Truth told, river views would still factor; just in a most rural not swanky setting. Our current digs do overlook the estuary of the mighty Shannon which centuries ago Viking long ships rowed up to invade central Ireland. Whilst awaiting my very current Nordic hifi invaders, let's revisit stereo 2.1 basics. Why not get full-range towers and be done with two passive boxes? Rooms dominate sub 200Hz performance. It's why bass is the least predictable potentially most conflicted parameter of speakerdom. It propagates omnidirectional to play three-dimensional snookers with all our surfaces. That means at minimum four walls plus floor plus ceiling plus hard reflective furnishings. Room geometry is defined by length, width and height which creates standing waves between the side walls, front to rear walls, floor to ceiling and corner-to-corner diagonals. When triggered, frequencies correlating to those distances cause annoying boom notes. Bigger passive tower speakers tend to have very few spot options to go in. Their bass response is a crap shot and sorrily non-adjustable. If our low end is too dominant or lumpy, we can't attenuate or linearize it. Meanwhile small stand mounts are cosmetically more tolerant in more varied locations. They give us more placement options for better results. For best free-space soundstaging, they can also be easily moved out for serious listening then parked back against a wall for a family-friendly outa sight. Being smaller, their cabinet panels are shorter so more easily braced. That means less box talk; or less money spent on squelching it.

At its most basic, separate active bass allows independent placement plus volume control over it. Many modern subs add comprehensive EQ facilities to further tune their bass to your room. And because their woofer only does bass with naught ambitions at midrange or smooching a tweeter, it becomes a specialized bass weapon. Compare a sub's woofer with a standard passive 3-way's. The difference is obvious. One is a wimpy pocket knife, the other a macho machete. Compare today's 4" mid/woofer to the 9.5" or 15" woofers in our subs. Pocket knife devolves to paper cut. We're not even in the same universe.

Diamond drivers excepted, the most expense thing in a passive loudspeaker tends to be the pursuit of extra bass cycles; plus the burden that puts on quieting an enclosure shared with midrange and tweeter. Look at the floorstanding lineup in a speaker catalogue. The main or only thing to change is the size and/or number of woofers; the size/weight of the box; and disproportionally higher pricing. In trade one goes from (cough) 40Hz to 33Hz to 28Hz. That's not even an octave's worth of extra bandwidth. Yet the ask could triple or quadruple; for a few more lousy low notes. A quality subwoofer will be far more cost-effective, buy greater reach and power, use a superior bass driver and routinely include adjustments well beyond phase, volume and low pass. That being so, the smart money combines a sub with small monitors whose cut-off the sub reaches easily.

Phase-linear active hi/lo-pass crossover for subwoofer integration planned for Acelec.

Any good 2-way monitor makes 70Hz at -3dB. Implement an external active analog 80Hz hi/lo-pass and enjoy phase-consistent continuity¹. At that frequency you won't localize a mono sub. As shown above, my upstairs sub sits against the left front wall 86cm closer to my seat than those tiny 4" isobaric 2-ways from Korea. That offsets the Dynaudio's 2.5ms digital latency for proper time alignment. Downstairs the sub is fully passive. I drive it through an external 80Hz low pass via a Kinki Studio EX-M1. That's a 200wpc class A/B lateral Mosfet high-bandwidth integrated so superior to virtually all plate amps. It also adds remote volume in ¼dB steps. With no latency, the sub can sit centerstage right between the speakers. In neither setup can my ears point at where low bass originates. Having owned numerous passive 3-way or 4-way towers over the past two decades, my conclusion is that a properly integrated 2.1 system is the most cost-effective best performing speaker solution for normal to smaller rooms. It just relies on filtering both sub and mains. Here is more about that.

¹ From Cees Ruijtenberg of Sonnet/Acelec: "There's more about our design which I think is important. Suppose the satellite has a natural 12dB/oct. roll-off because it's a sealed box. With a 24dB -6dB Linkwitz approximation, the behavior of the satellite will be almost the same as a 6th order 36dB/oct. slope. This is actually a mismatch and will be less of a problem when coupling a woofer to a midrange as there is more overlap. If we want a true 24dB slope for this satellite, we will have to use a 12dB high pass in front of it. What we have done for our external xover is build in a simulated slope, about the same as most small satellites (in our case we can do this exactly for our own Model One). The result is that the total filter with its high and low outputs gives a signal with a pure phase sum assuming woofer and satellites are in line. You can calculate such a thing by comparing the amplitude and phase of the input signal with the sum of both outputs. If you look at most small speakers, aiming for 60Hz at -6dB seems most realistic. It's why we have a switch for 2nd and 4th-order attenuation on our high pass. It accommodates both sealed and ported designs.