a bit confused

[GovtMule]

Hi...
I was looking for plans to build a bang for buck home theater subwoofer. I have read several posts and seen some seemingly older posts about builds but nothing with actual plans. Am I in the wrong section or wrong forum. I had found plans on another forum that someone here was building (Infinity Kappa VQ) but some of the more experienced members here seemed to frown upon the design/speaker. I just really want to build the best sub I can build for my space. My room is a basement room of about 4800 cubic feet with a drop ceiling and one doorless opening into a hallway. If it turns out that I could buy a suitable sub cheaper than I can build that would be fine as well. Any help woud be appreciated.

[Hdale85]

Well the reason you don't see plans is its not hard to design a sub. Pick a driver pick an amp build an optimal enclosure size. Thats about it. You can copy someone elses if you want though.

[ThomasW]

I had found plans on another forum that someone here was building (Infinity Kappa VQ) but some of the more experienced members here seemed to frown upon the design/speaker.

There are better drivers for the same money.

The designer has designed and built one sub in his life.

If you have woodworking tools you can build a very good sub for a fraction of the cost of a retail model.

Regarding 'plans' there are some generic ones floating around but it best to custom design for each installation. Designing and building a box or tube sub isn't very difficult. We'll be glad to assist with the design process...

What's your budget?

[cobblepots]

I am actually the one building the sub. It was frowned upon for a few reasons. One, it will technically not match the output levels of my Mini Statements which are some pretty high output speakers. The sub is a perfectly fine sub and will perform better than almost all comercially available units near the price. Due to my current living conditions, this sub is a iterm build for me as I will eventually move to a dual 15" setup.

The second is the apparent lack in quality of the older design. The new model has been used quite a bit in other forums and I've seen reports of a blown speaker.

The third is that you will have to put a low pass at 20Hz on it. Many will say this limits the total subs rumble factor (which it does) but at the same time 20 Hz is a LOT lower than most comercial subs.

This is just my opinion but I would buy this amplifier and place it in a seperate box (or adjust the interior dimensions of the box to fit it). DON"T PUT IT IN THE PORT!

http://www.diycable.com/main/product_info.php?products_id=675

It has a built in adjustable low pass and at 500 watts it will be just about right for that subwoofer. Having the recomended ep2500 is nice but with a seperate eq you're looking at close to 400.

Unless you are looking for an extreme design, I don't think you'll be dissapointed. Feel free to PM me with any more questions you may have. It really isn't a difficult project.

EDIT: As stated above, you may be able to find a better sub for the money. I bought the woofer for about 150 after shipping. My total cost sans glue and finishing materials was:

25 for MDF
250 for the amp
150 for the driver

[Hdale85]

Don't put the amp in the port?

[cobblepots]

Well I can't imagine having the amplifier installed in a cut out inside the port. It wouldn't be benificial to the design that's for sure. (Someone asked this question at some point in time so even if it's common knowledge it can't hurt to say it)

[ThomasW]

Don't put the amp in the port?

The design has a slot port that runs down the middle of the back of the cabinet. So it's not a good idea to place a plate amp in that part of the cabinet...

[Hdale85]

Ohh hmm

[---k---]

Hi...
I was looking for plans to build a bang for buck home theater subwoofer. I have read several posts and seen some seemingly older posts about builds but nothing with actual plans. Am I in the wrong section or wrong forum. I had found plans on another forum that someone here was building (Infinity Kappa VQ) but some of the more experienced members here seemed to frown upon the design/speaker. I just really want to build the best sub I can build for my space. My room is a basement room of about 4800 cubic feet with a drop ceiling and one doorless opening into a hallway. If it turns out that I could buy a suitable sub cheaper than I can build that would be fine as well. Any help woud be appreciated.

We can help you. Because subs are so big and heavy, DIY is almost always much cheaper than the comparable commercial subs. Though, that doesn't mean it is cheap. It is sometimes hard to DIY cheap.

The current value leader in subwoofer drivers is the Tempest-X . They might not be as well know, but very nice drivers. For that big of a room, you might want 2 - depending on how much shaking you want.

What are you're goals and budget. We'll help you from there. Believe it or not, we're actually really friendly here - even Thomas. :P

[cobblepots]

I didn't read the spot about the room size. Sorry... Considering that I think the Infinity is a bit undersized. My current HT room is about half that size.

Have you looked into using winisd pro? It's a shareware that will let you design boxes for almost any application. Take a look around at some accomplished designs in the subwoofer thread and what their frequency plots show. I'm sure many will be willing to help you out. If you play around with that program for a few hours you will become quite proficient at it.

