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Sub(s) aren't working right

Old Apr 11, 2010 | 10:21 AM
  #1  
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Default Sub(s) aren't working right

i have two 12" alpine subs in a bandpass box, carpeted the whole deal you know..

there are two 300w alpine amps powering them..

i installed everything myself with the help of a friend but one of my subs isn't hitting as hard as the other. it's noticeable just by looking at it..

here's my sorry *** pic of how it's set up;
question is, wtf is wrong with my 2nd sub?



if this pic is any easier, colors aren't the same, hope it makes sense :X
 
Attached Thumbnails Sub(s) aren't working right-100_0107.jpg  

Last edited by Dontoh; Apr 11, 2010 at 10:41 AM.
Old Apr 11, 2010 | 10:32 AM
  #2  
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What alpine series subs do you have and are they dual voice coils or single.. also what ohms they suppose to be wired are ?

if you know much about subs and amps you can check out http://www.the12volt.com/caraudio/wo...igurations.asp

pick how many speakers you have and what ohm and coil they are and it will show you the possible ways to wire up the subs.. hope this helps you
 
Old Apr 11, 2010 | 10:39 AM
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i don't know anything about subs and amps.. but i can find out if they are dual voice or single and the ohms
 
Old Apr 11, 2010 | 10:46 AM
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alright, dug up what i could..

the subs:

Voice Coil: Dual
RMS Power: 500 W
Nominal Impedance: 4 ohm(s)

Power & Sound
Total Peak Power Output: 1500 W
Total RMS Power Output (4 Ohms): 500 W
Sensitivity: 87 dB
Nominal Impedance: 4 ohm(s)

the amps:
Details:
150 watts RMS x 1 at 4 ohms
300 watts RMS x 1 at 2 ohms

i also read that the amps are NOT bridgeable, could that be the problem? i dont know what the consequences would be
 
Old Apr 11, 2010 | 10:50 AM
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Yeah I would find out and then use that site to find out exactly how to wire the subs up. You might not have the subs wired up right inside the box. But at any rate anyone that helps on here will need more information about the subs and if them amps can even be bridged and such but ill check back on here later tonight.

edit... check this site up and match your wiring up and see if you have the subs wired right http://www.the12volt.com/caraudio/wo...2&I=42#results
 
Old Apr 11, 2010 | 11:18 AM
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I don't see how amp #2 is doing anything with no input! You must feed both amps with an RCA input. If your head unit has only one sub output, use a RCA Y connector to split it into two. Head units that have "left" and "right" sub outputs actually feed the same signal to both outputs, so you can use a dual RCA cable to the front of the car and plug one end into each amp. No need to worry about left and right.

Wire the dual voice coils of each sub in parallel to make it a two ohm speaker. Parallel wiring means you connect both + terminals on the speaker together and to the + output of the amp, same for the - side.

Bridging an amp is a way to operate a 2 channel amp as a single channel. Since you have one channel amps in the first place, there's no concept of bridging. Wiring the power, ground, and remote in parallel like you have done is correct-- but don't call it a "bridged" arrangement.
 
Old Apr 11, 2010 | 12:01 PM
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Originally Posted by mahoney88
Yeah I would find out and then use that site to find out exactly how to wire the subs up. You might not have the subs wired up right inside the box. But at any rate anyone that helps on here will need more information about the subs and if them amps can even be bridged and such but ill check back on here later tonight.

edit... check this site up and match your wiring up and see if you have the subs wired right http://www.the12volt.com/caraudio/wo...2&I=42#results
I didn't put the subs in the box or do that wiring. I bought the subs how they are, all the internal wiring was done and in working order when it was showed to me.. If I can't bridge these amps, how would I get power to both of them and such?


Originally Posted by mk378
I don't see how amp #2 is doing anything with no input! You must feed both amps with an RCA input. If your head unit has only one sub output, use a RCA Y connector to split it into two. Head units that have "left" and "right" sub outputs actually feed the same signal to both outputs, so you can use a dual RCA cable to the front of the car and plug one end into each amp. No need to worry about left and right.

Wire the dual voice coils of each sub in parallel to make it a two ohm speaker. Parallel wiring means you connect both + terminals on the speaker together and to the + output of the amp, same for the - side.

Bridging an amp is a way to operate a 2 channel amp as a single channel. Since you have one channel amps in the first place, there's no concept of bridging. Wiring the power, ground, and remote in parallel like you have done is correct-- but don't call it a "bridged" arrangement.
The second amp has no rca input, you're right, but it still has a small bit of bass when music is played.. It's weird, I disconnected the second amp, so only the first one had power and was connected to the first sub- but both were still playing, what could cause that? It seems impossible.

My head unit has 3 RCA ports. "F", "R" and "SW", I'm guessing, front, rear and subwoofer so thats why I was only using one RCA cable.. I had 2 sets of RCAS so I cut them up so I could put one end into the HU and the other end had 2 sets of RCAS- one for each amp.

I guess I misunderstood what bridging meant, but things still aren't working right.

Is there any way to troubleshoot? This is driving me nuts
 
Old Apr 11, 2010 | 06:36 PM
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Both subs are NOT playing, it's the air pressure from the first moving the second. You NEED a pair of RCAs going to each amp.
 
Old Apr 12, 2010 | 03:21 AM
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Originally Posted by Superfly
Both subs are NOT playing, it's the air pressure from the first moving the second. You NEED a pair of RCAs going to each amp.
that's what I was thinking, but it seems like its hits to hard to just be from the other amp..

so my problem is that my sub won't play if it's amp doesn't have rcas?
 
Old Apr 12, 2010 | 06:29 AM
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There is no signal going into the amp, so there will be no power coming out of it. The only reason the sub's cone moves at all is like the other guy said, air pressure from the one that does work since they're in the same box.

What is the model number of your amps? You can go to Alpine's website and download a manual for them.
 

Last edited by mk378; Apr 12, 2010 at 06:32 AM.

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