Possible power issues w/ new system?
07-10-2005, 05:16 PM
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Possible power issues w/ new system?
I just finished an pretty involved install and for the most part everything is good, but I'm having one problem I hope somebody can help me with. I *think* I know what needs to be done, but i'm pretty much a car audio noob, so any advice would be great.
The system sounds great, but sometimes when I turn up the volume quickly or occassionally when listening at high volume for extended periods, the subs cut out. If I turn off the head unit and then turn it back on, the subs are back.
I'm running 3 amps w/ a class D for the subs (Alpine MRP-F240/MRP-T220/MRP-M350). The amp looks to be fine and doesn't seem to be overheating or going into protection mode. I suspect that the head unit (Alpine CDA-9851) is not getting sufficient power and is cutting out the bass channel. Originally I was pulling power for the head unit off the car's wiring harness. I ran a dedicated lead to the battery and that seemed to help the problem but not completely fix it.
Does my idea that it's a lack of power to the head unit make sense? or can somebody think of something else?
My thoughts are to do the big 3 and see what happens, but if anybody has a better idea feel free to chime in.
Thanks,
JC
The system sounds great, but sometimes when I turn up the volume quickly or occassionally when listening at high volume for extended periods, the subs cut out. If I turn off the head unit and then turn it back on, the subs are back.
I'm running 3 amps w/ a class D for the subs (Alpine MRP-F240/MRP-T220/MRP-M350). The amp looks to be fine and doesn't seem to be overheating or going into protection mode. I suspect that the head unit (Alpine CDA-9851) is not getting sufficient power and is cutting out the bass channel. Originally I was pulling power for the head unit off the car's wiring harness. I ran a dedicated lead to the battery and that seemed to help the problem but not completely fix it.
Does my idea that it's a lack of power to the head unit make sense? or can somebody think of something else?
My thoughts are to do the big 3 and see what happens, but if anybody has a better idea feel free to chime in.
Thanks,
JC
07-10-2005, 08:10 PM
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I would check your wiring for the sub. I can tell you this though, I highly doubt it has anything to do with the power at the HU. More than likely its a lose wire somewhere...
07-10-2005, 09:05 PM
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Originally Posted by darkknight1999,Jul 10 2005, 11:10 PM
I would check your wiring for the sub. I can tell you this though, I highly doubt it has anything to do with the power at the HU. More than likely its a lose wire somewhere...
07-11-2005, 04:37 AM
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Thanks guys, I will double check the wiring related to the subs tonight. I'm still puzzled though why bad/loose wiring would be correctable by turning off the system and then turning it back on. Probably one of the many things I don't completely understand about this stuff 
Will let you know what I find.
Will let you know what I find.
07-11-2005, 07:03 AM
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What could be happening is that you have a loose power wire and its going to ground every once in a while or one of the speaker wires is shorting on the other... then its goes into protection... then you shut off the system and it resets... then turn it back on and you hit another bump and it shuts off again... I would think its the wiring somewhere. Start at the sub and work back. Even the smallest strand of wire can send it into protection mode. So make sure you look at it close. The sub once turned back on can rattle the trunk enough to jump the wire around enough to short it out.
07-11-2005, 08:58 AM
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You mentioned subs. More than one, I assume? Any chance the voice coils are wired to less than 1 ohm? I know you said it doesn't look like the sub is going into protect mode, but having to turn off the head (which turns off the amps by proxy) makes me think it might be the resistance. Especially becuase it only happens after you have been running the system hard for a while.
07-11-2005, 09:26 AM
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Celeritas also makes a good point...
make sure your subs aren't wired to a load that is less than the rated load for the amp. my guess w/ an Alpine D-class amp would be anything less than a 2 ohm load.
(yup, checked... the MRP-M350 is only stable at 2 ohms and greater.)
so, check wiring, check resistance, and check for loose connections.
make sure your subs aren't wired to a load that is less than the rated load for the amp. my guess w/ an Alpine D-class amp would be anything less than a 2 ohm load.
(yup, checked... the MRP-M350 is only stable at 2 ohms and greater.)
so, check wiring, check resistance, and check for loose connections.
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07-11-2005, 07:18 PM
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What size power wire and ground are you using?
Based on the limited info you presented Im betting either you're running the amp at too low of an ohm load and/or you're clipping the amp by improper gain setting.
