Scott Dorsey wrote:

Pooh Bear wrote:

Any room modes are likely to be unrecognisably different when there's an
audience in there. Fiddling with graphics is the most time wasting and
useless exercise ever imposed on sound engineers by musicians during the
sound check who think they know better.

I disagree. The first couple feedback modes aren't going to change much.
They're going to be due to resonance issues around the stage area and
leakage from the rear of the speakers directly into the stage mikes.

Beyond the first couple modes, though, yes there will be a lot of modes
that do change totally when the audience arrives, which is why it's not
worth spending a huge amount of time notching everything possible out.
But those first couple notches can mean a huge difference in available gain.

My own experience with small halls such as pub gigs suggests that the only modes
that stay much the same are the low frequency ones. The audience is normally so
close to the stage - and the venue so closely packed that you have a huge
absorber in front of the system.

Considering that I never used a graphic back in my hire days it's curious that
*no-one* ever accused me of having insufficient gain.


I always used some recorded material to check the performance of a system I
hired out. Each track was specifically chosen to represent certain
instruments ( and frequency ranges ) fairly accurately. I'd *lightly* EQ it
by ear so it sounded right to me and screw anyone else who thought they knew
better. There is no better instrument to assess sound quality than the human
ear btw. Even the modern clever RTA stuff is seriously never going to
replace a set of good ears.

Absolutely. That's why I recommend listening to music as you add notches,
so you can hear what the notches are doing. THEN, after that, you can
think about doing some more broad shaping EQ to change the sound of the
system if you're into that.

In one memorable instance 25+ yrs back when we were providing the PA for the
support act for a band with the then new *Turbosound* equipment we finally
though we'd met our Nemesis !

After a succesful sound check we played a new test track ( from Pink Floyd's
The Wall ). Two things happened. (a) one of our 'roadies' who used to work
on aircraft carriers commented that is was exactly just like a real
helicopter (b) the engineer from the main act went visibly green and rushed
to his bloody graphic - as if he thought it would save him ! We retreated to
the bar looking smug.

I never ever used a graphic on my rig. Never wanted to. Never would do.

I don't much like them at all, but the one good thing about them is that
when you hear the system ringing, you can quickly pull down the slider
corresponding with the note that is ringing. It's very fast to operate
on the fly once the system is running and things start moving around.
When Monte McGuire and I wind up working together, he is always about
having graphics so you can do that in an emergency, and I am always about
using parametrics to notch out the most obvious modes so you don't have
an emergency.

I'd certainly prefer the parametric approach. For example, if the sytem rings at
2.3 kHz do you 'pull' the 2 kHz slider or the 2k5 or both ? Both will miss the
spot. You might get 4dB of attenuation @ 2.3k but 6dB unwanted attenuation @ 2k
or 2k5 by using a single slider - waht you get by pulling both dpends on the
design of the graphic.

For 'ringing out' I think the feedback eliminators are far better. They have
adaptive filters that can home in on the troublesome frequencies with a decent Q.
Set them and lock them. Of course then you have the problem that it's ok for the
sound check - but a full hall's going to be different.


Graham

Pooh Bear wrote:

Any room modes are likely to be unrecognisably different when there's an
audience in there. Fiddling with graphics is the most time wasting and
useless exercise ever imposed on sound engineers by musicians during the
sound check who think they know better.

After a few decades of ringing-out and only a graphic EQ at hand, I have
yet to see a room's modes change significantly with addition of
audients. Absorption within portions of the spectrum? Yes; but room
dimensions, no. Depending on room size and surface materials I may have
to adjust the degree of attenuation within a band or few, but not enough
to have rendered a good job done pre-soundcheck into worthlessness.

--
ha

lhorvat wrote:

I wanted to see if anyone knows where I can find a good detailed step
by step system on "ringing" out a sound system for live gigs. I've
searched the net for it but I'm still a little doubtful on the process.
Any info would help...

The Yamaha SR handbook has a good discussion of the process.

I willing to suggest that you might want to try using the RTA function
of a Behringer DEQ2496 in conjunction with a careful ringing-out of a
few rooms. It works surprsingly well, and if you move the cursor to the
hot band and then switch to one of the EQ modes, the cursor will come up
in the EQ on the hot band. One can move rather quickly this way while
still learning everything you'd learn by the trypical sweeping ringing
process. And the DEQ offers both "graphic" EQ with selectable filter
bandwidths, and parametric EQ, as well as dynamic EQ. Pretty cool tool,
in my book.

--
ha

Arny Krueger wrote:

FWIW, I recommend only 3-5 bands of notching, even when a parametric
is used.

The room and the music tell me how many of what I'll have to use. In
some cases, none will be needed.

