Can a homebrew sonotube powered subwoofer sound as good as an hsu?

example: 18" ported sonotube
amp-$300
bfd-ebay-$50
(alternate-amp with built in DSP $350)
materials for cabinet-$100 (could be less)
18" driver-$300

so you would have $750 plus your labor in a sub that should spank the HSU. It may not look as nice, nor be as compact (you could build a 15" version).

plus you would have these components already purchased for use in the future in other combonations.

Vitamin nailed it pretty good.
With the ability to buy pro amps for power, and make the cabinet as big or fugly as you want, you can save a lot of money, or rather, get a lot more for it.

I built my two LLT sonotubes in 24 hours, and I would be willing to put them up against just about any commercial or ID offering. Yes, there are a few out there that would beat them out. but they are good for 115dB down to 11hz and that is pretty darn solid. I will now have to use 8 sealed drivers to get that same response. Eh, I might take those LLT's off the classifieds and just give em another shot

Absolutely, and then some... My own subs are not specifically sonotube, but based on the same design principles I now have 'the bass of my dreams'.

Yup.

The Dayton 18" Reference sub, combined with a powerful enough amp (1000+ watts RMS), in a decent box, can spank the HSU. Sounds easy enough, but there is a lot involved to really tweak the sound.

Depends on the driver's power handling. The dayton ref 18 can take 1000 watts and be happy. So you find a 1000watt amp to pair it with. If you are doing two or leaving room for expansion, get a 2,000 watt amp (like the behringer ep4000). How much output are you looking for? Something along the lines of the HSU? That is about what I said earlier of around 115dB from 20hz and up, and you will be able to spit on the HSu's pricetag.

100 watts isn't going to get you anything. Try something more like this:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-809

well, the dual drive system is two sealed 15" subs, with two 1000 watt amps. Not just the size of the driver matters, but its specs as well. some 15 inch drivers only have 3mm of xmax while others have 53mm of excursion These are major differences!! Bottom line, if you were to get two of the dayton 18" ho's and built two identical boxes to the hsu's only a little bigger, and gave each sub around 1000 watts, you would still blow that HSU out of the water, and trim the AT LEAST in half!!!! I would say at that point to not purchase a plate amp that I previously linked, but a standalone professional amplifier like the EP4000. It would power two just fine you could also go for a 15" variety if you have space constraints, which at this point I would suggest the Stereo Integrity 15ht.

EDIT: Just saw Mike beat me to it

eh, read a little and post your questions here, we are all happy to help. Seems this might be your first foray into DIY, so welcome! Being in Atl, if you ever wanted to hear the benefits of going DIY, you could demo my theater, where every speaker in it is DIY from the subs to the surrounds

First, you need to decide driver and then plug into WinISD, then use the volume of the box that is vented and calculate the cylinder volume needed using the calculator you posted above.

Keep cranking,

Robert

First, you need to decide driver and then plug into WinISD, then use the volume of the box that is vented and calculate the cylinder volume needed using the calculator you posted above.

Keep cranking,

Robert

It's great that you are learining the nuts and bolts of this hobby and that's probably the best way but...if you get frustrated and just want to start building something, just simply look through threads on other people's projects and copy what they did. There's no shame in that. Lots over at hometheatershack as well.

With ported it's pretty critical that you get the details right (or close). With sealed, not so much.