korenek%ficc@uunet.UU.NET (Gary Korenek) (04/10/90)
First thought:
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It occurs to me that the goal of "high end audio" is to reproduce the
_source material_ as fully and accurrately as possible. This means if
it's crummy source material (a bad recording), at best I will be able to
reproduce it to it's own limits. I'm not going to get a great soundstage
from a recording that was engineered with no thought as to soundstage.
What you get is directly proportional to what's there.
Once you reach this point, the question becomes: how accurately is
my equipment reproducing what's there (on the recording)? There are subtle
differences in electronics. There are great diffences in speakers, in the
rooms in which the speakers are located, and in the placement of the
speakers. For this reason, I'm more concerned about the speaker/room/
placement variable (rather than the electronics variable).
I can take an audio system and change the results (the sound) just by
changing how the speakers are placed. I'll get the least low frequency
reproduction from a speaker by having the speaker up off the floor, and
away from walls and corners. I'll get an increase in low frequency
reproduction by putting the speaker on the floor. The next increase is
on the floor and up agaist the wall. The next increase is on the floor,
and in a corner. Personally, I place speakers with more regard to
soundstage, and less regard to off floor/on floor/in corner. The reason
for this is: equalization. A speaker system can be equalized to the
room (and to the speaker placement), thus "cancelling out" whatever the
room (and speaker placement) emphasises/deemphasises.
The points to all this:
1. You can only reproduce "what's there" to reproduce (with regard
to the source material).
2. In reproducing "what's there", the first variable to be concerned
with is room/speaker placement (what's the room doing to the sound,
what's the speaker placement doing to the sound).
3. Then work on the other variables (electronics).
Second thought:
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The next great service that the consumer audio industry could provide
is test/measurement gear such that home audio enthusiasts could
_affordably_ measure the performance of their systems. Like, an
affordable (accurrate) real-time analyzer (to measure what the room and
speaker placement is doing to the sound). Like, an afforable pen
recorder such that each piece of gear could be measured to see what
that piece of the system is doing (does the piece accurrately reproduce
what's there, or does it add/take away something). An example is a
turntable/cartridge combination: I've seen people change the high-end
response of a cartridge just by varying the length of the connecting
cable (from the turntable to the amp/preamp). This changes the capaci-
tance in the cable, thus changing the high-end frequency response.
Another example is blank recording tape. Different tapes will produce
different repsonse characteristics. What's tape "A" doing to the original
source? Tape "B"?
The one thing I can think of that cannot be easily (read: affordably)
measured is: how well a speaker system "images" (like, _really_, what
is the soundstage/soundfield of a given speaker system, in a certain room,
with the speakers placed a certain way).
Gang, we are really left to guess at most of this stuff, to the point
that it really works to the manufacturer's advantage. They know that
we will keep buying stuff (and making guesses). Why not eliminate
the guesswork? Offer us a way to measure our systems (affordably!).
I'd like to be able to say "I _really_ know, overall, what my system
is doing to the original source material".
Gary Korenekchowkwan@aero.org (Raymond Chowkwanyun) (04/12/90)
Have you tried the LEDR test? It was described in Stereophile (forget which issue but sometime in the last 6 mo). It's available on the Chessky sampler disk for about $15. (This is not the full test as described in Stereophile but an edited down version. However, as the full test costs much more ($50) and the Chessky version does the essentials I think it's a valid compromise). We tried the Chessky disk at our audio club at work and you could really hear the blips arcing over the speaker. (Some wag asked what would happen if we turned the speakers upside down? Would the blips arc under the floor?) We also found that toeing in the speakers helped the imaging tremendously. -- ray