One of the selling points of the modern double din car stereo (and single din, if you must), is its ability to playback music directly from your iPod or iPhone. But most people don’t have them setup to maximise the music quality, especially when it is streamed to a car stereo.
There are two basic and simple ways that this can be fixed and you can optomise the sound quality of the music coming through your car’s speakers.
The first is in using a lower level of compression (higher bitrate). Most people will settle for a high level of compression (lower bitrate) so that they can fit as much music as possible on their mp3 players, which have a finite amount of storage space. This makes sense if you’re only going to listen to the music through a set of headphones/earphones, since they can’t produce a higher quality sound level even with a low level of compression. When you attach your mp3 player to a car stereo though, you have a higher quality of speaker from which the music is coming from, and thus, if you use a higher bitrate, you will automatically gain an improved sound quality.
The second way is to not use the built-in digital to analog converter (DAC) of your iPod. The DAC changes the digital information (all those 1s and 0s that computers use) into an analog signal (ie. sound). The DAC on the iPod, and most other mp3 players, is good enough for a simple pair of earbuds, but the DAC in most modern car stereos is much better, so by using the car stereo built-in DAC you will actually get a better sound quality than from the mp3 player’s. You need to connect the player ia usb cable to your stereo system though, so make sure the stereo can do this before buying.