naturerecordists
[Top] [All Lists]

Re: A simple noise test

Subject: Re: A simple noise test
From: "Rob Danielson" danielson_audio
Date: Sun Apr 26, 2009 8:57 am ((PDT))
At 7:12 AM -0700 4/26/09, Jim Morgan wrote:
>Having noticed an excessive amount of noise in my recordings I 
>decided to see just how much was ambient and how much was from my 
>equipment.
>
>I used my workshop room located in the in the corner of my house 
>that is constructed of two concrete block walls on one side and 
>frame walls on the other two walls as a sound room. The first test 
>had very faint 60 cycle buzzing and the ticking of a battery 
>operated clock. The second test was with the clock removed and the 
>lights turned off.
>
>This recording was noiseless to my ears when played through 
>headphones at normal volume. The waveform on my monitor screen was a 
>single straight line with a few tiny dots on it.

Hi Jim--
As you seem to have determined, what one considers to be "normal 
volume," has many consequences. The judgement, for example, tends to 
reflect whether one is considering the "room tone" or "ambience" in a 
recording to be part of the "subject" or meaningless "background" 
upon which, louder, meaningful sound events occur. If the local, 
acoustic qualities of a quiet setting are considered part of the 
"subject," (not a typical assignment for a dish, of course) one will 
usually be able to hear noise in the background if of interest to the 
recordist. I believe this will be the case even with the quietest 
mics and pres.  In most cases, if a dish is used, as designed, to 
amplify a selected, non-background sound source and the level of that 
sound source is played back at a comfortable level, then the 
background (and the noise embedded in it) has been rendered pretty 
inconsequential by the use of the dish and lower playback volume.


>My conclusion was the noise in my recordings was, for all practical 
>purposes, all ambient noise, mostly wind and distant road noise.

You wrote that you are hearing unwanted noise in your outdoor 
recordings,..  Have you concluded that you'd prefer to not hear the 
environmental noises the gear is picking up should you crank-up 
playback?

>My equipment is good but not state of the art and consists of:
>
>Telinga parabolic stereo mic
>
>Sony MZ R50 minidisc recorder
>
>A SONY MDS-JB 920 deck for downloading to a Turtle Beach Santa Cruz 
>sound card and played back thru a Sony 6GCH amplifier using Sony 
>MDR-7506 head phones.

Probably helps that you are using using digital transfers, too.

>
>Needless to say I was very pleased with the test results.

I agree that there may not be too much reason to get caught-up in the 
frenzy for the new recorders.  One has to listen to the recordings 
several times anyway; once during the real-time transfer shouldn't be 
a problem. :-)

Some of the Sony and Sharp MD's appear to have lower-noise mic pres 
than quite a few of the new pocket recorders and significant 
improvements in quality usually start with the mics. The Telinga is 
solid, low-noise/high output component in your set-up and a good 
match for the MZ R50 minidisc recorder both in terms of "specs" and, 
most importantly, to your ears.  Rob D.


>
>Best regards to all,
>
>Jim Morgan
>Prescott, Arizona
>


-- 







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

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