Well, I'll eat my words about the LC6i. I got it sounding crystal clear. No hiss anywhere now. It just needs to be rubbed the right way which can be a bit frustrating. The level-matching has to be spot on between it and the amp. I also had the issue of the only getting high frequencies to the sub. The LC6i has an automode that will take the channel 2 frequencies and put them to the channel 3 frequencies if theres no signal in channel 3. Turns out the sub signal from the ML amp was not strong enought for the LC6i to detect, therefore it was sending in the channel 2 signals. I emailed AudioControl about this issue and here's what they told me to do: see photo.

http://img190.imageshack.us/img190/3087/lc6igray1.jpg

Haven't done this yet, but right now, just using the scosche LOC it's sounds perfect, however the LC6i will allow some more power to the sub, which I think it lacks just a bit right now. So, in conclusion, the LC6i can be outstanding....if you know what the heck you're doing. I didn't.

What do you mean by this? Summing up the front and rear?

Well, when I wasn't getting my frequencies from my stock sub (due to the LC6i), my subwoofer was hitting with the same "notes" as the midwoofer in the front door. I was missing the lower frequencies. Basically, when I put my sub on a lowpass filter from 60hz, nothing would come from the sub. This tells me that the stock ML amp cuts the front woofers off at around 60hz. So, I'm simply saying for people running a sub only setup, they need to sum the front woofers AND the subwoofer to get a "full" signal. Does that make sense?

When you mentioned summing the sub + front. Is this the front "high" or the front "midwoofer". I have a LC2i and about to install onto the 2012 IS-F. I have wiring diagram (just go to Lexus dealership and ask for it).

Thanks

Front mid woofer with rear sub for sub install only. I did all of mine though, because I replaced the front speakers.

I finally installed the LC2i, wicked CAS seal enclosure, JL 600 XD/1 and 10W7AE.

I tapped the subwoofer and front mid woofer.

Some of the Bass are perfect, but I noticed on the certain frequencies the bass is delay by about 0.2 second. Any clue?

Can anyone post the schematic to the 2012 ML system? I contacted ML directly for it, but they did not reply.

Does the '12 speaker wire color match the ones in my pics? If so, just use what I did.

Haven't checked and my audio guy will be doing the install. Figured I'd forward over any schematic info if any of the members had it handy.

ML doesn't seem to customer service oriented, may just have to contact Lexus directly for it.

Is it possible to use the positive and negative inputs from the back or the factory sub instead of cuting into the inputs of the ML amp?

Yes you can.

Thank you for the clarification!

Why is it most are cutting into the harness for the sub signal?

Easier access. Everything is right there at the amp. I'll just put everything back together and tie it all up with e tape when I decide to part with the car. But I'll leave the Polks in the doors.

Curious as to how much of an improvement there was for your system with replacing the door speakers?

I've considered just starting over with my system and letting my audio guy run wild with it. I like the head unit and all the functions, but I want some better sounds and definitely some volume + bass.

Ever since I modded my exhaust, I didn't bother with a sound system.....often times I lower my music just to hear my exhaust...every time I drive I'm at a crossroads like "not sure if listen to exhaust or blast music". For me the ML is loud enough to drown out exhaust noise.