Subs cut out at LOW volume - Please Help!
09-18-2008, 03:52 PM
#1
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Subs cut out at LOW volume - Please Help!
Greetings!
Well.. after many hours of frustration and numerous phone calls, it is time to ask for help on the forums!! Thanks in advance to anyone reading this thread. Much appreciated.
Here is my problem: For the past few months or so, my subs have been cutting out at relatively low volumes. If I turn them up loud enough (about 1/2 max volume), they pound like crazy! It's just at lower volumes or songs with little bass that the subs seem to cut out or simply produce no sound at all. This is a new problem as I've had the system for nearly two years with no issues.
My setup: The sub amp is an Alpine MRD-M1005 1000w monoblock. It is powering two Alpine 12" type R subs (2ohm) in a sealed box. I also have a 4 channel Alpine MRP-F250 powering my speakers, but this amp has given me no problems. Both amps are connected to a 1.2 farad cap. Alpine head unit and speakers. Everything was professionally installed about 2 years ago.
What I have tried/checked so far:
I don't know what else to try.
My biggest fear is that the amp is on its way out... but it does work fine at higher volumes so I don't know. The local shops want ~$60 to run a diagnostic on the system but they will probably just tell me to replace the amp. Any suggestions or explanations are appreciated!! Thank you!
Well.. after many hours of frustration and numerous phone calls, it is time to ask for help on the forums!! Thanks in advance to anyone reading this thread. Much appreciated.
Here is my problem: For the past few months or so, my subs have been cutting out at relatively low volumes. If I turn them up loud enough (about 1/2 max volume), they pound like crazy! It's just at lower volumes or songs with little bass that the subs seem to cut out or simply produce no sound at all. This is a new problem as I've had the system for nearly two years with no issues.
My setup: The sub amp is an Alpine MRD-M1005 1000w monoblock. It is powering two Alpine 12" type R subs (2ohm) in a sealed box. I also have a 4 channel Alpine MRP-F250 powering my speakers, but this amp has given me no problems. Both amps are connected to a 1.2 farad cap. Alpine head unit and speakers. Everything was professionally installed about 2 years ago.
What I have tried/checked so far:
- All the connections are tight, including the ground
- There are no pinched cables
- I have confirmed that the head unit is working properly
- I tried replacing the RCA cables for the sub amp
- When the subs cuts out, both amps are still on
- I tried turning the gain on the sub amp down
I don't know what else to try.
My biggest fear is that the amp is on its way out... but it does work fine at higher volumes so I don't know. The local shops want ~$60 to run a diagnostic on the system but they will probably just tell me to replace the amp. Any suggestions or explanations are appreciated!! Thank you!
09-18-2008, 07:28 PM
#2
It sounds to me like your sub is probably NFG.. likley a bad solder joint/connection where the tinsel leads meet the coil leads.. at low voltage it's basically open... apply a bunch of volts and the current forces it's way through to the coil...
Try another sub and see what happens..
Try another sub and see what happens..
09-18-2008, 08:18 PM
#3
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Join Date: Sep 2008
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Hey thanks for the quick reply.
I have thought about that, but I have two subs in parallel... and their output is always identical. Are you saying you think they're both NFG or one is busted and its just affecting the other one too??
I have thought about that, but I have two subs in parallel... and their output is always identical. Are you saying you think they're both NFG or one is busted and its just affecting the other one too??
09-19-2008, 02:56 PM
#8
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Join Date: Feb 2006
Posts: 16,855
There is the possibility that you have a bad solder joint in an RCA pathway. I know I have this going on with my crossover right now on my right mid output - if I jam the volume the speaker comes on and will play for a while. Turn it back down for two long though and it cuts back out until I jam it again. extremely annoying.
09-21-2008, 09:03 PM
#9
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Join Date: Sep 2008
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Hey guys,
Thought I'd give you an update on the situation. I removed both subs from the box today to check for a bad connection but everything was tight and clean. The subs, from what I could see, were still in perfect condition and nothing appeared to be wrong.
Dukk, the issue you've described involving your right mid output... it sounds basically the same as my sub problem. If I crank the volume, I can get the bass to kick in but if I turn it back down for a few seconds, it starts to cut out and eventually turns off completely. Lately, I've actually noticed that the problem is becoming worse! It cuts out at higher volumes and faster then it previously did.
My guess at this point is that the issue is within the sub amp. The RCA output from the deck is working properly. The only other thing I can think of is removing the capacitor from the equation. It was a pretty cheap one off eBay so perhaps it is not delivering power like it used to.... however you think if that was the case, my 4 channel amp would also cut out along with the subs. I don't know.
Does anyone think that power could be the issue?? My civic battery is about 10 years old now and the cap is a cheap one...
Thought I'd give you an update on the situation. I removed both subs from the box today to check for a bad connection but everything was tight and clean. The subs, from what I could see, were still in perfect condition and nothing appeared to be wrong.
Dukk, the issue you've described involving your right mid output... it sounds basically the same as my sub problem. If I crank the volume, I can get the bass to kick in but if I turn it back down for a few seconds, it starts to cut out and eventually turns off completely. Lately, I've actually noticed that the problem is becoming worse! It cuts out at higher volumes and faster then it previously did.
My guess at this point is that the issue is within the sub amp. The RCA output from the deck is working properly. The only other thing I can think of is removing the capacitor from the equation. It was a pretty cheap one off eBay so perhaps it is not delivering power like it used to.... however you think if that was the case, my 4 channel amp would also cut out along with the subs. I don't know.
Does anyone think that power could be the issue?? My civic battery is about 10 years old now and the cap is a cheap one...
09-22-2008, 02:58 PM
#10
Administrator
Join Date: Feb 2006
Posts: 16,855
Nah, the cap or battery won't do that. If anything you would have issues at high volume. How you made a battery last 10 years though is amazing 
Try this - while the amp is cut out or playing low, unplug one of the RCAs. The sound will stay the same or cut out altogether. If it stays the same, plug it back in and unplug the other RCA. You should be able to see which channel is not seeming to work. Now, take the RCA that appears to work and plug it into the suspected dead side of the amp. By trying both RCAs in both amp inputs you will figure out if it is either one input of the amp that died, or if the amp is fine and one of the RCA channels is dead.
If it winds up being one of the RCA channels, move to the other end of that RCA (crossover or CDplayer) and play the same switch game to see if it is the cable or the deck/processor. At some point you'll find the dead lead.
And to think - people come pay me to do this
Try this - while the amp is cut out or playing low, unplug one of the RCAs. The sound will stay the same or cut out altogether. If it stays the same, plug it back in and unplug the other RCA. You should be able to see which channel is not seeming to work. Now, take the RCA that appears to work and plug it into the suspected dead side of the amp. By trying both RCAs in both amp inputs you will figure out if it is either one input of the amp that died, or if the amp is fine and one of the RCA channels is dead.
If it winds up being one of the RCA channels, move to the other end of that RCA (crossover or CDplayer) and play the same switch game to see if it is the cable or the deck/processor. At some point you'll find the dead lead.
And to think - people come pay me to do this
