An Introduction to
Tuners
While Napster has been making all the headlines, free music
is really nothing new -- after all, we’ve had radio for years. Almost everyone
recognizes that radio is a free and expansive music resource. In fact, if you have the
right broadcast and associated equipment, radio broadcasts can even be considered a
high-end medium.
To receive a radio signal in your system you need a tuner.
A tuner can be a separate component in its own chassis or it may come built into an
amplifier. In the first case, it's simply called a tuner; if it comes in an all-in-one
amplifier unit, the whole unit -- amp and tuner together -- is called a receiver.
Before you go out and buy a tuner or receiver, you may wish to know a few things that will
help you determine what kind of tuner is right for you.
Tuners differ from other audio source components in the way
they receive their music signal. CD players produce an analog signal from what might be
called a "hard" medium -- the compact disc, a music source that is physically
present in your system. Obviously, that is not the case with tuners, which lock onto
signals in the air. The radio station that’s broadcasting probably is using a
compact disc (or tape or LP), but your tuner receives its signal from the air (although
radio can also be received from other sources such as cable or satellite).
For many years we had only two types of radio stations, AM
and FM. AM stands for amplitude modulation. FM means frequency
modulation. It's not necessary to discuss the technical details of how each works now,
but as an audio enthusiast you should be aware of both and also know that FM broadcasts
are considered to be much higher quality and are, really, the only reason to carefully
pick your tuner. This is because FM's frequency response (or bandwidth) is much wider, so
you have better highs and lows. Also, in the old days, AM wasn’t even available in
stereo. Frankly, even in stereo, AM is so low fidelity that if you only want to listen to
AM radio with your tuner, you might as well skip the rest of this article and simply buy a
table radio.
For FM buyers, it’s important to note that many tuners
are AM/FM capable (particularly in receivers), so you get the AM as sort of a bonus. But,
there are some higher-end tuners that are dedicated to FM only.
Today there is also another option everyone should know
about. Digital Audio Broadcasting (DAB) is a new type of radio source that encodes
the signal -- you guessed it -- digitally. Since DAB is new, some countries are further
ahead in its development and deployment than others. For example, in Britain the
technology is well established, with an increasing selection of digital programming and
radios available, and companies like British-based Arcam have developed considerable
expertise in the design and production of digital radio products. The Arcam website has
some useful information about the technology and the products they’re developing (www.arcam.co.uk/support/digitalradio/index.cfm).
If you want to learn more about DAB in general, another good place to go is the World
Forum for Digital Audio Broadcasting (www.worlddab.org).
Just as the CD took over from the LP, it’s likely that DAB is going to slowly take
over from AM and FM radio broadcasts. Even so, it won't happen overnight.
So, what we have is AM, FM, and DAB. As noted above, if you
are only interested in AM, then there's no point in spending too much time or money on the
decision. Although you can receive AM in stereo today, it is still too low fidelity a
source to be considered seriously. FM and DAB are where the serious sound lies, and there
is plenty to know and to research before you buy a product or make any type of investment.
For example, you need to know if there is a high-quality FM
station in your area. This is important because FM broadcasts don’t carry nearly as
far over the air as do AM broadcasts. Does your local station broadcast the type of music
you like? Are you in a good area to receive the broadcast or are there impediments that
can restrict the quality of the signal? Will the station continue to operate in FM for
years to come? The last question is an interesting one since DAB is being adopted more and
more worldwide. For example, when our publisher, Doug Schneider, was in Germany, this
spring he attended a press conference where it was explained how traditional radio
broadcasts would be phased out in that country over the upcoming years and DAB phased in.
DAB may not be the answer for you just yet, either. Is DAB even available where you live?
And when will it be?
In the next two installments of this column I’ll
discuss some other people’s theories on how to buy a FM tuner since the option to
receive FM is still very viable for some listeners. And then we’ll delve more deeply
into the wonderful new world of DAB.
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