Oh my, this is the
part that I must refrain from typing 10 zillion pages. Differences exist
in speakers that are so large that they can be heard in seconds--especially
at the sub $150 level. Also, ridiculous specs like 1000W PMPO (peak music
power output) boggle the mind. Yeah, like you should believe that some
wall wart labeled as 10W can pump out 100 times that to your shiny new
$49 boomers. PMPO is not a verifiable spec in any way shape or form, that's
why over 20 years ago, the FTC developed strict standards for amplifier
claims.
Because 99% of all
computer speakers are BYOA (bring your own amps), power ratings are essentially
meaningless. Since one can't be evaluated without the other, only the
end result (total output) holds any significance. But do you need something
that can make your pants/skirts flap? Some of the highest quality sound
can be had with less power than you might think. It all depends on the
total efficiency of the system, not just a wattage printed on a box side
panel.
Efficiency
This is where SPL
rears its head. Speakers have a particular efficiency. When a set amount
of power, say 1 watt, is fed to the device, output is measured at a certain
distance, say 1 meter, and SPL can be calculated. If a certain midrange
produces 90dB SPL @ 1W @ 1m, then we have a known reference from which
to base further calculations.
But most computer
speakers have their own internal amplifiers, so individual efficiencies
can't be measured easily. Total SPL can be measured and these output specs
are becoming the defacto standard--you can find max SPL's quoted on an
increasing number of speakers boxes. Here's a quickie guide to how loud
is loud; every 10dB increase is a doubling of perceived loudness.
|
Sound
Level
|
Loudness
|
|
0dB
|
Threshold
of perceivable sound
|
|
40dB
|
Quiet
country night, breath sounds
|
|
60dB
|
Smooth
running car engine
|
|
70dB
|
Average
conversation
|
|
80dB
|
Background
music
|
|
90dB
|
Average
music listening level
|
|
100dB
|
Loud
music
|
|
110dB
|
Most
rock/pop concerts
|
|
120dB
|
Threshold
of pain over time (e.g. hours)
|
|
130dB
|
Rapid
hearing loss over time (e.g. minutes)
|
|
140dB
|
"WHAT!
I CAN'T HEAR YOU!" <---deaf in seconds
|
|
150dB
|
Heart
attack possible
|
If you enjoy your
hearing, don't subject yourself to more than 110dB for an hour, some say
even less. If the speakers you just purchased actually reproduce sustained
levels of 110dB, please set an egg timer or something. Ringing ears and
headaches are not cool.
Subjective Listening
Tests
The conundrum: who's
right? With an ever growing base of review sites, who's subjective opinion
matters? With other hardware like motherboards and chipsets, all is needed
is objective data and practical tests. Very little is actually subjective.
It's impossible to review speakers without amps and a sound source. Therefore,
the believability of the reviewer must come directly under fire. The crux
of the argument is this: only those with studio recording experience can
really know what certain instruments (including the human voice) sound
like.
All my subjective
listening sessions include a wide variety of tunes to be sure, but they
also included several selections that I personally multi-tracked using
my own analog/digital gear. I still periodically master or re-master various
types of radio/TV ads and personal material when the situation arises.
Because tube microphone pre-amps can run into the $1000's, I designed
and built my own hybrid class A, no feedback pre-amp in 1996.
Merely saying, "I
cranked 'em up with Q3 'til my ears bled" doesn't hold much water.
What does that mean? Were the test units just loud? Measurements can,
most of the time, shed some light as to why a particular set sounds weird
in certain areas. On a rare occasion, tests cannot reveal
why a speaker sounds good or bad. Transient analysis is still under development
and besides, some of that high end evaluation gear is only available to
the high end mags, like Stereophile. At $25K and up, I won't ever have
the golden opportunity to even touch one...
If you glean nothing
else from this article, remember the following: listen extensively for
yourself. After all, whether I recommend something or not, you may have
vastly different requirements. I only get excited when I hear "audio
truth" or accuracy and emotion in the reproduction chain. I have
one overriding rule: the midrange (200Hz-3kHz) must be neutral sounding.
If voices and the vast majority of woodwind (unamplified) instruments
sound like other instruments, I personally can't stand to listen
for long.
