Need help with a speaker/sub setup

**smartass365** · 10-29-2009, 05:01 AM

Crutchfield has a good guide.

http://www.crutchfield.com/Learn/lea...de.html?page=3

With the meter set on the "v" with the straight line (dc voltage), you should read about 12-13.8v on the yellow all the time and same on the red when the ignition is on.

On the ohm setting (horseshoe) measure each speaker. The wires are usually the same color with a stripe or something on them. Like YES was saying, you should be reading about 4 ohms, but with dual voice coils like the speakers you linked to, you can only get 2 or 8 depending on how they're wired. To test the ground, use the same setting with one probe on the black wire and the other on a good bare metal surface (if you can't fine one, the seatbelt bolt will do)

As far as the speakers go, if you measure pretty close to two ohms on a speaker you should google series vs. parallel speaker wiring. Most head units can't handle 2 ohm speakers and the output protection kicks in. On the polar, 8 ohms won't be able to provide as much power as rated, so that could explain why you have to turn it up nice and loud.

**Senith** · 10-29-2009, 02:07 PM

Well i know its the speakers because i looked at all my wiring on my stereo and its perfect. I also took the speakers out from the back and i was able to raise my volume above 30 with no problem. So i believe the speakers are putting out more wattage than my car can handle and i dont know what how to fix that.

**soundman98** · 10-29-2009, 03:12 PM

Originally Posted by Senith

Well i know its the speakers because i looked at all my wiring on my stereo and its perfect. I also took the speakers out from the back and i was able to raise my volume above 30 with no problem. So i believe the speakers are putting out more wattage than my car can handle and i dont know what how to fix that.

ok, first speakers don't put out wattage, they are dumb devices-- they take whatever voltage/wattage you give them-- though 1/2 watts do anything, and 2000 watts will blow them.

don't just go over the wiring physically, check it with a meter set to volts or ohms, depending on what your measuring.

also check that the radio is actually grounded(disconnect harness form radio, and use ohm setting on meter and measure between harness ground, and a known good ground point-- should be near zero).

also, if the speakers negative leads are grounded, or combined, this can cause a issue with some radios-- each speaker should have its own positive and negative wire off the the headunit.

just becuase everything looks good doesn't mean it is-- i learned this the hard way-- it cost me a radio and 3 amps-- i had pinched a rca cable in the door sill re-installing the cover, and it slowly fried the rca connections on all of them-- and everythhing looked fine the entire time.

**kross** · 10-29-2009, 03:37 PM

Since you took the speakers out, check the resistance on them. Use the ohm setting on the meter (the Ω symbol). It should read around 4 ohms. Anything significantly lower (such as 2 ohms) would indicate a problem.

If the speakers are fine, and you want more volume, then you need an external amp. The amplifiers built into all headunits are only capable of putting out around 20-30 watts RMS. Your speakers are capable of handling around 100 watts RMS. (Always look at RMS wattage ratings, not peak ratings. The RMS rating is how much power it can put out sustained, without significant distortion, for amplifiers. For speakers, the RMS rating is how much power it can accept for sustained periods of time without damage.)

You can get 2-channel 100 watt RMS amplifiers for around $100 online. Of course, the wiring and installation can be tricky if you're new to this. But there are some good guides online we can point you to if you decide to go this route.

Hope this helps!
-- Kevin

**YESindeed** · 10-30-2009, 01:35 AM

yeah but test it where the speaker wires go into the stereo (with the harness unplugged) that way it will tell you if theirs a short.

**audiophyle_247** · 11-01-2009, 11:50 PM

2 things will cause that problem, both of which are wiring issues.

1. If the radio is not getting a clean & unrestricted power flow, it will shut down at high volume because it is not getting enough juice to power the internal amp & keep itself on. So when the internal voltage drops below 9v the radio will shut off. A poor ground or a high resistance between the battery & radio's power wire will do this.
Test the resistance (horseshoe icon as described above) between the black wire at the radio & the battery ground, and then test the resistance between the Yellow wire at the radio & the battery positive.

2. There is a short somewhere in a speaker wire, and at high volume there is enough juice running through the speaker wires to jump the gap. A short of this kind will always shut the radio off because it is going into protect to keep itself from shorting out the internal amplifier. These shorts are extremely hard to hunt down because 90% of the time just checking impedances with a dmm wont tell you anything helpfull, but are most common at connectors. I would look at the wires behind the radio, see if any of the connections have bare copper that could be coming into contact with metal. Also check the connections at the speakers, make sure the speaker wires are not contacting the speaker baskets, or any metal the speakers are mounted to.

The fact that unhooking the rears fixed the problem says nothing. Cutting the speaker load in half reduces power consumption by the radio, which could have been enough to keep the radios power supply from dipping below 9v, or it could mean that the wiring issue is with one of the rear speakers. Adding an amp will only fix the problem if the problem is the radio not getting enough juice, in which case it is an expensive bandaid. An external amp wont do anything if it is a speaker wire issue, it will just shut the amp off instead of the radio. (or blow the amp, depending on how good the amp's protection circuits are)