wiring two speakers, you
have two choices as to final
impedance: double or half
the impedance of each.
So, let’s look at a decoder that
likes 8 ohms, but will toler-
ate 4 to 16 ohms. If you are
really lucky, the speaker size
you planned on will be avail-
able in a 4-ohm version. Since
LokSound has designed their
decoders for a 4-ohm target,
there are more and more 4-
ohm speakers showing up in
the DCC shops. That’s great.
Wire two 4-ohm speakers in
series and you have 8 ohms,
as shown in (7). Note that the
connection between speak-
ers goes to the marked termi-
nal on one speaker and the
unmarked terminal on the
other. This is how the speak-
ers are wired in figure 5. Don’t
worry; there is a capacitor
between the two speakers
instead of a wire, as the older
decoder needed a capacitor.
Modern decoders would just
use a wire.
If you cannot find a 4-ohm version of your desired speaker,
then use an 8-ohm version and still wire them in series. This
will give a 16-ohm load that is usually better for the decoder.
DCC Impulses Column - 6
of sound” worked better than the point source located in the
middle of the flat car in this instance.
Speakers are usually marked as to polarity. If you look at the
terminals on the (identical) speakers you are installing, you will
probably find some mark next to one of the terminals. It may
be a drop of paint or a variation in the shape of the terminal
or something. Absent any other indication, just line the speak-
ers up on your workbench, cone side down with the terminals
facing you. Take a marker and put a dot next to the terminal on
the right. Now you have a mark to use in wiring the speakers.
Two speakers
Be sure to know the allowed range of load impedance before select-
ing and wiring two speakers. Why? As I mentioned previously, when
7: Two speakers wired in series – the final impedance will
be twice the speaker rating – 8-ohm speakers yield a 16-
ohm load or 4-ohm speakers yield an 8-ohm load.
8: Two speakers wired in par-
allel – the final impedance
will be half the speaker rat-
ing – 8-ohm speakers yield a
4-ohm load.
8
7
MRH-Jan 2014
