I have 2 12" type-r at 4ohm with the MRD-M500 mono, and a 7892 alpine deck. i'm not getting a lot of loudness of bass, don't get me wrong it's loud as hell. When matched with a friend's 2 12" type-r powered by a alpine v12 600w 2channel, he has way more bass. We are both in a sealed enclosure, he has a capacitor and a 5 volt preout, (where mine is 4) but these are the only diffrences. Is there some setting on the amp that i'm not setting, or do i need a cap??
what is your load at the amp? You want to get it to 2ohms to double your power. The settings on the amp are important but your power comes from the resistance. As far as the settings go, make sure you have setting 1 on 2 channel, and make sure you have your frequency around 80hz. You can also go into your parametric eq and adjust the bass boost and bandwidth, but your amp shouldn't need too much tuning in that area since your deck does everything. If your type r's are single voice coil then you're at 2ohms at the amp, but if they're dual voice coil then they must be wired in series, and can't reach their potential power needs. My advice is to get single voice coil type r's, or 1 dual 4ohm type r, or another amp.