Is that the alpine amp with the digital gain setup or the regular potentiometers (use a small flathead to adjust by turning)
either way to simply verify either, meter the subs to make sure they are not below 2 ohms total at the amp, if so rewire accordingly if possible, or if thats correct and your gain is cranked pretty high, as well as the bass boost on the amp, turn them both down considerably and listen to it again at the same high volume. will not be as loud, but if it doesnt shut off you know the amp was clipping and all you need to do is readjust the gain settings.
If lowering the gains does not satifsy your bass craving, you have a couple of options...all will cost you more money though
You can add a line driver to step up the input signal, if the headunit you're using has a weak preout; you can get a bigger amp and all the necessary wiring upgrades with it, if the wiring you are using is insufficient. For example, if you're running 10 ga. now on the alpine amp, thats too small. Not too small to cause major problems, but if the amp is wanting to suck down the necessary current to satisfy your output requirements (a.k.a cranking the volume) and the wire isnt large enough to supply the amp quickly enough or with enough period, the wire then becomes the greater resistance and the amp will gradually start to get hotter over long periods of time and eventually go into thermal protection. Since you said the amp doesnt appear to be overheating, its probably just clipping from either too low of an ohm load from the subs or improper gain setting.
Always check the little things first.
Based on the limited info you presented Im betting either you're running the amp at too low of an ohm load and/or you're clipping the amp by improper gain setting.
Is that the alpine amp with the digital gain setup or the regular potentiometers (use a small flathead to adjust by turning)
either way to simply verify either, meter the subs to make sure they are not below 2 ohms total at the amp, if so rewire accordingly if possible, or if thats correct and your gain is cranked pretty high, as well as the bass boost on the amp, turn them both down considerably and listen to it again at the same high volume. will not be as loud, but if it doesnt shut off you know the amp was clipping and all you need to do is readjust the gain settings.
If lowering the gains does not satifsy your bass craving, you have a couple of options...all will cost you more money though
You can add a line driver to step up the input signal, if the headunit you're using has a weak preout; you can get a bigger amp and all the necessary wiring upgrades with it, if the wiring you are using is insufficient. For example, if you're running 10 ga. now on the alpine amp, thats too small. Not too small to cause major problems, but if the amp is wanting to suck down the necessary current to satisfy your output requirements (a.k.a cranking the volume) and the wire isnt large enough to supply the amp quickly enough or with enough period, the wire then becomes the greater resistance and the amp will gradually start to get hotter over long periods of time and eventually go into thermal protection. Since you said the amp doesnt appear to be overheating, its probably just clipping from either too low of an ohm load from the subs or improper gain setting.
Always check the little things first.
07-12-2005, 04:59 AM
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Hey all thanks for the input. I'm still researching 'cause we've had lousy weather here in Tampa.
Just to answer some questions, I've got 2 SVC 10's wire up at 2 ohms. I have been playing w/ my gain settings quite a bit as I try to fine-tune the setup. For wiring I have 4 gauge to a distribution block and then 8 gauge to each amp. I've also got the amp turn-on running off a relay. I have a 1F cap left over from my previous system which I didn't install here b/c I didn't think it really did anything. Is it worth installing here? It wouldn't be that big of a deal.
Also I'm going to do the big 3 re: of whether there's a power from the car issue or not. I figure it can't hurt and I can get the cabling for free.
I'll let you know when/how I figure out what's happening. Thanks again.
Just to answer some questions, I've got 2 SVC 10's wire up at 2 ohms. I have been playing w/ my gain settings quite a bit as I try to fine-tune the setup. For wiring I have 4 gauge to a distribution block and then 8 gauge to each amp. I've also got the amp turn-on running off a relay. I have a 1F cap left over from my previous system which I didn't install here b/c I didn't think it really did anything. Is it worth installing here? It wouldn't be that big of a deal.
Also I'm going to do the big 3 re: of whether there's a power from the car issue or not. I figure it can't hurt and I can get the cabling for free.
I'll let you know when/how I figure out what's happening. Thanks again.
07-12-2005, 05:14 AM
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Lets not start another cap thread....I dont think Shifty wants to get banned again. j/k There is a thread on here about capacitors, and views vary greatly. Do a search and it should come up. "MacGyver" I think knew the most about it and made some good points. As far as the amp cutting out, I am not sure, I would think the load would be the problem, but it obviously is not. Are you blowing fuses?
John
John