Originally Posted by JT78681
So there will be no advantage to adding a second LV12R? No increase in SPL?
You will definitely get an increase in SPL at certain frequencies. The amount will depend on placement and your room. If two subs are co-located (stacked or placed next to each other), you should expect about a 6db increase across all frequencies. From what I have read, two subs will essentially act as a single source when located within 1/4 wavelength of each other. For frequencies above that, you may get more or less than 6db.
Originally Posted by jbrown15
Any time you add a second sub that's the same as the one you have you will gain extra db. If you were to say stack one on top of the other you gain around 6db or if you had one located say one in each corner of your front area you gain around 4db.
I have seen many posts saying you get average of a 3db or 4db increase when adding a second non-colocated sub to a room, but have never seen any evidence of this. The measurements I have seen show that you do not get a steady increase across all frequencies and I don't think talking about an "average" increase is beneficial.
Look at this example. There is about a 6db gain for everything below 40hz. At 50hz, there is a 10db gain, at 60hz there is a couble db decrease and above that even more variance.http://www.data-bass.com/data?page=content&id=80
Brian already covered the differences between 2 LV12Rs and 1 FV15HP. If a smooth FR, especially across multiple seats, is important, dual LV12Rs are potentially better. If you want more output, especially below 20hz or want the built in PEQ, the FV15HP is better.