C230Komp

The driver's side speaker has developed a "buzz" or a rattle sound. I just noticed it, and I wonder if the dealer will give me grief since I have the Audio 10 installed now. It is an MB product after all, but I hope they see it that way too. Anybody else had an experience with the dealer after Audio 10 install? The car only has 2,000 miles, and the radio has been in for about two weeks.
Thanks

trench

I've always wondered about blown speakers and warranty issues. I don't think a dealer would replace a bent rim or fix a dent under warranty (damage caused by the user) - why should they fix a speaker that has potentially been blown by perhaps being played too loud (not that you did but that will likely be the dealer's arguement)? If the Audio 10 puts out more wattage than the stock system my guess is you're probably screwed.

If they're the same it will probably depend on your particular dealer whether or not they'll replace it or not. The only way to find out is to call or go in. The individual speaker price may be low enough that they will go ahead and replace it to keep the customer satisfied.

BT

young

can you replace the head unit back to stock?

C230Komp

Yes, I could replace the head unit. Kind of a PITA, but do-able. I don't know about wattage comparisons, but I can tell you that it sure as hell appears to get louder than the original unit! And yes, trench, I have played it a little loud! I'm 40, but I haven't grown out of the heavy metal phase. Don't know why exactly, but Iron Maiden still sounds so good! A buddy has a BMW 330ci, and he said his speakers buzzed too, and they replaced them but he had a stock CD player. I guess the worst is that they say no, but I assume that only radio/speaker related issues could be voidable since that's the only mod I've done. Funny thing is, it is a direct plug and play MB (Becker) unit, and I still have the original MB box.

trench

Up the Irons!

BT

Rick

Rick

If you have Bose, keep in mind that the in dash unit is just a pre-amp....I think it's the same for the stock set up. Amplification is handled by a separate amp. That and the speakers are covered under warranty.

It's more likely a loose connection....

vadim

It's not the head unit that drives the speakers - it's the power amplifier. The head unit's output is supposed to be standard - "line out" level, so no head unit can be blamed for a speaker failure.

If a speaker fails because you played your music too loudly - it's not your fault, it's a clear indication that the speaker wasn't capable of handling the load put by the stock amplifier, meaning - engineering fault.

By all means, go to your dealer and request the speaker fixed or replaced.

art_Ccoupe

hey man it's a wearable give it a try! but i would change the head unit back first... but MB guarrentes all the wearables... so go postal in there!@!!!!

hokusbenz

my buddy had a speaker go in his clk and they replaced it no problem under warranty

C230Komp

I don't have the Bose.

I'm really tempted to take it in as is and give it a whirl. Raymond, who I bought it from, said that when he took his car in to the dealership (not for the radio), the guys were more interested in playing with it cuz it was different. They didn't hassle him. Since it's a speaker issue, I just expect the worst. If they give me crap, I guess I could replace the speakers with aftermarket units if I could figure out how to get to them.....

mdp c230k

The stock system seems to have some sort of limiter circuit or 'soft clipping' and most likely can not blow the speakers because before the amp goes into clipping the gain is reduced. Its clipping that is the most common cause of a blown driver, clean power (in the proper freq range for the driver) is rarely the cause of driver failure in a decent setup. Enough rambling...take it in to the dealer for him to replace the defective, not abused, driver. Either that or to fix the loose connection.

vadim, its the amp that would be at fault, not the speaker. A burnt voicecoil is usually the result of too little clean power, not too much.

vadim

Could be the amp, of course, or the other way around - the point was: the speaker couldn't handle the power suppiled by the amp. The result - blown speaker coil (or what have you). Either way, it's not the user's fault.

What's "too little clean power", BTW? What's an alternative - dirty power?

mdp c230k

Yes, it is dirty power. Meaning that there is a lot of distortion in the output of the amp. If a lower powered amp is driven into clipping it is more likely to blow a speaker due to the fact that a clipped signal is essentially DC during clipping. A speaker disipates power in two ways, movement and heat, if it can no longer move in the direction of the applied signal it must make heat out of the voltage. This happens when a speaker reaches its limit of travel, as is the case when a DC voltage is applied from a clipping amplifier. The longer the amp clips, the more heat to the voicecoil. If the amp never clips and you dont exceed the excursion limit of the driver you will not blow the voicecoil. I have played speakers rated at 50 watts with my 500 watt amp at very loud levels and never blown one but have blown the same speaker with a 20 watt receiver. Its all about clean power.

vadim

Of course, if the amp is poorly designed, it's easy to blow a speaker, but line input level is not supposed to cause clipping under any circumstances, and even if you overload the input, there are numerous ways to prevent DC transfer to the output. I would be surprised if MB/Bose put such a crappy (sub-Radio Shack) amp in their car.

WyattEarp

It really has nothing to do with the design every amplifier will clip when driven hard enough.

Clipping is simply a function of the amplifiers inability to reproduce, at the requested amplitude, the original signal. It is called clipping because if you've ever observed the phenomena while it is happening on an oscilloscope you would see the peaks and throughs of a pure sine wave chopped off and replaced by a straight line (Since I mention a sine wave I will assume that everyone knows that music and/or speech is merely a sum of sines and cosines of different amplitudes and frequencies. This is commonly reffered to as a Fourier Series). That straight line corresponds to a positive / negative dc signal at the amplitude where the amplifier gave up.

