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Re: Equipment Testing Goals Methods

Subject: Re: Equipment Testing Goals Methods
From: "Walter Knapp" waltknapp
Date: Mon May 7, 2007 10:15 am ((PDT))
Posted by: "Rob Danielson"

> At 12:53 PM -0400 5/6/07, Walter Knapp wrote:
>> >Even as a technical equipment group, I'm offended by the lack of scient=
ific
>> >method in all that.
>
> Hi Walt--
> I'm sorry if my tests offend you. I'm open to suggestions for
> improving my methods.

Note I was specific, lack of scientific method.

> In the recent test Jerry and I collaborated on, our goal was to
> compare the high-gain self-noise performance of six mics operating on
> Hi-MD PIP. I'm pretty sure recordists will not encounter noise
> differences in the field inconsistent with those in the tests when
> recording ambience in quiet locations on Hi-MD recorders. So far, I
> am not aware of field results that have conflicted with the
> comparisons I've made and documented, but that is always remains a
> possibility.
>
> Of course, the A/B comparison testing I do is not aimed at numerical
> outcomes. The goal is to enable subjective evaluation for a very
> specific type of recording which is stated as a premise when I post
> them to the list.
>
> I believe listening tests can be telling for judging noise
> performance-- not for the sake of claiming one component as generally
> better than another-- but for making more tangible the differences
> involved.  Though the tests have found a few surprises that have been
> valuable,  they are not ambitious in their goals. They are admittedly
> most effective at evaluating upper frequency self-noise of recorder
> mic preamps. A few have compared mic self-noise and fewer still,
> stereo imaging.
>
> Applying subjectivity is one of the important ways recordists and
> engineers place quality in perspective. For example, in the press
> release regarding their new high-end mics, Sennhesiser reports, "The
> technical development was supported at a very early stage by sound
> and listening tests, and the sound engineers involved in the tests
> confirmed that the new microphones have an incredibly impressive
> sound quality that even goes beyond that of the innovative MKH 800."
> Rob D.

I like what you do with the exception that you depend too much on your
hearing to make fine distinctions. Since what we hear is too influenced
by our attitudes, our minds transform the sound to fit what we think
about equipment for instance, it's really very hard to know what your
hearing brought you. That makes your detailed statements hard or
impossible to confirm by repeating the experiment. And that's the basics
of science, what we find must be repeatable by others. Be aware I don't
take folks statements without trying to repeat the experiment to verify.
I'm a scientist, it's built into my nature.

As equipment rises and falls in popularity in this group I've seen
plenty of rising and falling in what people hear in the output of that
equipment. The equipment output pretty much does not change (or we would
send it in for repair) but the reports of this group over time often
make major changes. At least some of that is the collective mental
filtering of the group's attitude and has nothing to do with what the
equipment is doing. Some is, of course, learning to listen better with
experience. For technical discussion there needs to be a lot more
awareness of the limitations of analysis by hearing. If you want to
report tests as precise you preferably have to back up your hearing with
calibrated measurement.

I filter comments made by the audio equipment industry with the
awareness that it builds equipment to produce entertainment. While we
certainly do record at times for entertainment, at least some of us
record for as accurate as possible representation of nature, a different
goal with different demands on equipment. I have no judgement on the new
MKH mics, except to expect that, unfortunately, they will be expensive
while being good. What Sennheiser says about recording music is
interesting but tells me little. I'd love to stick a pair of the new
omnis in a SASS and go out for a season or two of recording. But I'll
have to wait until used ones turn up cheap enough on ebay.

I tend to use nature itself as my test environment for equipment. That
at least eliminates one source of variance with what I record, I test
with what I want to record. I also don't depend on single recordings to
evaluate much of anything. It may take a season or two to evaluate a
piece of equipment, many recordings under many conditions. It may take
that long to even have some idea how to properly use a piece of
equipment, particularly true of mics. Not the sort of thing our modern
folks are good at with their demand for instant results and absolute
winners. I'm aware that what I hear is being filtered by my mind, and
the long run of use in the field is deliberately designed to get around
that as much as possible.

Walt





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