Good afternoon. I've done some Internet research, as well as in NAM, and I am unable to find anyone with a similar problem. I have the factory head unit in my '06 MCS. The factory speakers have been changed out with a Kicker setup. I also have a Kicker ZX250.2 amp and a single Kicker 300W 10" subwoofer. The problem is, when I crank the stereo up fairly high (hey, I love jamming to Techno), the unit spontaneously cuts out audio. The head unit is still lit up. Now, whether I leave it on or cut it off, if I am travelling at highway speeds (i.e. > 55 MPH), the residual road noise becomes amplified through the subwoofer. It's like playing a single bass note really loud. If I slow down, the sound goes away.

I initially thought the problem was my old amp, a Kicker KX200.2, for which I thought was damaged when I totalled my '02 MCS. I just changed it out last week, but the problem remains. For the RCA pre-amp pickups, I tapped a set of RCA drops into the rear speaker wires at the head unit location and ran a shielded RCA wire all along the passenger side behind the panels and along the floorboard by the door.

My question is... is the cut-out a feature built into the newer 1st-gen head units, or is it a defective unit? The head unit in my old '02 MCS did not cut out, but it did cap the volume level. I'm satisified with the stock unit (it's by Alpine for BMW), so I will replace it if that's the case.

I appreciate your input. Thanks.

 

I believe your Mini can not provide enough current for the bass in your techno music and the amp is clipping for lack of current. Also if the Amp gets too hot it will go into thermal shut down (Protect mode)....kind of like clipping.

The head unit should not be the problem. I have pushed above 120 + db with the stock HU (non HK) without any problems. I do have lots of Dynamat.

I used a JL clean sweap to convert speaker level output into line level with full digital DSP on my stock HU. I also have (1) JL HD Amp pushing 900w (1) JL Audio 10w3v2 and a set Focal 165 KR2 seperates.

I wanted and iPod only (no CD) set up so I switched out my HU to an Alpine IDA -X305.

Try looking into a 1 Farad cap for your Mini.

 

OK, I do have a 1 Farad capacitor I picked up a few years ago. I just never installed it. I will make the effort to get it installed and report back. Thanks.

 

Hmm, I've been thinking. I never had the stereo cut out in my old '02 MCS. All the speakers, amp, and wiring were transferred to this '06 MCS. The amp power and ground wires are 8 gauge and run directly from the battery terminals with a length of approximately 4 feet.

I do still want to install the capacitor. My mind just keeps thinking it will not solve the cut-out problem. I will admit the lights in my old '02 MCS would dim a bit when the bass would hit at a high volume, so I know it's needed. One possible factor is this MINI has Xenon headlights; the other did not. If memory serves, I don't hear them "buzzing" until I turn on the running lights. I do have a daytime running light option turned on, but it's a lower-power version of the high-beams, which are Ultra-Stars.

Still researching along the way.

 

P.S. - I installed the Kicker amp and sub back in February. The cut-out problem first occurred in mid-April (since the weather was warmer, and windows were down, the stereo was cranked louder). I did not get around to replacing the factory speakers with the Kicker ones until late June or early July.

 

Ok, what HU do you have? I have my old stock one here if you want it. PM me with an offer or your phone # and we can talk about your issue and where I added my Cap under the hood. (1/2 hour install)

My HU is out of my 2005 MCS JCW it is NOT the HK unit. I have it right in front of me and I can read you any of the numbers off the back if you need them. You should be able to use it to plug in and check your system with it.

Maybe your stock Alpine unit is slowly comming to the end of its life.

My HU is:
Model No. CD53 R50
P/No. 65.12-6 961 275
S/NO. AL 5014 5 05 70475

Manuf. 05 MAY AP

 

The '05-'06 (i.e. July 2004 and newer production) non-HK head units are the right kind, as they have MP3 capability. I know the capacitor is needed, so I will definitely do that first between now and the weekend. Once I can retest, I will repost.

I am in agreement, though. I think this HU is slowly dying.

 

Hey Man, I put my cap under the hood on the top left inder the cowl vent.

I wired (-) Neg to a good frame engine ground and wired POS (+) to the jump power post by the air box. (Careful charging the Cap)
This way the 1 Farad cap is a nice in-line high power electrical noise filter that also supplies quick on demand current when its needed for your stereo.

 

Perhaps the sound cutting out was you going deaf...

Just teasing, that was a little mean. I have nothing to contribute so you can ignore this post. I can't give you a minute of your life back so here's some

Good luck getting it fixed!

 

Just curious - what is your HU's speed volume (press & hold the musical note) set at? You might try turning it down.
Luck!
bo

 

Installed the 1 Farad capacitor. I bought a couple 1W 1K Ohm resistors to charge it up. Used a computer power supply. Verified it held a pre-charge of 11V overnight, so it's still good. Went out for a test drive today. Head unit still cuts out.

bodinski, Speed Volume is set at 4. I have no idea what this setting was in my old '02 MCS. Not sure if it really has any bearing on the problem. The way the old one Head Unit functioned, it leads me to believe there should be a volume cap no matter whether this is set high or low.

Chili Mini PA, I'll definitely pick up your stock Head Unit. Let me know how much you want. Payday is Thursday. I'll PM you then. Thanks.

 

Received head unit yesterday. Thanks.

I will swap it out this weekend and post a followup.

 

Aww, man, this stinks. I swapped out the head unit, but it still cuts out. Guess I have a short somewhere.

