Quick help, please! Using factory wiring to speakers

[StuartV 10+ year member]

I had my Rainbow Germaniums installed on Saturday by a local shop. They're hooked up in an active config with the 6.5" woofers driven directly by a Carver amp that is rated for 100W x 2 at 4 ohms. This amp is fused with two 25 amp fuses. (The tweeters have their own Carver 90x2 driving them.)

The guys at this shop ran speaker wire from the amp into the dash behind the HU and spliced into the factory wiring harness for the door speakers and then hooked up the Germanium woofers to the factory wiring harness in the door.

This is in an '06 Ford F350 Crew Cab.

I saw that they had done this while they still had the dash all apart and I told them that I wanted it re-done with the speaker wires from the amps going all the way to the speakers in the doors, not using any of the factory wiring harness. I just checked (by looking inside the wiring boots that go from the cab into the doors) and verified that they did not do that.

I am about to take my truck back to them for them to finish a couple of other things that they didn't have time for over the weekend.

My question is, other than just "what I want", is there a professional justification that I can give them for why what they did is not right and that they need to fix it (so that the speaker wires go straight from the amps to the speakers in the doors)?

The factory wiring looks like it's 20 ga. or smaller and, personally, I think that I'm probably loosing sound quality there, but, more importantly, I'm concerned that putting the power I am into that wiring is going to eventually cause the insulation to melt or crack and I'm going to end up with a short or possibly even a fire under the dash.

Can any of you give me some real ammo to back up my position? Are there any standards that a pro shop should be going by that say that this much current/power should not be put through such small wiring?

Help! I'm leaving in about 30 minutes to take my truck back to them and I'd really like to have some facts to lay on them.

Click to read more...

 

[supraman1379 10+ year member]

Maybe they had a good reason to do it that way. But I would ask them if I were you.

 

[bikinpunk 10+ year member]

According to this chart, if you're running the wires about 10 feet, you'll need 6 guage for 50 amps power. Considering y ou'll only really use about 5 feet, I'd say 14 guage should be fine. But you can at least use this to show them that 20 guage won't cut it.

http://www.amplepower.com/primer/gauge/

 

[StuartV 10+ year member]

I did talk to them about it at length on Saturday, during the process of explaining that I really preferred it to be re-done. Their only explanation was that that is normal for how they do things and that it would be a pain in the butt to run the speaker wire into the doors.

The amp is fused at 25 amps per channel. If the amp has 45% efficiency, that means it could be putting as much as 11 amps of current through that 20 (or maybe even 24) ga. factory wire. That just doesn't seem safe to me. And, of course, the amps could possibly be a fair bit more efficient than that.

 

[project f-150 10+ year member]

You dont have to worry bout runnin so high of a current through the wire that you'll heat it to the point of failure causing a short or fire. The only downside to using that smaller guage will be a slight drop in speakers performance mainly in the midbass

 

[bikinpunk 10+ year member]

From IASCA Handbook: (go to section 2.3)

http://www.mobileaudio.com/rac-faq/

Length of run (in feet)

Current 0-4 4-7 7-10 10-13 13-16 16-19 19-22 22-28

0-20A 14 12 12 10 10 8 8 8

20-35A 12 10 8 8 6 6 6 4

35-50A 10 8 8 6 6 4 4 4

50-65A 8 8 6 4 4 4 4 2

65-85A 6 6 4 4 2 2 2 0

85-105A 6 6 4 2 2 2 2 0

105-125A 4 4 4 2 2 0 0 0

125-150A 2 2 2 2 0 0 0 00

 

[StuartV 10+ year member]

Thanks, Bikinpunk. Realistically, we're probably talking peaks of around 10 amps of current in each channel going about 15 feet from the amps (in the back of my Crew Cab) to the speakers in the doors. This chart indicates that I should 12 ga. for that.

That definitely oughta help my case!

Anybody else got any more info like this? I'm actually not sure what class the amps I have are, so I don't know what their efficiency is, so I really can only guess at what the actual current through the speaker wires will be. The amp in question is a Carver/KLW Audio KMOS 2200.

