The other problem with this approach is that each channel is designed for a specific location in the car. There are 8 channels as listed in In this thread and a couple others. Here is the listing again.

1. 40W - rear left woofer
2. 40W - rear right woofer
3. 25W - rear left tweeter
4. 25W - rear right tweeter
5. 25W - front left woofer
6. 25W - front right woofer
7. 25W - front left mid and tweeter
8. 25W - front right mid and tweeter

Most of these channels seem to have some sort of filtering either hi-pass or low-pass or a mix to them.

Just swapping wires at the amp is not just that easy. And as others have said it is one of the hardest items to get to.

 

good work guys, this is like landing on the moon and all i can do is watch, but we will all benefit from your hard work.

thanks, my hifi clubman sounds like crap and drives me nuts, i hope its a simple fix.

 

DANG! They sure didn't make it easy to swap out the amp! Crap, on my 06 it was under the passenger seat!

 

That is now taken by the DSC computer.

 

I can't say it enough....THANKS for going to all the hard work and posting about it. The system definately lacks and if tearing out the interior to swap some stuff around makes it better then I'm all for it.

I appreciate the work you guys are putting into this!

 

Well after 6 hours of testing i have found that the amp in my car is

A. No Good - shot, kaput, worn out, broken, how ever you want to put it.

or

B. There are major wiring problems in the car.

What i have found is that the Output of the amplifier starts distorting at around 5 watts output. Now people may say how can you even hear that. Well measuring a 40 hz tone and seeing it start to distort on an oscilloscope is an easy way to tell.

After setting up the test to check the frequency response i did the response test .5 watts just to see what it looked like. I then turned it up to 2 watts and had very similar results with in one percent. Then went to 10 watts and was seeing some very strange readings for frequency response. so i looked at the out put with the scope and sure enough there was the distortion.

I will post pictures in the next day or two.

 

I look forward to seeing pics -- is the distortion roughly symmetrical? At the peaks, zero crossings, or in between? Are you sure it's at the amp?

Pisser! I ran things at about a 3-4w level, and when I did initial gain setting (setting the AUX/iPod level into the head), I found I could overdrive the head, and had to back off -- low master volume, cranking up the AUX level, seeing distortion, backing off on the AUX level a few bars, and I could turn up the master volume quite a ways.

 

Schatzy, are you accounting for the 2-Ohm load when you calculate the power?

 

A little about my background in audio electronics

I worked for the High End audio manufacturer Cello Ltd for 6 years during the late 80’s early 90’s.I started as a electronics quality control tech and one year later was promoted to the quality control managers job while he was move to another roll in the company. During those years wrote the standards and procedures by which all of the equipment was tested. Cello Ltd manufactured some of the most high end equipment mad at that time. The equipment was used in homes and studios such as Sterling Sound in NYC, Sony Recording Studios NYC and LA, and DMP (digital music productions) in Stamford CT and many others. Other interests have taken over my life since then but I still keep in touch with the industry and continue to dabble in speaker manufacturing and repair as a hobby.

So yes I have taken into account the two ohm load.

So on to the info at hand.

Test equipment: (this is what I can get my hands on currently)
Techtronix TDS 224 Digital O-Scope
Heath EUW-27 Signal Generator 20hz to 2Mhz
HP 3400A RMS Volt Meter (read in volts or DB)
Fluke 8050A True RMS Volt Meter (reads DB or Relative DB)
2 ohm 60 watt, non inductive, non capacitive, pure resistance load
3 ohm 60 watt, non inductive, non capacitive, pure resistance load
4 ohm 60 watt, non inductive, non capacitive, pure resistance load

Test procedure:
1. Remove panel over right rear speakers.


