I have asked a few questions before, but have recently been working a lot a a DIY sub was forgotten about for a while. I have never built a DIY sub, so you guys are the people to ask.. I wish to build a music only sub to match up with a very decent 2channel music setup. Consists of nOrh marble 7.0's, Cyrus 3 amp and a NAD 540 cdp (weak link.). I am after very fast bass to match in with the very quick bass offered by the nOrh's. I dont want slow, boomy bass. I think a Sealed sub is the safest route to take, as it has the least questions about performance, and is easy to construct. I have modeled the SB-12 sealed sub and have come up with an F3 at around 30Hz, no matter what the volume increases about about 80L. The qtc lowers in WinISD as the volume increases. I dont really want a 200L box in my room...Can anyone more experienced than myself estimate what would be a good volume to suit my needs? I get the same response with the SB10, in a smaller enclosure, but it is very inefficient, hence will need more power, and will therefore be more expensive to drive... The rolloff seems quite flat, and I am wondering about how much the extension will actually change. My room is about 5.8m deep, 3.8m wide and 4m high. It is plastered brick walls, carpeted floor, bed, and glass windows, with curtains. Can anyone give me an estimate as to what will actually occur in my room. I would like to get below 25Hz, is this possible??? I am on a very limited budget ($US400,tops), and live in Australia. Shipping on these things aint going to be cheap. I have an Adire Dealer in Australia, who sell drivers for about 2.5x the $US price in $AU, so they are a little more expensive for me... Any other driver which give a better response without creating slow bass? Thanks for your help.