From: Rob Danielson <>
> Thanks Walt. This seems consistent with Bob Cain's computation for
> MP-2 as having around 4-5 dB(A) self noise. Would be interesting to
> try this test with the Portadisk pre.
I'm very reluctant to try and pin numbers on any of this. Too informal a
test.
In comparison, the Portadisc at full crank is a little noisier than the
MP2, I'd guess less than twice as noisy, but it's not that easy to get a
direct comparison.
While the MP2 it makes no difference if the phantom power is on or off
to the levels, it does with the Portadisc. Particularly with the inputs
floating with nothing connected turning on phantom power increases it's
full crank noise some. Much less difference with a mic connected to
provide load. Moral of the story, if you don't need phantom power on the
Portadisc turn it off in the input options. The Portadisc's phantom
power is clean and pretty good, other problems will surface before it
limits you.
And, the MKH-80 is still the dominant self noise by far.
In general, I don't think you want to get into situations with the
portadisc in which you are using it full cranked, but that's also true
of the MP2. Both produce noise with that high gain. I always try to
figure out another way if I'm in the top 1/4 or so of the gain on either
equipment. As I've said, I've not had this problem very often.
Last night I was out recording after midnight in a soft mist. I was
using the MP2 front end doing some testing. The clip level was at about
1/3 up on the MP2. Though that was frogs. I deal with upper end clipping
far more than any worries about too quiet in my recording.
>>>I don't push mics to do things they were not designed for, like trying
>>>to get mics designed for local subjects to record distant ones. I try to
>>>use mics designed for the job or get closer. Which may also be why I'm
>>>not running around setting my gain on the top peg.
>
>
> Nor does anyone if they can get adequate saturation ottherwise. The
> fact that the lowest noise mics and pres are being pushed when trying
> to record rural night ambience shows how easy it is to get very
> noticeable amounts of noise recording natural ambience if one is
> using gear with self-noise rof 10-15 dB(A) more-- like that consumer
> MD mic pres.
Rural night recording is something I do a lot of with my specialization
on frogcalls. Seems almost abnormal to record in the daytime sometimes.
I would agree, really quiet situations are going to have, particularly,
the mic's self noise, in them. If you work out how much we amplify that
quiet ambiance by the time we listen to it it's unavoidable as we are
amplifying the mic's self noise too. And it's not just consumer MD's
that will do this, top end gear is going to do it too. This is actually
where you get into evaluating the quality of a mic's self noise with a
eye to how much it can be audible before it intrudes too much. Generally
the smoother and more even the self noise the better. This is a separate
thing from the absolute level.
It comes down to matching gear. When I worked with consumer MD's and
mics with self noise in the 20's it was fairly well matched, but the mic
self noise was what was noticable. The first quiet mic I got was the
Telinga. Just using that direct with the Sony MD gave me considerable
improvement over the noisier mics, but the telinga's self noise still
turned up first. Probably the improvement was as much because of the
stronger signal allowing less gain to be used. Moving to the Portadisc
was another jump in quality. These were fairly significant jumps, and
only a small part was the self noise. I have the MP2, but the difference
in using it or not with the Portadisc is a much smaller difference, if
any. And, in addition to the telinga I'm now using a bunch of MKH mics.
Which work well with the Portadisc.
I do not believe that you can get the full advantages of the Portadisc
with anything you can hang in front of a consumer MD. You will get
improvement, just not as much as the Portadisc by itself would do. And
you have the disadvantage of a compromise in portability, extra cables
to deal with and so on. In the high end of pre's, particularly with
A/D's you are getting into a combined price for the pre and MD that's in
the ballpark of the Portadisc. Because of the practical problems of
moving around in the environment with gear I'll always choose the
physically simplest solution that get's what I want. I don't like
carting the pre along.
Cost is a important consideration in all this, in fact most of why it
turns up at all. We are really looking for good solutions for all cost
levels, including the low ones. I'm of the opinion that funds should be
first spent on good mics, without that pre's will do you no good anyway,
simply giving the faults of low end mics louder. Once you have worked
with good mics you can get into going with a pre or upgrading your
recorder entirely. What we really need to be doing is digging through
the low cost mics with good specs to find the good ones to recommend.
Walt
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