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Discussion Starter · #1 ·
Ok, so I was over at another forum and asking about DIY subs, and the Shiva came up...well I knew I'd just want bigger, so when I finally got around to purchasing I decided to buy the Tempest 15".
I know that I want a ported design because I want to hit really low for HT use. I just don't know what size box to use, dimensions, or port size, etc. I looked at the app notes and thought the smallest ported box sounded pretty alright. I do have room though for a bigger box.
The space where it is going is only about 18"x25" but I can go as high as need be really...as long as it's under 50".
I'm having a hard time figuring out the box dimensions including the slot port and bracing and all that. If any help could be offered, I'd greatly appreciate it.
Also, is the PE 500 watt HPSA good for that application?

Any questions you have about my room or equipment, be sure to ask. I'll be around later tonight to check on the thread.

Thanks so much you guys!
I will definitely post pictures of everything once the build starts.
 

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I have a thread of my build on this page called "Exodus Tempest X-2 build", I went with a slotted port design that Kevin put out on this site. It's around 5.1 cf³ and is completely insane, the lower end frequencies are amazing.
 

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I have a thread of my build on this page called "Exodus Tempest X-2 build", I went with a slotted port design that Kevin put out on this site. It's around 5.1 cf³ and is completely insane, the lower end frequencies are amazing.
Yea... that is a good design. Everyone who has built it has been very happy with the results for both music and movies. It is reasonable in size and cheap and easy to build.

Kevin Haskins
Exodus Audio
 

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Discussion Starter · #5 ·
That design does seem like it would work, but according to my measurements, it wouldn't be out of the question to fit an LLT in the space. If it's 19x25 on the bottom, it would come in under 50" (around 46 or 47"). (unless I'm doing something terribly wrong.). The LLT is the big mama as far as bass goes, isn't it? Other than IB which is not an option. Do my numbers sound right?
How can I figure out the port size? Every time I try WinISD I do something wrong and can't figure out which numbers go where and it gives me ridiculous answers. Can someone calculate the port dimensions for a slot port on a 12 cu ft enclosure tuned to 12hz. I'm drawing up plans for the box right now and I'm trying to figure out port size but am not having much luck
 

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That design does seem like it would work, but according to my measurements, it wouldn't be out of the question to fit an LLT in the space. If it's 19x25 on the bottom, it would come in under 50" (around 46 or 47"). (unless I'm doing something terribly wrong.). The LLT is the big mama as far as bass goes, isn't it? Other than IB which is not an option. Do my numbers sound right?
How can I figure out the port size? Every time I try WinISD I do something wrong and can't figure out which numbers go where and it gives me ridiculous answers. Can someone calculate the port dimensions for a slot port on a 12 cu ft enclosure tuned to 12hz. I'm drawing up plans for the box right now and I'm trying to figure out port size but am not having much luck
An LLT will be very large. It will have less output above 20Hz because of the choice of tuning. I think most people think that they get MORE output from an LLT but if you sit down and listen to both that LLT will seem like it has less output simply because it goes deeper, not louder.

You have to set your priorities. I think most people with one subwoofer are better off setting a higher tune where the port contributes more to what most people think of as bass. Most of what people are thinking of as bass is above 30hz. Put your hand in front of a port tuned down around 12Hz and for 99% of movies it is contributing nothing to the output. Sure... there are movies with output down there but you have to look for it and for the most part movies are mastered with an accepted bandwidth limit of 20-25Hz simply because most theaters don't have bandwidth south of that.

Kevin Haskins
Exodus Audio
 

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Discussion Starter · #7 ·
I see what you mean. But let's say I have the space. I'm not looking for huge SPL, but accurate bass that goes LOW and I am really intrigued by the low extension capability even if it's only fully utilized on a rare occasion. (though I can guarantee I'll find ways to use it if I have it :D)

The reason I thought the LLT sounded like a good plan was because the frequency graph goes flat much deeper. Being capable of 115DB at around 25-40hz is still much louder than I'd probably ever care to listen. I figured that this design would provide the most "accurate" representation of the movie soundtrack, even if there isn't as much output in the >20hz range. I tend to think the fact that it extends to 12Hz easily makes up for that.
However, you know better than I would so your opinion does matter to me. It is great to be able to speak with the designer who's so involved in the community and their discussions. So if you think that it wouldn't work tell me.
 

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My considered opinion on your build is to follow Kevin's advice and do the Tempest x-2 build or better yet stack two of these in your space, just mount the woofers on the front of the cabinets. My IB has all the deep bass I need , yet I used a 5th driver in a bandpass cabinet and gained a increase in my transient response, the two systems compliment each other very well. The Tempest X-2 will have all the deep bass you need as well as substancial transient impact. Read Kevin's application notes on hes 21" driver, there is a lot of useful information about subwoofers and how the room is by far the biggest factor on the percieved bass you will have. With diy subs, your cost is so low and the results so impressive, neighbors and friends will constantly pester you to sell them your speakers, wich lets you try another build idea, or end up with 300 raw speaker drivers and a room full of boxes, like me! Anyway, good luck with your build, and yes bigger is better.
 

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Discussion Starter · #9 ·
Either build is using a Tempest x-2 15" driver. I do think that the 5.1 would be a very capable enclosure, but if "bigger is better"...and I have the room...then why not? (I'm actually asking) I would like to build one sub only for now. Let's leave the future to the future and not worry about what I'll add later or anything. I want accurate reproduction, as well as low extension. It seems that the LLT gives me this, but I'm not exactly an expert so anything you guys say is helpful. If anyone has knowledge of using a tempest LLT, let me know if they were satisfied.
 

