Speaker

[Suki]

Hi,
I have an R reg c250TD. It has done ~175k miles so it is doing reasonably well.
However.. due to the music I must be listening to (i.e. lots of base) I have manager to tear the speaker in the passenger door. Now it makes a buzzing noise which is not pleasant!
Does anyone know where I can get an after market speak that slots straight in?
Regards
Suki

 

[BlackC55]

Speaker manafactures have a database with details of which speaker fits original equipment mounts. Go into your local stereo shop and ask.

 

[wireman]

You could attempt to repair the speakers cone, it depends on where its failed but I have managed to sort out speakers with detached outer surrounds using tissue paper (the sort you get in a roll) and bicycle puncture repair solvent based rubber soloution.
Cut a small piece of tissue to cover the tear, paint the damaged area of the cone and surround with sticky stuff and place the tissue onto the damage moulding it to shape as the glue sets, add another coat of stickums all the way around the outer edge of the cone and its surround after its all set.
This proceedure will alter the speakers performance charateristics slightly but in a car door it wont matter a jot.

And last but not least turn down the bass it can and often does make you deaf.
To prove this speak quietly to an older recording engineer who spent his younger days in rock music his response will be "speak up" or the like.

Technicaly turning up the bass full makes the energy avalable at low frequencies much greater than the speaker can stand by a factor of at least ten times, 10dB (maybe as much as 20dB,100 times), then when you adjust the volume to make the parts of the sound that the human ear can use usable you are giving the speaker hell and it will fail as you have discovered.

What what.

 

[Cnics]

One thing missing from so many systems is a high pass filter. We're not going to get these type of indoor speakers to reproduce 20Hz and yet often when you turn up the bass you are boosting these frequencies aswell. This is a shelving filter which adjusts at a certain frequency and everything below or above it (below in this case). Without a suitable Hi pass filter (HPF) you are making wat wireman describes worse still.

it is the mid range that the human ear is more sensitive at and high volumes at this can cause hearing damage, however it is the low frequencies that use up all the available headroom from the amplifier in the system. This means that what little power is left for the higher frequencies will not be enough and will distort. Installing an aftermarket sub with an amp would possibly be an option for you after you have repaired or replaced the driver which should stop this happening again. But this would only work if there are certain controls on the unit itself. You'd be able to put a higher HPF for your main speakers, allowing more headroom to the mid and high frequencies and let the sub with a much much larger amp provide you with enough bass.

We're not talking 2 15 inch subs in the boot of an astra here but a more subtle approach. I'll admit i do have 2 10 inch subs off a 1000watt (rms) amp in the bulkhead of my van. But as a sound engineer i cannot listen to poor quality sound, and the sprinters speakers really aren't amazing.

 

[television]

Most MB's speakers have a 1 ohm impedence that makes after market very difficult, adding filters to standard radio's seldom works that well due to the type of output stages used

 

[Cnics]

no, the HPF would need to be active, ie before the power amp stage. It would be far too inefficient to do it passively.

1ohm eh? never knew that. Interesting one there, must give the amp a hard time, unless of course there are more than one on a channel in series.

 

[television]

no, the HPF would need to be active, ie before the power amp stage. It would be far too inefficient to do it passively.

1ohm eh? never knew that. Interesting one there, must give the amp a hard time, unless of course there are more than one on a channel in series.

In my 55 years of this I have never seen 1 ohm before, it was only when thinking of changing my 129 speakers, that I found this out.
I will look up some of the becker output stages later in the day

 

[kid-jensen]

Guys,

It's obvious why MB use such low impedance speakers, more power!

Power is V squared over R, and the V bit is what it costs so much to provide (and unless you take special measures, you're stuck with a maximum voltage swing between 0 and 12V).

By reducing the speaker impedance, you're increasing the power dissipated in it, so you get "more power for free". Obviously, the power output stages of the stereos have to be designed to handle it, or they'll just blow up.

Mercedes blowing up.........that's topical !

 

[television]

Guys,

It's obvious why MB use such low impedance speakers, more power!

Power is V squared over R, and the V bit is what it costs so much to provide (and unless you take special measures, you're stuck with a maximum voltage swing between 0 and 12V).

By reducing the speaker impedance, you're increasing the power dissipated in it, so you get "more power for free". Obviously, the power output stages of the stereos have to be designed to handle it, or they'll just blow up.

Mercedes blowing up.........that's topical !

It is not quite like that in real life as the output chip can only handle its rated output, as long as it is designed for the low impedence, its OK.

 

[Suki]

Thank you for all your help. I shall try and get a speaker with the correct resistance!

 

[television]

It could pay you to try a breaker, much cheaper