Folash Electronics

If you are a sound-inclined person, you should
really read this... Promisingly educating.
Configuring The Right Wattage For Loudspeakers
The REAL question is not what is the power
handling, but what is the OPTIMUM size power
amplifier to use on a loudspeaker?
“So how many watts can a loudspeaker take?” The
technical answer is that it depends on the thermal
and mechanical limits of the drivers and
crossover components.
The practical answer is that it depends on the
program material played: its peak/average ratio
or transient content and spectral (frequency)
content.
The REAL question is not what is the power
handling, but what is the OPTIMUM size power
amplifier to use on a loudspeaker?
Rule of Thumb
For a rule of thumb the best answer is found
using what is commonly called the loudspeaker’s
RMS (root mean square) power rating. Use an
amplifier that is twice the RMS rating. If you can’t
find an amplifier with that exact rating, multiply
this power rating by 0.8 and also by 1.25 to find a
range of acceptable power.
Example: A loudspeaker has a 250-watt RMS
rating. Twice this is 500 watts. Therefore the
acceptable range for the power amplifier to use is
from 400 watts (0.8 x 500) to 625 watts (1.25 x
500). Anything larger is potentially excessive
power. Anything smaller can cause damage from
the amplifier clipping. Remember that the power
amplifier output you select must be rated for the
nominal impedance of the loudspeaker (i.e., 16, 8,
4 or 2 Ohms).
The RMS rating represents the thermal power
limit for the loudspeaker. It is also a good number
to use for comparing products. Twice the RMS
rating represents a realistic scenario for most
actual audio signals. This is 3 dB more power than
the RMS rating. An amplifier’s RMS rating is based
on a sine wave measurement. The peak power in
a sine wave is 3 dB more than the RMS power.
Therefore using twice the RMS power rating for
the loudspeaker provides 6 dB more power for
short term power peaks.
A good loudspeaker can easily handle this. Why?
The RMS rating for professional loudspeakers is
almost always measured using pink noise for a
test signal. The content of this test signal is an
RMS level with peaks that are 6 dB above the RMS
level. Thus testing a loudspeaker with pink noise
requires an amplifier that can produce power
peaks of 6 dB above RMS level of the input signal
to the loudspeaker without clipping. The rule of
thumb provides an amplifier with this capability.
Real World Audio Signals
Real audio signals usually have peaks at least 10
dB peaks their RMS level. Therefore, with a
properly sized amplifier just below clipping on
those peaks, the RMS value of typical audio
signals will be at least 3 dB below or half of the
loudspeaker’s RMS rating. This provides a margin
of safety.
Still Possible to Damage a Loudspeaker
Having said this, it is entirely possible damage a
loudspeaker with an amplifier that is in the “rule
of thumb” power range. Why? Because power
handling depends on the type of input signal and
the user - not the manufacturer - controls the
input signal in actual use.
For example, the RMS and peak levels can be
about equal on compressed audio signals and for
certain signals from instruments like synthesizers
or highly processed electric guitars. This means
any amplifier power capability above the
loudspeaker’s RMS rating can damage it!
Also, no matter what size the amplifier is, clipped
signals are death to loudspeakers, even if the
clipping occurs in the mixer, equalizer or other
signal processor.
There is not a perfect answer to the power
handling question. This rule of thumb is a realistic
guide for the optimum size power amplifier to use
on a loudspeaker for MOST live audio signals. It
allows the loudspeaker to be used to its
maximum specified power rating.
Caveat About Distortion
Almost no loudspeakers are rated for their
distortion at maximum power. For this reason
there is nothing implied by the manufacturer in
the maximum power rating that says a
loudspeaker will still sound good at its maximum
power rating. If you find that a loudspeaker
“sounds bad” when run near its maximum rating,
then the maximum distortion that you find
tolerable will be the limiting factor rather than the
maximum power rating.
Note: This applies to professional loudspeakers
from reputable manufacturers, and includes
drivers as well as complete loudspeaker systems.
Written by Engr. Aluko Stephen

Guide to Professional Audio Practice.
"How do you achieve good equalization on a live
concert that pleases everyone?"
Well, can you indeed please all of the people all of
the time? And does that include the band?
There is a lot more to live sound than
equalization. If this were the only thing people
were commenting on then you would already be
a brilliant live sound engineer!
But let's assume that it is in fact only the EQ that
is the problem...
There are many similarities between live sound
EQ and EQ during the mixing process of
recording. The four basic functions of EQ are
these...
To correct problems.
To optimize the sound of individual instruments.
To help instruments blend together.
To optimize the sound of the entire mix.
All four points apply equally to recording and to
live sound. But there are differences...
Firstly, the live sound engineer has a tremendous
advantage - he hears what the audience hears ( if
the mix position is right). In recording, you don't
know what speakers, or in what acoustic, the mix
will be heard. So the engineer effectively has to
guess.
But there is a disadvantage in live sound too - the
engineer is constantly battling against the
occurrence of feedback. And unfortunately EQ
can make the risk of feedback greater. EQ is often
used as a measure to protect against feedback,
but sometimes that can work against the quality
of the sound as a whole.
So, a few guidelines on how to equalize a live
concert...
Identify and correct any problems, such as an
excessively boomy bass, or an overly aggressive
keyboard sound.
Use EQ cut to reduce the unimportant
frequencies of the main instruments. For
example, cut the bass on any instrument that is
not specifically a bass instrument.
Use EQ to help the instruments blend. For
example if the rhythm guitar is obscuring the
horn section, cut the frequencies in the rhythm
guitar where the horn section is strong.
Use a graphic EQ on the output to lower the level
at feedback frequencies, but not so much that it
affects the sound of the band significantly. Also
use the graphic to shape the sound as a whole to
suit the PA system and the acoustics of the
auditorium.
You know, even when everything is perfect, you
won't please everybody. But with sensible use of
EQ, the audience will go home happy
Written by Engr Stephen Aluko

Hey people sorry It's been too long...
An opportunity just open, if you want to learn the basics of sound engineering, you should drop your questions and your comments as well are welcomed. _thing