Poor sound quality when playing music from phone (aux)

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Snowman89

New Member
Joined
Jun 15, 2016
Messages
14
Car
Mercedes CLC 350
I own a Mercedes CLC 350 2008 that hasn't done many kilometers since it rolled out of the factory.
However the sound quality is really poor when I play music through the AUX port from my phone.
The same phone/cable combo works perfect in my Skoda Octavia 2010 and the sound is great.
However when i connect it to the CLC it sounds like the music comes from a paper bag..

The car has navi and i think it is called "comand", not sure though since this is my first Mercedes.
When i just play radio the sound is perfect, so it should not be related to the speakers being crappy, it seems as if there is something within the stereo or between the stereo-aux outlet that is messing the quality up.

Does anyone have any ideas on how to fix the sound quality?
Or should it really be this crappy?
When the car was sold new it was really expensive since it has the largest engine and also quite alot of equipment, so i would have expected the sound system to be better since my Skoda Octavia actually has a better stereo sound as it is right now...
 
Does anyone have any ideas?
I seems as if the bass is one of the things that dissapears..
 
There's a booster you can buy, MB's of that era are notorious for this. I'm sure I-Conica on here has one IIRC or another member

Someone will be along to name the proper device

Jack input on my W204 is the same. USB is perfect though
 
There's a booster you can buy, MB's of that era are notorious for this. I'm sure I-Conica on here has one IIRC or another member

Someone will be along to name the proper device

Jack input on my W204 is the same. USB is perfect though

Oh thanks for your reply!
I will look up the user "I-Conica" and throw him/her a PM!

Edit: ****.. I just noticed that I'm not allowed to send messages to users..
Could someone please ask I-Conica for me or just point to this thread?

Otherwise some advice on which booster to buy would be great.
 
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Does anyone have any ideas?
I seems as if the bass is one of the things that dissapears..

Hmmmm, I do the same thing as you are doing and have no real issues, apart
from the phone audio is a little bit quieter than the radio/cd player. But it's
still loud enough to use on full volume.

I wonder if the spacings of the 'left/right & common' connections on the jack
plug aren't quite lining up properly when you insert the jack into the Merc.

Different manufacturers sometimes use different spacing lengths to encourage
you to only buy their cables to get good sound quality. (Although, this is rare)

Or you might be using a cable with five connections - 'left/right common with
two extra connections - for data. (these extra connections carry phone communication
information, as you can see in my photos)

Ideally you need to be using a three connection cable.

It's obviously lining up correctly with your phone because, as you say, its fine in your
Skoda. Are you sure your plugging the jack fully into the audio port in the
merc? They can be quite tight when new.

You can also try not fully plugging it in too, see if this cures your muffled sound.

I use the audio cable that came with my Creative Soundworks 5.1 system which
I used to use on my old desktop pc. Its a good quality cable, but the 5.1 system
is now sadly defunct. :0(
 

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Not sure if it's the case with your car, but on mine each audio source has its own audio settings (bass, treble etc). So on mine I can have max bass, no treble on radio and no bass and max treble on the media drive and it remembers the audio settings and uses it for the audio source each time you select it.

There may be a faint possibility on aux source your treble may be set to minimum accidently?
 
Hmmmm, I do the same thing as you are doing and have no real issues, apart
from the phone audio is a little bit quieter than the radio/cd player. But it's
still loud enough to use on full volume.

I wonder if the spacings of the 'left/right & common' connections on the jack
plug aren't quite lining up properly when you insert the jack into the Merc.

Different manufacturers sometimes use different spacing lengths to encourage
you to only buy their cables to get good sound quality. (Although, this is rare)

Or you might be using a cable with five connections - 'left/right common with
two extra connections - for data. (these extra connections carry phone communication
information, as you can see in my photos)

Ideally you need to be using a three connection cable.

It's obviously lining up correctly with your phone because, as you say, its fine in your
Skoda. Are you sure your plugging the jack fully into the audio port in the
merc? They can be quite tight when new.

You can also try not fully plugging it in too, see if this cures your muffled sound.

I use the audio cable that came with my Creative Soundworks 5.1 system which
I used to use on my old desktop pc. Its a good quality cable, but the 5.1 system
is now sadly defunct. :0(

Thanks for your reply.

The volume itself is the same when using AUX or Radio.
However the quality drops badly when switching over to AUX.

The cable I'm currently using looks like the green one you have a photo of.
Yes I'm sure it plugs in correctly, however the sound is similar to the sound i get in the Skoda when the plug is not inserted all the way.
If i dont insert it fully into the Merc the sounds becomes even worse..
 
