Author Topic: Trouble Shooting suggestions?  (Read 2156 times)

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Offline fuzzy

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Trouble Shooting suggestions?
« on: April 12, 2014, 03:00:09 am »
Hey guys, I recently ran into some subwoofer installation issues. I havent installed a car stereo in any of my vehicles since high school days, so im a bit rusty.  O0

Either way, a few months ago i picked up a single din Kenwood deck, MRP m500 Alpine amp, TS-SWX251 10" pioneer subwoofer and wiring and all the bits and ends.

So yesterday i got around to installing it. I triple checked everything i could, powered it up, and it sounded alright for the first 20 seconds. Once i turned the master volume up slightly the subwoofer cut out, the amp was still receiving power (blue LED was glowing). I wasnt able to get any signal from the subwoofer until i restarted the head unit. The second time around it did the same thing.

Some of the troubleshooting ive done so far...
-Rewired everything
-checked the ground
-checked the resistance at the ground (indicated next to nothing)
-adjusted all the options i could in head unit's settings
-adjusted the settings on the amp (gain, frequency etc...)
-opened up alpine unit to see if anything is damaged (looked clean)
-Went out and bought a new amp.

After installing the new amp, i was able to generate sound out of the subwoofer and adjust the volume and settings on the headunit without having the subwoofer shut off permanently. But the sound wasnt deep or loud enough, so i adjusted the gain and frequency slightly. after doing so, the amp blew the fuse. I should mention that before and after adjusting the settings it was barely noticeable that there was a subwoofer installed in the vehicle. This amp was only 50 watt underpowered than the alpine.

As oddly as it sounds, im starting to think its the Kenwood deck thats causing all this. Ive read in the other forums that some decks just arent compatible with certain amps, and will force it to go into the protection mode, no matter what type of volume youre trying to pump it at.

 On top of all this, ive noticed that my back speakers wont play anything when im using the Bluetooth feature however, AUX and CDs have no issues with my back speakers.

Anyways, im now losing my F***ing mind over this, as ive spent over 7 hours trying to figure this out and i still dont have a solution. Im really hoping someone can suggest something. I already narrowed it down to the fact that either the amp, or the head unit is faulty. i just cant figure out which one it is. Already thinking of going out and just purchasing a Brand New set up, but would like to figure out whats wrong with this one, as it wasnt the cheapest choice of hardware.



Offline fuzzy

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Re: Trouble Shooting suggestions?
« Reply #1 on: April 12, 2014, 03:08:39 am »
I own a 1998 subaru impreza WRX.
Its completely stock
I used a harness to connect the stereo (no jerry rigging was done here)

Offline jvd

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Re: Trouble Shooting suggestions?
« Reply #2 on: April 12, 2014, 08:39:35 am »
What deck are you using?

Offline fuzzy

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Re: Trouble Shooting suggestions?
« Reply #3 on: April 12, 2014, 08:06:35 pm »
some sort of a kenwood single din. did you want the model number? never bothered to look at it

Offline jvd

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Re: Trouble Shooting suggestions?
« Reply #4 on: April 13, 2014, 10:36:05 am »
some sort of a kenwood single din. did you want the model number? never bothered to look at it
Yes.

And we need more information on settings being used.

Filter settings in radio. On amp, etc.

Fire me a text and I might be able to assist in a more efficient manner.

403-five6zero-three4three8

Offline Unholysavage

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Re: Trouble Shooting suggestions?
« Reply #5 on: April 13, 2014, 11:12:19 pm »
I don't buy the idea that some head units aren't compatible with some amps for a second (this is coming from someone who has competed in SPL off and on since 1995). none of my friends or I have ever had that issue, and we change systems as often as people change underwear.

sounds to me like your sub amp went in to protection. and that's usually caused by heat, low voltage (electrical not up to snuff), or too much current draw (running too low of an impedance, or cranking the gains to get the amp to output more power than it can cleanly do (clipping/square waves)).

what impedance is the sub? what minimum impedance is the amp capable of handling? are you sure that it's wired correctly (ie: you don't have a 2 ohm load wired to an amp that can only safely handle 4 ohms daily)?
factory Subaru electrical systems are tiny IMO, but likely fine for small systems. what sized power/ground cables are you using? you didn't say what the new amp was, but I assume that it's another 500-watter (8-10ga is likely fine if you haven't already upgraded, depending on how long the run was). 

I'm not at all keen on your "wasn't deep or loud enough, so I adjusted the gain" comment. the gains need to be matched to the output of the head unit's preout voltages to ensure that you're not creating clipped output signals to your speakers/subs. the gains aren't a volume knob, and should never be used as such. ever.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.

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Offline fuzzy

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Re: Trouble Shooting suggestions?
« Reply #6 on: April 14, 2014, 12:14:10 am »
Okay, so just got around to finding the model number on my deck which is KDC-BT652U.

The "new" amp that i bought was just a crappy Dual from Walmart. Which i bought to see if i can rule out any specific issues in my set up. it is now resting on the shelves again.

So i hooked up the Alpine once again today, set the frequency to 75hz filter and set gain at 6dB. I could only have the HU set at about 24, before the amp went into protect mode, i think the max HU can be cranked to is around 50. The HU settings like bass, sw bass and bass boost were all at minimum.

Im running 8 gauge wiring. which has always flawlessly worked.

The amp is capable of 2ohm and 4ohm set ups. Im not exactly sure how to wire the subwoofer up at 4 ohms without pulling it out of the box (which ive already done to check it). The subwoofer comes in the box from the factory with a terminal on the side which you plug the wires into.

Im starting to think the amp is bad, as it works but only at low power. I checked all the wiring, which seems totally fine to me. Maybe the engine bay fuse?

Offline fuzzy

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Re: Trouble Shooting suggestions?
« Reply #7 on: April 14, 2014, 08:58:33 pm »
Figured out the issue  ;D

Turned out to be a dead voice coil. So went out and bought the exact same subwoofer, and now it pounds :)

Big thanks goes out to a fellow member jvd. Would have still been scratching my head over this, and scrapping my amp.