Bridging subs

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=11515
Printed Date: August 17, 2025 at 5:29 PM

Topic: Bridging subs

Posted By: luxuryrules
Subject: Bridging subs
Date Posted: March 27, 2003 at 6:59 AM

OK, I have a Lanzar Vibe 420 amp and pair of JBL 12" subs. The amp is 4 channels, and i'm interested in bridging the subs, to run each sub from 2 channels. How do I do this? Last time, I tried splitting my rca signal to go into both line in plugs on the amp, then split the wires for the subs and plugged each sub into two channels. Somehow, my deck got fried in the process. I don't need to know what I did wrong, but what is the correct way to do this?

Replies:

Posted By: Powerslave0
Date Posted: March 27, 2003 at 8:02 AM

Does your amp have a BRIDGE option?

I have a KENWOOD, that is 400Watts, eight terminals (two sets of four), but on each set there is a BRIDGED indication, and shows you where to hook up two speakers, one on each set, instad of four (two on each set). Then you slide each side od the amp to BRIDGED. . .

I think there is a diagram here somewhere on how to bridge connections if the amp does not have the option.

Posted By: thepencil
Date Posted: March 27, 2003 at 8:34 AM

I don’t see how you can possibly short out your deck at all since you haven’t done anything other than plugging in the RCA cable. The only foreseeable accident you could have had is accidentally touch the blue/white wire on your head unit running to your amp, which is the switch wire to turn on your amp to some metal body of the car or on the amp itself.

Usually, an amp is bridged by connecting the speaker leads to the positive (+) terminal from one channel and the negative (-) terminal from the other channel. With the Vibe amp that you got, the connecting terminal to bridge is connecting the first and the fourth terminal to you first sub. Counting the terminal starting from the left side going to the right side. For your other sub connects the fifth and eighth terminal. Keep in mind that most amplifiers need to see a 4-ohm load when bridged to mono operation. When bridging an amplifier, use one 4-ohm speaker or, if you prefer multiple woofers, connect two 8-ohm speakers in parallel. Again, consult your manual before operating your amp in bridged mode. One final thing, do you have two sets of RCA cable (Front and Rear set) going from your head unit into your amp? If not, you will only get sound coming on to one side of your speaker.

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