| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 2441.1 | possibly trim mismatch | DYPSS1::SCHAFER | I used to wear a big man's hat... | Mon Sep 10 1990 17:03 | 14 |
| Your problem is likely pre-amp clipping (in the mixer). First thing to
do is to make sure that your mic and input line attenuations match
(variable on the board by the "TRIM" or "ATTENUATION" pot. Usually
you'll want to be all the way down (assuming -50db). Use the volume
slider to control level.
If that doesn't cut it, either:
a) get a compressor
b) teach the singer how to use a mic 8-)
My 2�.
+b
|
| 2441.2 | Some comments | MAIL::EATOND | In tents | Mon Sep 10 1990 18:37 | 25 |
| Can you fill in a couple more details? I'm not sure I'd classify
your system as "small" when you're carrying around FH1's. How are you
connecting them to your powered amp? Are you running everything in
parallel? If so, I didn't think the MFX1's had a built-in crossover.
My impression is that a system like this would need an active crossover
to split the output from a mixer to two separate amps feeding the low
end (the FH1's and the hi end (the MFX's).
This, of course, doesn't deal directly with your clipping problem.
Clipping is a function of the board - especially if its an integrated
one like you have. Do you have an input pad on the board? It is
sometimes called "trim" or "pad", etc. This is where you need to deal
with clipping. Cutting back at the trim pot and adding gain on the
channel fader should do away with the problem (though it may add hiss).
When you experience "clipping", what are the characteristics?
Distortion? Distortion may be a result of simply not having enough
power to acheive the level of volume you're trying to get. Try
borrowing someone leses power amp and plug it into the pre-amp out
(sometimes called the mixer output or sub-output). If the problem
still occurs, you'll need to look at having the mixer repaired or
replaced.
Dan
|
| 2441.3 | | DNEAST::PUSHARD_MIKE | | Tue Sep 11 1990 09:37 | 11 |
|
My mixer has an input "gain" control. It also has an led which shows
when the input is too high,causing noise in the system. I set the input
"gain" to where clipping occurs when I shout right into the mic. I will
use a word with a "T" at the beginning to give a lot of volume. Once I
see where its clipping I back-off the "gain" pot until I cannot make it
clip,then I use the channel fader for the rest of the level setting.
Mike
|
| 2441.4 | Not enough power? | LEDS::ORSI | Iwillnotdrawpicturesofnakedladiesinclass | Tue Sep 11 1990 13:57 | 23 |
|
Ron,
If the horns and FH1's have passive crossovers between them,
and you are driving them with only 150 watts, you may indeed
be clipping the power amp in the mixer head. 150 watts may not
be enough to drive your system to the volume you desire. Pass-
ive crossovers generally suck up 10-20% of the power available
to them, and the 15" spkrs will use the most power. Is the 150
watts rated at 4 ohms or 8 ohms? Your speaker set-up would be
a 4 ohm load to the mixer/head.
On the other hand, if you have no crossovers, and just
connected everything up in parallel, you have a serious problem.
The total load would be around 2 ohms and that could blow the
head and/or your spkrs if you continue to run it that way. I
hope this is not the case.
My opinion is that the system is underpowered. 15" drivers
require alot of power to reproduce low frequencies efficiently.
The name of the game in sound reinforcement is HEADROOM. If you
need 200 watts, get a 300+ watt amp. The 200 watt amp will clip
too soon. Not only does it sound bad, but can be awfully expensive.
When an amp blows, it usually take the spkrs with it.
Neal
|
| 2441.5 | a SOUND resource! | SMOGGY::TURNER | | Mon Nov 19 1990 12:54 | 9 |
| For $2.00 E.V. will send you their "PA Bible" which is a good resource
for evaluating your needs and problems in the sound realm.
E-V "PA Bible"
Electro-Voice, Inc.
600 Cecil Street
Buchanan, Michigan 49107
regards, paul
|