Aftermarket Kenwood cuts off w/high volume

[kruuth]

I have a Kenwood KDC-X792. When I turn it up a little loud it shuts down and then comes back on. If I leave it at the same volume it shuts off again. If I turn the volume down all is well.

Does anyone know how to stop this? Here are the specs:

Kenwood KDC-X792Metra Wiring Harness2009 Nissan Altima coupe

OBTW, it's not the radio. I've already replaced it and each one I've tried has the same problem.

[Blood1]

I have the same HU and don't have this issue. Is it hooked up to an amp or are you using internal HU's AMP to power your speakers?

I've got it hooked up to an amp with no issues except for a wonderful alternator hissing noise.

[Blood1]

Yeah, what speakers are you trying to power with it? If its the stock speakers, I know mine were 2ohm so this HU might not support powering 2ohm speakers. Just guessing here...

[kruuth]

I'm just trying to drive the factory speakers. They sound fine, just not when you turn it up. No amplifier. Is there a way to get this fixed?

[Blood1]

Okay I'm pretty sure the HU doesn't support 2ohm speakers which the stock speakers are. I'm thinking it's causing the HU's built in amp to freeze/ take a break then re-try sending watts/power to your speakers.

Try googling it if kdc-x792 supports 2ohm speakers. Send a request to kenwood tech support.

[Blood1]

That is the problem. Look at manual:Audio sectionMaximum output power: 50 W x 4Full Bandwidth Power (at less than 1%THO): 22 W x 4Speaker Impedance:4- 8 0 <---- OHMS.. Stock is 2ohms Tone actionBass: 100 Hz ±8 dBMiddle: 1 kHz ±8 dBTreble: 10kHz ±8 dBPreout level I Load (CD)KDC-X792/X692: 4000 mVl10 kOKDC-MP738U/MP638U : 2500 mVilO kOPreout impedance: ~ 600 0

To fix, replace speakers with 4 ohm ones.

[AppleBonker]

Blood is right. The amp doesn't "freeze" from driving lower impedance speakers, it overheats. If you turn the volume up too high, the internal amp doesn't see enough resistance so it actually puts out more than the 22 watts RMS it's rated at and starts to fry. The amp can tolerate the load at lower volumes, but that's why it goes out when you turn it up. I would highly recommend not doing this. It's a great way to destroy the internal amp and head unit.

Three (4?) options:1. Change the speakers out to something 4 ohm2. Get an external amplifier that can handle 2 ohm (not the best option cause you'll almost certainly blow the speakers)3. Go back to the stock head unit4. Change speakers and get external amp (best option sound quality-wise, worst option monetarily)

[kruuth]

Oh goodie, I have to spend more $$ on the speakers.

Ok. How many are there and where? I was really hoping to not spend an insane amount of $$ on this.

Actually, would it be cheaper to get another HU?

[kruuth]

I think I answered my own question...It looks like I can probably get another head unit for the cost of swapping the speakers. Is the 2ohm a problem I'm going to have with all the aftermarket head units?

I'm not unhappy with the factory speakers. If possible I'd like to keep them, since the head unit cost me about $150, I figure I could replace it cheaper than getting good speakers.

Would a low power amp work? It's going to be cheaper than replacing the speakers or the head unit.
Modified by kruuth at 4:13 PM 7/17/2009

[Blood1]

Kruuth, I think your best bet would be and cheapest way to fix this would be to get new 4 ohm speakers. I'm pretty sure there are no HU that support 2 ohm speakers.

Cheap speakers for the front:http://www.crutchfield.com/p_1...p=105On eBay: $37 shipped:http://cgi.ebay.com/New-Kenwoo...%3A50

Rear 6x9's:Look through here and take your pic:http://www.crutchfield.com/g_4...l?l=EMaybe these:http://www.crutchfield.com/p_1...specsOn eBay:http://electronics.shop.ebay.c...14936

[kruuth]

I forgot to mention these are not bose....

I called Metra and they told me to disconnect the blue/white wire so far no shutdowns. Not yet anyway.

[Blood1]

What wire did that control?

[kruuth]

It controls the amp apparently. Since I don't have an amp I don't think it matters.

*Edit:

Ok, it's doing the exact same as before. What are people grounding to? I'm just grounding to one of the 4 mounting screws. Is there a better place?

Also, these are not bose speakers. Does that make them 4 ohm?
Modified by kruuth at 9:30 PM 7/22/2009

[saywat]

I have the same HU and don't have this issue. Is it hooked up to an amp or are you using internal HU's AMP to power your speakers?

I've got it hooked up to an amp with no issues except for a wonderful alternator hissing noise.

are u running car audio rcas? ud be suprised at how much it eliminates the hiss sound. i didnt believe it at first so i used jus regular home audio rcas. then i bought car audio rcas from best buy for only $10 a pair and no alternator noise at all and all my wires are running along the driver side

[Blood1]

Well it was wired with the RCA's that 6th AVE had which were i think Stinger. I also bought 4 of these:http://www.monoprice.com/produ...style=which I tried hooking up directly from the HU to the AMP not routing it through the car just down the middle of car to back of rear seat where amp is and the noise was there.

The noise is coming from my power/battery/alternator. I have a thread going in this forum which covers everything I did, tried but it just did not go away.

[Blood1]

Kruuth, disabling that wire would not make a difference.The stock (non-bose) speakers are clarion 2ohm speakers. Crawl into your trunk and look at the back of the 6x9. It says 2 ohms on them.The HU CANNOT drive these speakers. You need to replace with 4 ohm speakers.Check out the ones I posted b/c those fall w/in the RMS power output of the HU.

[kruuth]

Oh great. I was afraid of this

Is there a way to get speakers in there without having to snake new speaker wires?

For that matter, isn't there something out there I can use to step the resistance up to 4 ohms?

[AppleBonker]

It's always best to replace the tiny factory wiring. If you're running off an external amp, it's pretty much required. Though I would recommend it in your case, I don't feel it is a requirement.

As far as changing the impedance of your speakers, it's not really an option. While there may be ways that would work from a physics perspective, you're looking for sound reproduction, not building a simple circuit.

[kruuth]

Well I called metra and eliminated the grounding issue. Now its an issue with the speakers. I would hate to void out the warranty on this. Isnt there some way to fix this without ripping out the speakers?

[kruuth]

As I recall there was some sort of step-up device that could be installed between the stereo and the factory harness to jack the resistance up. Anyone know what those are?

[AppleBonker]

For the record, you wont void the warranty on anything but the stereo (more specifically the speakers), which you have already done by replacing the stock head unit. Though, if it came down to it, you could replace everything with stock and they wouldn't know the difference, so in reality no warranty has been voided.

I still cannot come up with any reasonable way to change the impedance of a speaker. A couple of cheap pairs of speakers can be found for around $100 total (a pair for the front doors and a pair for the rear deck). At that price, you wont get anything amazing, but it will be far better than the stock paper speakers.

[kruuth]

You make a good point. I was hoping that there was a replacement HU that could handle 2 ohms but apparently not. What about the tweeters in the dash?

Any recommended installers in the Dallas area? I have limited use of my hands and lack the dexterity to do it myself.

[AppleBonker]

If you want to get tweets in the dash, you can go with a 6.5" component set up front (will probably require some wiring) and 6x9's in the rear (this may get closer to $200ish). The install is quite easy. I don't personally know of any shops in that area, but there may be someone on these boards that would be willing to help. An install shop will almost certainly overcharge you for this based on how simple it is (it probably shouldn't take more than about an hour of labor - if they're working slowly).