By Al Fasoldt
Copyright © 1991, The Syracuse Newspapers
Whenever I need a little outrage in my life, I turn to my brother
Bob. He's got enough for both of us.
He's a big fan of audio and video and all the other consumer electronics
stuff, just like me. He's maybe an even bigger computer nut.
He's always been a great source of advice on these subjects, not
necessarily because he knows more than I do—modesty keeps me from
saying more, you understand—but because he uses all these things
constantly.
Despite what you may think, I'm not a gadget freak. So, I depend
on Bob for the some of the weather vanes that I need now and then
to know which way the consumer breezes are blowing.
His latest outrage has to do with his new audio-video control
center. It's a receiver, just like the regular old audio receivers
we've been used to since the 1960s, except for one thing: It lets
you switch, listen to and copy video sources as well as audio
ones. It's even got built-in surround sound, so you can play the
front speakers and the back apeakers and get great audio effects.
Nice, eh?
Not so nice for Bob, who complained right away that the company
that made his new A-V receiver cut the very first corner it came
to. This company made it just about impossible for him to play
two sets of speakers at the same time.
Whenever he tries to, the volume goes down instead of up, and
the sound just isn't as good.
What apparently happened is this: The engineers who designed the
amplifier section of the receiver—that's the part that takes junior-league
signals and blows them up to power-blaster size—had orders from
the bean counters to save a few bucks (or, more likely, a few
yen) in what's called the final stage of the amp.
The finals stage, as I hope you can see from the name, is where
the electrons get kicked out the door on their way to the loudspeakers.
They need just the right momentum, so to speak, to reach those
woofers and tweeters with the right oomph.
The left and right sides of the amplifier work pretty much independently,
so the two streams of electrons go on their way without interfering
with each other. It's just like having two separate doors at the
power plant. Left-side electrons, this way! Right-side electrons,
that way!
That's all well and good if the little critters don't have to
do two jobs at once. But once you switch on Speakers A and Speakers
B together—the ones in the living room and the ones in the family
room, for instance—the electrons need a stronger push right from
the start.
And that's something that amplifier companies had been doing for
years.
Instead of designing the amps that give those electrons a little
bitty boot out the door, they used to build in a wallop. Smack!
Out you go, pal. Smack! Same for your buddy!
Technically, of course, this sort of explanation just won't do.
The electronics engineers in the audience would like me to talk
about voltage drops and impedance levels and all that sort of
thing. But trust me on this one: We're lookin' at the big boot
vs. the tiny one, that's all.
So what's wrong with my brother's amp? It's just plain wimpy in
the smack-'em department. It's got plenty of watts—don't get me
wrong about that—and it can handle a single pair of speakers perfectly
well.
But it wasn't designed like the ones in the good old days. A circuit
designed to keep the impedance from dropping too low—er, I mean,
to keep kicking those little electron butts—would have cost too
much.
Humbug. The next time you're shopping for an amplifier or receiver,
ask somebody at the store if the one you're looking at can really
whack 'em.
If you get a strange look, shop somewhere else. No sense spending
your money where they don't know the lingo.
technofile:
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