Originally Posted by markus767
How do you define entry level? A subwoofer needs to be able to move lots of air. A single 10" just can't do that. It's simple physics.
I'm glad some physics is simple. Makes me question the complex Physics I studied for 3 years for my Physics degree!!
Ok, to the "simple" physics....
First, size isn't the measure, its volume displacement. SPL at any frequency is governed by the volume of air that needs to be moved. An 8" driver moving 1" pk-pk moves more air than a 10" moving 1/2" pk-pk.
As frequency goes down, we need to move 4 times the air volume to maintain a constant SPL. So, in a subwoofer, we have a trade off between SPL and low frequency capability. Whereas at low levels we can get an extended low frequency response, it won't play equally loud at all frequencies. Once we hit the volume displacement limit output capability drops like a stone. So, How loud? Well that depends on how loud you want to play. Not all of us have listening rooms where we can play as loud as we want. Therefore, for some listeners, 10" may well be enough if the low frequency response is extended enough to give a good aural impression of bass.
Now lets complicate matters...What is the listening environment? The level we can generate at low frequencies in a bounded room is very different from that in free space. Firstly, ignoring the modal response of the room, the SPL is dependent upon room volume. So a small driver in a small room may again outperform a larger driver in a larger room.
Now lets add room modes. The way a sub couples into the room is dependent upon its location and how it couples into the modes. A corner location maximizes the coupling and gives the most gain, though perhaps with an uneven response. Moving the sub out into the room now selectively couples it to the room modes. Not all of them are excited, and this may or may not give a smoother response at the listening location. So once again a small sub coupled optimally into the room may outperform a larger sub sub-optimally coupled (pun intended :-) )
However, talk of room modes brings up the other problem, that of response varying dramatically with listening location. EQ of a single subwoofer cannot
fix this. However, the approach of multiple subwoofers spread throughout the room certainly can. variation with listening location is reduced, making EQ fr the remaining variations more acceptable. However, many large subwoofers are probably not domestically acceptable, whereas multiple small subwoofers possibly are. Combined they may have larger volume displacement tah the single large sub, and if they are designed to have the same low frequency extension as the single large sub, then overall this can be a much better solution.
I know the last option goes away from you assertion about a single 10" sub, but I hope you see my point!