After pulling the sub out of the shipping box, you immediately realize that this is not typical, ugly black box subwoofer: the fit and finish is just great, with a fine wood veneer covering the entire cube, and the base, designed to leave some breathing room to the downward firing reflex tube, is a svelte black. The stock unit is a quite good performer, a good compromise between Home Theater and Music requirements: the bass is deep (down to 25 Hz, even if the real response is greatly determined by the placement in the room), the crossover settings let you integrate the sub in a two channel music system in a matter of hours, most of them spent looking for the correct position in the room. So if your listening habits are a 50% HT, 50% music, the stock unit will perform admirably, and you will be able to just sit and enjoy the emotional involvement that a good sub provides. Music lovers won't be so satisfied however. Bass is deep, but it is also quite slow. Attacks are very powerful, more than they should be, so the sub may appear more like an ego-centric speaker aiming at the center of the scene rather than a discrete bass supporter. Time to tweak.... Let's start from a design compromise, definitely necessary in a HT sub, but a bit harmful in a purely musical sub: the bass reflex tube. Closing the tube with a soft tennis ball completely changes the behaviour of the Arbour: the bass becomes much quicker, with no codas or excessive distortion, but we lose at least 5 Hz of bass extension, and we have to turn the volume higher to compensate the efficiency loss. Even a brief listening session reveals that we're getting much closer to our goal.  So the next step is adding some polyfill to the sub case, entirely filling the reflex tube and then some. This step should easen the work of the driver, making it operate in conditions more similar to the original ones, with the open reflex tube. The exact amount of polyfill is more a try-and-test process, adding and removing until the sub plays correctly. Well, boring to say the least, and your parents will think you are completely nuts listening the same song over and over...  Now we have a definitely musical sub, but we need to improve its efficiency, so that the volume can be turned down, reducing distorsion. So there is only one place it can go, the nearest corner! Placing a sub in a corner maximizes its efficiency (this a 6 dB increase compared to a typical middle of the room placement), at the expense of a slight degradation of stereo imaging, that can be minimized choosing a low crossover frequency. Now the sub does not need the black base anymore, as there is no reflex opening, so the base can be removed  and you can place the cube straight to the floor, adding an additional surface to maximize its efficiency (some minimal isolation from the floor can be achieved with soft decoupling surfaces, such as a carpet, or spikes if the bass is still to fat).  There is still something we can do: the sub keeps shaking during heavy bass passages, so adding weight to this already hefty sub will further lower the frequency of vibrations. A marble slab, customly cut to fit the top of the cube, is covered with a damping sheet, making it even heftier and completely dead sounding, and it is then placed on top of the sub. This is not a "day and night" tweak, but bass notes will get even more defined.  Now it's time to properly feed the sub, and a beefy custom power cord (modeled after TNT-Audio's TTS) will make it sound more powerful and controlled (really, I'm not kidding!). A good quality signal cable replacing the wimpy stock one may give some improvements, but in my experience the power cord is much more effective. Opening the case removing the driver or the amp panel may suggest some additional tweaks, but both are completely glued to the case and firmly kept in place with lots of screws: this sub is built to last! That's all for now. I'm going to experiment some vibration control tweaks, but by now this sub is such a smooth performer that I don't really feel the hurry to try them.