I used a pro shop to install my amplifier under the passenger seat today. I supplied the amp and an amp install kit. They charged me $125 labor, and $42 in additional parts / shop supplies (24' Stringer 9 conductor speed wire was $36 of that). It took them about 3 1/2 hours -- not sure what takes all that time -- but install was nice and clean. They let me into the shop to see the install before they buttoned everything back up.

However, I was not invited, nor did I ask to participate in the tuning (setting gain and deciding whether to turn on high pass filter and if on decide what frequency to set it at). I guess I should have ...

On the ride home, it was clear that my Polk speakers which I put in eighteen months ago had been hindered in what SQ they could deliver by being driven my the stock Mini head unit. With the new amp, I was hearing a lot of detail in the music that I was not hearing before. And it seemed like the music sounded more fuller even under the assault of Mini road noise (I do not have any sound deadening installed, and the 17" tires I have are noisy suckers). But, where was my bass? I kept going "next song", "next song" on the USB to try to find a song with bass. It was missing, gone, lost.

I'm not a subwoofer type of person, but I need some bass! The shop is 30 miles away, so I did not head back. But I did call them when I got home. "Do you have the amp filter switches set to off (full range speakers)" I asked. "Hold on, let me check" the guy on the phone says. A minute or two later he comes back and says "they had a lot of speaker distortion at louder volume with the setting at full range, so they turned on the high pass filter and set it to 120 Hz". I said "Ok" -- what else was I going to say? Of course when I gave them the car, the bass was set to +5 and it was still +5 when I got it (i.e. it must be saved in some type of flash memory unlike the time of day which was lost with the battery disconnected).

Not a problem -- next weekend (or perhaps some evening this week), I'll just unbolt the passenger seat, tip it back (leaving the airbag connector attached), pop the plastic under seat cover that protects the under seat enclosure, set the head unit bass to 0, and see if I can't either set the amp to full range speakers or at a minimum dial down the high pass filter frequency -- its settable from 40 Hz to 500 Hz.

But, despite the minor issue / adjustment needed, I'm still happy with the install as I wasn't entirely comfortable with doing the power / ground, and the disassembly of the X9331 pins and subsequent connection to the speed wire 9 conductor going to / from the amp and the routing of said wire to the amp. Plus I didn't have to fight getting all the trim pieces off and put back as I did when I replaced the speakers.

Bottom line, hard part of the install is done and 120 Hz cutoff not good! But, I can easily play with "tuning" to get it more to my liking.

 

At least it is an easy fix, that's good. I believe the radio settings (stations, preferences, etc) are stored on the key fob.

 

I may be wrong but I don't believe the bass and treble "settings" are a setable parameter. I think they work like all old fashion radios do + or -.

 

Some order returned to the world. Got home early from work today. A bit of the pain to unbolt the seat and the under seat plastic cover, but fairly simple.

I just left the air bag connected and tilted the entire seat out of the car onto a box I placed next to the open passenger door. Then I was able to access the amplifier switch for the high pass filter and dial for the frequency. What seemed to work best was to turn off the high pass filter entirely on the amp channel for the rear speakers, and to have the high pass filter on for the front speakers but dialed down to 50 Hz (the lowest value). I did find some distortion when set to full range on the front for some songs at a high enough volume.

I'll see how this sounds for a while. At least I know it's relatively simple to change it if I desire.

I was also pleasantly surprised at how little heat the amp had, but then again it is a class D amp so it should keep the temps down.