RollsPB224-%3eHiMDMicPreAIF.mov
>>
>>The QuickTime movie should stream in your browser
>>if you have a fast connection or you can download
>>the movie(s) by going to the directory at:
>>
>>http://www.uwm.edu/~type/Mic%20Preamps/
>>
>>and look alphabetically for the links
>>
>>RollsPB224-_3eHiMDMicPreIMA.mov
>>or
>>RollsPB224-3eHiMDMicPreAIF.mov
>>
>>to right-click( mac option-click) on.
>>
>>Think I'll go pour a single malt whiskey now.
>>Seems more affordable. May I be the first to
>>toast Klas?! Rob D.
>>
>> =3D =3D =3D
>>
>>At 12:58 PM +0100 3/25/05, Klas Strandberg wrote:
>> >No, not too early, cause nowadays there is no reason to make a mic inp=
ut
>> >noisy. You can presume it is good (low noise) enough.
>> >
>> >The cheapest little chip amp has a better noise performance than the b=
est
>> >mic amps 10-15 years ago.
>> >
>> >The design challenge is to make a mic preamp running on 1/ low voltage=
, 2/
>> >low current consumption, still 3/ good headroom and 4/ low noise.
>> >
>> >All "walkman" size recorders that I know of sacrifices the headroom in
>> >favour of low noise.
>> >
>> >Klas.
>> >
>> >
>> >
>> >At 03:42 2005-03-25, you wrote:
>> >
>> >>Might be too early to conclude the R-4's mic pre quality is good
>> >>enough for the general sensitivity of "todays" mics. Of course,
>> >>Volker's thunderstorm is not a good recording situation for judging
>> > >noise. Side-by-side comparison tests with known gear can be very,
>> >>very telling. It could also be the R-4, like the R-1, is designed
>> >>more for music recording with a mic pre gain of 40dB compared to the
>> >>~55-60dB we're used to with MD's. That would be consistent with the
>> >>Oades' report. Rob D.
>> >>
>> >> =3D =3D =3D =3D =3D
>> >>
>> >>At 2:21 AM +0100 3/25/05, Klas Strandberg wrote:
>> >> >At 00:45 2005-03-25, you wrote:
>> >> >
>> >> >>It would be great if they could specify what they mean by
>>not so great?
>> >> >
>> >> >I agree! Again: ALL mic inputs today are good enough if you use hi=
gh
>> output
>> >> >microphones!! Most microphones today are such high output
>>mic's! What is
>> >> >the problem??
>> >> >
>> >> >Klas.
>> >> >
>> >> >
>> >> >>I actually purchased an Edirol R4 recently.
>> >> >>It was the Oade page that made me aware it existed.
>> >> >>According to my dealer I am one of only few people to have one in
>> Germany.
>> >> >>
>> >> >>My main interest in bying it is to make the switch away from DAT =
as
>> well
>> >> >>as the 4 channel opportunity.
>> >> >>
>> >> >>My (couple of days) experience so far is quite positve.
>> >> >>
>> >> >>I've done 4 channel early spring birdsong recordings with a modif=
ied 4
>> >> >>channel Jecklin disc (2 Audio Technica AT3031, 2 Audio Technica
>> AT3032),
>> >> >>that I like very much.
>> >> >>With my mid class surround system, I feel in the middle of the fo=
rest.
>> >> >>
>> >> >>Coming from Sony DAT and Sharp MD mic preamps, I am satisfied, bu=
t
>> I am by
>> >> >>no means short of a recording professional.
>> >> >>My main interest in recording is ambience anyway.
>> >> >>Just today I did a recording of the first spring Thunderstorm fro=
m my
> > >> >>balcony with a stereo Jecklin setup (AT3032 again).
>> >> >>And I really rocks.
>> >> >>
>> >> >>In case there is anyone who would like to have more detail about =
the
>> >> >>Edirol R-4 or even sound samples, just let me know.
>> >> >>I would also be interested in an exchange of experience with othe=
r
>> users.
>> >> >>
>> >> >>
>> >> >>Volker
>> >> >>
>> >> >>
|