[Rclark]

http://audiojunkies.com/forum/subwoofers/416-brahma-15-mkii.html

 Link above to the T/S parameters for my subwoofer drivers, a pair of Adire Audio Brahma 15 Mk II's.

 

 I am building my first hifi. I'm very very excited, this thing has been a long time in the coming for me, I've been using sub-par equipment for a long time, just never had the budget to spend on gear, and now I do so

 My components thus far are:

 Emotiva ERC-2 (the new one) cdp
 Emotiva XDA-1 DAC (plan to upgrade this)
 Virtue Two.2 with battery PS
 GR Research N3S monitors

 
 preamp is up in the air at the moment. Both the XDA-1 and Virtue Two.2 have volume control built in and will suffice in the short run. I will decide which one sounds best for now and bypass the other. NO idea If I need one or not, or if I do need one, what type I need, but I'm considering the feature rich Emotiva XSP-1 when it comes out or the highly regarded Dodd buffer.


 I don't know what to do about my subs. I'm for sure going with PartsExpress sealed enclosures because they're inexpensive and I live in an apartment and have no garage for building enclosures. Not sure which size I need, guessing 3.0 cube?

 And not sure what I need for amplification. Do I need something with an EQ built in given the XDA nor the Two.2 have bass management features? I'm guessing I do if I don't want a massive hump of bass. Do I need as DSP?

 so main concerns:

 A) size of boxes

 B) amp or amps. WIll one suffice? Rackmount or right into the sub box?

[JohnR]

Hi, try putting the driver parameters into a box modeling program such as Unibox or WinISD. Then ask questions about the results you get

[Rclark]

which one is the best? Are they easy to use? How much are they?

[JohnR]

They're free. How hard to use? Hard to say - give it a try and ask if you get stuck unibox is probably easiest as it's an excel spreadsheet.

[2gumby2]

Take a look at what Elemental Designs has to offer. I bought two of their A5S subwoofers for one of my 2-channel systems. Outstanding performance and a great value IMO.   http://www.edesignaudio.com

[Rclark]

There's no way I'll let those brahma 15s just go to waste. I'm fairly certain I could lay waste to an edesign sub. My sub driver cost more than their whole sub:)

I'll check out winisd this week

[Tyson]

I'd recommend going sealed, the low end roll off tends to match room gain nicely.  Probably part of why sealed subs sound so "tight" and musical.  2 feet cubed would be a reasonable size for them, although 3 feet might be better if you can swing the space.  I've heard a LOT of subs, and I've never heard a vented one that really sounded very good. 

[Rclark]

 Tyson I appreciate your input and hope you can help me through this. I've been looking at a million things (putting together your first is an overwhelming process, at least it is for me, because there are so many options +the desire to get it right), and haven't had the chance to look at winisd yet. I'll DL it before I go to bed here.

[Muser]

RClark:
Just a couple of comments to share. I wouldn't be too much of an ideologue about sealed or ported. I've heard excellent examples of both. Perhaps a more relevant feature for you is that sealed boxes are easier to build because you don't have to contend with port size, air speed in the box and getting a long enough port length in a relatively small box to avoid port chuffing.

Also, with a larger box you'll have a lower "q" which will allow the sound to be a bit more natural (relaxed?) than a high q that will be "punchy" but he subwoofer's presence will be evident.

FWIW, I thought WinISD was pretty easy to use. I haven't tried unibox. A key to getting WinISD to work is looking at the box that shows a cabinet with a driver in it - put your mouse in there and drag it around to see what changing the size of the box does for the speaker response. Here's a WinISD page where you might be able to locate your driver: http://www.hometheatershack.com/forums/diy-subwoofers-general-discussion/14410-downloadable-winisd-pro-files.html.
Be aware that if you read the suggestions at home theater shack they tend to think that subwoofer that aren't "flat" to 20Hz are midbass drivers, and if they don't output 120dB at their rated low point they're a little weak. That's probably irrelevant for your planning.

[walkern]

Regarding amplification, I'd recommend a dedicated plate amp for each subwoofer, and mount it on the subwoofer box.  Danny (GR research) used to recommend Apex Junior amps for his subs (before he started offering the servos), and they have an Apex Senior amp that is reasonably priced, and that you can easily mod to give you a little bass boost in the very low frequency end if you wish to use sealed boxes and could use a little extra oomph there.

Check them out here: http://www.apexjr.com/Apexsenior.htm

I can also recommend the BASH amps often sold by Parts Express.  The 300 wpc amp would work like a champ, and is the same price as the Apex Senior.  http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-750

Hope this helps.

Neil

[Muser]

RClark:
Here's how your driver models in WinISD Alpha Pro. Note this is for a 2.5 cubic foot box, as WinISD models for the internal, unoccupied space, rather than the external dimensions. I modeled this way because you were looking at the Parts Express 3.0 box. If you insert a plate amp and the driver, you may "lose" as much as 0.5 cubic feet, thus yielding 2.5 ^feet internally.

The delineation on the graph starts with 20Hz, i.e. the left border is 20Hz performance, the first vertical line drawn in the graphed image is 30Hz, etc. That's just how I set up WinISD for myself
FWIW, your driver, while quite robust, wants a really big box. When I let WinISD choose a size, it modeled to a 22 cubic foot box. Whether that's ideal or not, that's quite at odds with the 3.0 cubic foot size you seemed to be shooting for. It doesn't mean the driver won't sound good in 3.0 cubes, but that larger still would probably be closer to ideal and you'd get both a lower q (probably a more natural sound) and better dynamics with a smaller amplifier.
Best wishes,
Larry

[Tyson]

A 3x3x3 box has an internal volume of 27 cubic feet.  A 2x2x2 box has an internal volume of 8 cubic feet.  I'd rec going for the 3x3x3 if possible.  But, that's a pretty big box

[Rclark]

Thanks guys! Too many threads going. I'm going to have Danny Ritchie give me specs for two sandboxes.

[Speedskater]

A 3x3x3 box has an internal volume of 27 cubic feet.  A 2x2x2 box has an internal volume of 8 cubic feet.  I'd rec going for the 3x3x3 if possible.  But, that's a pretty big box

Off-Topic but:
How many cubic yards of dirt are in a 3x3x3(feet) hole?

[JohnR]

None.

Hah hah

[Marbles]

You didn't ask, and I know it's the LAB, but....

I would sell those drivers and buy one of Danny's show special servo subs.

http://www.audiocircle.com/index.php?topic=93338.0

Last I heard he still had one or two.

$750 plus shipping.

I have four of these (servo) subs in my main HT/2 ch room.  I just added a show special for my wifes main tv room/ second ht room.

[Rclark]

 can't . I've had them sitting around for 4 years and I've been dying to hear them intellectually I know the servo subs will outperform them yes, but I don't expect they will be far behind. These were near $500 drivers considered the peak of their class. They are massive 45 lb sq rigs. I expect each sub to weigh over  100lbs.

once I've had the chance to wring them out and get tired of them (probably a few years at least) I'll step up to the GR servos.