Codifus wrote:
Gary Eickmeier wrote:
MD wrote:

From text I sent to Stereophile

I have been a subscriber for about 15 years. In that time I have
learned, and tried to put in practice, good room treatment techniques.
I use test CD's and a sound meter to aid in placement and I treat all
the room hot spots like first order reflection, echo flutter and
deaden the area behind my head (my Triangle Celius speakers sounds
their best in a spot that forces me to the rear wall- I have an odd
room). What confuses me is the double speak on tone controls and
equalizers as well as exactly which test tones I should use when
running the tests.

On equalizers/tone controls. I can't count how many times I have read
that these are either the bane of our collective electronic existence
or a necessary tool to help make some recordings sound right
(specifically tone controls). On equalizers I read that they induce
too many problems but your magazine has recommended several of them
(all in the digital domain I believe).

In my room I have several strong nodes below 300hz (as do most people
I am sure). I have a small dent at 50hz, huge plus ups at 60hz and
120hz and a dip at about 250hz (Here is where the test tone confusion
comes in. With warble tones the aberrations are far lower. With
straight tones I have a 16db shift from 120hz to 250hz - with warble
tones the shift is about 5db. Which am I to use? Seems to me warble
tones are more effective because the approximate the changes that
occur in music?). After studiously using my test gear/tones, set up
programs, several suggestions from professional sources (read in your
mag and others) as well as installing some room treatment (albeit none
for bass control) I am left with the predicament described. As far as
I can tell room treatments, designed to help in the low end, are not
discriminate enough. While they will tame my hot spots they will also
negatively affect my dips(?). Using a bass tone control won't work for
basically the same reason. At the end of the day (which I assure you
is a grossly understated metaphor) I decided to try a cheap 10 band EQ
I had on hand (I would try the digital products but they are way too
expensive). Utilizing the EQ and other associated items I was able to
smooth out the bumps, in both directions, to a very significantly
measurable degree. Now here's the rub. When I asked my daughter to
help me A/B the difference (which is easy with an EQ - one button) I
had to work at hearing the difference - more often than not. (I should
note that I could go flat to 40hz and only 3db down at 31.5hz). While
I was able to discern the difference on some recordings (bass notes
ended sooner - no bloat) it was not a startling difference. As such is
it "better" that I use the EQ to settle the bloat or run away from the
wretched beast, and all it's detriments, and deal with the bloat
because its less damaging? (I should also note that I heard no
negative artifacts with the EQ - no imaging change or high frequency
issues). Finally - does anyone make an affordable analog EQ that only
affects the range below 300hz? (Or a digital unit that is affordable
and isn't meant for subwoofers?)


I could give you another way of looking at the problem. Sometimes we get
too absorbed in hi-fi trivia, trying to get some sort of perfect curve
to our frequency response and reduce all contributions from the room,
which is based on a misunderstanding of the system.

Not it's not. any contributions to the sound from the listening room is
a coloration. it is not trivial. now one does have to pay attention to
the speaker design since many speaker designers design with room
colorations in mind. It is not trivial and IME the best sound comes
from speakers with very low distortion in rooms with very little sound
of their own.



Imagine hiring a piano quartet or similar to come to your home and
perform in place of your system. Would they sound real or not? Stupid
question, right?

In this context yes. fact is if they overload the room they will not
sound real in the way we want things to sound real.


Now, the point of the exercise is to make your room
sound good for MUSIC, and let your system simply play in this good
sounding room.

You couldn't be more wrong. the acoustics for good live music are
nothing like the acoustics for playback. For live music, the room sound
is part of the performance. For playback that kind of reverb, good
reverb for live music, would be terrible.

Sure, if there is some ridiculous resonance at some bass
frequency you want to dampen it. But the system itself will be basically
playing flat into your room,

No it is not. frequency responses are measured well into the room and a
reverberant room will profoundly affect that response not to mention
all the smearing you will get.


just as the quartet live is playing "flat"

Are they? You think they would sound the same regardless of the space
they are playing in?


and sounds perfectly real without even any EQ!

And in the wrong room perfectly awful. But your premise is painfully
flawed.


So set up a reasonable
system, get a good balance between your mains and your subs, between the
fronts and the surrounds, and enjoy the music!


That is a good basic formula for the bare essentials of playback. But
with time, care and the right equiment there is a lot of room for
improvement. That is what the high end is about. your advice is quite
right for casual listenes not for audiophiles.


If you didn't need any
fancy digital room correction for the live music, you don't need it for
the reproduction either.


Oh that is ridiculous. How can you possibly compare such two entirely
different things? The reverb in live music is an intregal part of that
music. If well recorded *that* reverb is already there. Adding the
everb of yet another room, the listening room for playback is all
wrong. It's not the same thing at all. The only way to make listening
room reverb work the same way as concert hall reverb is to have a
seperate channel for each instrument with zero cross talk from the
other instruments, and then have a mic/speaker system that can mimic
the radiation patterns of the original instrument, then place each
speaker in the room in the same configuration as was the original
performance. That would ridiculous. But if this isn't what you are
doing then you are simply comparing apples and oranges. Speaker/room
interaction is nothing like live acoustic music/room interaction.

And remember, EQ is not supposed to be flat at
the listening position.


Why not.

The room gives it a natural taper at the high
frequencies, which is part of the deal, so don't go to any lengths to
"correct" that.


Wrong wrong worng. correct it please. Don't let the room ruin the
playback.



Gary Eickmeier

So well put. People try so hard to get that absolute flattest response
in their room, but really, they should simply achieve the best balance.



The best balance usually is a flat response. Certainly there are other
issues but all else being equal flatter is usually better with
speakers.




I say to simply move your speakers around in the room untill you find a
spot where the speakers seem to come "alive." That's it. Any EQ or tone
controls added afterwards should be mild, plus or minus 4 db.


I agree with this more or less. You will likely do much better with
careful speaker placement and room treatment than you will with EQ. I
wouldn't mess with EQ for room correction. If the speaker room
interface is sooo bad that it needs EQ I would look to one of the
digital room correction devices. They are far more precise and the good
ones do more than just fix frequency response.


Then
you're good and all is well. It's not perfect, but its' probably perfect
for that room or very close to perfect, and, ultimately, you'll be happy.


Not to be a nay sayer but it takes a lot of work with speaker placement
and usually substantial room treatment to get anywhere near the best
sound possible from your system.


Scott