Vandersteeen 2wq (or any sub) in small room

Smooth bass = "fast" bass, because frequency response peaks in the bass region literally decay more slowly.  It doesn't matter whether these peaks originated with the subwoofer or with the room - the effect is the same.  But the room is almost always a far worse offender than the subwoofer itself. 

Non-smooth bass = either boomy/slow bass or weak bass.  When we set the level of a subwoofer system by ear, we're probably taking our cues from the loudest peak(s).  So if we have a 9 dB in-room peak, and we set our subwoofer level so that the peak is 3 dB above the average level of our main speakers, then the average level in the subwoofer region will be 6 dB below the average level of the main speakers, and the bass will sound weak.  But if we turn up the level on the sub, now the peak starts to stick out like a sore thumb, and the bass sounds boomy and slow.

At low frequencies, we must consider speakers + room, or subwoofer(s) + room, to be a system.  In fact, by the time the ear/brain system begins to register the pitch of a low frequency tone, the energy has been reflected by the room many times so the room-induced peak-and-dip pattern is already all over it.  In practice, we cannot hear subs apart from what the room does to their outputs. 

In general the smaller the room, the more audible and objectionable the room-induced peaks and dips in the bass region.  Therefore, the more room for improvement we have by adopting an approach that smoothes out the room-induced peaks and dips. 

In general, the more intelligently-distributed bass sources in a room, the smoother the in-room frequency response in the bass region, and the less variation from one location to another within the room.  This latter characteristic of a distributed multisub system makes it arguably superior to using just one sub and relying on equalization,

So here comes the highly counter-intuitive conclusion:  The smaller the room, the more subwoofers we need scattered around the room in order to get smooth in-room bass!   Obviously these needn't be high output ubersubs, and they needn't even be all the same.  But two subs intelligently placed will be about twice as smooth as one sub, and four subs intelligently placed will be about twice as smooth as two subs. 

Duke

dealer/manufacturer/distributed multisub advocate