What is bridging??

[rock883]

I just got an amp and a sub and I think I know what bridging is, but I need some help. The amp is a 4-channel Kenwood and all I have is one 10" sub, does bridging mean putting like all the channels together for more power or what?? I want as much to go to that sub as possible also, I should switch the switches over to mono right?? and do I only need one RCA wire running from the head unit to the amp since it is going mono??, thanks for the help.

 

[Dignan]

It sounds like you have a basic idea, but if you need any help with the options (series or parallel) or anything just ask. My only concern is blowing the sub, how big is the amp and how much power can the sub handle? Don't forget that bridging the amp will reduce the resistence (ohms) and give you more power so be sure you amp can handle that.

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If everybody is different, how can anyone be normal?

91 Explorer XLT
4.0L OHV V6

 

[bstjnky]

Turn the gains down, hook the positive wire from the sub to the right positive input and the negative wire on the left negative input on one of the two sets off the 4 channel amp. You will have another set of channels to use, so hook them up to your front door speakers. Now adjust the gains accordingly. This setup will bridge two channels together and allow you to use the other sets for the highs. Just make sure your amp has a crossover and set it to 85 hertz on the low pass filter, and if you use the other channels set the crossover to either 85 hertz and up or no crossover for full range.

 

[bstjnky]

Oh yeah, to answer your ?, bridging is using one pos. input of one channel and one neg. of the other channel. This will lower your ohm load, usually from 4 ohms to 2. Since its a Kenwood, i'm almost sure it'll handle it. If it doesn't it will shut off due to overheating and you then need to reconfigure your hookup. If you have any questions just post here and I'll help you if I can. You will need 2 sets of RCA wires if you plan on using the other channels of the amp, but only one (left and right, usually red and white) if your only using the amp to power the sub. What kind of sub is it, and what is the model number of the amp so I can help you more?

 

[rock883]

Ok, thanks for the responses. In response about the sub and amp power, the sub is a Pioneer and it says 350 watts on it, so it can handle 350 RMS. And the amp. I don't really think it is really powerful, and the model number for the amp is KAC-742. Now I know the wiring for the remote lead, battery, grounds, and the RCA cables, and basically get the idea of the bridging. But I have one more question about the RCA cables. Now you (bstjnky) said that I will need to hook up both the RCA plugs even though I am only running one sub? Also, which side do I plug the RCA cables into if I bridge it, the A channel or the B channel or does it matter? Thanks agin for all your help.

 

[Dignan]

If you only hook up the one sub you could just hook up the white RCA (left channel). If you do have trouble with the amp heating up (which you probably won't with a kenwood) then use a fan and it should stay cool enough to run bridge. I'm running my subs with a rockford fosgate amp at 1 ohm so I'm sure your kenwood will handle 2 ohms.

------------------
If everybody is different, how can anyone be normal?

91 Explorer XLT
4.0L OHV V6

 

[Kenneth Walsworth]

Just to clear up some things. Bridging an amp doesnt change the "ohm load" but rather adds another channel with the same current limitations. Lets say the one channel has a 20Vrms (yes volt) max output and is limited by design to 10A of current. A 4ohm load would yield a current of 5A and a Wattage of 100W (20^2/4). The current is determined by the load (unless your amp is current limited then it adjusts Vmax accordingly) therefore when you apply a 2ohm load your amperage is 10A and wattage is 200W on that channel. When you bridge two channels the current limitations are the same for each channel and the voltage is doubled (40V). With a 4ohm total load applied across both channels your wattage would be 400W and current 10A. If you applied a 2ohm load to this bridge the current would be at 20A which is beyond the capacity of one channel. This is why your amp will handle a 2ohm load per channel or a 4ohm load bridged.

Something to consider...

When you increase your load (lower the resistance) you also decrease your dampening factor of the amp. The dampening factor is the ability of the amplifier to control the speaker. This can result in bass that is not tight sounding because the amplifier is fighting the inertia of the cone as it excurts.

-Ken

 

[rock883]

I got it all hooked up!! I didn't bridge it, I just wanted to see if it would be fine, and I think it sounds great!! Its not extremely loud, which I didn't want, but it sounds good. Although, I can hear a lot of stuff, besides bass, coming from the sub and I will probably go get a crossover pretty soon. How hard are those to install? Also, I noticed that my cd player was gettin a little hotter than I have felt before, but I did keep it running while ran all the wiring for the amp and when I hooked it up I listened to it for a while, then I went out somewhere and I haven't had it off a long time since I started all the stuff (about 4:00 today) is it just hot cause of the long use or is it the amp? Also, I hooked up the cable to the battery, and I also hooked up that blue one (remote somethin??), will I be able to start it up tomorrow morning before school? Thanks for all of your help everyone.

 

[Dignan]

It is probably just hot because it was on for a long time.

You said that you hooked it up to the battery. That is fine, but with mine I hook all of my accessories to the little block that the positive cable goes to (sorry I can't think of what it is called right now, just follow the positive cable and you'll see what I'm talking about). It protects the wires from the corrosion surrounding the battery terminals.

------------------
If everybody is different, how can anyone be normal?

91 Explorer XLT
4.0L OHV V6

 

[rock883]

Yeah it was hot because it was on so long, cause today it was just fine. I also did get it started this morning, so everything got hooked up right and all, thank God. Thanks for the help.