I went and did it.... I bought the best 18" speakers I could find for the money and I purchased 2 of them. So there is no turning back now.

Here are the theile numbers.

Electrical Q Value -Qes: 0.476
Mechanical Q Value -Qms: 3.214
Total Speaker Q Value -Qts: 0.415
Free Air Resonance -Fs: 16.742 Hz
Equivalent Compliance -Vas: 384 liters
One-Way, Linear Excursion -Xmax: 22 mm
Efficiency -SPL 1W/1m: 87.65 dB SPL
Effective Piston Area -Sd: 1210 cm^2
DC Resistance -Re: 1.4 ohm
Nominal Impedance -Znom: Dual 1 ohm
Thermal Power Handling -Pe: 1500 W
Force Factor -Bl: 14.56

I really need some help, I have never built a speaker box before. I am a contractor and have all the tool but never had to do any math like this. I purchased the hwk15 plans and just need help getting started.

I plan on using 1" mdf for the construction and it I can get away with a 24" wide box I may add a layer of 3/4" mdf to help cut back on potential losses. I am prepared for the 400lbs it will weigh. Any help guys on actual dimension running these 2  18"s both pointing up on there own baffle?

Well quite a few hours later I have determined that for this to be a true house/home wrecker it needs to be 21 cubic feet with my selected drivers. Nearly a flat response from 40-20hz and only losing 15db by the time I hit 10hz.  

The 15" plans by comparison are roughly 8 cubic feet. I already have a pair of 12" and 10"s for the 50hz on up bass. This is for waking up the neighborhood. I am going to need to purchase a crown xti-4000 to power this monster, maybe 2 of them.

If anyone wants to ask me any questions after this turns out just ask. I will give the dimensions to anyone that purchased plans to this forum. I optimized it to cut down on the amount of full sheets. 77" tall with 1" mdf double wall top and bottom.

Well with a little quick math and because of the simplicity of my double wall setup, my external dimensions did not change. I just removed the internal pieces which can be substituted for corner bracing. This brings the weight down to just over 300 pounds without speakers. This is much more doable. It will however increase my internal volume, I can live with this. It will allow a larger port up top and longer ports on the bottom.

Wow, someone responded...!!!! I have settled on a 1"mdf and a crown 5000 amp. The speakers have still not been shipped and I am waiting on them.

I purchased a new 1500 watt front channel subwoofer amp and receiver. This powers my 2 12" for the 25-100hz bass. I also bought a digital preamp to tweak it all for optimum performance. I am waiting on my 102" track saw track to cut the mdf with. It is much easier to have sheets laying flat instead of trying to guide them on the table saw. I may try to use my 59" track in 2 passes.

God be willing I should have it completed in under a months time. I am just waiting on everything. Maybe I should make the whole box round to assist moving it around the house

Mx18 REaudio Speakers are here.... They are an absolute work of art.

I have tried uploading pics and it will not allow it. I resized the pics to 65kb and tried 3 times now.

I may start working on the box tomorrow, but my amp has not shipped and my 102" track aint here yet either

Well this is taking much longer than I thought. But I guess good things come to those who wait. I was able to fit one 18" in place and ran one channel to it at around 200 watts. I have the box nearly rough finished and can honestly say it has been allot of fun. I went with 1"mdf and corner braced much of it. I ended up deciding it needed 10,000 watts of power running to it to really wake it up. with the one speaker resting in its cutout I heard deeper notes in one of my favorite songs that I had never heard before, for deep base you need a big box. I hope to approach 140 db in the 16hz range, I really want to shake the house off its foundation.

I bought a separate breaker box to wire in the 2 dedicated 20 amp circuits. The Crown  xls 5000 requires a 20 amp plug.... more work and more money. This is going to end up costing around $3k to complete with speakers amps and materials

PS: I have a days work done on the box after that pic was taken and I have to port the bottom and figure out how I want to do my lexan for viewing. Then I should be able to run 1500 watts to it and fine tune it with stuffing and port changes. Then it should get carpet and all the other goodies.

I got the bottom ports in today and braced them to the floor of the box. I am running 2 4" ports 20" in length. 5" ports where going to cost me twice as much and I can always run a third port if it sound like it needs it.

This pic was from yesterday. God be willing I should be able to get the speakers mounted tomorrow and get the lexan mounted. I like the look of rounded edges so I may do all the outside box edges to make it more pleasing on the eye and less prone to damage. I hope I gave enough setback to all the screw heads to do it, the carbide will cut through them no matter

Well I have yet to hookup both amps and I am clipping the 5000 watt. I watched Batman begins last night and when he starts tripping on the blue flower and the bass hits with his hallucinations....well it was like being there. I havent done anything with the top porting other than leave the glass out. I am contemplating what to do.

I would like to be able to vary upper chamber dimension along with port length and diameter. I could remove the whole top and make something that could slide internally adjusting volume and port size.