4 ohm on dual 4 ohm voice coils
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=22332
Printed Date: May 11, 2025 at 1:40 AM
Topic: 4 ohm on dual 4 ohm voice coils
Posted By: flashalexb
Subject: 4 ohm on dual 4 ohm voice coils
Date Posted: December 04, 2003 at 10:23 AM
Is there a way that I can hook up a subwoofer that has dual 4 ohm voice coils at 4 ohms? Or is the only ways i can hook it up 2 ohms or 8 ohms?
Replies:
Posted By: flashalexb
Date Posted: December 04, 2003 at 10:31 AM
I want to know if i can do this because i had 2 Lanzar MXW12D subwoofers given to me. (dual 4 ohm voice coils) and one of them is now in the trash because it doesnt work. I have an Audiobahn A8002T amplifier and its 2x200rms at 4 ohms so if i can bridge this I can hook it up and it would be perfect for the subwoofer because the subwoofer max is 900 and the amp would be running at 800 max.
Posted By: bfog99
Date Posted: December 04, 2003 at 12:52 PM
When you compare an amp and a sub, don't look at the max powers. This will only be reached right before the amp melts or if you car gets hit by lightening. You want to look at the RMS output numbers. With your amp, the bridged output is 800 watts RMS probably at 4 ohms. The max for you sub is peak power. The RMS value is usually about 1/2 the peak value. I looked online, but can't find a RMS calue anywhere. For using this sub and amp combo, your best bet is to make sure you have a single input source. A good way to do this is to use a RCA Y splitter. This will take one input source and split it into the two that you would need. Then wire each voice coil to its own channel. This will give you the 200 x 2 @ 4 ohms, which is right about there the sub RMS is. Now, because the 400 watts RMS is a guess, I would be careful will the gain levels.
Posted By: Ketel22
Date Posted: December 04, 2003 at 7:15 PM
bfog99 that is a bad suggestion. wiring a voice coil to each channel can cause the sub to destroy itself. even with a source from the same place, the amp can have "mistakes" which will cause the voice coils to hit each other, not work together. I speak from experience because i originally had the same ideal and i blew a jlw3v2 within a week of using a setup like that.
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Quad L Handyman services
Posted By: bfog99
Date Posted: December 04, 2003 at 7:34 PM
I will disagree with you. I have done it many times, and I have also read where Bberman1 and I think Forbidden have suggested it too. If your voice coils are hitting each other, you have it wired wrong, or the source signal is not the same.
Posted By: Ketel22
Date Posted: December 04, 2003 at 8:01 PM
well we can advise all we want, its the user that decides no need to argue, both sides are out there ------------- Quad L Handyman services
Posted By: forbidden
Date Posted: December 04, 2003 at 8:39 PM
Now someone tell me how on one voice coil former, two coils can be hitting each other..... what can happen if a dvc sub is wired out of phase is the voice coil will want to go in two different directions at the same time, in other words it wants to pull itself apart. Now while the differences in output levels between the two channels of an amp are indeed present, it will no doubt cause problems for the subwoofer, thus it is NOT RECOMMENDED. It is definitely not recommended to wire a dvc out of phase between the two coils for the reasons above. Now there may be some exclusions to this as sometimes the difference between channels is extremely low, the amp is usually controlled by 1 gain for both channels, 1 crossover for both channels and both channels can be fed with the same mono signal. In a case like this you certainly can use a 2 channel amp to power a dvc sub in stereo mode. It is just not a favorite of mine for long term reliability. If the customer has to work with what he has for now, all the power to him, just do it right, but down the road a proper match of equipment is in his future. You guys are right, there are two sides to every issue, just be sure about your advice, even the best (not saying me cause I learn new things every day) can make mistakes.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: flashalexb
Date Posted: December 04, 2003 at 9:39 PM
I think I'm going to try and hook it up at 2 ohms. But my piece of sh*t audiobahn A8002T amp that i bought brand new (not referbished or anything) doesnt work so I have to send it back and wait for it to be repaired or for them to send me a new one. Luckily it was a authorized dealer where I bought it from and it has a waranty. And its good thing I have a amp to use as a back up. My friend is letting me borrow one of his. But yea If the sub breaks (hey it was free) Im planning on getting new subwoofers soon. Prolly around Christmas. Prolly 2 flameQ 12s. Thanx guys.
Posted By: bberman1
Date Posted: December 04, 2003 at 10:04 PM
forbidden wrote:
Now while the differences in output levels between the two channels of an amp are indeed present, it will no doubt cause problems for the subwoofer, thus it is NOT RECOMMENDED. It is definitely not recommended to wire a dvc out of phase between the two coils for the reasons above. Now there may be some exclusions to this as sometimes the difference between channels is extremely low, the amp is usually controlled by 1 gain for both channels, 1 crossover for both channels and both channels can be fed with the same mono signal. In a case like this you certainly can use a 2 channel amp to power a dvc sub in stereo mode. It is just not a favorite of mine for long term reliability. If the customer has to work with what he has for now, all the power to him, just do it right, but down the road a proper match of equipment is in his future. You guys are right, there are two sides to every issue, just be sure about your advice, even the best (not saying me cause I learn new things every day) can make mistakes.
Forbidden could not have said it any better
Posted By: Stevolon
Date Posted: December 05, 2003 at 9:58 AM
why does everyone want to try this 4ohm stereo thing with a dvc. it is exactly the same as series wiring the voice coils to 8 ohm and bridging the amp. safe and easy. i have mentioned this before but noone seems to listen. just do this and feed the signal normally into the amp. you dont have to y-off the imputs even.....Thank you forbidden for saying how unsafe the other way is.
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Steve@A.E.S
Posted By: DYohn
Date Posted: December 05, 2003 at 3:54 PM
Stevolon above is correct, and this is how I would also suggest using a single 4 ohm DVC sub with an amp that cannot handle a 2 ohm bridged load. Wire it at 8 ohms and bridge, presenting a net 4 ohm load on each amplifier channel. By the way, DVC does not mean there are two seperate voice coil formers, so nothing can "hit each other." It means there are two windings on one former. The problem of wiring in stereo (or or using seperate amps on each VC input) is that during those moments when the two channels of the amplifier are slightly out of phase with one another (and this will ALWAYS happen for small amounts of time, even with the best equipment and the most careful setup) the physical momentum generated by the two electrical signals will cancel each other and cause the VC to stop moving (momentarily.) When this happens, the electricity from the amplifier is disapated as heat and it is possible to burn out one or both VC windings.
Posted By: flashalexb
Date Posted: December 05, 2003 at 7:23 PM
Hey my friend just gave me his Lanzar rack series RK1000-4C to use while my amp is being fixed and every time i hook up both rcas the protection light comes on and the amp doesnt play. Howerver if i just hook up the right rca into the right rca input then it will work. Its a four chanel amp and i have it bridged into two channels. One channel going to each side of the voice coils. My sub it a Lanzar MXW12D It is dual four ohms. I tried using a y splitter and the same thing happens. Why will only the right rca work and does anyone have a clue on how many ohms its set at.
Posted By: forbidden
Date Posted: December 05, 2003 at 9:05 PM
Disconnect the speaker wires from the amp, then hook up the rca's, does the light still go on? If not then you may have a bad speaker (dead shorting) or a speaker wire going to ground between the speaker and the amp. If you take the right rca and hook it to the left input does the light stay on. Unbridge the amp and check each channel with the same speaker and same rca. Try all possible combinations.
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Top Secret, I can tell you but then my wife will kill me.
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