[jwardell]

Very occasionally, when it is cold out, within a minute of starting my MINI, I hear a high pitched tone through all my speakers. Then seemingly randomly, music will be garbled and staticy through the rear speakers. The static may occur for a few seconds or minutes, go away, come back at random. The high pitch sound is always there.

This won't stop unless I fully turn the ignition off and back on. Turning the stereo off and on has no effect. It will do the same at low and high volumes. It will continue no matter what input is selected. I've experienced this about 10 times and again today was the last straw. It is obviously very annoying while driving.

It has been unseasonably warm, in the 30s and 40s, then today it finally dropped, my OBC read 25. Every other time this has occurred has been when it was cold out, usually a cold morning but in this case was the evening.

Here is my post when I first experienced this...warmer but also a relatively and suddenly cold morning.

I strongly suspect my HK amp as it adds complexity and it also treats the sound to the front and back differently, but it it could be the boost head unit I suppose.

6-month-old 2004 MCS with HK plus AUX input and Sirius satellite (again it occurs on any and all inputs).

Has anyone else experienced this?

[jwardell]

Occurred again today, this time as I was leaving at lunchtime, temp 25.

I decided to root around a little more. At first the high pitch sounds like it is coming from all speakers, and the static from right rear, but it's just acoustics. Moving around and playing with the fade, the problem is actually only with the rears. The front speakers work fine. Both rears are producing the high pitched tone and both are making the staticy scratching noises.

Turning the volume up slightly you will also hear clicks when changing things such as sound mode etc, you are picking up interference from the headunit sending commands to the amp. If you change modes while it is making its grumbling static, it does change the tone of the static along with the soundfield. So the source is before the soundmode DSP. Still not sure if it is the HK amp or headunit.

Sadly after searching and lack of response it seems I'm the only one with this issue.

[GBMINI]

Josh,
I have never heard this - or heard of this particular issue.

The fact that the sound is only from the rears is conclusive proof that the problem must be with the HK amp, unless it is some wierd pickup with the wiring to the rear speakers (very unlikely because they are low impedance).
There is only one set of left/right signals from HU to amp - if it was a HU problem you would hear it on front & rear the same, subject to the filtering - and since it is a high pitched noise, it should be clearer in the fronts if present.
I think you need a new amp!

[ALD0]

Is it like a Interfierence noise first thing in the morning and you can hear it more when you pull away or rev the engine?

[jwardell]

It is not interference noise, and it is not related to the engine.

Next time it happens I will get a recording of it. Right now I'm interested to see if anyone else has the problem.

[jwardell]

I recorded a video of it with my cell phone, which doesn't sound so great to begin with and certainly compresses out the high-pitched tone, but you can certainly hear as I fade to the rear only how the music is almost entirely garbled, then as I fade back to the front the music is clear again:
http://www.jwardell.com/mini/misc/HKnoise.mov

[GBMINI]

Sounds like loads of clipping!
If it was an analog amp, I would say it was being massively overdriven.
Since it is a digital amp, there presumably is a fault in the amp circuitry (unless you have blown the rear speakers - but then the distortion would be continuous). Maybe a cap in the switcher supplies, flaky at some temperatures ...

As before, since the fault is only in the rear, it cannot be a head unit problem. Get the amp replaced.

[jwardell]

I think the amp finally kicked the bucket today. A whopping six degrees when I went outside this morning, the system immediately produced static from the rears (and much more of a static sound than the typical grumbling noise). At least it was immediate and I was in my driveway, so I did the usual and turned the car off and back on. Well the static was gone. Then I realized my system sounds like a cheap clock radio. Sure enough NOTHING was coming out of the rears. Fade control had no effect, nothing from the rear. Drove for a while to let things warm up, restarted the car in traffic, still nothing. Once I got to work I turned the car off, pulled the keys out for a minute. Turned the system on but still nothing from the rears. All fronts working fine.

I'll wait till it warms up this afternoon to the mid 30's but it sounds like it is finally time to contact my dealer. They know me all too well although this is actually the first actual factory defect I've come across (I'm not gonna count the HK rattle as a functional defect). If it's still bad tonight I will try removing and reinserting the wiring harness to the amp, that's the last possibility I can think of.

