Anyone have a clue why the sound cuts out at high volume? I do have the front/rear speaker swap and an amp running the front boston acoustics. The sound never cuts out at lower volume, just when it gets pretty loud. It will come back after the car has been shut off for a few minutes. It seems that if it were shorting out wouldn't it do it at any volume?

 

You are sending your head unit into thermal protect shutdown. It resets on power-down.

 

OK what does that mean? What would cause that?

 

Turn down the volume. Or invest in our Soundstage upgrade, which will relieve the head unit of the duty of driving the speakers and give you all the volume you can stand.

 

What type of radio? After market or stock? Do all the speakers cut out? How high is "high volume"? Where is the amp mounted? Where are you getting power for the amp from? What gauge are you running to power the amp? Is the amp shutting down or is it the speakers? Did you buy the amp new? How old is the amp?

Lots of questions here. But it could be any number of things.

 

Whoops, I missed that the OP has an aftermarket amp installed....so bishop is correct, there are lots of questions there....

 

It's the stock 09 stereo. The amp is mounted in the trunk. The front speakers are Boston Pros and the rears are Kicker 3 ways, not sure the model. The amp is a Sundown Audio amp and just a few years old. The amp does not turn off. The sound just suddenly cuts off. it has to be something in the stereo shutting off because both the front and rear speakers lose sound and only the fronts are connected to the amp. By high volume i mean loud enough to hear easily at 80 with the windows down.

 

How is the input signal connected to the amp?

 

Ok if all 4 speakers shut off and only 2 are connected to the amp, I'd have to agree that you are over driving your stock stereo and its shutting down its internal amplifier.

I've never heard of the type of amplifier you have, so I'm not sure of its specs. You're really getting to the point of needing someone near you who knows about stereos to look at your install and offer advice.

Without being able to see what's happening exactly I can really only offer you things you could look at. None of which may be the cause, or some of which may be the cause.

I assume the amplifier is hooked up through speaker level inputs and not rcas. Have you tried disconnecting the amp and seeing if the rear speakers shut off in the same situations? This could be a faulty amp or faulty wiring. Have you adjusted the input level on the amp to match the output level on the radio?

There's just so many things we could go through that its literally like trying to play pool blindfolded. I may get lucky and hit on the problem, but without seeing the setup, I'm just poking in the dark.

 

The imput signal is connected through RCA's. I cut the RCA connectors off one end and wired them in at the X9331. I bought the amp when I had the S2000 as it came highly recommended on s2ki.com. Before I changed out the speakers and only had the channel swap done the speakers would pop if I turned it up too loud. These don't pop so I very well may be over heating the stereo amp. I am wanting to upgrade to a 4 channel amp anyway. Since the rear channel has the built in crossover at 100Hz I have all 4 speakers (2 through the amp and 2 straight off the sterro) running off the front channels. Is that correct.

 

Ok yeah. You need someone qualified to work on your setup.

It sounds like you're running 6 speakers off a 2 channel amplifier? Is that right? And 2 of these speakers are 3 ways? You're over driving your amp. It cannot handle what you're trying to use it for.

I understand what you were trying to do, by bypassing the rear outs, you wanted your rear speakers to put out more bass. But this really isn't the way to do it.

I recommend a 4 channel amplifier. Hooked up correctly. Let a qualified person hook it up. You'll spend a bit more money, but you'll be much happier in the long run. I think what would be best for you might be to run the front and rear speakers normally, off the head unit and use the amp to run a small subwoofer.

Seriously, if you hooked all this up yourself, good try. You had some interesting ideas, but you went about the the wrong way. I never try to tell someone not to try DIY, but there comes a point where you need to seek someone with more experience than yourself. I think you're at this point.

 

No only the door speakers are connected to the 2 channel amp in the trunk. The 2 rear speakers are running directly off of the factory stereo. what i meant was that the rear speakers are running off of the front channels and the amp is getting its input from the front channels. should the amp be getting its input from the rear channel or will the 100Hz crossover built in to the factory stereo still block the lower frequencies?

 

So yes, all the speakers are running off the front channels.

You're expecting too much out of the front channels of the radio. It's going into thermal shutdown for sure.

You should set it back up the right way (fronts running off front channels and rears running off rear channel) and see if everything works correctly then. It should.

I'm not 100% familiar with the stock stereo and any crossovers it has internally. But if it limits what is available to be output to the speakers it will do the same thing to the amp. I will defer to others when it comes to the stock head units specific stats.

 

This is the tough thing with trying to piece together an upgrade with disparate off-the-shelf components - everything has to work together with the car and with the other components. The MINI HU has a balanced, floating-ground output signal. With the way you've hooked up the input signal to the amp, the amp needs to have a balanced differential input to be able to handle that. If it does not, it could be your problem.

As bishop mentioned, you may want to enlist the help of a qualified professional. Looking at it again, thermal shutdown may not be your issue. The HU output is BTL designed for 2 ohm operation (the front speakers are connected in parallel). Your aftermarket speakers are most likely 4ohms, and the input impedance of your amp should be on the order of 10kohms or more, so even with both loads on the front channels your output current should be within design limits (there are caveats here, but they are WAY beyond the scope of a post). I suspect that your amps input stage references signal ground to power ground with some resistance and that once your voltage (volume) gets to a certain level you are essentially shorting the HU and it is going into over-current protection. This won't reset until the car is powered off and back on.

 

Yeah. What he said.

He knows more about the mini head unit than I do. I know stereo installation stuff (was mecp certified) so I know after market stuff.

But it looks like we both agree, time to call in some back up.

 

Big question here to cooperjunkie. What OEM system do you have base or Hifi. Sounds like probably the base system. If so then yes there is a 100hz cuoff on the rear channels.

But as both others before me have stated you need a pro to help you on this. Just cutting off the ends of an RCA cable to hook to the X9331 connector is "absolutely" the wrong way to do it.

As for the amp. You may have already damaged it as well depending on the type of input it is supposed to take, line level or speaker level. The oem head unit outputs speaker level signals so running that to a line level input on an amp will easily cause tne head unit to over heat and may also damage the input stage of the amp depending on how robust it was made.

 

Ok I hear that I need to consult a pro in my area but i'm confused all to hell. Last year when i was asking about how to set this up i was told that I didn't need an LOC for my amp. I could just simply solder RCA's onto my input signal wiring so thats what i did. Now you all are saying NOT to do that. So should I get an LOC or no?

 

As was mentioned in that previous thread, it depends on your amp. If your amp can properly handle the balanced input and the 7V signal, you are ok with your current setup. Otherwise, as Schatzy mentioned, you need to deal with it another way. You should also keep in mind that most LOCs will have a noticeable negative impact on sound quality.

Based on the problems you are having, I suspect your amp may not be able to appropriately handle the input signal.

 

Thanks for clearing that up. So I guess the first thing I will do is get with Sundown and see how the input is set up on the amp. Then I will at least have clarification on that. My plan is to get an Alpine MRX-F65 4 channel amp that accepts speaker level inputs in a few months.

 

Since the ARC 125.4 MINI is a known quantity (i.e. you know it works in the configuration you already have since that's the way we use), comes in a much smaller package that fits under the seat or behind the rear panel, has better topology and a better designer, why would you not go with that?

There's nothing at stake for me here, I'm just genuinely curious since I see folks make decisions that come back to haunt them all the time. Look through this sub-forum - you see thread after thread of folks having frustrating and mysterious problems because they've selected gear, for one reason or another, that doesn't work well and/or integrate well with the MINI.