At 10:13 AM +0000 3/27/08, Philip Tyler wrote:
>Thanks Rob, I was enquiring as there have been a number of people
>looking at using external pre-amps in an effort to improve the
>performance of some of the solid state recorders around or that they
>already own. Now if they ever need to replace their recorder with a
>new one, and as they are already in possession of a reasonable 'low
>noise' mic pre-amp, then it might be more cost effective to buy one
>of the less expensive recorders and continue to use their current
>mic pre-amp
One should be able to determine from ballpark numbers whether a
particular, lower-cost external pre will improve the performance of a
given a recorder/mic combination. The time I ran the numbers with the
better external mic pre made by Sound Professionals ( ~$250USD), the
answer was, "no."
Two conditions must be met:
(1) The mics must have fairly low self-noise or they will mask the
the recorder's pre noise anyway. The self-noise of WL183's at
Message: 22.
Subject: 5dB(A), for example, cannot be improved by using any external mic
pre or any "better" recorder. One needs mics with no more than
17dB(A) self-noise, something closer to 14dB(A) is safer.
(2) For the noise bed of the external mic pre to be inaudible
"behind" that of the mics' self-noise, the pre's noise bed needs to
be 7 to 10 dB(A) lower.
The noise floor of the lower cost external mic pres I've seen are in
the -97 to -110 dBu range. This is not low enough to offer
significant or any improved noise performance. I tend to use the
noise for a Hi-MD recorders' mic pre, -124dBUv as the maximum amount
of noise I can live with in a pre for nature recording.
>So I was thinking that some indication the device delivers on its
>line-in might prove useful? (I like to keep in mind that there are a
>number of enthusiasts that pursue their hobby on a 'tight' budget
>and it may be that the difference in price between the various
>recorders can make a big difference to them, also not forgetting
>size.)
>
>I agree that the line-in 'should' produce decent results, but you
>can never be too sure due to some of the shenanigans some
>manufacturers get up to :-))
I have used the -10dB line inputs on more than 10 MD and DAT
recorders with a Sound Devices MP-2 as a the mic pre. Its a sad
over-sight on the part of a manufacturer if a newer recorder does not
meet these standards. The -10 line input on Sharp and Sony MD
recorder will allow one to make great recordings IF a very high
quality mic pre is used "up front." They are expensive unless one
makes on DIY. Some may remember that Klas' "on the cheap" external
mic pre box for unbalanced mics turned out to have more noise than
that of the Hi-MD's pre. In short, the cheap external pres that say
they have "low-noise," seem to be referencing higher sound levels
than those we encounter.
Curiously, all of these new recorders could include mic pres with
noise performance on par with those in the Hi-MD units. There seems
to be a lack of awareness and priority on the manufacturers' part,
not prohibitive production costs. See discussion
http://bioacoustics.cse.unsw.edu.au/archives/html/naturerecordists/2006-07/msg00192.html
regarding the $4 mic pre ad component, the AK-5356VN-L, used in the
Hi-MD recorders.
Could we be applying more pressure on these manufacturers to include
low-noise, high-gain mic preamps in their recorders? I personally
think so. The demand seems to be growing rather than diminishing.
>Another thing I am beginning to see as an advantage to these
>'point-and-shoot' style recorders is the versatility they can offer.
>I am a fan of the MZ RH1 due to its small size, but it lacks
>microphones. So having a device that would allow you to go into the
>field which you can use hand held to capture material when you were
>not after 'ultimate' quality.. But would then lend itself to being
>used with an external pre when you wanted to say 'take more care'
>over what you were recording would seem an ideal tool.
I'm not a fan of built-in X-Y arrays for any sound sources further
than a few feet away. I'd rather use body-worn mics when hiking and
be completely hands-free. Why use noisy mics at any time in quiet
locations? Time and circumstance are too precious.
There was a intriguing quest proposed a while back to liberate the
omni mic capsules and circuitry from the larger AT-3032 housing and
re-house them more like Klas's has with the EM-23's,.. Curt Olson
found he could remove the circuitry from the metal case of the Art
Phantom III unit ($60USD) without problem. Seems like there's a neat,
low-profile. low-noise mic project or product waiting to be made. :-)
Rob D.
>
>I for one often go birdwatching, and carrying a tripod and telescope
>over my shoulder and a pair of binoculars around my neck, don't
>fancy adding a recording kit as well as I walk around. But something
>like the Olympus which would slip into a shirt pocket by the looks
>of it would be great. Ideally I would like it to be a dual purpose
>device so on those occasions when I wanted to record an ambience
>using low noise microphones it was able to deliver the goods. It
>would also serve as a memo recorder, which I carry anyway, to record
>the birds seen on my wanderings. But at the moment my Sony MZ RH1 is
>still going strong so I wont be buying anything new for a while :-(
>
>Phil
>
--
|