Blazer Forum - Chevy Blazer Forums - New setup MTX THUNDER 7801 and 2 AUDIOPIPE TXX BD2 12'S

Here's relatively close to what you need to do.

First off, the gain sensitivity button should probably be turned on to 10x as I would imagine your HU will max the amp out on the 1x setting. Set the gain with your ears, no DMM, and definitely no SMD DD-1. Play songs you're very familiar with and turn the gain up just to the point of hearing distortion or stress from your subs and then back it down a little. Every song is recorded with different reference levels, has different compression to the dynamics, and has different amounts of bass. Because of those reasons no single gain setting (bass level, etc.) is perfect for every song. Use your ears and the big spongy organ between them when listening to your system. Listen for distortion, noises, and stress to the sound itself and turn it down when you do. Turn the remote level all the way up, set the gain, and then use the remote level to adjust the output of the sub so that it doesn't overpower your highs.

Second, turn on the subsonic filter. It will help to protect the subs should you play something below the tuning of the enclosure. The only problem with it is that it's a fixed SSF at 30hz and is not adjustable. That means if you're tuned much higher than that there is still a danger of driving the subs beyond their mechanical limits. If your enclosure is tuned within 3 to 5 hz of the SSF's 30hz fixed setting you're golden. If you're tuned higher then watch the super deep stuff.

Third, DO NOT turn on the EQ Boost. It's just bass boost with an adjustable setpoint by which to set the frequency it's boosting. Turn it to the center and leave it there.

Fourth, Turn the low pass crossover as close as you can to the point you have your highs high passed at if you do indeed have them on a high pass crossover. In either case adjust the LPF to where it blends with the rest of the speakers/system. Will be more of a personal preference than anything concrete.

Fifth, the prism is part of the lighting on the amp, go for whatever floats your boat there.

Hope that helps.