Need help building my home theater subwoofer enclosure... - AVS Forum
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post #1 of 15 Old 09-04-2012, 06:32 PM - Thread Starter
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Upgrading from my BIC VK-12, I wanted to build something that would really shake the house.

Thus far I have purchased a 15" 500rms dayton audio driver RSS390HF-4 (quite popular), a bash 500rms plate amplifier, and 2 port tubes.




I don't have the tools nor ability to build an intricate large setup like lilmikes f-20s. I was looking for a simple box yet the only one I've taken a liking to is this one:
http://www.ebay.com/itm/CAR-AUDIO-SINGLE-15-PORTED-SUBWOOFER-BOX-COATED-MDF-BASS-SPEAKER-SUB-ENCLOSURE-/330789035909?pt=US_Speaker_Sub_Enclosures&hash=item4d04901f85&vxp=mtr
yet even packed with polyfill I'd likely only achieve 3 cubic feet. I don't think that would be enough for this sub...?

Since that might be too small I figured I'd build my own box, simple rectangular and throw in the two port tubes. I'd build it large enough to the point where the tubes will produce the right frequency.

I have a good grasp on everything, yet I need some guidance...

Not an audiophile so anything I create will likely blow my mind. I'm just looking for some quality earth shaking boom. This will be only for heavy bass music at larger parties. Or perhaps this won't be powerful enough? Should I add a second 15 powered by that same amp? etc etc. I was hoping for something really scary. I am coming from a 250rms 12" sub that rocks this place.
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post #2 of 15 Old 09-04-2012, 07:11 PM
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You have a good start! I would suggest downloading winisd and do some modeling. I'll start off by saying that those ports will not work, unless you plan on tuning in the 40-50 hz area. The 15" HF needs a very large box if you're porting, like 5 or 6 of your BIC put together.

Dan
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post #3 of 15 Old 09-04-2012, 07:21 PM
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Yes, 6 to 10 cuft enclosure, two 4" pvc ports at length to give 18hz tune, put it all together paint it up and your done.
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post #4 of 15 Old 09-04-2012, 07:27 PM
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You should send those ports back... They are WAY to short. What you want instead is a pair of these heavily flared 17" long 3" ports

http://www.parts-express.com/pe/showdetl.cfm?partnumber=268-350

Here is a 8 ft3 box with the pair of 3" x 4.5" ports



Dropping the box volume simply moves the peak higher in frequency, and you would need something like a 20 ft3 to move the leak low enough to not be more then a couple db

Here's the same 8 ft3 with the pair of 3" x 17" ports



You could even drop down to around 6ft3 which gives a minor 1db hump at 40hz. This driver needs a large box, if this seems to big, you need to switch to the HO model.
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post #5 of 15 Old 09-04-2012, 09:45 PM - Thread Starter
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Thanks for all the help! Couple more questions for any of you.

- I'll ditch the ports. They were cheap. Just ordered 2 ports from that link above. I've found calculators to find single port length, I suppose I'll have to find the math for 2 ports of this size. The enclosure I now plan on building is around 6.5 cubic feet.

- Why 18hz tune over the 30ish most recommend? I definitely want the most ground shaking.

- Also, so why does the HF need such a large box? Is bigger better, is the end result much better than a 15" that doesn't need such a massive box? I do have the space, so I guess it's not too big of an issue. (also, is the HF considered a long throw woofer as stated on ebay?)

- Do I even need to polyfill a box of this size? Plus that would adjust the tune..


- How will the end result of this compare to my old BIC VK-12?
http://www.amazon.com/America-VK-12-1000-Watt-Front-Firing-Subwoofer/dp/B0016J3H18/ref=sr_1_1?ie=UTF8&qid=1346820184&sr=8-1&keywords=bic+vk-12
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post #6 of 15 Old 09-05-2012, 10:19 AM
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Quote:
Originally Posted by bobbobobbo View Post

Thanks for all the help! Couple more questions for any of you.
- I'll ditch the ports. They were cheap. Just ordered 2 ports from that link above. I've found calculators to find single port length, I suppose I'll have to find the math for 2 ports of this size. The enclosure I now plan on building is around 6.5 cubic feet.

You will be tuned to approximately 17-18 hz using the full port length in 6.5 ft3. That's a very good match for your amp which has a 18hz HPF.

- Why 18hz tune over the 30ish most recommend? I definitely want the most ground shaking.

30hz might be recommended for car audio or even a pro audio type setup, but definitely not recommended for HT. Movies actually have a tremendous amount of content very low in frequency, even lower then 18hz. Tuning around this range is usually the most ideal for your typical driver/amp/box combination.

- Also, so why does the HF need such a large box? Is bigger better, is the end result much better than a 15" that doesn't need such a massive box? I do have the space, so I guess it's not too big of an issue. (also, is the HF considered a long throw woofer as stated on ebay?)

The HF is optimized for deep bass in a large sealed enclosure, this means a vented box will need to be even bigger. The Xmax of this driver is average.

- Do I even need to polyfill a box of this size? Plus that would adjust the tune..

You can use fill as long as you dont block the ports, lining the walls with mattress foam is something you can do as well. the purpose is mainly to prevent internal noise from escaping and messing up the SQ

- How will the end result of this compare to my old BIC VK-12?
http://www.amazon.com/America-VK-12-1000-Watt-Front-Firing-Subwoofer/dp/B0016J3H18/ref=sr_1_1?ie=UTF8&qid=1346820184&sr=8-1&keywords=bic+vk-12

Think of it like you just upgraded to a HSU VTF15 or Rythmik FV15, cause that's the performance/capability level this sub will be in
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post #7 of 15 Old 09-05-2012, 03:55 PM - Thread Starter
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Thanks Jay1!

