subs, cant figure it out

I have a Kenwood DDX 7015 with a sub preout. The specs says the output is 2Vs. I am using 2 10" 4 ohm Rockford P110S4 subs wired in parallel to be 2 ohms powered by a Alpine M350 mono channel amp with 350Ws at 2 ohms. The subs operate at 150Ws continuous. My problem is that the subs doesnt seem to be producing "tight bass". I may not know the right terms to explain this but I will give it a try. It'll can be loud but not clear. It seems it drags it out and sounds muffled. The air space in the box for each sub is approximately .65cuft as what is recommended for the subs. Originally I thought the power cables I used were too thin so I ran 4 guage wiring but the problem still persists. I also took out my amp and box and put it into my friend's car where he tapped the rear speakers with a hi/lo convertor to connect to my sub and it sounds clear and tight. Can anyone shed some light on this ?

My guess is you first need to ensure the gain is set on your sub amp to match your HU output (use the SEARCH function above for "gain") and then you should also play around with placement in your vehicle.  Sometimes orienting the speakers one direction or the other will make a dramatic change to how it sounds.  But first, make sure you are not clipping the signal by matching the gain.Support the12volt.com

Yes, and just to add to what Dave suggested, sometimes switching the speaker wires around (either at the amp or speaker- doesn't matter) will help clear that up as well.My ex once told me I have a perfect face for radio.

On I read a bunch of threads and did the calculations but it doesnt seem to help. I am just clueless as to what is wrong. Does it matter if I take the preouts or the speaker level inputs? That is the next thing I thought I could try.

I tried putting the sub in a different position with no success. Also swapped the speaker wires.

Have you checked the settings on the headunit? Where is your low pass freq set at on the amp?

I set it as low as 60hz to 100hz. I also set the amp lpf crossover point to be at 50hz to 100hz.

Disconnect one sub only and listen to it again, how does it sound?Top Secret, I can tell you but then my wife will kill me.

Thank you for all the responses. I disconnected one of the subs and it sounds a little better but only probably because it isnt as loud. I had taken the amp and sub out and tried it in a friend's car (2004 Honda Accord) with a stock headunit where he used a line convertor. And that sounded much better. The amp had the same gains of NOM in both. Any other suggestions? This would be the first time I am adding a sub to a car but I beleive it did it all correct. I did my share of research to find the amp with the right amount of power, the enclosure to have the right space, etc... Is there anyone here on the NYC area that could help me take a look?

Forgot to add this. The Kenwood unit goes to about volume level of 35 or even higher but not too much, it got way too loud. I dont listen to music really loud. I usually have it set for 13 or 16 but 18 would be the most I would set it for.