 

Reviving this old thread. Attached is a diagram of the stereo layout in my '06 MCS. I am guessing there is an overload due to the fact I may be pulling more power from running some speakers in parallel, which is halving the impedance from 8 ohms to 4 ohms. Any ideas or suggestions are greatly appreciated. Thanks.

 

If you have an overall 4Ω impedance on each front channel (taking the crossover into account) and an 8Ω impedance on each rear channel, that shouldn't cause your problem. The speaker-to-RCA converter into your sub amp won't cause an excessive draw either, since the input impedance of your amp is so high. The stock head unit is designed to drive a 4Ω load on each of its four channels, so a 4Ω load on each front channel and an 8Ω load on each rear channel would actually be a very light electrical load.

Are you sure the impedance for the rear channels is really 8Ω, though? You mentioned speakers in parallel, which would halve the impedance, not double it. So if you have two 4Ω speakers on each side in the rear, and each speaker is 4Ω, then the overall impedance on each rear channel would be 2Ω, not 8Ω, and a 2Ω load on a single channel would certainly be low enough to cause the head unit to cut out.

 

Hmm... I will have to go back and look. I think I assumed (gasp!) the speakers are 8Ω. If I did halve the impedance to only 2Ω, do they actually make a resistor that can compensate?

 

Ugh, you're right. I think all my speakers are 4Ω, which means all my numbers are half of what I have in the diagram. Interesting thing is the old deck I had in my '02 MCS never cut out. It simply capped the volume level. The only other difference is the auto shop that installed the wiring kit in the '02 tapped ONLY the right rear speaker for the two RCA drops for the sub amp. I changed that in the '06 MCS by tapping both rear channels.

I like having the MP3 support, so I'm not gonna put in the old deck. So, yeah, as I mentioned in my other post, I will need something that can help compensate for the decrease impedance.

 

First, what is the part in your diagram labeled "distribution box"? Is it just a simple parallel connection, or is it something like a crossover network? That will make a difference as to what the load is on the deck's front channels. If it's just a simple parallel connection, then the 2Ω load on each front channel, is almost certainly what's causing the deck to cut out.

Your rear channels should be okay if each channel has a 4Ω load, so it appears that the problem is with the front speakers. You can't just add in a resistor, because the typical Radio Shack carbon film resistor can only dissipate 1/2 Watt or 1/4 Watt. You would need a "power resistor", which cost as much as a speaker, and it would be a waste anyway because all you'd be doing is putting off half of the deck's front-channel power as heat.

The simplest solution would be to go to a single pair of speakers in the front. Since your speakers are 4Ω each, disconnecting one of the front pairs would get you back to the 4Ω per channel load that your deck needs. If you want to have two pairs of speakers in the front, another option would be to get two pairs of 2Ω speakers and wire them in series for an overall 4Ω load per channel. There are 2Ω specialty speakers out there, although they're not as common as the standard 4Ω ones.

 

From what I am reading, the distribution box is actually a two-way crossover. The mid leads to the 5 1/4" speakers are split into mids and highs. The factory high-range connections are not used at all. This is part of a component kit (was in my old '02 MCS and installed by a friend/previous owner; I migrated them over to the '06 MCS). They look similar to what you see in this ad: http://www.crutchfield.com/p_158GTX1...1S.html?tp=106.

 

So you have two pairs of speakers in the front, along with the crossovers. Did the crossovers come with the speakers, or did you mix-and-match parts from two different component sets? If the crossovers came with the speakers, then the overall impedance for each front channel should only be 4Ω and therefore not a problem.

 

Yes, the crossovers came with the speakers. Maybe the issue is with how I changed the way the amp gets its RCA signaling?

 

I updated the diagram to reflect what we've discussed. The only section I'm not sure on for impedance is the RCA taps.

 

I am having this EXACT same problem with our 07 MCS system. I'm so glad I'm not the only one with the problem because I've been so fed up with trying to find it. It only happens at high volume just like yours, but here's my specs.

I upgraded the entire stereo system except the stock head unit. I have the 10 speaker system, but upgraded all speakers to Polk 4 ohm, with the Integral Audio sub system in the back. 1 4 channel amp and 1 2 channel amp to push all the door speakers. Both are Kenwood.

Here's some info that may help us figure this thing out...

When I was first installing everything, I didn't have the gain controls setup yet and it was getting some distortion, and with any kind of moderate volume, it would cutout and die, until I restarted the car (resets the stereo somehow). After I set the gains properly on the amps to get rid of distortion, I thought it fixed it, but still, at any kind of high volume, it will intermittently cutout and I have no sound until I turn the car off and "reset" the system. It's intermittent in that sometimes I can crank the bejesus out of it, and its fine, but other times, it will cutout.

And on at least one occasion, it cutout simply by plugging in the Aux cable to an iphone! no sound ever came out except a slight blip thru the speakers. I haven't tested the radio yet, but all my tests have been with an apple device plugged in.

All 3 amps in the car die at the same time, so its not an amp overloading. the factory amp has been removed from the car. I'm getting the audio signal from the front and rear speaker inputs that were going to the stock amp, and using a RCA converter cable to run RCA cables to each amp.

I'm pretty convinced the stock head unit is setup to cutout the audio when it sees some kind of distortion (even though it sounds crystal clear). I just can't figure out how to correct it!

To test this, try setting your amp gain really high, so that it will distort on purpose, and slowly crank the audio. I bet it cuts out on you.

 

Audio cutout always is a result of not enough power to the amp. You might need a second battery. Any good audio system will have a battery to power it.

 

Not in this case. This is a different issue. Read my post above.