Hmmm... 5.25" and calling it a subwoofer.
Sally, what are some of the specs on those speakers? Particularly frequency response. Will they give you what you want in the 20-50Hz range?
On my new install, I went from a single 10" sub to a pair of 10" subs installed in a common enclosure, just so I could get my cone area up to around 160 square inches in order to drop my lowest attainable frequencies down to the 20-30 Hz range. It wasn't a matter of power, or volume, or punch or anything like that. It's just that, as a general rule, small cone area means loss of low frequency response. When that pipe organ in the Albinoni Adagio starts rumbling, you want speakers that can go almost subsonic. I would go with 10" subs in undersized boxes before I went so small as 5.25". But, I haven't seen nor heard your speakers, and it's quite possible they are working some technical magic I am unaware of. The only thing that counts is this: Are you happy with them?
tanstaafl.
"There Ain't No Such Thing As A Free Lunch"
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"There Ain't No Such Thing As A Free Lunch"