Home Theater Forum and Systems banner
1 - 18 of 18 Posts

·
Premium Member
Joined
·
10 Posts
Discussion Starter · #1 · (Edited)
First, I must thank everyone on the forum for the expansive amount of info. It has been extremely helpful.

So I would like to build my first sub. I plan to use the following

1" MDF 32" x 33" x 42" (Front will be 2 sheets thick)
Titanic Mk III (seems to be a good fit for the amp, and is fairly cheap)
O Audio 500 Watt plate amp (I already own this. I bought it on a whim for a bachelor party for some good ol rock band fun. I used it to drive an old car audio 15" sub I have had since I was in high school)

The sub will mainly be used for movies, and of course some videos games, mainly rockband 3.


I think I would like to try and tune to 15 Hz. With the current bracing it looks to be around 20 cubic feet. I have not taken the volume of the woofer or amp into consideration yet. I imagine your suggestions are going to change the design somewhat. The thing is bigger than I expected.

Also I am confused by the vent length in WinISD. Right now I have a 4" x 26" rectangle, but it shows the length being 55". If I change it to 2" x 26" the length is 26", but air velocity increases.

So I guess I would like to hear your thoughts on my design. The more I look at it the more I think I will need more bracing. Do you think 15 Hz acceptable? Woofer and amp combination?

I have some renders of the box but since this is my first post, no links. As soon as I hit 5 I will provide a link.

Thanks in advance for all input. I am really looking forward to this project!
 

·
Premium Member
Joined
·
10 Posts
Discussion Starter · #4 · (Edited)
Thanks Mike P for the reply. I have been messing around with WinISD but I can't seem to get the same outcome as you. I have uploaded my files.

https://docs.google.com/folder/d/0B1sQ4Om7EV8rdFNlSWpsWHRYTEE/edit



I have slimmed down my box size to 33x22x44. That will fit nicely next to the TV, so I am ok with that size. Close to 14 cubic feet with the bracing taken out.



More bracing at the bottom?

I guess I just need help figuring out what I am doing wrong. I would like to start the project this weekend if that is possible. Any help is much appreciated. If the woofer seems to be a good fit I will purchase it today. I am not set on any one woofer but for the power I have it seems a good fit. I could buy a $400 woofer but with the current amp it just seems like a waste. Of course I could always sell it later and buy a stand alone amp (behringer or the like) and just put a box around the plate amp for now. Options options. :scratch:

Thanks again


ALSO! The sub is on sale through parts express for $199 with free shipping! Probably will pick up the Jasper Circle Jig Model 240 also.
 

·
Premium Member
Joined
·
2,620 Posts
The Jasper tool is great! You will need a router than can plunge into the MDF, tho. I did not, but bought one when building two car subs and the plunge one is definately the way to go.
 

·
Premium Member
Joined
·
10 Posts
Discussion Starter · #6 ·
The Jasper tool is great! You will need a router than can plunge into the MDF, tho. I did not, but bought one when building two car subs and the plunge one is definately the way to go.
I believe the craftsman router I "borrowed" years ago from my mother is a plunge router. Although I am hoping that I might have access to a true wood workshop for the build. The father of a childhood friend of mine built houses and then cabinets for a living and from what I remember it is pretty expansive. :T
 

·
Premium Member
Joined
·
10 Posts
Discussion Starter · #8 ·
You should add one more vertical brace in the bottom section above the port. Your modeling shows 13.8 cu. ft. tuned to 15 hz. WinISD models with the net volume, to that you add the displacement of the port, driver and bracing to find out the total internal volume.
Ok so the port is not included in the total usable/working volume? I understand I will need to subtract the bracing and woofer volumes to get the total usable/working volume. I will add some more bracing to the bottom. Thanks again for the advice.

The woofer should arrive this Wednesday, 9-12-2012, alone with the Jasper circle jig and some other components. I decided to not mount the plate amp onto the box. I figure this will work out better if I ever decide to change out woofers and increase power.
 

·
Registered
Joined
·
683 Posts
I'm interested to see how this turns out for you. I've been really wanting to do a build likewise with the Titanic Mk III, but have no money right now as it turns out, so I may be doing this build vicariously through your effort if you don't mind :whistling:.

Your renders look nice, keep the pics coming!
 

·
Registered
Joined
·
315 Posts
Check mine out to see something very similar (link in sig). Don't waste money on Jasper, build your own (see my thread).

If I were to do mine over, I would slot port. Much easier to build. Make sure you do some rounding over though.

I *highly* recommend adding a MiniDSP. Your 500W is ok, but an EP4000 (~800W-RMS into 4ohm), or similar, would be better.

And I guarantee that you'll be happy with your Mk III. There is simply no better $/performance ratio IMO.

Actually, beware, your amp may have an HPF built in that will prevent you from reaching your 15Hz tune.
 

·
Premium Member
Joined
·
10 Posts
Discussion Starter · #12 ·
Check mine out to see something very similar (link in sig). Don't waste money on Jasper, build your own (see my thread).

If I were to do mine over, I would slot port. Much easier to build. Make sure you do some rounding over though.

I *highly* recommend adding a MiniDSP. Your 500W is ok, but an EP4000 (~800W-RMS into 4ohm), or similar, would be better.

And I guarantee that you'll be happy with your Mk III. There is simply no better $/performance ratio IMO.

Actually, beware, your amp may have an HPF built in that will prevent you from reaching your 15Hz tune.
LOL well the money is already wasted, ohhh well. I did see your build, very impressive. I plan on adding a 1/2" radius to just about every edge I can find. I read through your build again and plan on keeping your tips in mind as this thing progresses.

I just found a wood shop close to where I work that has 1" MDF, Lowes and Home Depot don't carry it. I was playing around with the idea of HDF but I really doubt I can find it, and with enough bracing its probably not relevant anyway. I also read about people using some sort of no void plywood. I am by no means an audiophile so again its probably not relevant. The room its going into is just a family room. And if we do move and I finally get my theater room, well I guess I can just build another box. :bigsmile:

The O Audio amp should be ok. It has a crossover at 120 and 40 Hz but can be disabled. It also has a subsonic filter at 12, 16, 20, and 25 Hz so I think I am ok with getting down low.

O Audio

So now I just have to borrow the F250 to pick the materials up and go from there.
 

·
Registered
Joined
·
38 Posts
Well it looks like you are headed in the rite direction. The O audio amp is plenty powerful enough for the box you are wanting to make. I have the exact sub and amp in a 11.5 cube box tuned to 15hz. I have to have the amp set at the 16hz high pass or it will easily bottom the sub out. With the high pass on its just rite for what the sub wants. I played with winisd until I got the highest amount of low frequency output that was possible with the 450 real world watts of the O audio. I got the exursion of the sub to just be at max at 15hz with full power. Seems that winisd was prity spot on to.
 
1 - 18 of 18 Posts
Top