MD wrote:

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).
Any tool can be misused and some lend themselves to misuse. Tone
controls are most effective for source correction, not room
correction. EQs come in many formats, varieties and capabilities, so
no blanket assessment is appropriate. BTW, we (I) have recommended at
least one analog EQ, the Rives Audio PARC.

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).

Your preference for using the warble tones over the extended pure
tones is probably right. Even better are gated sweeps or pulses but
you need appropriate software for those. So far as deciding whether
it is better to make a seemingly subtle EQ or eliminate the EQ and
live with the 'bloat.' only you can decide. I would suggest, however,
that A/B testing can help you with discerning the difference but is
less useful, for psychophysiological reasons, than extended listening.
The difference may be subtle but it is, now, a change from your
internal reference. Try living with the EQ correction for a few weeks
and then repeat the A/B. Your response may be different.

You should also be aware, as you have implied, that trying to correct
for a local peak or null may make things a bit worse elsewhere in the
room.

Ultimately, however, you only have to satisfy your ears and mind, not
your graphic displays. Try surfing the room EQ discussions on
www.avsforum.com for a lot of heated but informed commentary.

Kal