Subwoofer not responding
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=85533
Printed Date: April 28, 2024 at 9:21 PM
Topic: Subwoofer not responding
Posted By: bchoi414
Subject: Subwoofer not responding
Date Posted: November 12, 2006 at 3:46 PM
Hey everyone, I'm notororious for running into problems with audio and here again I share another. Hopefully everyone can help me out here. To begin, I have 4ch amp running the speakers with no problems, so now Ive decided to add a sub, powered by a mono amp (MRP-350). Heres a quick graph I sketched out with my wiring:  Once I tested it out...the subwoofer was not responding, but the speakers were okay. The mono amp was on (blue lit), however. I'm running an 10" Alpine Type R S1042. I set it up so that it would run 2 ohms. I followed the settings from the manual so there shouldnt be a problem there...I had the jumpers set accordingly:  Also, I could hear a little squeaky distortion with everything plugged...once I unplugged the rca from the mono-amp it was gone...so could it be bad rca cables? My friend gave me his spare Radio Shack rca (gold ends). I just wanted to use those for the mean-time. As for the sub...I doubled check the wiring (basic stuff) and everything looked good. I'm still a newb at this so please let me know if there is any more info I could provide. Any suggestions would be great, I really appreciate it. Thanks -Kevin
Replies:
Posted By: bchoi414
Date Posted: November 12, 2006 at 3:48 PM
This may sound stupid but the wires DO go in with the jumpers right? Because there isnt any other input I can find on the sub itself.
Posted By: DYohn
Date Posted: November 12, 2006 at 6:42 PM
Are you using any crossovers? Is the line-level output from your 4-channel amp full-range? ------------- Support the12volt.com
Posted By: mike12volt
Date Posted: November 12, 2006 at 7:14 PM
What kind of amps do you have? Some multi channel amps have 2/4ch. switch.
Posted By: bchoi414
Date Posted: November 12, 2006 at 9:01 PM
I have an Audiobahn A4004T 4 ch. amp. Yeah, not the best pick...but I got it for free. Heres the manual:
https://www.audiobahn.com/Audiobahn06/images/tech/Manuals/2004Manuals/Amplifiers/Intake%20amps.zip
I wish I could answer your questions DYohn but I'm not too sure myself. So is it possible that the audiobahn amp is not compatible with my alphine mono?
Posted By: boulderguy
Date Posted: November 12, 2006 at 9:18 PM
There's no reason why they wouldn't be compatible that I can see. First things first - take the RCA's from your 4-ch input & route them to the sub amp (IE bypass the 4 ch amp altogether) - does that get you sound?
You should tinker around like that & narrow down the possibilities of where the problem could be. Connect the sub to the 4-ch amp, try different RCA's, etc.
I'm betting it's a setting on the 4-ch amp that affects output on the passthru.
Posted By: astro88
Date Posted: November 12, 2006 at 9:23 PM
boulderguy wrote:
I'm betting it's a setting on the 4-ch amp that affects output on the passthru.
Thats what i figure too,run another set or y cables,crossover etc...
Posted By: bchoi414
Date Posted: November 12, 2006 at 11:51 PM
boulderguy wrote:
There's no reason why they wouldn't be compatible that I can see. First things first - take the RCA's from your 4-ch input & route them to the sub amp (IE bypass the 4 ch amp altogether) - does that get you sound?
You should tinker around like that & narrow down the possibilities of where the problem could be. Connect the sub to the 4-ch amp, try different RCA's, etc.
I'm betting it's a setting on the 4-ch amp that affects output on the passthru.
I will definetly try using a y-adapter through the input...the only thing i've done was run the rca from the HU directly to the mono amp but didnt even get anything...but I will try the other options you guys suggested and ill get back, thanks!
-Kevin
Posted By: bchoi414
Date Posted: November 13, 2006 at 12:13 AM
so I tried routing the rca...I'm still not getting anything from the sub. I originally have the rca's split for the 4ch amp since my HU only has one set of outputs. But all I did was left either ch 1/2 or 3/4 empty and plugged it into the mono amp instead but nothing. So I'm still clueless on this part...and another thing is...my speakers makes this distortion noise everytime the mono amp is connected too. I'll try messing around with other things and hopefully Ill get some kind of response
Posted By: DYohn
Date Posted: November 13, 2006 at 10:26 AM
Your mono amp may be toast. ------------- Support the12volt.com
Posted By: boulderguy
Date Posted: November 13, 2006 at 10:36 AM
Still unclear why your mono amp requires all those jumpers...What model is it again?
