necessary to replace OEM speaker wire with larger gauge?

I have been out of this arena for quite a while now but I remember a whole lot research was done by Electronics Australia when thick speaker wires first arrived.
The short answer is that once a certain size is reached increasing the thickness further has no effect.

I started to write a more detailed response on how loudspeakers worked and eventually thought:
http://en.wikipedia.org/wiki/Loudspeaker
and
http://en.wikipedia.org/wiki/Voice_coil

(doh). I will summarise though.

Electricity from the amplifier is fed through a coil of wire that is attached to the speaker cone. This voice coil is positioned inside a large magnet - floating as it were in a sea of magnetism. As the signal varies, the magnetic field generated by the voice coil changes. This reacts to the passive magnetic field and causes the speaker cone to move in and out, thus generating the sound waves that we hear.

But a speaker isn't passive - it doesn't just create sound, if you talk into a speaker it will actually generate an electrical current. (Does anybody remember those old press-to-talk intercoms where the speaker doubled as the microphone?). The other problem is that the cone has inertia.

The signal that initially moved the cone out of the speaker, now reverses direction and attempts to pull the cone into the speaker - but the inertia of the speaker actually generates an electrical current that opposes this 'request'.

This is not generally a problem as the amplifier can supply more than enough current to overcome the small current generated by the speaker.

But if the wire between the amplifier and speaker is too thin, if it has too much resistance, then distortions can arise. The question is how thin is too thin?

From a distortion point of view:
Most amplifiers have an internal output impedance of around 0.01 of an ohm (do check yours). So providing the resistance of the wire is less than that of the amplifier, distortion shouldn't be an issue.

From a current point of view:
A 100 watt amplifier running from a 12v power source causes a little over 7 amps to flow down the wire. Obviously if the wire has too much resistance then issues will arise. Since most speakers have an impedance of about 2 ohms, providing the wire has a resistance 100 times less than this; wire thickness shouldn't be an issue. 2/100 gives 0.02.

These are rough figures and personal preference may push the resistance of the wire down from 0.01 to 0.005 or less.

If the wire gets hot while you're listening to Metallica, the wire is too thin.

Hope the install goes ok.

Cheers
Warwick

 

In audio chat groups, speaker wires are just as hotly contested as tire pressures are, around these parts. I will only say that if your oxygen-free monster cables cost more than your speakers, that may not be a good sign

 

factory is like 22

i ran all new 16

i just couldnt put 60w rms throu 22

run new wire if your adding a amp

 

Audio wiring is a complex subject. Simplified, more power requires larger, lower resistance wiring to ensure that the speakers will perform at their best. Speakers are not just a resistive load. Impedance is a combination of resistance plus reactance (from inductors and capacitors in the crossovers) See: Home Toys Article - Speaker Impedance, Your Amplifier And You.

 

The more power you push, the larger the wire you need.
Amps, capacitors, sub's and the like, need a larger wire, you'll be better off in the long run. As for rewiring your speakers, you should be fine up to about 75 watts with the stock stuff, of course if it's easy to do, replace those wires with heavier stuff.