I'm on the lookout for a reasonable quality, but portable active sub that will compliment my speaker set ups (A pair of Yamaha DBR12s/ A Pair of W Audio PSR8As).

The obvious choice in my price range is an Alto Truesonic TS Sub15 but I'm also considering the smaller dB Technologies 12D. The former will presumably pack a little bit more punch but the more compact 12D has its appeal too, especially as I will have to lug it up and down my cellar stairs every time I want to use it.

Can anyone give me the pros and cons of these two, particularly if you have experience of both. I'd also be interested in hearing about any other subs I should consider looking at (particularly if you happen to have a second-hand one that you would consider letting go for a bargain price). Before anyone suggests anything upwards of a grand I should probably point out that my budget is sub £250 (pun intended).