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Either build is using a Tempest x-2 15" driver. I do think that the 5.1 would be a very capable enclosure, but if "bigger is better"...and I have the room...then why not? (I'm actually asking) I would like to build one sub only for now. Let's leave the future to the future and not worry about what I'll add later or anything. I want accurate reproduction, as well as low extension. It seems that the LLT gives me this, but I'm not exactly an expert so anything you guys say is helpful. If anyone has knowledge of using a tempest LLT, let me know if they were satisfied.
You are right... the LLT will go deeper and you get tons of output from even the LLT. For movies, you need every bit of output the thing will deliver. If anything, movies are becoming more demanding as time passes and what used to be a killer sub is now considered modest. You also have to realize that the 115dB is from the model and that is measured 1M from the device in free-air. Once you put a sub in a room, and place it 3M from your seating location you have drastically different output measured at that location. Not only does the distance impact the SPL level at the seat, the room has +/- 15dB peaks and dips. That is part of the reason that one person will build a sub and have their socks knocked off and other will say it doesn't have enough output. They may both be right!

If you had multiple LLTs or 18"s I'd favor going with the LLT because you have output to burn. With a single 15" I tend to recommend people shoot for the higher tune and get a little extra headroom where you need it most. For music... it doesn't really matter either way because there isn't any output down below 18Hz in anything I listen too. Sure... you can go grab those bass show-off soundtracks but they are just for giggles. I would never play any of that stuff under normal circumstances. The only reason I've ever even used them is because I sell subs. Only you can evaluate what you want the subwoofer for. For music, both will sound great. For HT, you will get more headroom for 99% of what you playback with the higher tune/smaller box. If you want to chase numbers... the LLT will allow you to chase a lower one at the expense of output up high.

Kevin Haskins
Exodus Audio
 

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Discussion Starter · #11 ·
Ok that's exactly what I needed! You're very helpful Kevin, and I'm happy I chose to buy your drivers. I haven't even received it yet, but with how much passion you have for the hobby, I can't see myself being disappointed. I think I see what you're saying, and I guess that makes a lot of sense. I guess what would be in my best interest would probably be to build the smaller ported enclosure for now, and when I want to upgrade later to some lower numbers I can upgrade to a larger driver perhaps. This build will also be much easier to put together with the smaller size. Thanks a bunch.

One other thing. I see your design calls for the driver to be downfired. Can I just move the driver to the front and call it a day or would that totally screw everything up? I like seeing the drivers...maybe it's a guy thing.

Sorry, I must seem like a huge noob and an annoyance, but I really want to do this right.
 

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One other thing. I see your design calls for the driver to be downfired. Can I just move the driver to the front and call it a day or would that totally screw everything up? I like seeing the drivers...maybe it's a guy thing.

Sorry, I must seem like a huge noob and an annoyance, but I really want to do this right.
No problem and it makes no difference which way you point the driver. Technically it will have a small impact on boundary re-enforcement but in the real world both give you about the same result.

Kevin Haskins
Exodus Audio
 

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Discussion Starter · #13 ·
Thanks. I didn't think so.

Just gotta wait for payday and I'll go over the budget and see if I'm getting the amp/wire/gasket tape this week or next. (I'm ordering the PE 500 HPSA) I'm hoping I don't get screwed for duty/tax as anything crosses the border.

I'll be reworking current designs to accommodate my space over the next few days trying to get the port right, etc. Lots of rough drafts, I'm sure.

Expect pictures of the driver when it gets here, everyone. Then more as the build progresses. I think I'll use screws this time. Building speakers without screws is so overrated.
 

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Discussion Starter · #14 ·
Well, the driver is in my city, however UPS says there is "an exception", which basically means customs thought it was a bomb and opened it up. I just hope I don't have to pay a buttload to go pick it up. God, I hate UPS. Let's hope this works out ok. Also, let's hope they don't break anything.
 

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Discussion Starter · #15 ·
YAY! The driver has arrived. I took some unboxing pictures and whatnot that I will post in the next couple days. I just wanted to let everyone know what I thought. The driver was packaged VERY well. The box was beat up a bit from UPS, but there was no damage to the woofer and you'll probably see why when I post what the packaging looks like. Thanks Kevin!

Then I took it out. Holy smokes this thing is nice. This thing just screams quality. Looks amazing. If it sounds as good as it looks then I will be 100% satisfied that's for sure. Should be picking up the MDF some time this week as well as ordering the plate amp. Even the girlfriend is a little excited for me to get this thing working :)
 

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Discussion Starter · #16 ·
Alright Everyone, like I said I have pictures. Sorry it took so long. After resizing the first time and still being too big I gave up for the night and have been busy since. As you can all see it got here quite safely even with a bit of box damage. Thanks Kevin! Thing's a beast!

(Edit: Pics have been resized. Mike P.)


Update:
I ordered the PE HPSA 500, gasket tape, 10-32 mounting kit (hope that's the right one), radio shack spl meter, jasper 200 and another bag of acoustastuf. Oh and 12 awg wire.

Looks like the assembly should go quite smoothly since the parts are very close to getting here. Going a little over budget but hopefully it won't be too bad once all is said and done :spend:

Thinking about going to get the wood for the build tomorrow. I am going to try and get home depot to cut the panels. They have this really cool wall mounted saw that was very accurate last time. I figure I mention a tip and the guy can do a nice job and it'll save me forever.

Any tips or anything?

The last picture shows the space I have. The subwoofer is replacing the fridge. Speakers are Tritrix 10L sealed.

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