Subwoofer & Amp Wiring
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=69237
Printed Date: July 19, 2025 at 5:19 PM
Topic: Subwoofer & Amp Wiring
Posted By: pdmech73
Subject: Subwoofer & Amp Wiring
Date Posted: December 26, 2005 at 8:01 PM
This is my first time here, so I'm not quite accustomed to how things run here. Bare with me. I will provide the link to similar pictures of what I have. This is my equipment: 2 Audiobahn 12" AW1251T, 2 single 12" subwoofer enclosures, Polk Momo C300.2 amplifier Amplifier Specifications: https://www.polkaudio.com/caraudio/specs/amps/c300_2/ Subwoofer Specifications: https://www.cardomain.com/item/ABNAW1251T Subwoofer boxes: https://www.electronicsoutpost.com/images/psolo10_12_15.jpg This is what I want to see will work: I have 2 single boxes, 2 subwoofers, 1 2-channel amplifier. I want to bridge the amp at 4 ohms. How do I wire the subwoofers? The subwoofers are dual voice coil and 4 ohms (can be 2 ohms or 8 ohms depending how you wire them). Do I wire the subwoofers in series each (8 ohms) and then parallel at the amplifier? Thanks guys, -Paul
Replies:
Posted By: geepherder
Date Posted: December 26, 2005 at 8:05 PM
Yup, series the coils, and parallel the subs at the amp.
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My ex once told me I have a perfect face for radio.
Posted By: pdmech73
Date Posted: December 26, 2005 at 8:33 PM
Sorry, I'm a newbie at car audio. Just for clarification- each subwoofer will be in a single enclosure, each dual voice coil will be wired in series (8 ohms). Together, both subwoofers will be 4 ohms. If I bridge the 2-channel amplifier, it will be 4 ohms. The subwoofers 4 ohms will match the bridged amplifiers 4 ohms? I want to make sure the RMS on both subwoofers match with the amp. The amp states 450watts rms bridged and the subwoofers are 400rms. Perfect match? You guys sure do respond quick. Thanks again guys, -Paul
Posted By: geepherder
Date Posted: December 26, 2005 at 8:36 PM
Yup, that's what I meant.
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My ex once told me I have a perfect face for radio.
Posted By: speedwayaudio1
Date Posted: December 27, 2005 at 6:35 AM
 Each voice coil will get 112.5wrms. A perfect match would be a 800wrms @ 4ohm amp. Each sub would get 400wrms. Each voice coil would get 200wrms. ------------- Big Dave
Posted By: pdmech73
Date Posted: December 27, 2005 at 11:36 AM
The diagram you showed is a series/parallel design right? My question is- Is it possible to wire the subs like the diagram when I have 2 single 12" enclosures?
Posted By: speedwayaudio1
Date Posted: December 27, 2005 at 5:37 PM
yes it would be the same. just follow the diagram
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Big Dave
Posted By: pdmech73
Date Posted: December 28, 2005 at 1:29 AM
This the current setup I have in my truck. I am wondering how much RMS power am I actually getting? This is my equipment: 1 Audiobahn 12" AW1251T and 1 Polk Momo C300.2 amplifier. The sub is a dual 4 ohm voice coil that is wired in series (8 ohms). The amplifier is unbridged. Unbridge the amp is 220 rms watts x 2 (2 ohms) and 150 rms watts x 2 (4 ohms). Amplifier Specifications: https://www.polkaudio.com/caraudio/specs/amps/c300_2/ Subwoofer Specifications: https://www.cardomain.com/item/ABNAW1251T Thanks, -Paul
Posted By: stevdart
Date Posted: December 28, 2005 at 1:45 AM
This two-channel amp is unbridged? And you have the voice coils connected in series...so....what are you doing, using one channel for this sub? The specs for this amp show output rated at 14.4 volts at 1000 Hz. This output will go here and there from that point across the frequency range. What is it outputting in the sub frequency range? We don't know. And will your car's electrical system be supplying 14.4 volts during play time? We don't know that either... You should know that when amplifier specs are provided in this manner that this would be a best-case scenario and that your actual results will be less. Just FYI, if you want to figure the output into an 8 ohm load by using the rated specs into a 4 ohm load, just cut the rated specs in half. Doubling the impedance load will halve the output. If you intend to use these pieces of gear together, bridge the 8 ohm load across the channels. Using the rated specs, the output would be 150 watts. If you want to figure what it would be if the electrical system were supplying an actual 12 volts, just figure wattage per volt. 150 / 14.4 = 10.41 X 12 = 125 watts. You can read actual input DC voltage using a meter at the amp. ------------- 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: geepherder
Date Posted: December 28, 2005 at 7:35 PM
Actually, steve, in order to find the output, you'd have to play a test tone, and measure ac voltage at the amp's speaker outputs. Then you'd square it, and divide by the ohm load. If you did it your way, it wouldn't be accurate since wattage isn't linear as input voltage changes- the higher the voltage into a given load, the more amperage also, meaning a more than proportional increase in wattage.
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My ex once told me I have a perfect face for radio.
Posted By: pdmech73
Date Posted: January 14, 2006 at 1:19 PM
My friend kept arguing with me about the way to wire my subs. I gave in and wired it "his way" which is the one in the diagram I have drawn. That doesn't look like 4ohms bridged. I think it should be wired the way you guys were telling me which is- 
Basically, I just want to bridge my amplifier and have everything work out to be 4ohms to produce 400watts rms. Which is truly the right way? Thanks again guys, -Paul
Posted By: pdmech73
Date Posted: January 18, 2006 at 6:31 PM
Posted By: Hornshockey
Date Posted: January 19, 2006 at 1:00 AM
the first diagram you have will produce 16ohms, the second one will prodice a 4 ohm load on the amp. You can proceed with rubbing it in your friends face  ------------- Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.
Posted By: downstarinc
Date Posted: January 19, 2006 at 1:48 AM
everyone has that friend...hes pretty popular.
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jl audio..nuff said
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