At the Velodyne CHT-10 price point (just below US$300), I'd go for the Hsu STF-1. I haven't heard the STF-1, but I have heard the CHT-12 and I own a STF-3. Huge difference.
The cht-10 can be had for under $200 at onecall.com. But, it really depends on how much you want to spend. If you can afford it, then the Hsu subs is the way I'd go. However, considering the price, onecall has an extremely good deal on their Velodyne CHT subs.