Not sure if it's the case with your car, but on mine each audio source has its own audio settings (bass, treble etc). So on mine I can have max bass, no treble on radio and no bass and max treble on the media drive and it remembers the audio settings and uses it for the audio source each time you select it.

There may be a faint possibility on aux source your treble may be set to minimum accidently?

Yepp it is the same on my car.
I have however tried fiddling with the bass and treble settings without any luck.
I also tried to run the same settings on AUX as on the radio setting, but it still sounds crappy.
 
Thanks for your reply.

The volume itself is the same when using AUX or Radio.
However the quality drops badly when switching over to AUX.

The cable I'm currently using looks like the green one you have a photo of.
Yes I'm sure it plugs in correctly, however the sound is similar to the sound i get in the Skoda when the plug is not inserted all the way.
If i dont insert it fully into the Merc the sounds becomes even worse..

Ok, lets start from the ground up.

Your next step is to try a different audio cable. (if you haven't already done so).

Failing that I would trace the cable from the audio socket in the glovebox
to the wiring loom its plugged into. look for any nicks or cuts in the cables
that could short against the body of the car. It's also possible it has become
loose and is only half plugged in.

I believe the loom its plugged into on a CLC is in the passenger foot well.
You'll need to pull the trim up and off the door sill and the loom is in
between the carpet and the body of the car near the hinge end of the door opening.

If it is plugged in properly and you still cant get good sound quality, then
my money is on the socket in your glove box being at fault.

I would buy a new OEM Audio socket.

One like this, from here: NOTE!!! THIS LINK IS FOR THE CABLE I BOUGHT FOR MY CLK.
I DON'T KNOW IF IT WILL FIT YOUR CLC!!! YOU'LL HAVE TO FIND THE 'A' NUMBER TO
SUIT YOUR CAR!!!

CABLE HARNESS - unspecified All Years General Repair - Mercedes-Benz Parts, Inchcape

I fitted this one myself in my CLK because it didn't have one when I bought it.
They were the cheapest I could find and it's OEM.

I don't think your radio is faulty or you would have the same sound issues
with the CD and radio. The same applies to your speakers, amp, etc.

There isn't much else that could be at fault other than that.

Well apart from a cable shorting somewhere against the body of the car, that is.
But that would certainly not be the case if its only MB who has touched your car.

Theres no accounting for what the previous owner(s) has/have done to the
car before you bought it.

Hope this helps.

This is the method for fitting a new Aux cable on a C class:

http://mbworld.org/forums/c-class-w203/81978-diy-setting-up-aux-input-ipod-mp3-player-etc.html
 
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Going off what it says here:

https://www.commandonline.co.uk/aux_input_w203.html

The Aux cable is the same as the one I used in my car.

But... your W203 CLC being a 2008 is a bit tricky.

Because they facelifted the W203 CLC in 2008.

You'll need to find out which one you have so you don't waste your money
buying the wrong cable.

That said they may have used the same cable pre and post facelift.

I just don't know.

Erm I'm not so sure if this helps at all actually, sorry. :0(
 
All these replies are misleading

It is literally the Jack input on the AUX, it's quieter than other inputs, no different cables will help and everyone's perception of loud audio is different

The only thing that helps is the booster thing
 
All these replies are misleading

It is literally the Jack input on the AUX, it's quieter than other inputs, no different cables will help and everyone's perception of loud audio is different

The only thing that helps is the booster thing

Erm the OP's issue is with sound quality, not volume.

It says so in the title of the thread...

And here:

I own a Mercedes CLC 350 2008 that hasn't done many kilometers since it rolled out of the factory.
However the sound quality is really poor when I play music through the AUX port from my phone.
The same phone/cable combo works perfect in my Skoda Octavia 2010 and the sound is great.
However when i connect it to the CLC it sounds like the music comes from a paper bag..

The car has navi and i think it is called "comand", not sure though since this is my first Mercedes.
When i just play radio the sound is perfect, so it should not be related to the speakers being crappy, it seems as if there is something within the stereo or between the stereo-aux outlet that is messing the quality up.

Does anyone have any ideas on how to fix the sound quality?
Or should it really be this crappy?
When the car was sold new it was really expensive since it has the largest engine and also quite alot of equipment, so i would have expected the sound system to be better since my Skoda Octavia actually has a better stereo sound as it is right now...

And here:

Thanks for your reply.

