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I'm getting ready to install a Subwoofer/Amp (JBL Bass Hub)

This unit comes with a 10-AWG for ground and power and appears to be Stranded wire made out of Alumnimum (really annoyed by this cost cutting).

My question is when I have to extend the power cable and ground the negative-terminal, should I go to 8 AWG ? or will there be no difference and just get 10AWG since these wires will be the weakest link (so to speak ?) I plan on getting a pure copper wire from Home Depot.

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2 Answers 2

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I am no expert when it comes to audio in vehicles. That said, you can not go wrong with larger wires and upgrading them from 10 AWG to 8 AWG will only help. The second thing to consider is, instead of just grounding the negative side, it is usually recommended you ground it directly at the battery by running a long lead for this. When grounding to the chassis (as it sounds you are headed to do) can cause interference and introduce audio artifacts into your output. I don't like aluminum for this either. Be aware of copper coated aluminum (CCA) when purchasing your replacement. If you are looking for the best power transmission, get pure copper wiring.

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House wire is not for cars

Cars are a much more demanding application (in different ways) and you should use SAE rated wires (Society for Automotive Engineers).

Cars vibrate and are subject to extremes of temperature and harsh chemicals. (not least, the crud on the road but also under-hood chemicals and battery acid).

That stuff is tinned copper. Not aluminum.

There's nothing wrong with it. It's tinned to make it easier to solder, because sometimes that is a correct splicing technique for cars.

Your mileage may vary on cheap Cheese junk received direct mail and not from a reputable seller. (3rd party sellers on eBay, Amazon Marketplace and wish.com are not reputable sellers).

By the way, in houses, there is nothing wrong with (larger sized) aluminum wire there, as long as it is properly installed on terminals rated for aluminum wire. (and torqued to specification, which we only figured out in the 2000s when copper wires kept failing the same way). None of this was done in the 1960s when aluminum was tried for small 15-20A branch circuits; hence the bad reputation. (for which we kind of owe aluminum an apology). #10 copper (30A) costs about the same as #2 aluminum (90A) so if someone asks about a 30-60A feeder I advise a 90A feeder. At that large size everyone agrees aluminum is OK. For houses. Small size aluminum is also legal, but impolitic - insurers hear that and assume it's a faulty 1960s era installation.

Don't fake your way through the Voltage Drop calculation.

People often go "I'll just increase the wire 1 size and pretend I did the calculation". That often ends badly. 12 volts is unforgiving when it comes to voltage drop.

There are many voltage drop calculators on the web. You need

  • the size of the wires
  • the length of the wires (many calculators assume round trip; if so, the actual voltage drop will be half what they claim).
  • The actual amps of the load.

If you have a mixed bag (two different sizes) then you need to do each section separately and add up the voltage drop.

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