Hardline

I have an aftermarket indash navi with all the bells and whistles. When I bought the car I didn't buy it for the sound system so I didn't bother blasting the music or whatnot.

However, lately the unit shuts off and turns back on, shuts off and turns back on, etc when high volumes are being played. The thing works great when you are listening to music at a normal level, but when you turn it up it immediatelys shuts down and starts back up and will keep going through that cycle until it stays on long enough for me to turn the volume down.

Also, it doesn't always do it and it does it more often when I am using my ipod (by using I mean scrolling through songs and whatnot)

If fabrik8 or anyone could provide me with a solution I would be extremely thankful!

Fabrik8

Shutting off like that and cycling on and off at high volume sounds like the head unit is going into protection mode. Usually that's because it's trying to put out too much power or getting too hot. If it's something that it just started doing, it's possible that there is a fatigued solder joint in the amplifier section of the head unit. It's also possible that the head unit might be having a problem staying cool if it's too close to the heater ducts in the dash. If the problems coincide with cold weather and having to use the heat a lot more, that might be a real possibility.

Oh, and it's also possible that you just have a wiring problem and the voltage at the head unit is dropping too much when trying to put out lots of output power.

So...it could be one of a few things..

Hardline

Well it definitely does it regardless of if heat is on or not at high volumes. Uhm, scuse my ignorance but does the headunit have its own amp? I have a WRX and the indash just looks like a basic headunit. Although I think there is amp under the passenger seat... I'm just confused as to where to start looking. Thanks for the help though I appreciate it

Fabrik8

The amp in the head unit is what directly powers the speakers, just like the stock head unit. It's a fairly low power amp and not that great for distortion, which is why external amps are an upgrade for higher power and cleaner sound. You might be thinking about the factory subwoofer under the passenger seat, it has its own amp onboard..


Here's the specs on it, notice the 50x4 (max) power output amplifier.

http://www.eclipse-web.com/us/avn/avn6620spec.html


So yeah, I would imagine that the onboard amplifier is trying to output too much power or is getting too hot at high volume. I don't know much about the stock speakers (or whatever speakers you're using) but it's possible that the impedance is getting too low when the speakers are moving a lot. Impedance is dynamic (a 4 ohm speaker is really never 4 ohms) with frequency and speaker excursion, and the impedance is the "load" that the amplifier has to drive. So low impedance means higher power output, which means more heat.

It could still be a power or ground problem though. A navigation unit with a big screen probably draws a lot more power than a stock head unit, so it might be having problems with the stock wiring or the stock ground point.

This is hard to diagnose over the internet because a few different problems can show very similar symptoms.

Hardline

Ahh I see. Thank you for clearing that up . I wonder where a good place to start diagnosing would be...If I remove the headunit, would a bad solder in the amp section be visible or?

Fabrik8

Wait, wait, wait.. So the entire head unit is shutting off, then turning back on? The sound isn't shutting off but the head unit stays on?

If that's the case, it's probably not a thermal problem. That sounds more like a power/ground problem or a solder joint problem internally. Thermal protection usually only affects the amplifier section, so the sound will cut out but the head unit will stay on because the head unit just shuts off the internal amplifier. This isn't always the case, but it's the way that most head units have traditionally worked.

Why the iPod would have any affect, I don't know. Maybe it's just the extra power draw from having to process communication between the iPod and the head unit, can't say for sure. That's a strange one.

Hardline

Oh no, all of it shuts off, then turns back on (repeat until I hold down the volume down and it gets a chance to actually turn down the volume). As in, music goes away, headunit turns off and turns on (has eclipse loading screen), etc..

Fabrik8

So if you mute the iPod during this process, so there is no music output from the head unit, what happens?

Also, are you using the little iPC-106 iPod interface box?

Hardline

Sorry, I am a bit confused as to what you mean? Mute the ipod as in, turn down the volume on the ipod locally? or press the mute button on the headunit? (Havent tried doing either as i've always just turned down the volume on the headunit when it goes haywire and deal with quiet music. however, i will tonight when I head to class after I get your response).

It is just weird because it isn't like im blasting music...it is loud when the problems start, yes, but nothing that would cause a problem I would think. I guess I'm giving my electronics too much credit.

Fabrik8

Yeah, it doesn't sound like everything is working properly. So either you need to revisit the wiring, or the head unit needs repairing. Luckily the wiring is pretty easy to check.