 

[snoopdan 5,000+ posts]

you let a local chop shop install rainbows?

//content.invisioncic.com/y282845/emoticons/ban.gif.ce8465566702ef9f72e97e794ed1c86a.gif

 

[StuartV 10+ year member]

I talked to them about it first and one of their guys has worked on SQ cars that have trophied at the Spring Break Nationals. Supposedly. He talked the talk, and I didn't have any better alternatives. I was not up for doing it myself.

Besides, as long as they address this one issue, what's the problem? So far, everything else looks decent. They used appropriate sized power wires and good quality cables. And, even though it's running through the factory wiring harness to the doors and I've only tuned it by ear so far (PXA-H701 w/Germs and a JL Stealthbox), it sounds pretty darn good already. I think I'm going to take it elsewhere, though, for proper tuning, with an RTA, etc..

 

[StuartV 10+ year member]

Well, gotta head over there. Thanks for the help, guys.

 

[KaeZoo 10+ year member]

You are entitled to ask them to run new speaker wiring into your doors. They are entitled to expect you to pay more for the service.

According to this chart, if you're running the wires about 10 feet, you'll need 6 guage for 50 amps power. Considering y ou'll only really use about 5 feet, I'd say 14 guage should be fine. But you can at least use this to show them that 20 guage won't cut it.
http://www.amplepower.com/primer/gauge/

Bikinipunk, that chart's designed to select a power wire size, not a speaker wire. While the physics are the same either way, you're mixing up input amperage with output amperage. 100 watts RMS into a 4-ohm load will result in 5 amps of current. For normal listening, the average will be considerably less.

 

[crow 10+ year member]

The main ammo you have is that you asked them to do it that way and they didn't do it. KaeZoo is right, though. Unless you specified that before they gave you the estimate for the work, you should expect to pay extra to run the wires to the doors. It's not that difficult but it is a bit time consuming.

I don't think you'll note much of a difference. I like to run new speaker wires mainly because I can use wire with a much higher build quality than factory and I can leave the factory wires taped off in the door if I ever want to go back to stock to sell the truck.

 

[BassAddictJ 5,000+ posts]

you let a local chop shop install rainbows?
//content.invisioncic.com/y282845/emoticons/ban.gif.ce8465566702ef9f72e97e794ed1c86a.gif

x2

lol i dunno about ban.....but i wouldnt let those greasy *****s touch my rainbows.......when i own a pair eventually one day lol

 

[bikinpunk 10+ year member]

You are entitled to ask them to run new speaker wiring into your doors. They are entitled to expect you to pay more for the service.




Bikinipunk, that chart's designed to select a power wire size, not a speaker wire. While the physics are the same either way, you're mixing up input amperage with output amperage. 100 watts RMS into a 4-ohm load will result in 5 amps of current. For normal listening, the average will be considerably less.

Didn't even catch that. Thanks for noting that for me.

 

[wesl56 10+ year member]

dude i live closeby i woulda helped ya install them and run NEW wires... stock wires are made to be cheap, not quality... and sometimes they run thru factory amps and all sorts of weird stuff... they should have most definitly ran new wires all the way for those, now if they were just like jensen speakers okay, but not those... thats just laziness... what shop was it??

another "justification" i can think of is... what does a stock headunit put out to the speakers? i know some of the new fords have the fancy smancy "mach" stereos but since you said the wiring was so small im guessing it was just the base stock system? well anyways... i dont know for a fact, but just think if an aftermarket deck only puts out about 15~20 watts RMS, what do you think a stock deck puts out? well its gotta be less than that and do you really think ford is gonna use bigger wire than it has to? hell no they use the smallest wire they can get away with to save money... why do you think doing the "big 3" upgrade helps? cause the factory uses the cheapest/smallest wire they can get away with... so that wire is just barely made to handle (hell ill go with 50 just to overestimate) 50 watts MAX.... and you're sending them 100 watts RMS (was it rms? i dont think u said)... but anyways, you can see that stock wire is absolutely not acceptable

the shop/installer should know this so they're either just lazy and dont care about thier work or they're just plain ghetto