Things to look at:

First, find a subwoofer that fits your wallet. Select this woofer from the drop down menu in the program.

Tuning frequency: You'll have to play with the box sixe, port length, and port dimemsions to get a flat frequency response. You can just play with numbers until you see something you like or take what other's have posted with regards to sizing and adjust them to fit your needs.

Port size/number of ports: You may be limited to port size by what's available locally or on the internet. A slot port, altough more difficult to build, is more versitile is it's sizing requirements.

Size of the box: Will it fit through the door or next to your couch? (You may laugh but my first car sub did NOT fit inside my buddies vehicle...)

Next you will need to look at the Xmax of the simulation at "X" wattage so you will not break your woofer.

There are of course other things to look at but that should get you started. I'm sure someone can further that list! Keep in mind no design is perfect, just a series of compromises to fit your individual needs. I've built quite a few ported car sub boxes using this program and have been happy with all of them. I have limited experience with HT subs but some if not many principles still apply. Plus, there are MANY on this board with dozens of speakers under their belt. Feel free to post whatever you come up with.

[GovtMule]

Wow... that was fast... thanks a lot. Well, as for budget, I would just like to keep it under $1000. If going a little over means more bang for buck then I am game. As far as sound, I want my chest cavity to vibrate during explosions, etc. LOL. I am a pretty good woodworker in that I have built dining tables, shelving units, etc. When I was younger I built a few car sub boxes but didn't know to put any design work in other than cosmetic. So, is it the common opinion that the Tempest driver is the value leader? Is there a 1 sub solution or will I need 2? Also, should I go with a ported box or a sealed box? How do I decide? I realize that a sealed box is just a matter of volume but with a ported box how do I know how the port should be designed (i.e. round ports like some I've seen on here or slotted ports like the Infinity design)? I have read about different modeling software-which one is best? (I have downloaded WinISD and Unibox.) I am just new to all this. Thanks so much for all you guys' help. It is very appreciated.

btw... have any of you guys personally checked the output of the above mentioned amp to verify?

[ThomasW]

Speaking of plans, Kevin has sealed and ported plans for the Tempest posted on his website. We can walk you through the build process...

For an 'all-in-one-box' system the O-Audio amp is a good choice. But if you can live with a fan cooled amp the Behringer EP2500 is a great deal and IMO a better long term investment.

The choice of how many drivers? Depends on your room, distance to the listening position, and how loud you want the bass.

[---k---]

You've got a big room and a desire for "impress your friends" bass. With $1000 budget, you can easily afford a Tempest-X Two Pack, a Behringer EP2500, and still money left over for the wood and all. I think this will put a smile on your face.

The choice in sealed versus ported comes down to budget, size constraints and how much of that low low rumble in the seat feel. Look at the application notes for the Tempest and look at the models in there. Also, get good at converting liters into something meaningful. If you wants lots of rumble in the seat feel, you either need to put up with the large ported box or spend more money on an EQ like the Behinger DEQ2496 that has shelving filters.

[Hdale85]

1000 bucks you can just about do anything you want 2 IXL-18.4's with an EP2500 is my plans. Sealed in 28x28x14 cabinets. This is what Mike on our forums did and they look quite appealing to me. Drivers are 265 each and the amp is like 350. Could also use Maelstorm drivers. They are a bit more and would be just slightly over 1000 with the amp. This is before shipping though. The Maelstorms have 40mm of xmax though where as the IXL-18.4's of 22mm.

IXL

http://www.mach5audio.com/zen/index.php?main_page=product_info&cPath=65&products_id=181

Maelstorm

http://www.diycable.com/main/product_info.php?products_id=681&Cid=fd810233c7d5184177b6186d4eb897f4

EP2500

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=248-747&FTR=EP2500&CFID=9389823&CFTOKEN=74777712

If 18's are to big then there are the Tempest X's :B

[GovtMule]

I have no problem going with the Behringer amp as that was my plan from the other design. As far as "loud" goes, I am not a hip hop junkie or anything, I just want a theater-like experience in my basement theater. Don't laugh but my current setup is:
Panasonic AX200U projector
Homebuilt 100" screen
Homebuilt front cabinet (for holding my equipment)
Panasonic SA-XR50 rcvr
Panasonic SB-PF500K mains
Panasonic SB-AFC500K Center
Technic rear surrounds and rear center (cant remember models)
I like the sound of the equipment I have but it is missing that chest thumping rumble... and yes I am a fan of Panasonic. I have just never had any trouble with the products or the company. My seating area is about 12-15 ft away from the screen with a couch and love seat in an L position against a wall on the left and open to the back and to the right (somewhat center in the length of the room which is about 30 ft). My initial plan was to build two of the Kappa subs and basically set them in end table positions at the end of the love seat and b/w the couch and love seat (both against that left wall). I will try to get a drawing of my room uploaded.

