It's all about the bass (or lack of it).

[lightning]

I like the Sony as it has a traditional rotary control for volume.
Some have buttons you have to hold down to increase/decrease volume, which is a pain when driving.

 

[t-tony]

The factory one in my Z4 is rotary, but since fitting a multi-function steering wheel they're at my finger tips. Much better.

Tony.

 

[lightning]

Well yes if you have a remote that's ideal

 

[Sean d]

Well yes if you have a remote that's ideal

The factory one in my Z4 is rotary, but since fitting a multi-function steering wheel they're at my finger tips. Much better.

Tony.

I've always thought that a remote control with a car stereo was a waste of time but when I was driving last week it got me thinking that one fixed to the back of the steering wheel would work rather well once you got used to the buttons

 

[t-tony]

Did one come with your Sony head unit Sean? You can probably buy one if not.

Tony.

 

[Rudyrov]

"Sounds to me" (no pun intended) like what you need to do is diagnose the source of the trouble.
A frequency sweep recording played back through the system would allow you to hear whats coming out of what speaker.
These kinds of sweeps and many other test tones are often found on test CD's, perhaps a local audio shop or music store can help you locate one?
For example:
http://www.kicker.com/test-tones
http://www.audiocheck.net/audiotests_index.php

Download and play these back through the system either by burning a CD, tape or USB stick depending on your radio's capability will help you identify whats, what.

 

[Sean d]

Did one come with your Sony head unit Sean? You can probably buy one if not.

Tony.

No it didn't mate, I'll take a look to see if I can get a generic one,