2. In place of rear right woofer place 3 ohm load. (I used this as the actually AC resistance of the woofer ranges from 2.1 ohms to a little over 4 ohms. DC Ohms reading is 2.23)


3. Set input signal to 20 hz and set input to Aux connector for .775v (1 DB on HP 3400A) (I used this setting to ensure that i did not overdrive the input)

4. Check output signal on scope and set volume control for a two volt RMS output. ( this gives it an output of 1.33 watts, low listening level in a car) (I started with 20 Hz due to the fact that I know there is a signal boost in the amp but was unsure how much so to be safe I set the output at 20 Hz instead of 1000 Hz so that I would just measure the drop in output as I went toward 1000 Hz.)



I ran frequencies up to 1000 Hz and found a20 DB roll off. So I went to reset the power output to 5 watts. This is what I got at 1.58 watts at 20Hz for a signal



I then continued to increase the volume and got to this at 2.48 watts output.




So I decided to do a test at 1000 hz and was not able to get more than 5 watts of power output before I started getting similarly distorted sine waves.

I ran thru a bunch of other tests including testing at X9931 with a 3 ohm load. I could get about 16 to 18 watts output from the head unit before distortion at frequencies from 20 hz to 20KHz.



So the car is going into the dealer on Sept 15 for a check up. We will then see what they have to say about this.

 

schatzy62,

Given the amount of distortion you're seeing, was your system *audibly* bad before you began doing the testing, or were the test results the first indication you had that something was wrong?

Obviously, the readings you're seeing aren't good, but I'm wondering if there's anything *wrong* with your amplifier, or if the readings are typical of the HIFI system.

You said the the response from the X9931 connector was good throughout the audio range - how does the output of the HIFI amp look at higher frequencies as you increase the power?

(In short, I'm wondering if the response from the HIFI amp might just go to crap at the low extreme, but could be okay at higher frequencies.)

EDIT - I just saw the line in your last post saying that you got similarly-crappy results at 5 W / 1 kHz. Still, I'm curious if you noticed anything wrong audibly before the tests.

 

I'm not surprised by Schatzy's results. 10 channels @ 40 watts per channel from an amp the size of the HiFi amp?

Also, I'm curious what the supply voltage was at the amp under the measured condition?

Bill in P.G.

Edit; Actually, I am surprised that the sine wave would be that distorted at just over a watt, and agree that something's amiss..

 

Yes, Did i notice it the first day i had the car, No, but i was so excited about finally getting it i did not really listen to the stereo, I listened tt he sounds of the exhaust and the engine. I did notice that it did not sound goo about day three or four, but have just not had a chance to look at it.
I would hope that this is not normal for the HiFi system as it is supposed to be better than the standard system which mine is not.
It looks bad at higher power output through out the entire frequency range.

First of all it is not ten channels and not all of them are 40 watts.
There are 8 channels, 6 at 25 watts and 2 at 40 watts. The size of the Amp is not bad I have had mine apart and it has good (not great) parts used in it. I think that it is just bad.

The car was running and i assume (since all the fuses are good) that the amp was getting better than 12 volts because the car was running. I will admit that i have not checked the power supply line to the amp to see what voltage it is getting. I see now reason that it should not be getting 12+ volts. All testing was done with the engine running. I will have to check that . Thanks for bringing up this one very easily overlooked thing to check. Although it is not easy to get to, so it is not an easy thing to check.

There is definately something amiss

 

Anyone know what the morning line odds will be on the "Cannot Reproduce Problem" response from the dealer!
In any event, I'll have the torches and pitchforks ready if they blow-off Schatzy after all the work he has done!

 

100 to 1

 

I'm going with a 80% probability of no satisfaction on first visit. I think it's too technical a problem for most service shops to recognize and respond to, unless it's very obviously fubar to the average ear.

 

I suspect the same thing.

schatzy62, are you going to bring along your signal generator and oscilloscope? That way, you can compare your car's output to one of the dealer's cars and at least get them to try swapping the amp, even if they can't hear anything wrong.

