As you’re probably aware, connect a speaker to an amplifier with wires and you’re going to have power losses. Resistance due to wire length and gauge are the primary problems and there is no shortage of wire loss calculators available on the Internet.
Note that we aren’t talking about speaker impedance here (4 Ohm, 8 Ohm, etc.) nor are we talking about series or parallel connection methods. We’re simply talking about the voltage drop across long wire distances impacting the amplifier’s ability to generate sufficient output levels and dynamic range. This stuff is of particular interest when you’re designing distributed audio systems with long speaker wire runs.
The heavier the wire gauge (the smaller the number), the less loss there is across distance. Remember, lower numbers means larger wire gauge and heavier gauge copper means less resistance. To be safe, we recommend at least 16 ga. speaker wire, even for short runs.
Other general wire recommendations include:
- Use good quality wire – the cost difference between good and mediocre quality speaker wire isn’t all that much. We’ve seen many poor quality copper wires rapidly oxidize to a bright green state of corrosion. Not good.
- Use a known wire brand. There’s certainly no lack of them available.
- Use high quality terminations and solder connections where appropriate.
- It can be useful for long term reliability to “tin” bare wires with solder before inserting them into binding posts speaker connectors.
- Use a “real” wire stripper not a knife or pair of wire cutters to strip insulation. You’ll lose fewer stands of copper.
- As a general rule, don’t use electricians metal wire staples to attach wires to studs.
- Be sure to maintain phase, positive to positive, negative to negative. Get yourself a phase checker and use it.
70.7-Volt wiring
We’ve mentioned 70.7 volt distributed audio systems several times in past newsletters. Although there’s a slight compromise in fidelity using such systems due to transformer losses), there are several benefits as well.
Shameless Plug — Of course, using high quality transformers and excellent speakers like ours can mitigate these effects.) Among those benefits are reduced concern about wire length losses and speaker impedance issues. We recommend you use 16 gauge speaker wire for most 70.7 volt applications just to be safe and you can ignore the rest of the wire related concerns we’ve discussed here, other than wire and connector quality.