It is impossible for anyone to tell you what sound will be like with 2 CIs.
However, it will be more balanced and you will notice a fuller, richer sound.
I have bilateral CIs and love them. I received my first CI in 2004 and my second in 2006.
I originally thought that learning how to hear with the second CI would be more difficult, but the opposite was true. In fact, my progress was much faster and it took me less time to understand speech with my second CI compared to my first.
One of the things I want to strongly emphasize is not to expect dramatic results when your second CI is activated. It won't be as exciting and you're not going to notice much of a difference in what you hear with the exception of hearing bilaterally and hearing voices/environmental sounds from a further distance. In time, you will also notice a fuller, richer sound. When I wear one CI, sounds are tinny and more difficult to hear/understand. When I wear 2 CIs, everything sounds so much clearer and speech is much easier to understand. I also hear better in noise with 2 CIs as opposed to one.
I would also suggest that you keep your expectations low when learning how to hear with your second CI so as not to be disappointed if you do not hear the things you expected to.
I also recommend that you spend some time during the day listening only with your second CI. This will help strengthen it and allow you to become used to the sound quality. When I practiced listening with my second CI, I spent anywhere from 30 minutes to an hour on various websites. The remainder of the day I used both CIs together.
It will take some time before the sound of both CIs blends together. Your first CI will sound much clearer and louder than your second CI for awhile, but this will gradually improve with each new map you receive. Once your dynamic range increases, this will allow you to further customize your maps for better sound quality.
In my case, it took a little over a year for both of my CIs to sound natural and as if I was hearing in in stereo.
Keep in mind that your experience may be quite different from mine and you may progress much faster than I did.