Size... I don't want refrigerator sized subs or anything but up to maybe 2.5 ft tall and no more than 3 ft deep.

[ThomasW]

Kevin has posted that the Maelstroms are sold out.

[Hdale85]

Oh they show in stock now on his website?

[Amphiprion]

I found that a single vented original Tempest (from Adire) was more than enough for my bass tastes after I built two of them. I think a single Tempest-X in a sensible design with the aforementioned Behringer amplifier would be fine. I would save any extra money for other upgrades, such as a subwoofer equalizer.

[GovtMule]

so.... 1 Maelstrom... 2 Tempests... or 1 Tempest?

I must admit, the idea of having an 18" sub is a little appealing... lol

[Hdale85]

Well if your interested in the 18" the Maelstorm is apparently sold out? I'm not sure I'd contact Kevin and ask? But that amp can easily do 2 of the Maelstorms or the IXL-18.4's and both subs are very good candidates. Both will work pretty good in a 4cu ft sealed enclosure. The Maelstorm could use more space though if you had it to spare. It's just all about what you want. One would be fine, 2 would be better I think if you really want your cage rattled its the way to go though.

[kingpin]

I think 1 works well for music. For ht use I like using the 2 by far.
Where you put them is ging to be a big factor also.
I have mine on the side walls parallel to the couch and the tv about 2 feet forward of the couch facing each other.
If you're ever feeling gassy or constapated they're the best form of rolaids. :B

Mike

[GovtMule]

So would 1 Maelstrom be equal to or better than 2 Tempests? If not then I will go with the Tempests.... since 1 Maelstrom is about twice the price of a Tempest.

Also, I tried using WinISD but I don't know what I am looking for in the curve... also how do I know how it relates to cabinet design?

[ThomasW]

Compare the Vd (swept volume of air moved by the cone) between the drivers you're interested in......

Vd is calculated by taking the Sd (area of the cone) multiplied times the Xmax doubled.

[GovtMule]

...so would I double it for 2 Tempests vs 1? and I assume higher is better...

[ThomasW]

Yep...

[GovtMule]

So if I am reading you correctly... two tempests will outperform one maelstrom... by these calculations... correct?
that is probably a little better for space management and WAF anyway. So could you tell me why ported is better than sealed and/or vice versa.

[fbov]

Two subs will also allow you to position them for a more-uniform SPL in the seating area...

Personal recommendation (for what it's worth) is to go with the Tempest X. I have one in a 3 cu ft sealed box driven by the Oaudio 500W plate amp and it's everything I needed in my 2600 cu ft room with the amp at ~half power. Two in sealed boxes (if size is a limiting factor) will work very well, especially if driven by an EP2500 with proper EQ. If that might not be loud enough, and the room will fit them, build a larger, ported box.

As ThomasW notes, their web site has plans and resulting performance plots. (And I went with the littlest boxes because they were free.)

Have fun,
Frank

PS Ported vs. sealed? Let's see if I've been listening ...

Ported are more efficient (louder) and have better low-frequency extension so they require less equalization. And you can fine-tune them by adjusting port length and internal damping material if they don't sound right.

Sealed are smaller, less efficient, and NEED EQ to get low frequency extension. I'm fighting a ~12dB roll-off at 20Hz with my boxes, and room gain only gets me 6dB back. Therefore, I need 4x more power at 20Hz to match the SPL I get at 50-100Hz. EQ eats power, so I figured a 4x power increase over my mains would retain reaonable balance, and 110dB SPL is more than enough for my room.

In contrast, a 12 cu ft box tuned to 16 Hz is only down ~2dB at 20 Hz, and actually ~2dB higher, 20 Hz vs. 50Hz, once room effects are included. That means your power goes into SPL equally at all frequencies, up to 120dB in-room.

[ThomasW]

If all other things are equal the subwoofer setup that moves the most air plays the loudest and lowest.

Ported vs sealed is apples vs oranges...

With a port there's a resonant mass of air (think of blowing air across the top of a wine bottle) to boost the output at the port tuning frequency (Fb) . One must be careful with ports because playing frequencies below Fb causes the woofer to 'unload' and that can destroy it. The solution for this situation is using a high-pass filter that removes the frequencies below Fb.

