I had an alpine head unit with an RMS of around 17. They sounded pretty loud with the volume set at 13-15. Now, i have a kenwood head unit with an RMS of 22. With the volume set to 15, the sound is low, way lower than the alpines. I usually have to set the volume to 20 to get the kenwood a little loud. I was assuming the kenwood would've been louder since it's RMS is higher. Do you think my head unit is insalled incorrectly or something???