Finally amplifiers from the cheapest to the most expensive are nothing but a Transfer Function. They agree to amplify the signal provided you agree to give them an input signal not exceeding a certain amplitude. Most good amplifiers will have a range that they accommodate as far as the peak voltage of the input signal but if you exceed that voltage you will drive the input stages to distortion. It would be cost prohibitive to design an amplifier to compensate for infinite variations of amplitude at the input.

Harris

Hey, maybe its time for you to change the speakers with some better aftermarket ones.

C230Komp

Harris,
That's kinda what I was thinking too. I don't have the Bose system, and the rear door speakers suck even at their best. I've never heard any OEM speakers sound that crappy before. Are they hard to get to? Any recommendations as far as brands/model numbers? I don't want to spend too much since I just bought the car and I'm working it into the budget anyway.

vadim

Wyatt, if it's driven by a standard unit that's not supposed to exceed the "line out" level, no clipping should occur. We are not talking about some hypothetical situations, but about stock car audio components that are designed to work together. So it does have a lot to do with design *if* clipping does occur.
The cheapest ones - yes. More robust ones use soft compression/limiting to prevent the aforementioned clipping if overdriven.

Harris

I think 10 out of 10 ppl you asked will ask you the same question: How much are you willing to spend? Its very hard for us to give you any specific brand/model because of the following reasons:
1) music taste varies by ppl, there're speakers designed for Pavarotti and there're speakers designed for Bon Jovi.
2) speakers do fall into the general rule of thumb...the more expensive they are, they better they sound
3) there'll be not much difference if you just change the speakers alone, what matters most is you have to at least change the head unit, (preferably add an amplifier) in order to feel the difference. Otherwise, dont waste yr few hundred bucks JUST to change the speakers.
Also, I would suggest you to bring the car to the dealer and ask them to replace the speaker for you. My guesstimate is they will because its very hard for them to "prove" that you've "blown" it by yourself. And of course, I would still recommend you to change the speakers after you've got the replacement because those speakers are really crappy! If you're buying nice speakers now, you'll need the stock ones when you're selling your car because you wont be giving away yr aftermarket ones, right? The speakers are not hard to take out (at least for my C32, I guess the C-coupe has a similar interior design?!).
Good luck!!

mdp c230k

Vadim,
your suppositions are incorrect. True quality amps do not use compression/limiting as it is not true to the source materials dynamic range, they rely on having the user be smart enough to turn it down if they hear distortion. It is very easy to exceed the line level input of an amp unless the amp is designed to have an enormous amount of headroom to enable it to cope with the use of EQs. If you expect to be able to turn the bass control up all the way and get louder bass without clipping reguardless of where the volume is set, it wont happen. Every 3db of boost requires double the power. If the amp is not to clip then the volume at midrange freqs would have to be 3db lower than if no EQ was applied making the system sound less loud. More boost less average level. They build the system to reach a decent volume level with a little bass boost, it will be overdriven if there is too much boost or the average level will be very low to assure that the max output of the amp is not exceeded by the bass requirement. Thus the bass will be 12db over midrange level but it will be much lower than if no boost at all.

vadim

Oh, puuuhlease! We are not talking hi-end $3+K worth tube amplifiers here (which, BTW, provide soft limitation due to inherent amplification properties of a tube). Car stereos are different since they are designed to work under noisy conditions, meaning 1) they should lift the signal above that noise level and in so doing 2) they must NOT cause sound distortion in form of clipping. How? By narrowing the dynamic range of the source signal (compressing).
If they (MB/Becker/Bose folks or whoever else is involved) are advanced enough to have put a DSP and speed-sensitive volume control in the MB sound system, wouldn't it be logical to assume that they also use some sort of input circuit overload protection?
Then I'd chuck this amp.

But then again - we're not plugging, say, a guitar into this amp - that would certainly be quite an issue due to wide dynamic range of its output. We have a CD player a digital source that has a rather narrow dynamic range (16 bit), and 2 sources (Cassette, FM) that present even less challenge to the amp.

Let's straighten this up a little: we're not discussing some hypothetical issues related to sound amplification, but a car sound system that was designed as a whole from the start, with all components well fitted together.

If you have any proof that the MB/Bose amp clips the signal, please produce it (an oscilloscope screen shot will do). Otherwise, let's just close it up since the original question has already been answered.

mdp c230k

If I had that much free time I would love to show you what I'm talking about. Since I don't, I'll just rest easy knowing I'm right. It is obvious that you do not agree, so be it. I'm sure that if you took a good look at the amount of power needed to drive the stereo to normal levels with the windows down you would see that there is virtually no way of the amp not running out of power if the bass is boosted unless there was serious compression, which would sound like an old DBX unit breathing away. But, I enjoyed your arguement.

WyattEarp

Once again we agree even though I know you don't like it. Vadim does not understand amplifier circuitry / design.

WyattEarp

Are you really that foolish?