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Click on any
topic to view the full question and answer!
 Not
enough PA volume...- Should
I run the power amp at full volume?
- Parallel
speaker connections?
- Plug
everything into the PA?
- How
many channels do we need?
- Is
there really a difference in microphones?
Q.
I just bought a 50 watt PA, and when I put my pretty cheap
1/4" input microphone into it, it isnt loud enough to hear
for my band. Even with full volume! What should I do to make
it louder? Also does the impedance make a difference on
volume?
A.
Unfortunately,
50 watts just isn't going to cut it for PA, unless you're
playing way soft tunes at the Holiday Inn. The impedance can
make a difference in the mike...if it's a low impedance
mike, make sure you have the 3-pin style cord. If it's
really a high impedance mike, the 1/4" plug is the correct
one. Other than that, most people need at least 200 watts to
get a good, full, clean sound from PA while you're
combatting guitar amps and drums.
Q.
I have been told to
run a power amp at full volume into the mixer and to adjust
the mixer to the desired volume. Is this to eliminate
spiking? Is this the correct way? Would a
compresser/limiter/gate help with the spikes?
A.
Specifically speaking, you are running the mixer into
theamplifier. The pathway is as follows:
Microphones>>mixer>>amplifier>>speakers.
And of course, effects are generally patched into the mixer
through the effects loops.
To ensure plenty of
headroom (clean signal with little or no clipping) you
should run your power amps full or almost full. Some people
like to pull back to about 8 1/2 or 9, probably because when
we were kids, we were told never to turn anything all the
way up. This stuff sticks with us for the rest of our lives,
you know?
If you set your amplifier
levels low, you often end up running the mixer levels too
high to get your desired volume level. Most mixers will clip
(spike, distort) before you get anywhere near the maximum
settings. You'll notice that on many mixers, and also
multi-track recorders, that there are indications on the
fader controls around the 7-8 range that suggest you not
pass that range, often called the nominal level.
What you want to achieve
is having lots of power to spare, so that you can run your
mixer low, get plenty of volume at those settings, and still
have a super clean signal, both for the sake of audio, and
the preservation of your speakers.
The use of a
compressor/limiter will also ensure that you're putting out
a clean and controlled signal. When set properly, a
compressor will cut off the jagged top bursts of your
output, and create a smoother, more studio type sound. Spend
a lot of time learning how to use your compressor properly.
Many people are dissatisfied with the results at first, but
when it's doing what it should for you, it will become your
most valuable "silent partner".
Q.
On the back of each of my biampable PA speakers are four
input connections. One is for "HI", one is for "LO" and two
"Normal". Are the two input connections labeled ( Normal
Full Range) parallel and thus may
be used to connect to
a another set of speakers?
A.
Yes!
Q.
Can we plug all of our instruments into the PA
system?
A.
If you want to
blow it up and buy a new one, sure...Seriously, now. PA
speakers are used for reinforcing sound, but they're not
designed to play instruments such as electric bass and
distorted guitar directly through. You can mike your amps,
or send a signal from your "line out" (if your amp is
equipped with one) but generally speaking, instrument
amplifiers will make your axe sound like you want it to,
then you can make it bigger by running through the PA
afterwards as we outlined above. Plugging directly in can
damage your speakers.
Note: The above
answer was in reference to using small-house PA equipment.
In reference to professional setups, PA Guru Rich
Morgan expands on our answer Oct 18,
1998...
One way or another the
mikes and instruments have to pass through the PA system.
The delivery system of the signal really doesn't matter. I
just wonder if you are suggesting that the lighter
instruments go through the PA and the louder, heavier sounds
go off the stage into the audience. Thats a soundman's
nightmare! If you don't put all the instruments through the
PA, you cannot mix the sound. You are a slave to the loudest
instrument. The hot thing today is running directly through
the PA, no amps. All the audio information is processed back
to the artists via monitors. Bass, guitar, drums, keyboards
and alike. The only way you can accomplish this is to be
directly connected to the board via a processor or just out
of the line-out of an amp. This gives you a studio sound and
studio control over the mix. If, as you suggested, they are
going to blow up their system, they just need a bigger
system. Do you think the Eagles let Timothy B. Schmidt play
off stage, did Ginger Baker not mike his drums? It's the
same thing. The only difference is that they used a mike
instead of direct plugging to a board.
Q.
How do we determine how many channels we need in a
mixer?
A.
You always need more than you think you do! Don't try to buy
a mixer that has "just enough" channels because you'll
outgrow it in two rehearsal sessions. Any changes such as a
new band member, drummer adding more toms, someone sitting
in for "just one tune", all of this will eat up your
valuable inputs very quickly! Let's break it down: if you
think you need 4, get 6. Need 6, get 8. Need 8, get 12. You
figure out the rest. Or contact us, we'll do the math for
you.
Q.
Are microphones really that much different from each other?
A.
That's where it all starts! An OK mike will work, and
plugging into a good recorder or sound system will make an
inexpensive microphone sound pretty good, but if you compare
them side-by-side, you will notice a startling difference
between $50 and $100, $100 and $150, etc. Transparent
clarity in the high end, and bass without boominess are the
first things you'll detect as you move up the ladder, plus a
more natural sound overall. One warning...when you try an
excellent quality microphone, you'll never settle for
anything less again!
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