funkrush: From the three subs you listed, I'd say the Hsu and Velodyne are comparable. But neither will perform that well in your room volume. I would check with Premier Acoustics about cost and shipping for their PA-150 to Canada. One can deal with Premier Acoustics and that $499 price can often be lowered to well under $400. This is a large ported design known for output above 40 Hz.
To ljmart and localghost: The following is part of the PM I sent to funkrush. I hope it's helpful:
There are several factors when looking for a subwoofer that suits your needs. The main factor is room volume (width, length, height) and whether your room is closed or open to other rooms. The deeper a subwoofer's frequency, the longer the wavelength is and the more volume it sees. At 20 Hz we're talking about 56 feet. At 25 Hz we're talking about 45 feet. And at 16 Hz (the lowest pipe organ pedal note) we are talking 70 feet.
Because of these long wavelengths, subwoofers are difficult to setup correctly. One can't just plop a subwoofer down because it looks good in that corner or area. One must do a subwoofer crawl test. This is done by placing the subwoofer on top of your main listening position (chair or couch). Then one crawls around the perimeter of the room while playing test tones or music with low, sustained notes. One can do this by ear, but I (and many) also use a dB meter. As you crawl around you'll find areas where you will hear little or no bass (nulls, where there is frequency cancellation from reflected waves). There will be other areas where the bass sounds pretty horrible (muddy or boomy). These are peaks where the reflective waves gather (usually in corners). Hopefully there will be areas where the bass is loud, smooth and succinct. That's where you will place your subwoofer. One guy noted that the best place he could put his sub was in the foyer by the front door!!
Another factor is what one is trying to achieve. Music differs from movies. In movies one is usually seeking impact. There are two kinds of impact. Upper frequency impact (above 40 Hz), known as chest thumping bass. Lower bass impact (under 40 Hz) where pictures rattle, your chair vibrates and it may feel like your house is coming apart. Under 20 Hz, it's bass you feel more than you hear. For music, one is seeking to support lower frequencies of the instruments. Most instruments don't get down below 30 Hz, but synthesizers and pipe organs can go below 20 Hz.
Another factor is output. Price of subwoofers are based on how low and how loud they can get in the lower frequencies. The larger the volume of the room is, the more difficult it is to achieve loud output levels. Human hearing is such that we don't hear lower frequencies as well as midrange and treble frequencies. It takes more sound pressure levels (SPL) at the lower frequencies for us to hear it. So if one is listening to main speakers around 90 dB, you'd need 100 dB output for your subwoofer. Those subwoofers that can attain loud SPL at 20 Hz are the most expensive (and most impressive).
And finally there is the WAF. Not only on the looks of the subwoofer, but where it is placed and how big it is. The bigger the subwoofer, the deeper and more powerful they can play. Simple law of physics. Yes, one can achieve surprising results from a small, powerful sub (such as the SB13-Ultra), but that costs a lot of money.
Music area: Magnepan 3.6, McIntosh MC2205 & C48, SVS SB13-Ultra, Oppo BDP 95 and assorted equipment.
Movie area: EMP Tek R5Bi, PSA XS30, Denon X2000, Oppo BDP 83.