[Superstroker1]

I have had a system in my truck for a little bit now and i didnt have my subs bridged so i decided to do that today but now i have a hum of the engine going through my system and it gets louder when i hit the gas any one that can help would be greatly apprecated

Thanks
Gib

 

[gregrob]

probably need to change to different spark plugs LOL

 

[Superstroker1]

ointlaugh:I tried that and it didnt work

 

[QtrHorse]

When you say your subs bridged, I assume you mean your amp/ amps? Did you move your RCA's or just switch the one connection so the amp would be bridged?

 

[THEDIESELMAN]

You don't have to move your RCA's around to bridge your subs and you don't bridge your amp you bridge your subs.

 

[QtrHorse]

You don't have to move your RCA's around to bridge your subs and you don't bridge your amp you bridge your subs.

Really, please explain to me how you bridge a sub? You bridge an amp by combining channels. For instance, if you have a 4 channel amp that puts out 100W per channel, you can bridge it to a 2 channel by combining all 4 channels and it will put out around 200W per channel. You do this by moving one of the speaker wire leads to the other channel. You can wire a sub down to different ohms but they do not call that bridging a sub. When I asked if he moved the RCA's, I was only meaning did he actually move them. Sometimes if you get them too close to the power wire, they will make engine noise come through. I combinded the sentences about moving the RCA's and bridging the amp by moving one of the speaker wires, my mistake.

Bridged Power
When you bridge an amplifier, you combine the power output of two channels into one channel. Bridging allows you to drive one speaker with more power than the amp could produce for two speakers. Because of this high power output, bridging is an ideal way to drive a single subwoofer.

If your amp is bridgeable, the owner's manual will have directions that tell you how. 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. However, you should be sure to consult your owner's manual before attempting to bridge your amp.

Also, keep in mind that most amplifiers need to see a 4-ohm load when bridged to mono operation. If you want to bridge your amp, you should use one 4-ohm speaker or, if you prefer multiple woofers, wire two 8-ohm speakers in parallel. (Again, consult your manual before operating your amp in bridged mode.)

 

[Superstroker1]

I bridged my subs when you have to subs you obvisly have two positive and two negative wires right so you take on of the positive to the left but put the negative wire of that sub to the right then vise versa

 

[QtrHorse]

That's not technically called bridging your subs. You may be changing the the ohms that the amp is seeing now. Most two or 4 channel amps are only good down to 2 ohm and most any mono amp is good down to 1 ohm. Look at the page below and put in how your subs are wired and what impedence they are. That will tell you what final ohm load they are wired down to. What subs do you have and are they a single 4ohm, D4, D2 or D1? I put a basic configuration in so you could see what it might look like. Also, what amp are you running them off?

Voice Coil Wiring Options

 

[THEDIESELMAN]

Yes you are right I was thinking about thinking about changing the ohms not bridging so what I said was wrong. Also why run a 2 or 4 channel amo for subs I have always just used a 1 channel amp for my subs.

 

[Superstroker1]

Im running two kenwood 12 inch 4ohms on a sony expload 950 watt 2 channel amp

 

[QtrHorse]

It can be cheaper and a smaller amp. For instance, if you had one or two 8in subs or even a 10in sub that did not require a lot of power (400W max), you could bridge a 200W 2 channel amp to get that. In most cases the 2 channel amp will be cheaper and smaller. Most mono amps put out full power at 1ohm, so a 1500W mono amp might only put out 400W @ 4ohms and a 200W 2 channel amp will put out the same at 4ohms and be 30% cheaper and about half the size. There are only a handfull of mono amps that put out full power at 1ohm, 2ohm and 4ohms. Most put out much less power at the higher ohm loads. I would run a mono amp for anything above 400W but I'm a firm believer in the more power, the better if you adjust the gains correctly.

 

[QtrHorse]

Im running two kenwood 12 inch 4ohms on a sony expload 950 watt 2 channel amp

I'm assuming they are single 4ohm subs? Did you find a wiring diagram on how you wired them up on the page I posted? You might have them wired too low for that amp. That can make the amp run hard and hum. If that is the case, you will kill that amp. That Sony amp is most likely only good for a 4ohm load. Below are the only two ways you can wire two single 4ohm subs together. Are they wired like either picture below?

Singl 4ohm wiring options

 

[THEDIESELMAN]

Im running two kenwood 12 inch 4ohms on a sony expload 950 watt 2 channel amp

It can be cheaper and a smaller amp. For instance, if you had one or two 8in subs or even a 10in sub that did not require a lot of power (400W max), you could bridge a 200W 2 channel amp to get that. In most cases the 2 channel amp will be cheaper and smaller. Most mono amps put out full power at 1ohm, so a 1500W mono amp might only put out 400W @ 4ohms and a 200W 2 channel amp will put out the same at 4ohms and be 30% cheaper and about half the size. There are only a handfull of mono amps that put out full power at 1ohm, 2ohm and 4ohms. Most put out much less power at the higher ohm loads. I would run a mono amp for anything above 400W but I'm a firm believer in the more power, the better if you adjust the gains correctly.

I didn't think of it like that .I have 2 DVC 12's 600 RMS 1200 peak and I run a 1500W mono at 1 OHM and with that right there it hits hard going to make a ported box for them and might even add 2 more subs and another amp if I can find some bucket seats to put in the back for cheap.

 

[Superstroker1]

I had it just like the wiring first diagram then a buddy of mine told me to do what i have done now bad idea i guess

 

[QtrHorse]

I had it just like the wiring first diagram then a buddy of mine told me to do what i have done now bad idea i guess

Always a good idea to never listen to what friends tell you to do. I would either put them back the way they were before and see if the humming is gone or buy the correct amp to get the load you want.

 

[Superstroker1]

ill change them back for now thanks for the help


Gib

 

[QtrHorse]

I didn't think of it like that .I have 2 DVC 12's 600 RMS 1200 peak and I run a 1500W mono at 1 OHM and with that right there it hits hard going to make a ported box for them and might even add 2 more subs and another amp if I can find some bucket seats to put in the back for cheap.

That is going to be tough to get 4 12's in a correct ported box in our trucks without actually removing the back seat completely. You will need a lot of cubic feet and a lot of port area. You would be surprised at how loud a correctly tuned ported box will get with just one 12in sub.

What subs and amp are you running? Do you have the subs wired down to 1ohm or .5 ohm? Are the subs D4 or D2?

 

[THEDIESELMAN]

That is going to be tough to get 4 12's in a correct ported box in our trucks without actually removing the back seat completely. You will need a lot of cubic feet and a lot of port area. You would be surprised at how loud a correctly tuned ported box will get with just one 12in sub.

What subs and amp are you running? Do you have the subs wired down to 1ohm or .5 ohm? Are the subs D4 or D2?

I think I'm just going to stick with the 2 subs in a ported box because it will be alot cheaper for me.

I have 2 Massive Audio CW 12's and 1 Massive Audio P1500.1 mono block amp and I have them wired down to 1 ohm. I don't know what you mean by D4 or D2 please explain.

 

[QtrHorse]

D4 is dual 4ohm voice coils and D2 is dual 2ohm voice coils. Two D4 subs will wire down to 4ohm or 1ohm and two D2 subs will wire down to 8ohm, 2ohm or .5 ohms.

 

[QtrHorse]

I just looked those subs up, they are D4. Nice looking subs. If you think about changing subs and are looking for something loud, you might consider the FI BL's. They are rated at 1000W and you can add quite a few different options to make them handle even more. Of course, there are tons of other options but the person that designs the FI subs (also the owner) used to be the person that did the designing for Resonant Engineering.