Sealed starts rolling of below the driver's Fs. The sealed box itself acts as a filter so there's no need for a high-pass filter. Sealed is -3dB less efficient compared to a ported box.

It's important to factor the purchase of equalization into the budget. EQ is used to boost the low frequencies for a sealed box. And it's used to assist in controlling the effects of the room with both sealed and ported designs. Most use either the Behringer DSP1124P or the new FBQ2496 for their EQ

The easiest subs to build are small sealed boxes. The smaller the box the more EQ (boost) is needed for the lowest frequencies.

[cjd]

At least 8 Tempests for music... if not 12. or 16...

[GovtMule]

LOL.... Yeah.. now that I know will have 0 for WAF. Well, 2 of the Tempests will run me just over $400. DSP1124 at $100. Sounding pretty good so far.
Should I use the behringer amp or the plate amps?
Oh, and the EQ... is that just any parametric eq?

[ThomasW]

The DSP1124P is parametric EQ

I think the Behringer EP2500 is the best long term investment.

[Hdale85]

Thomas which of those EQ's do you prefer?

[ThomasW]

I prefer the FBQ2496 because it offers a better/wider choice of filter settings and it's easier to use. It's not the EQ of choice for those wanting different settings for HT and music.

[GovtMule]

Excellent.... I am ordering 2 Tempests, a Behringer EP2500, and a Behringer DSP1124P this weekend.
Now, what will I need in the way of binding posts/plates/wiring/baffling? ... and where is the cheapest place to buy that stuff (partsexpress, diycable, etc.)? Should I use MDF or cabinet grade plywood? 3/4 inch?
And then on to box design... I will certainly need some assistance with that as well.

OHHHHH... and THANKS SOOOOO MUCH for helping me with all this, fellas. I really am interested and want to learn more about designing speaker systems and how to understand the jargon, graphs/plots, and how to put it all together. I think I will be able to pick up on in pretty quick with some assistance. Can any of you recommend a book or videos, etc that might help me?

Again, thanks soo much too all of you.

[Hdale85]

Binding posts and what not just order them from PE and its really up to you as to which you like. Make sure they have a rather long connection post. As for MDF or something like Birch Plywood its really up to you. The plywood is supposed to be better and its a bit lighter but you may have problems finding a good place to get it from. Home Depot and lowes stuff is not very good its rather the opposite of void free. If you plan on veneering anyways you can go either way. If your cutting MDF definitely get a decent dust mask.

[---k---]

At least 8 Tempests for music... if not 12. or 16...

I'm looking forward to hearing your IB upgraded to 16 Tempests.

[Hdale85]

Is he really upgrading to 16 tempests? Wow....

[cjd]

That would be for the living room. A lot more air to move there! Easily 4 times as much. I said MUSIC system.

The HT is essentially 900 cubic feet plus a hallway of about 300 cubic feet, and has 4 of the Tempest-X. Scaling that to 4x the room volume for my music system would end up with 16...

It is not in the works currently, but when I end up tearing out the carpet it is something I'm pondering...

C

[---k---]

You're insane.

But maybe if you had real "full range" speakers, you wouldn't need to add an IB for music upstairs.

[kingpin]

You're insane.

But maybe if you had real "full range" speakers, you wouldn't need to add an IB for music upstairs.

opcorn: :E :rofl: :rofl:
That was funny.
Quite a dig.
But funny.

Poor Chris. After all's he's done for you. :B and everyone else. To rip on him like that. :B

[cjd]

Poor Chris.

Yes, after buying 16 Tempests (well, 20 after all is said and done) and amplification for them and building a sub crossover and re-doing the floor from the carpet, I'll be rather poor for a bit.

He just wants me to actually build such a thing, and somehow thinks this will push me closer to actually doing it...

[GovtMule]

Talked to Kevin at DIYCable (super nice guy). He suggested I go with sealed boxes to avoid the complexity and size of the ported system. I thought my mind was made up on two tempests but I find myself thinkin alot about the Maelstrom (and adding a second in the future). I am gonna measure tonight to see just how large an enclosure I can stand. I have ordered the EP2500 and DSP1124p. I have tried using WinISD Pro and entered all the data from the sub but need filter information.
.... you know what ... just decided to go with the Maelstrom. Just ordered it, too.

BTW, Kevin said he does have them back in stock

[Hdale85]

I thought so.... I hope he has them in a couple weeks as I may order 2

[cjd]

Kevin IS indeed a super nice guy. Awesome product, awesome service.

[---k---]

Yeah. Kevin has even talked me out of buying his products because he thought I would be better off with a competitors product. No snake oil from him.