There is very definitely a significant different in how these two systems sound.

The older one has much more low end above a setting of about '45' on the volume ****. Used to be, 50 was comfortably (barely) loud. 50 is now the near-normal listening level for music on the same MP3 player, without any adjustment since my '08.

Frequencies below 200-250 are severely attenuated above this, and the bass never hits as hard in my '12 as the '08. Not even close.

I wonder if there's a way to fix this, because the old sound, IMO, was much better. Much fuller.

Being as I have rear A/C, trunk space, while not exactly tight, I don't want to take up another few cubic feet with an amplified sub.

 

This has been an observation I've heard of before. It's a shame, because that ol' ML was a beast. I miss it VERY much, even though my current SONY Premium in my SHO is "good enough". I am of the understanding that Ford nerf'd the new ML to prevent the ongoing issues with blown amps in the pre-12 MY's. I wonder if one could just swap out the nwew ML and replace it with an older amp? That's where I'd start. I also wonder if United Radio has any info on this? Maybe they can help fix you up.

 

the ML in the 2007 - 2009 LS was really good. The 2010 - 2012 units were terrible. There were a few posts back in 2012 where a few of us were quite surprised with how bad the ML units were. I bought a 2012 LWB with ML and did not really check the music system the day I bought it. The next day when I did turn it on my first thought was that the sub was not working. I had it checked out by lexus, including someone from their corporate team and got the stock answer - works as designed.

 

The ML system in my '07 LS was phenomenal. The ML system in my '14 LS sounds worse than the base system in my '08 IS! I think they de-tuned the ML system at some point because of people blowing out amps and subwoofers.