[GBMINI]

That's good really Josh ... much easier to fix a repeatable fault

Of course, GBMINI has very little bass this morning also - those speakers really stiffen up at these low temps. I wonder if MoP keep HK an amp spare on the shelf.

[RenaultF1]

Quote: Originally Posted by GBMINI

That's good really Josh ... much easier to fix a repeatable fault

Of course, GBMINI has very little bass this morning also - those speakers really stiffen up at these low temps. I wonder if MoP keep HK an amp spare on the shelf.

Ok...So then the low bass in the cold is normal? I've done searches for this and haven't found anything. I have an 05 MCS (I too am an MoP customer - from Maine) with HK and have been wondering if the issue was speaker or amp related. Once the car is warm, the sound is normal.

Just a question for you...I checked out your site, but didn't read thru the whole HK speaker info. Did you have MoP fix your speaker rattle or did you take the car somewhere else (other than Tweeter) and have it fixed?

[GBMINI]

My experience - the loss of bass at very low temps is normal. I have read of some expensive aftermarket speakers featuring "good performance at low temps" so I think it is probably normal for most speakers.

The vibration in the passenger door is not so much "speaker rattle" as "speaker induced door panel rattle"
I did not have MINI Peabody look at it - I was an early HK owner and it was not then general knowledge that this was an issue. Since I had the door panels off anyway for other reasons, I just felted the backs of the door panels.

Josh (original poster of this thread) did his panels too and has an excellent How To write-up

[RenaultF1]

Quote: Originally Posted by GBMINI

My experience - the loss of bass at very low temps is normal. I have read of some expensive aftermarket speakers featuring "good performance at low temps" so I think it is probably normal for most speakers.

The vibration in the passenger door is not so much "speaker rattle" as "speaker induced door panel rattle"
I did not have MINI Peabody look at it - I was an early HK owner and it was not then general knowledge that this was an issue. Since I had the door panels off anyway for other reasons, I just felted the backs of the door panels.

Josh (original poster of this thread) did his panels too and has an excellent How To write-up

Excellent info, thanks I'll check it out. Oh, and I hear you about the "speaker induced door panel rattle". It is impossible for me to not crank up the sound, especially since I had the iPod adapter installed.

[jwardell]

Yesterday when leaving work, everything was working normally. So (unfortunately?) it is not fried and continuously reproducible. Then again last night when moving cars in the driveway it happened again. And again today, but went away after turning off and back on. We're looking at 50% I guess.

Yes, my dealer MOP did "fix" the speakers...apparently tightened the grills (which are riveted not screwed in). It didn't help the problem at all. A dollar's worth of felt did it. See me how-to. I'm thinking of adding a note to simply pop out the bottom front of the panel, not to bother with the whole thing, and insert a strip of felt. In other words, 5 minutes.

I'll second Ian's experience that the speakers are quiet and less bassy at cold interior temperatures. It makes sense though, the speaker cones have to flex to produce sound.

[RenaultF1]

Quote: Originally Posted by jwardell

Yes, my dealer MOP did "fix" the speakers...apparently tightened the grills (which are riveted not screwed in). It didn't help the problem at all. A dollar's worth of felt did it. See me how-to. I'm thinking of adding a note to simply pop out the bottom front of the panel, not to bother with the whole thing, and insert a strip of felt. In other words, 5 minutes.

I'll second Ian's experience that the speakers are quiet and less bassy at cold interior temperatures. It makes sense though, the speaker cones have to flex to produce sound.

Excellent, excellent. I'll try it tomorrow when it warms up to 50 degrees here. Thanks!

[jwardell]

Yeah, aren't you glad it's now officially winter?

[GBMINI]

Yesterday I heard the awful noise that Josh' HK amp makes through the rear speakers when it is feeling "sick" (cold induced?)
Fading to the front gave clear sound proving the signal from the head unit to amp is OK (there is only one left/right signal to the HK, not separate front/rear signals).
Fading to the rear gave a "graunchy" noise slightly related to the music being played but basically unrecognizable. Very very sick.