--
ha

I find using music to eq systems nearly worthless, perhaps even beyond
worthless to the point of making quality eq decisions impossible
for me , my voice is all I need, though I do like to play with analysis
programs like MacFOH, though in the endI will always default to my
ear +my voice through a M88
george

or lays it down on the monitor when he walks off stage for reasons
unknown in mid song
George

Yes I meant "I can't"
use good stuff that is working properly at reasonaly spl and feedback
is not a issue

George

In article writes:

My own experience with small halls such as pub gigs suggests that the only
modes
that stay much the same are the low frequency ones.

Around here, we don't call pubs "small halls." But often the low
frequency modes are the most troublesome ones.

The audience is normally so
close to the stage - and the venue so closely packed that you have a huge
absorber in front of the system.

Then why is there a feedback problem? I don't suppose it ever occurred
to anyone to use a little less gain, for a little less volume, when
the audience is right in front of the stage.

Unfortunately, in pubs, the speakers tend to be put where they'll fit,
not where they'll provide the best coverage. More often than not, that
puts them behind the mics. Room modes don't usually have much bearing
on that feedback when the acoustic path is direct.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

hank alrich wrote:
Arny Krueger wrote:

FWIW, I recommend only 3-5 bands of notching, even when a
parametric
is used.

The room and the music tell me how many of what I'll have to use. In
some cases, none will be needed.

I did not properly say that 3-5 would be the maximum. The ideal
minimum is, as you say exactly zero.

Bmoas wrote:

Yes I meant "I can't"
use good stuff that is working properly at reasonaly spl and
feedback
is not a issue

Only if you can control the venue and the number of concurrent open
mics.

Master fader down.
Set the input gain for the vocal mics then bring their faders up to
unity gain.
31 band EQ flat, start increasing the master fader level SLOWLY until
you hear the first ringing note.
Find the band on the EQ that affects the rung the most and cut by 3 dB.
Increase master level until you hear the next note ring.
Repeat a couple times for the next frequencies, you may cut the same
one again.
You generally shouldn't need more than 3 or so dB cut at any freq on
the mains. All should be below 300 Hz. Any adjustments to higher
frequencies are pretty much to taste as long as you're amps are
balanced. Usually wait until the rrom is full and the band playing for
this. People soak up high frequencies.

For monitors it's a whole different bag with many more high frequency
cuts. Again, if you find you're cutting a lot of frequencies more than
a few dB you should reduce output level. It's a real trick. I've had
mixed results with feedback eliminators. Sometime they grab frequencies
they shouldn't and take the meat out of the signal.

Another trick, either use a high pass filter or just cut everything
below 50 Hz or so. Unless you have monstous subs you're wasting
amplifier headroom trying to get anything below 50. I see sooo many
graphics with 20, 30 amd 40 Hz boosted and folks wonder why they keep
blowing subs and getting little low end before the amps sag.

I find RTAs and pink noise relatively useless unless it's a single
point source system (1 speaker basically). If you've ever run pink
noise and walked the room you'll have heard wild comb filtering
sweeping as you move around.

My 2 cents YMMV

tymish wrote:

I find RTAs and pink noise relatively useless unless it's a single
point source system (1 speaker basically). If you've ever run pink
noise and walked the room you'll have heard wild comb filtering
sweeping as you move around.

With a small venue and the DEQ2496 I can put all mics to approriate gain
settings, leave them all open, raise master gain until the RTA and my
ears says we're observing a resonance, and deal with it. I don't invoke
the Pink Noise God at all.

Mind you, I stay very far away from high SPL situations these days.

--
ha

"Pooh Bear" wrote in message ...

Shame that you only get to do this when the room's empty and won't
remotely
resemble the sound when the audience is in there !


Graham


I find that the room more often than not sounds better when you get an
audience in there. In any case, I may adjust things in performance, but the
basic work is done when I get quiet. Getting soft bodies helps dampen rooms
which give you more gain before feedback. The frequencies where there needs
to be help don't change, but I may be able to get away with a touch less EQ.

--Ben

--
Benjamin Maas
Fifth Circle Audio
Los Angeles, CA
http://www.fifthcircle.com

Please remove "Nospam" from address for replies

Your bass frequencies don't change that much and they are your biggest
problem.

Julian


"Benjamin Maas" wrote in message
...
"Pooh Bear" wrote in message ...

Shame that you only get to do this when the room's empty and won't
remotely
resemble the sound when the audience is in there !


Graham


I find that the room more often than not sounds better when you get an
audience in there. In any case, I may adjust things in performance, but
the basic work is done when I get quiet. Getting soft bodies helps dampen
rooms which give you more gain before feedback. The frequencies where
there needs to be help don't change, but I may be able to get away with a
touch less EQ.

--Ben

--
Benjamin Maas
Fifth Circle Audio
Los Angeles, CA
http://www.fifthcircle.com

Please remove "Nospam" from address for replies