Sub wiring plus amp
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=71891
Printed Date: May 12, 2024 at 9:43 PM
Topic: Sub wiring plus amp
Posted By: hex0rz
Subject: Sub wiring plus amp
Date Posted: January 31, 2006 at 1:02 AM
Hey there all... I'm having some trouble on how to wire these subs to this amplifier. The wattage ratings and ohms dont make sense. I hope you can help! My sister has (2) Rockford Fosgate RFZ3812's, with a Dual XAF460 2/1 channel amplifier. I looked on the wiring diagrams and it said for two 8 ohm single voice coils, a parallel would be best. Well these subs were'nt wired like that. Each sub was going to a channel. But I dunno, because I reconnected them after I tried my system in her car, and they did'nt work. My sister was talking about how the subs would stop working and then would the next. I think her subs may be blown, because the new deck was supposedly the symptom to the subs problems. Because the older deck would always blow a fuse. The amp is running fine and the light stays a solid green. So I would think its the subs. I don't have a DMM or else I would see. I just dont understand how you wire 2 8ohm subs with each a 150 watt RMS rating... Ugh now I'm even more confused... ------------- Vehicle: Mazda B2200 1989 X-Cab
Audio System:
1. (2) MTX TA3401
2. (2) MTX Thunder 7500
3. (1) MTX TA3202
4. Eclipse Fujitsuten SC8264 Component series
5. Pioneer Premier DEH-P770MP
Replies:
Posted By: furflier
Date Posted: January 31, 2006 at 12:20 PM
Posted By: hex0rz
Date Posted: January 31, 2006 at 6:46 PM
:D Hey there. I viewed that page last night. That is why I posted a thread about this. Because I was confused. Originally the 2 subs had their own channel. So it threw me off track. But I talked to Car Toys, and they cleared things up. They reaffirmed my knowledge. Her subs are either going to be under or over-powered by the amplifier, depending on Ohm load... So I think she blew her subs. ------------- Vehicle: Mazda B2200 1989 X-Cab
Audio System:
1. (2) MTX TA3401
2. (2) MTX Thunder 7500
3. (1) MTX TA3202
4. Eclipse Fujitsuten SC8264 Component series
5. Pioneer Premier DEH-P770MP
Posted By: stevdart
Date Posted: January 31, 2006 at 8:41 PM
It sounds like the Duel amp is a two channel capable of bridging. Feed it a mono input, that is, the same signal left and right. Parallel the two 8 ohm subs together and bridge across the channels. The amp will output at its 2 ohm per channel maximum into the 4 ohm bridged load. You'll have to do some further testing of the gear to find out what is malfunctioning. If the subs were blown, they wouldn't work off and on...they just wouldn't work at all.
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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: hex0rz
Date Posted: January 31, 2006 at 11:42 PM
Well as of now, they don't work period. But it may also constitute because of me. But we'll find out... I'm thinking she either needs weaker subs or a stronger amp. Cause the way I see it when I do the numbers, it don't come out right. What I need, is the RMS range these subs will work at... All it tells me is 400 max output... And we all know how that goes... So correct me if I'm wrong. I will be wiring the subs into parallel. Which will bring them down to a 4 ohm load. Less resistance, more watt output. Then bridge the subs onto the amp. So then the amp is at a 2 ohm load on one channel. Now, someone care to enlighten me on amp and sub ohm matching? Because I always thought you had to match the ohms? And one other thing, If I wire them this way, will the subs be over or under powered? Because thats what I figure when the numbers are punched. Although, I'm still not sure... ------------- Vehicle: Mazda B2200 1989 X-Cab
Audio System:
1. (2) MTX TA3401
2. (2) MTX Thunder 7500
3. (1) MTX TA3202
4. Eclipse Fujitsuten SC8264 Component series
5. Pioneer Premier DEH-P770MP
Posted By: stevdart
Date Posted: February 01, 2006 at 12:52 AM
You don't "match" speaker ohms to amp ohms. Amps don't create an impedance load (ohms), speakers do. You just don't want to place a load on the amp that is lower than the amp's rated ability. The amp here is standard two channel, tested for output at 4 ohms/channel but is rated to handle 2 ohms without failure. A bridged load has to be at least double the lowest per-channel load rating of the amplifier...which is what I described to you above. It's probably unlikely that a Dual amplifier will overpower brand-name subs. But that's just a guess. You should look at the amplifier's rated RMS output into 2 ohms. It will be 2 X __ watts @ 2 ohms. That should be the amount of power that the pair of subs will receive. If it's too much you might think twice about using this combination of equipment. ------------- 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: hex0rz
Date Posted: February 01, 2006 at 6:49 PM
Aha! Well no more need for lecturing... I just wired them up real quick and hooked it up... They work great! (For her) I don't want to take any more risks of getting her subs blown so I keepin stuff down on her amp. I don't know how to really fine tune it with my ear... ------------- Vehicle: Mazda B2200 1989 X-Cab
Audio System:
1. (2) MTX TA3401
2. (2) MTX Thunder 7500
3. (1) MTX TA3202
4. Eclipse Fujitsuten SC8264 Component series
5. Pioneer Premier DEH-P770MP
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