onhometheater.com's Guide to
Audio Connections
To continue on the subject of audio connections, we now tackle the least complicated but perhaps
most important of them all: the speaker connection. After all, if your speakers aren't
attached to your amplifier, you won't hear much of anything.
You’ll encounter speaker-connection hardware in three
places: the amplifier, the speaker cable, and the speakers themselves. One key to getting
good sound is to ensure that the contact between the amplifier or speaker and the cable is
secure.
With inexpensive A/V equipment, the interface between
connector and wire tends to be fairly tenuous. Usually, inexpensive speakers and receivers
will accept bare wire (or wire that terminates in a thin metal pin) in an indentation that
clamps its strands with a spring-tightened edge. This is called a guillotine or spring-clip
connection. Because the only point of contact between the speaker wire and the connector
is that knife-edge strip of metal -- and because these types of connector do not typically
accept cables of larger gauge -- there's not much contact, and it's not all that secure.
Even the slightest tug will disconnect your speaker wire from its receptacle.
That doesn't mean you can't get good sound from equipment
that uses spring-clips, but if you have a choice between a component that employs them and
another that uses a more secure termination scheme, opt for the latter.
Another "indentation"-type connection is the banana
socket. You won't find this connection on many contemporary A/V receivers or
amplifiers, but you might see it on some speakers. A banana plug is a 4mm
metal barrel that terminates a speaker cable -- it's called that because it's shaped sort
of like a straight banana. The banana plug is technically a spring connector, too, because
the barrel bulges in the middle to push against its cylindrical receptacle and thus make a
tighter, more secure fit. A banana socket houses that receptacle.
While few contemporary US A/V components have banana
sockets per se, many components can still accommodate banana plugs -- that's because the
most common speaker connection found in better-quality gear is the five-way binding
post. This connection uses a cylindrical nut that fits onto a hollow threaded post.
The post generally has a hole drilled through its base, which allows you to insert the
bare wire (or a pin connector) into it and then snug it tight -- or you can just wrap the
wire around the post and tighten the nut. You can also insert a banana plug into the end
of the threaded post, or use a bifurcated flat connector, known as a spade lug,
that passes around the threaded post and is cinched in place with the locking nut.
If you've been counting, you’ve probably come up with
only four ways to connect to a five-way binding post: pin, bare wire, banana, and
spade lug. This one always throws me, too, because bare wire counts twice: once for
insertion through the transverse hole in the bottom of the post, and once for
wrapped around the post. Seems like cheating, doesn't it?
The most common type of five-way binding post uses
color-coded (red for positive, black for negative) plastic tightening nuts. Obviously, if
you torque the plastic nut down too tight, you can crack it or strip its inner threads.
Some manufacturers use metal nuts so you can use greater force and ensure a more
substantial connection, but you’ll still have to be careful. Because the threaded
post is hollow and pierced at its base, it can be snapped right off your amp or speaker if
you get too enthusiastic about tightening it.
There are a few other, less common speaker connections.
There's a locking collar/post assembly called a Speakon, which is used more in
professional audio than in home theater (although a few subwoofer companies use them). And
a variation on the banana plug, called a Deltron connector, is sometimes used in
British products.
Because of European Union legislation, however, bananas and
Deltrons are increasingly rare in European A/V components. A new termination, awkwardly
called the British Federation of Audio connector, or BFA, is used instead.
It was designed to be incompatible with other types of plug because of fears that the 4mm
banana could also be inserted into some types of European AC wall sockets. If your
components sport BFA connectors, you must have your speaker cables fitted with BFA plugs.
If you've stuck around for my whole series on A/V
connections, you'll be happy to hear that, with this installment, I've covered them all.
Now all you have to do is go out there and get connected.
...Wes Phillips
wes@onhometheater.com
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