How to Assemble a Portable
Audio System
While building a home stereo is fun,
having a great audio system you can take with you can really expand your listening
enjoyment. From portable CD players with headphones to boom boxes, there are many ways you
can assemble a system that can move with you. Since everything’s portable if you have
enough muscle and a big enough handle (witness early "portable" computers), the
dividing line separating portable devices from home-based gear can be somewhat personal.
While the traditional setup is a CD player with headphones, computer-like memory devices
and hard-drive-based sources are becoming more popular as their prices drop.
CD portables
In an odd twist, CD electronics have gotten so cheap that
you can actually buy a player for less than what a new music CD costs. I don’t know
that I’d recommend any of the $13 portable CD players I’ve seen, but it’s
nice to see them available at that price. A couple of major feature sets appear in the
more expensive units: Many players now support playing recordable CDs full of MP3 files
you might burn on your computer. This is a very compact way to get 12 or so hours’
worth of music on a single disc. The better players are distinguished by including a
better interface for navigating the music collection on the CD-R, with small panels
listing track numbers and other information.
Another popular feature are the "sports" or
"joggable" units, which include enough memory to keep the player from skipping
even as it’s being jostled around. A typical player might support ten to 60
seconds’ worth of playback between the times it needs to read the CD. These
shock-protection circuits work fairly well, but they have their limitations: if
you’re moving around a lot, the disc still might not play. Depending on the
design, the shock protection might work better with discs of MP3 files than with regular
CDs.
But even if you wanted to, it would be hard to spend more
than $100 on a portable CD player -- even the top-of-the-line models don’t cost much
more than that. The main thing that varies in portables is the sound quality of the
headphone amplifier. Models from Panasonic and Sony in the $70-$100 range have some of the
better headphone amplifiers you’ll find in a portable CD player, but even the best
units will support only headphones with relatively low power requirements.
Flash-memory devices
Computer flash memory has no moving parts, so products
based on that technology won’t skip no matter how vigorously you bounce them around.
They’re also typically much smaller and lighter than portable CD players. This
combination makes them the preferred source for runners, or people trying to put together
a super-compact system. The main downside is playback time: Entry-level 64MB units will
hold only about a single album, forcing you to connect the device to your computer
frequently to change the songs loaded onto it. Right now, 128MB and 256MB are also popular
capacities, with prices scaling almost linearly with storage capacity: in such devices, $1
buys around 1MB of memory.
Some flash-memory devices that play audio can also be used
to transfer files between computers -- a nice bonus feature. But since the power supplies
are so small in these devices, it’s even harder to power a good set of headphones
with them; they’re optimized to drive small earbuds rather than full-size headphones.
Hard-drive units
If you want to hold a lot of music on the go, nothing beats
a unit with a small hard drive. Apple’s iPod is currently the best-known product of
this type. The popular price point for this type of device hovers around $300, and
capacities of 5GB to 30GB are available. While some units will play music at CD quality,
most people instead store thousands of MP3 files on their drives. You’ll have to
manage installing files on the device with a computer, but if your music collection
isn’t that big, you’ll likely load most of your files once, and thereafter only
occasionally trickle new songs onto the drive.
Hard-drive players are on the expensive side and have beefy
power supplies, so their headphone outputs tend to be pretty good for portable devices.
Make sure to be careful with these relatively pricey units -- the drives aren’t all
that rugged, and can be destroyed if you drop or otherwise mistreat them.
Headphones
The core of most portable systems, headphones come in all
shapes and sizes.
Earbuds are the smallest, cheapest type of headphone, and
are mostly priced in the $5-$25 range. Many portable sources even include a set of earbuds
bundled in the box, though these are rarely very good. Because earbuds fit inside
your ears, they don’t need much power to play loudly. The isolation from outside
noise is marginal at best, and some people play their earbuds much louder than is good for
their hearing -- so be careful with your volume settings. Sony and Koss are popular
manufacturers of earbuds.
More traditional, full-size headphones start at around $20.
These are worn over your ears, and as a result usually need more power than an
earbud would to play at the same perceived volume. But because they can block out more
background noise, you might be able to play this type of headphone at lower volumes and
still be able to hear the music clearly.
There are two major variants of headphones that fit over
the ears. Open models vent music to the outside; this can give better sound quality, but
at the expense of less noise isolation, and you’ll leak more music in the direction
of those near you. Closed headphones keep your music and the rest of the world further
away from one another. Again, Sony and Koss make many of the less-expensive models, Koss
being a popular favorite in particular because of their impressive warranty. At $69, the
Grado SR-60s are likely the least-expensive full-size headphones you’ll find
audiophiles raving about. Since they’re open, they’re not the best choice for
everyone, but the sound quality is good, and they play nicely even with the lower-powered
headphone amplifiers that many portables have. Sennheiser’s HD-202 is a great,
inexpensive sealed headphone to try at $30.
Headphones are one of those things you can spend just about
as much as you’d like on, with exotic electrostatic designs going for thousands of
dollars. The quality you get goes up fast to around $200, and there are many makes and
models to choose from. Generally, more expensive headphones require more power, and
they’re less likely to work well with a regular portable device such as a CD player.
Headphone amps
To allow use of better headphones in a portable system, a
few manufacturers make headphone amplifiers. These plug into the headphone jack of your
portable source device, and the headphones plug into the amp. You set the volume control
on the source to a medium point where it’s not distorting, then use the volume on the
amp to adjust from there.
The best-known amps for driving audiophile headphones are
the models from HeadRoom. Their
portable amps, which range from the $119 AirHead up to the $729 Cosmic, can provide
dramatic improvements in sound quality when used with difficult-to-power headphones. While
a few other manufacturers, such as Creek, make amps that you can use at home, HeadRoom is
the only company I know of that focuses on the combination of portability and battery
operation with the ability to drive high-quality headphones.
Slightly less portable: boom boxes, clock radios, and
powered speakers
If your portability goal is more along the lines of
something you can fit in your car rather than in your pocket, don’t forget that
headphones aren’t your only option. It’s possible to find decent-quality sound
for very little money in many portable boom boxes, and even in clock radios. I recommend
taking a CD you’re familiar with and visiting a store that will let you listen to a
few models to find one you like (during your comparisons, make sure the tone controls are
set to consistent positions). Something you might not think about initially, but that
seriously affects the long-term cost of boom boxes, are the batteries. If you plan on
running the unit a lot, consider purchasing rechargeable batteries -- the costs of buying
new D-cells can add up a lot faster than you might think.
If you’ve already got a portable source and just want
to be able to play it without donning headphones, a variety of powered speakers are
available, some of which can run off batteries. A good source for these devices is the
computer industry, where compact powered speakers are popular items. Companies such as
Labtec and Creative can add a small set of powered speakers to a CD player for as little
as $20.
At the high end, the computer-sound satellite-subwoofer
systems from such companies as Klipsch and Altec-Lansing fit some people’s definition
of portable, being sized so you can put them into a suitcase and haul them along with you,
but these normally run only on AC power.
Upcoming trends
The increasing computerization of portable devices means
that prices will continue to drop each year, even as storage capacity and playback time
increase. It’s hard to complain about that, unless you spent a lot of money last year
and want to cry when you see the better deals now available.
Now that entry-level CD portables can’t get much
cheaper, the new status symbol is becoming the portable DVD player. While these used to
cost more than $500, companies such as Initial now make full DVD units with 4"
screens that run off rechargeable batteries and include a car charger, all for less than
$200. The better DVD portables even sport digital outputs -- if you wanted to, you could
use them to drive a home-theater system.
...Greg Smith
|