The volume itself is the same when using AUX or Radio.
However the quality drops badly when switching over to AUX.

The cable I'm currently using looks like the green one you have a photo of.
Yes I'm sure it plugs in correctly, however the sound is similar to the sound i get in the Skoda when the plug is not inserted all the way.
If i dont insert it fully into the Merc the sounds becomes even worse..

And here:

Yepp it is the same on my car.
I have however tried fiddling with the bass and treble settings without any luck.
I also tried to run the same settings on AUX as on the radio setting, but it still sounds crappy.
 
Coruscator said:
Erm the OP's issue is with sound quality, not volume. It says so in the title of the thread... And here: And here: And here:

Erm, Indeed

The quality via JACK input is also not as great

We're talking the same difference between a 192kbps YouTube rip and a purchased 320kbps or even a WAV

I know this because I've tested it

Higher volume doesn't fix poor quality, but it certainly helps towards the placebo
 
Erm, Indeed

The quality via JACK input is also not as great

We're talking the same difference between a 192kbps YouTube rip and a purchased 320kbps or even a WAV

I know this because I've tested it

Higher volume doesn't fix poor quality, but it certainly helps towards the placebo

I'm not sure if you understand what the OP is asking.

He isn't asking for higher volume to fix poor quality.

He's describing a noticable drop in sound quality whenever he uses his phone
through his Merc's aux input.

I use my phone as an audio player through my aux input and I don't get the
'lack of bass' or the 'sounds like the music comes from a paper bag' type of
sound quality he is describing.

The issue he is describing suggests to me that's is a poor connection somewhere
within the aux input wiring. Which is why I suggested checking it.

The sound quality drop he's describing is (to me) way more that the difference
between 192kbps and 320kbps or even a WAV.

Besides which, he has already ruled that out when he told us that the sound
quality is acceptable when played through another system (his Skoda).
 
I'm not sure if you understand what the OP is asking.

He isn't asking for higher volume to fix poor quality.

He's describing a noticable drop in sound quality whenever he uses his phone
through his Merc's aux input.

I use my phone as an audio player through my aux input and I don't get the
'lack of bass' or the 'sounds like the music comes from a paper bag' type of
sound quality he is describing.

The issue he is describing suggests to me that's is a poor connection somewhere
within the aux input wiring. Which is why I suggested checking it.

The sound quality drop he's describing is (to me) way more that the difference
between 192kbps and 320kbps or even a WAV.

Besides which, he has already ruled that out when he told us that the sound
quality is acceptable when played through another system (his Skoda).
Thanks for straightening this out Curator.
You are 100% correct and my problem is NOT with the volume of the sound, but the quality of the sound when i play music through my phone that is connected to the AUX-port.
The same phone/cable setup is being used in my Skoda and there it works flawlessly.

I will have a look at the AUX-port and its cabeling tomorrow and see if i can find any damages or nicks to it.
I seriously doubt that the previous owners have done anything to the AUX-port since he had been using the car with the speedometer language set to German and the units set to Imperial.
Instead of metric and English/Swedish as it should be..
The car was once imported to Sweden from Germany and the previous owners did barely use the car at all, in 6years the car had done about 16500miles..
 
Try a different device, an old iPhone was useless and a different hone was miles better.
 
Try a different device, an old iPhone was useless and a different hone was miles better.

If it would be related to my phone and its port, how come the sound quality is waaay better in my Skoda with the same phone?
 
If it would be related to my phone and its port, how come the sound quality is waaay better in my Skoda with the same phone?

Any harm trying?

Sod being helpful, normal service will resume.
 
Yes, I have a small headphone valve amp in my glovebox to boost it.

So it's powered from the cigarette socket in the glovebox, and takes a 3.5mm stereo jack lead as an input, other end in my iPhone.

The amp has a volume control on it.

The output is another 3.5mm jack to jack which goes into the aux input in the glovebox.

I then put a CD on, measure the average volume level in dBs with a phone app, then play the same song on my iPhone, iPhone volume on full, and measure again playing through the aux, turning up the valve amp until it's roughly matched (doing this to make sure I don't overdrive the input and cause some damage).

It's been working perfectly for two years, and is as loud as a CD. Quality is very slightly less than a CD, as there's a lot more analogue cables and gear in between, but it's perfectly acceptable.

I did try as an input to the valve amp, one of the cheap bluetooth audio receivers, but that has to produce the analogue signal, and for a couple of quid from eBay, the sound quality it produced was awful.
 

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