You will be tuned to approximately 17-18 hz using the full port length in 6.5 ft3. That's a very good match for your amp which has a 18hz HPF.


Using this site here http://www.the12volt.com/caraudio/boxcalcs.asp I can find the port length for a single port. How do I calculate the use of two ports?


30hz might be recommended for car audio or even a pro audio type setup, but definitely not recommended for HT. Movies actually have a tremendous amount of content very low in frequency, even lower then 18hz. Tuning around this range is usually the most ideal for your typical driver/amp/box combination.


This sub will only be used for music. Heavy bass songs, electronic, rap, etc. For larger parties. (perhaps HT in the future).
Would I want to tune higher for more chest thumping bass, or is low still the way to go?
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post #8 of 15 Old 09-05-2012, 04:04 PM
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I use win isd for box modeling, which allows you to figure out the port configuration. I wouldn't tune higher with this driver, in fact a sealed box is all you really need if you aren't chasing massive 20Hz output.
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post #9 of 15 Old 09-05-2012, 04:29 PM - Thread Starter
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Quote:
Originally Posted by Jay1 View Post

I use win isd for box modeling, which allows you to figure out the port configuration. I wouldn't tune higher with this driver, in fact a sealed box is all you really need if you aren't chasing massive 20Hz output.

Did I go wrong with this driver choice? I didn't do a ton of research I just saw it was such a popular choice... and was 4ohm that matches most plate amps. The frequency can get so low, I figured that meant more "feel" of the bass.

Again this is for large parties, all electronic, hip hop music, not home theater... even though that's what I listed. I just meant not for a car. Was looking for the most bass possible. Most bass meaning chest thumping, picture rattling, power. So when guests come they're like wow...

Should I have been looking at an 18" driver? Or a different 15" driver..?

I could easily return the driver.. (and amp if needed)
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post #10 of 15 Old 09-05-2012, 04:57 PM
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Quote:
"Again this is for large parties, all electronic, hip hop music, not home theater"


A pro sound 18" would likely be better for that goal.
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post #11 of 15 Old 09-05-2012, 05:16 PM - Thread Starter
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Quote:
Originally Posted by Jay1 View Post

A pro sound 18" would likely be better for that goal.

How significant is the difference between my setup and switching to a pro 18?

...I guess I should have been looking there from the get go. Even though the frequency doesn't get as low? 35ish hz..

I was looking at the pro 18"s but couldn't find an 8ohm plate amp..

Currently looking through these I suppose..
http://www.parts-express.com/cat/woofers-subwoofers-midrange-speakers/31?kg=497|3909&sort=revs



Maybe I should pick up this 18" and call it a day...
http://www.parts-express.com/pe/showdetl.cfm?partnumber=248-6546

A new thread may be imminent...
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post #12 of 15 Old 09-05-2012, 05:28 PM
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You would likely need an 18" woofer in the $300+ range to handle 500 watts tuned lower then 50hz. Another option I think might work really well is a pair of these ST385's

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-130

The pair wired to 4 ohms in a single cab, 6.5 ft3 with four of those 3"x17" ports will get you a 25hz tuned cab that can handle 500 watts with over 120db above 40hz, while still having the deep bass extension.

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post #13 of 15 Old 09-05-2012, 07:21 PM - Thread Starter
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Quote:
Originally Posted by Jay1 View Post

You would likely need an 18" woofer in the $300+ range to handle 500 watts tuned lower then 50hz. Another option I think might work really well is a pair of these ST385's
http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-130
The pair wired to 4 ohms in a single cab, 6.5 ft3 with four of those 3"x17" ports will get you a 25hz tuned cab that can handle 500 watts with over 120db above 40hz, while still having the deep bass extension.

Interesting. Very doable. Though end cost would be around $600 after full build.. For that same price I can get that prebuilt 18" behringer link from above (35 Hz - 150 / SPL: 133 dB / 1000RMS) Wouldn't that be a better choice?

I remade a new thread starting from scratch. I was way to focused on home theater before, when that's not what it's for.
http://www.avsforum.com/t/1427980/diy-party-sub-650-budget-recommend-me-something-beastly

Redirect there if you'd like, otherwise thanks again for all the time you've spent helping me!
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post #14 of 15 Old 09-05-2012, 07:41 PM
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I can pretty much guarantee you the behringers specs are highly inflated. You need strong 30hz capability with electronic music, and I'll go out on a limb and say that box is tuned to 45hz.
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post #15 of 15 Old 09-05-2012, 07:54 PM - Thread Starter
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Got it.

Any combo you can think of utilizing an 18" driver and a plate amp? Under $650? That was my first and original idea and seems to be what I'd really be looking for. Yet I can't find a plate amp that will properly match up with half the 18" pro audio subs on parts express..

Will exceed budget slightly but these seem to combo eachother.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-809
http://www.parts-express.com/pe/showdetl.cfm?partnumber=290-698
both 4ohms. RMS values within 250 of eachother.. Though that sub only goes down to 36hz..





Will that dual 15" combo posted above vastly outperform my original RSS390HF-4 setup? Or all setups? In terms of loudness, feel...
otherwise perhaps I'll just stick with my original driver/amp. (sorry if I'm frustrating. I'm not that great with all this.)
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