 

I was thinking about those O-scope pic's last night before nodding off, and it seemed the second half of the waveform was clipping, as if the second half of the complimentary pair(s) was(were) clipping. I looked at the pic's again tonight, and I see a bit of junk on the leading edge of the wave in the 1.58 watt pic.. Since the amplifying devices never actually turn completely off, could this be from the second "clipping" section, superimposing on the first section? Perhaps the second section is underbiased? I'm sure I'm blowin smoke here, just thinking out loud..

Since the car isn't going into the shop for awhile, would it be worth the trouble to look at other channels?

Bill in P.G.

 

On second thought, I don't think underbiasing wouldn't explain the clean waveform below a watt.

If we saw the same problems on other channels, then I'd say there was a problem with the phase splitter.

I guess this is all moot. I would think showing the service manager at Mini the O-scope pic's you have would warrant an amp replacement. They will either just stick an amp in, or they'll do a listening test and say it sounds fine at "normal" listening levels, and not to turn it up loud.. Which is a cop-out and unacceptable.. But we know you won't allow them to get away with that.

Bill in P.G.

 

And I think a MINI service manager would simply look at an o-scope pic with a blank stare and an awkward silence

 

Skip what I said previously.. Had my head up my kazoo.. The push/pull sequence transfers at the 0 horizon. I don't know why I was thinking it happened at the peaks of the wave. I swear to god I'm losing my wits.. I was laying in bed ( again ) thinking about it and the lightbulb went off ( and then my wifes alarm, thus I'm up early.. And I'm off this week! ).

Bill in P.G.

 

While I was speaking with the SA, there were other things going on in the house that were distracting me, so i did not pick up on the statement "We Can Get it Fixed In One Day. If I Have A Tech I Can Put On It All Day." But I did pick up on it when i was going thru my call notes yesterday.

Now, after having some time to reflect on the conversation and how it went and also looking thru my call notes again. I feel there are two possible senarios.

A. The SA knows what the problem is even though he stated "I have never heard this complaint before" and can have it fixed in relatively short time

or

B. He has heard this complaint before and will do his best to blow smoke up my a$$ as they do not have a solution.

Either way it is a 1-1/2 hour drive each way for me to the dealer, which is not that bad but I do not want to do the round trip twice in a week so i opted for the appointment were he can have a tech on it all day if needed. There was an option to bring it in today and leave it and they would get to it in between others cars and they would rent me a car. (they rent from National or Hertz or something i don't get a new mini or bmw loaner) But this would mean that i would have to go down today and then go down again some other day this or next week. Not an option. Now the dealer is in Boston so while there i will bring the dog and we will walk into the center of the city and take a stroll thru the Public Gardens while waiting for one of the two options above to happen.

We will see in two weeks.

The other thing is a bout this dealer ship is they know "I will not let it go, It will have to be rectified".

Edit: as for the scope pictures i am sure the SA would look at them and go "WHAT". And i have been able to recreate but not exactly the wave forms on another car amp by putting in speaker level signals to amp that uses line level inputs. I also have some knowledge of the Service Mode but have not been able to figure out all of it as it is in German abbrieviations, There is one section in there that has a LINE note but i have not been able to figure out how to change the setting. But you can bet i will be checking to see if that has changed when i get my car back.

 

Just how bad is it audibly? (and should we be using this thread for this conversation anymore....)

 

In My Ears BAD, But in my girlfriends sons ears it sounds great, but then again he listens to internet radio at 24kpbs and songs on his iPod are lucky to be 64kbps and nothing more. It is all in the preception.

#2 probably not, but when i get my car looked at i will post to say what they did, if anything

 

I have the HIFI sound system and I did this mod. now I'm just wondering if any harm may come about due to leaving the F/R channels switched, I really dont want to have to switch them back as it was kind of a pita

 

If you have Bluetooth, your phone conversations will play through the back speakers, rather than the fronts.

If you have the Park Distance Control, the beeps will play through the front speakers, rather than the rears.

I can't think of any other consequences.