Amp Install, lacks power
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=32960
Printed Date: July 15, 2025 at 9:12 PM
Topic: Amp Install, lacks power
Posted By: Jay T
Subject: Amp Install, lacks power
Date Posted: May 29, 2004 at 10:42 PM
Just Installed an Alpine V12 MRV F307 with 2 10" JBL. Everything works fine except that there is virtually no bass coming from the subs. I"m thinking that it needs a bigger amp and that its not strong enough. Yes everything is wired correctly. I'm using OEM speakers and a Pioneer DEH 1400. When the volume goes up... the cab speakers max out and distort and i'm not getting enough from the subs, regardless of gain settings. There is little to no control on the head unit besides a bass setting. etc. Is it possible that the car isn't drawing enough power for the amp? its a 90 ford temp with a half ass battery. Its not really a big amp and he doesn't have any other draws of any kind. I'm stumped Any Thoughts????
Replies:
Posted By: Manoftools
Date Posted: May 29, 2004 at 11:06 PM
On that radio you only have one set of preouts, which means that it comes set up as either the fronts or the rears, I can't remember. You have to change it to sub control and you will be get only the lows. Also that amp is pretty weak no matter what setting it is at. That is just a fact of Alpine V12's, except maybe the mrdm1000 and 500.
Posted By: stevdart
Date Posted: May 29, 2004 at 11:15 PM
That amp will run smaller speakers but not enough power for subs. Bridged, it makes 80 watts X 2. So if you are using the OEM speakers off the deck, and using the Alpine 4 channel amp to power two separate subs, they are getting 80 watts each IF they each have an impedence of 2 ohms. If they each are 4 ohms, they aren't getting enough power to make much sound at all. So, how do you have the system hooked up?
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: auex
Date Posted: May 29, 2004 at 11:39 PM
Try this, unplug one of the subs and see if it gets louder. Does your deck have rca preouts or are you using LOC?
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Posted By: Ravendarat
Date Posted: May 29, 2004 at 11:47 PM
auex is on the same line of thinking as me I think. Try reversing one of the speakers. That is try reversing the negative and positive on one of the sub woofers and see if it gets louder. Mabye one of the subs is out of phase.
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Posted By: Jay T
Date Posted: May 30, 2004 at 12:19 AM
RCA's Have them bridged across the 1 & 2 , 3 & 4 4Ohms. i'll try to reverse phase and see if that helps but I don't think so. I'm going to check subs and re-wire 2 Ohms. I think the amps is just not what i need for this application.
Posted By: stevdart
Date Posted: May 30, 2004 at 12:27 AM
If they are 4 ohm subs, there is no way to make them 2 ohm. Either single or dual voice coil. Is each sub separate from the other, and each bridged to the amp? Edited- sorry, I see you answered that.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: Jay T
Date Posted: May 30, 2004 at 12:30 AM
yes. I was just looking at that. now what is the best way to wire these things for optimal power?
Posted By: stevdart
Date Posted: May 30, 2004 at 12:36 AM
That's tough. The way you have it wired now is the only way. That amp would be nice in a multi-amp situation to run tweeters. I would get another amp for the subs. Meantime, it's easy listening music.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: Jay T
Date Posted: May 30, 2004 at 12:38 AM
ok i'll wire the components to the 4/3/2 and i'll have to get a new amp for subs. thanks for the help guys
Posted By: italnpimp59
Date Posted: May 30, 2004 at 1:22 AM
maybe the subs are out of phase
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