[Top] [All Lists]

Re: 722 vs PMD 671

Subject: Re: 722 vs PMD 671
Date: Tue, 21 Jun 2005 09:06:50 +0200 (MEST)
Hi Rob,

Yes, there is some additional hum that originates from electrical devices
(or electrical wires) in my office. I operated both recordes from their
batteries and switched off the devices that were not needed.

However, at least on the waveform (and spectrogram) display one should be
able to distinguish between the periodic 100 Hz (2 * 50 Hz) hum and the
random (brad-band) noise components originating from the microphones /

My office is not acoustically isolated, So there is some noise from the
street and aircrafts fying over. Some of the higher centered hiss that can
be found even on the dummy resistor test section of the SD722 file seems to
originate from the recorder itself. Such noise components are usually cause=
by the digital section of a recorder (square wave signals that are required
for converting the low battery voltage into the higher supply voltages for
the preamplifiers and phantom power).


>Thanks for the test! Seems like both recordings are noisier than what
>I'd expect. In addition to more hiss than I'm accustomed to with
>NT1A/722,  I'm hearing (and seeing on a graph) a pronounced line hum
>that's either in the room, in the signal paths, or both.  I usually
>have to shut down every appliance in the room and run entirely on
>batteries to rid all RFI. I can also detect that a good portion of
>higher hiss is centered suggesting its not from the mics. One should
>be able to hear the noise from the mics themselves with the 722 which
>is under 5dBA effective self noise at full gain- and its usually
>assymetrical. The hiss noise is so similar in both of your tests/pres
>that I'd guess its coming from a third source.

Geschenkt: 3 Monate GMX ProMail gratis + 3 Ausgaben stern gratis
++ Jetzt anmelden & testen ++ ++

[Non-text portions of this message have been removed]


<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU