When upgrading your factory Harley radio to a new aftermarket model there are a few things that you should consider.
First and foremost, you should ask yourself - why do you want a new radio? There are several good reasons to switch your radio out for a more modern unit, but not just any radio will do the job. Infact the wrong radio can be a step backwards!
Good Reasons to Go Aftermarket with Your Radio.
This is the primary motivation behind most peoples choice to get into an aftermarket radio. And good quality radio from Alpine or Kenwood can definitely get you there. When expecting a boost in sound performance in a radio it is vital to choose a radio that has a strong Preamp section, digital to analog converter, digital EQ, quality Bluetooth.
The preamp is the internal part of the radio that processes that sound before it gets to the amplifier, whether it be the radio's internal amplifier or an outboard amplifier. Preamps are rated in volts of output.
The D/A converter is the part of the radio that turns your digital music from CDs, Bluetooth, USB and so on into listenable music. When upgrading to an aftermarket radio one of the major benefits is that you no longer have to use the headphone output jack from your phone or iPod. The problem with the headphone jack on your MP3 player is that it is engineered for headphone sound quality. By plugging your device into a true USB jack or connecting via Bluetooth, you are bypassing the crappy D/A converter in your phone or iPod and allowing the superior D/A converter in your new radio to do the job. The D/A converter built into your aftermarket radio is more up to the task and will yield much better results. Assuming that you went with a radio that features a quality D/A converter.
Modern radios have onboard digital EQs that replace the old bass and treble adjustments of outdated radios. Not all digital EQs are created equal. The Alpine CDE-hd148bt & 149bt for example have 9 band parametric (the best kind) EQs built into them that can either be adjusted through the radios interface or better yet through your smartphone. You can do this in real time. Just touch, drag, and listen to the changes in sound. Baby simple!