Problem solving like this requires you to eliminate as many links in the chain as possible. So next I'd wire the sub directly to the working amp to be sure it works.
If so, then it's your amp, either not working or not setup properly.
Posted By: bchoi414
Date Posted: November 13, 2006 at 8:28 PM
its the alpine MRP-350...and damn..amp toasted?? I,too, dont understand the jumpers but Im just following the configurations thats shown on my first post.
Posted By: DYohn
Date Posted: November 14, 2006 at 9:58 AM
It's not an MRA-F350 is it? If so it is not a subwoofer amp and will only function properly with certain Alpine head units. The MRP-M350 does not have any such jumpers. ------------- Support the12volt.com
Posted By: bchoi414
Date Posted: November 14, 2006 at 1:32 PM
Heres the link to the ebay auction I won
Yeah, it is the MRP-M350, not MRA-F350. When I opened the box it did include the jumpers. Should I avoid using it?
Posted By: pss5075104
Date Posted: November 14, 2006 at 1:40 PM
The amp sonuld not have jumpers the jumpers listed in the pictures are on a alpine type r dvc sub. the jumpers are used to series or parallel the voice coils.
-------------
D
MECP First Class Certified Installer.
Nothing is impossable, it's just more expensive.
Posted By: bchoi414
Date Posted: November 14, 2006 at 1:41 PM
Sorry, bad link...it wont let me display ebay links for some reason. But for sure it is a MRP-M350.
Posted By: DYohn
Date Posted: November 14, 2006 at 1:44 PM
That amplifier has inputs on one side and power/outputs on the other. It is a very standard amplifier. I have no idea WHAT jumpers you are talking about. There should be no jumpers on this amp. ------------- Support the12volt.com
Posted By: xtremej
Date Posted: November 14, 2006 at 1:59 PM
We just installed a mrp-m350 it had no jumpers, are you talking about the jumpers that come with alpine dvc subs?
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Posted By: bchoi414
Date Posted: November 14, 2006 at 4:21 PM
Ah Im really sorry. The jumpers are for the Alpine Type-R sub...sorry, I wasnt aware you were refering the jumpers to the amp.
Posted By: DYohn
Date Posted: November 14, 2006 at 6:35 PM
OK. So you have one woofer? install the jumpers as your owner's manual instructs for a 2-ohm configuration and connect this to your sub amp. If there is no output, disconnect it and try connecting the sub to one channel of your 4-channel mains amp (disconnecting the main speaker first.) If the sub now makes noise, it is OK, if not it is bad or your connection is bad. Try connecting any other speaker to the sub amp (keeping the volume low when you do this.) If it makes noise, the amp is OK. If not, the amp or the connections to it has a problem. ------------- Support the12volt.com
Posted By: bchoi414
Date Posted: November 14, 2006 at 11:48 PM
I connected the sub to the 4 ch amp and it works...so my only assumption is that the sub amp is bad...I plan on returning it. My friend told me that this may have happened because I didnt pull the negative cable out before working on the connections? Is it true?
Posted By: DYohn
Date Posted: November 15, 2006 at 11:26 AM
bchoi414 wrote:
I connected the sub to the 4 ch amp and it works...so my only assumption is that the sub amp is bad...I plan on returning it. My friend told me that this may have happened because I didnt pull the negative cable out before working on the connections? Is it true?
EBay strikes again. And yes, you should NEVER work on your vehicle's electrical system with the battery connected, and this includes the power cables for an audio system. ------------- Support the12volt.com
Posted By: sin0cide
Date Posted: November 15, 2006 at 11:34 AM
DYohn is right but he forgot to express a certain thing pertaining to electrical systems. Just because you remove the ground "wire" from the circuit does not mean the power wire is not live Yes you won't have power in the circuit but if you disconnect the power and touch it anywhere it will short circuit and you will pop the fuse if it is fused properly. Anyways my point is this remove the fuse from the power wire and then you won't have to worrie about anything.
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