4 15s and 2 amps problems
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=127899
Printed Date: May 12, 2025 at 11:27 AM
Topic: 4 15s and 2 amps problems
Posted By: mofo15s
Subject: 4 15s and 2 amps problems
Date Posted: July 13, 2011 at 7:35 PM
I have 4 mofo 15s running on 2 boss ph5000d amps. i have it wired to run each amp at 2 ohms but it doesnt "hit" when both amps are hooked up. when i hook up all 4 15s to one amp running at 1ohm it sounds amazing. even when i run 2 15s on one amp it sounds louder then all 4 on 2 amps. i have no idea why when i try to run both amps something doesnt work. please help..
Replies:
Posted By: i am an idiot
Date Posted: July 13, 2011 at 9:52 PM
There is probably a phase switch or knob. One amp is on 0 and the other is on 180. Make them match, or reverse the plus and minus speaker wires at one of the amps. NOTICE I SAID SPEAKER WIRES.
Posted By: mofo15s
Date Posted: July 13, 2011 at 9:57 PM
Its all wired correctly, only thing i can think of is that both amps use up too much power. so im going to try a second battery. and the phase shifts and everything are right.
Posted By: i am an idiot
Date Posted: July 13, 2011 at 10:15 PM
When you run out of options, reverse the plus and minus speaker wires on only one amp.
Posted By: mofo15s
Date Posted: July 13, 2011 at 10:21 PM
could that hurt the subs or anything?
Posted By: i am an idiot
Date Posted: July 13, 2011 at 10:23 PM
Nope, audio is an AC voltage. The polarity of the signal is constantly changing. I would not give you any information that would damage your equipment.
Posted By: mofo15s
Date Posted: July 13, 2011 at 10:43 PM
ill give it a try. think it could be that the battery isnt giving enough power for both amps to hit?
Posted By: i am an idiot
Date Posted: July 13, 2011 at 11:08 PM
with both amps connected, play it at low volume, while it is playing, remove the RCA cables from one of the amps, does the bass increase or decrease when you unhook the cables?
Posted By: mofo15s
Date Posted: July 13, 2011 at 11:14 PM
at low volume it sounds decent. when i turn it up is sounds messed up..
Posted By: i am an idiot
Date Posted: July 13, 2011 at 11:19 PM
with both amps connected, play it at low volume, while it is playing, remove the RCA cables from one of the amps, does the bass increase or decrease when you unhook the cables?
In order for me to answer your question, I really need to know the answer of the above question. I need to know if the bass increases or decreases when you disconnect the RCA cable.
Posted By: KPierson
Date Posted: July 14, 2011 at 1:28 PM
It sounds like there is a phasing issue with the second amp....
 ------------- Kevin Pierson
Posted By: mofo15s
Date Posted: July 14, 2011 at 3:43 PM
the bass increases when i pull out the rca from one amp
Posted By: i am an idiot
Date Posted: July 14, 2011 at 4:50 PM
There is a phasing problem. Either switch one of the phase switches to 180, or switch the plus and minus speaker wires of one amp.
Kevin I need a nap, it's all yours from here on out.
Posted By: KPierson
Date Posted: July 14, 2011 at 7:49 PM
no no no!
-------------
Kevin Pierson
Posted By: mofo15s
Date Posted: July 14, 2011 at 8:08 PM
I tried switching one of the phase shifts and it didnt do anything. and so wire the negative to the positive terminal?
Posted By: i am an idiot
Date Posted: July 14, 2011 at 8:08 PM
On one amp, connect the positive speaker wire to the negative speaker terminal of the amp. Connect the negative speaker wire to the positive speaker terminal of the amp.
Posted By: mofo15s
Date Posted: July 14, 2011 at 8:15 PM
i wired the one backwards, it sounds better but the one amp wired at 1ohm pushing all 4 subs still sounds louder than running both amps at 2 ohms
Posted By: i am an idiot
Date Posted: July 14, 2011 at 10:16 PM
Do you have the cable needed to strap the amps together? Do not strap them, I just want to know if you have the cable.
Posted By: mofo15s
Date Posted: July 18, 2011 at 10:51 AM
Yes i have the data link cable. to make the amps into master and slave. im not using it though.
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