Infinity Kappa 120.9w Enclosure Help?

cjdog23, actually with using a prebuilt cabinet which may not be tuned or have the proper air space so your existing MTX's can play properly may be the issue. A custom box that is built and tuned to the specs of any sub will always out weigh any prefabricated one. You just may need a different cabinet to run your existing sub's in now. No don't take me wrong. Buying quality sub's is very nice and yes, you are receiving a better sound quality, but i've taken very cheap home speaker subs and installed them into a vehicle and people didn't know the difference until they actually saw them in the vehicle. Now to build this type of cabinet does take some mathematical knowledge about internal air space and any angles that are added. Then you need to buy the proper type of wood to use which is MDF, not particle board. MDF is much heavier and will out last particle board. You may want to inquire the cost between the new Infinity's you are looking to purchase compared to having a shop just build you a new cabinet for your existing MTX's.