Hi. I have the original Bolero sound system in my 2010 Skoda Octavia VRS. When using the AUX in port (in the centre box) with my phone to play music I noticed that the quality of the sound was in a word crap. I'm not overdriving the aux input. What I have found is that the right channel speaker output seems to be made by adding the left and right input channels together firstly phase reversing one of the channels. Eg if the same frequency and phase is fed into both channels then the right channel outputs nothing. If one of the channel inputs is 180 degrees out of phase with the other then you get the sound tone on the right channel. What is going on here ? If I play the same music using the SD card it sounds great.

Hi,

this is not meant to sound a daft suggestion but have you made sure that your jack plug is fully inserted. I had a similar problem with sound quality initially but found that I hadn't pushed the plug in up to the hilt, so to speak. I presume it is a decent adapter for you phone too?

Some phone cases stop the jack plug being inserted correctly, the symptoms of the OP suggest that the plug is not fully inserted.

I've got the same problem i think, i retro fitted aux port with a bolero and if i fully insert the jack lead most of the sound comes out of the drivers side, if i lift it and wiggle a bit then it seems to make a full connection and sounds spot on. I've tried numerous leads and ipods/iphones but all the same, im now getting an mdi instead!

Yes I've made sure both plugs were pushed in fully at both ends. I've even checked the cable with a multimeter.

Another thing, if I'm listening to music and adjust the balance control to full left it sounds ok but when I adjust the balance control to full right it's immediately obvious that something is wrong - sounds highly distorted.

It must be something in the aux signal path . If I play the same music via the SD card, both channel outputs are ok.