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First Subwoofer Build

post #1 of 9
Thread Starter 
I'm looking at my first subwoofer build and I have a couple of questions. The sub will be primarily for HT (80/20) and be in my basement setup, room is 14x18. I'm considering 2 different driver/amp combos and building corresponding boxes. I wondering if one combo is better than the other for my setup and if either build will provide me with something comparable to a SVS PB1000 or HSU VTF 2.4, either of which I think would be adequate for my needs.

Option 1:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=301-512 - Plate amplifier
http://www.diysoundgroup.com/flat-packs-1/subwoofer-flatpacks-2/3-sub-flat-pack.html - 3 cu.ft flat pack

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-514 - 15" Dayton Audio Ultimax

Option 2:
http://www.rythmikaudio.com/DS1500ci.html - Driver/Amp Combo
http://www.rythmikaudio.com/download/DS1500s_sub_plan.pdf - This enclosure

I will probably build the enclosure for Option 1 to the flat pack specs…I have the tools, materials and I’m pretty handy around the shop. I just don’t know much about the science of sound.
Thanks for any feedback.
post #2 of 9
for your room for home theater a ported enclosure would serve you better.

red is 15" um driver in 3 cubes. too small in my opinion. rolls off too quickly. q is too high.

white is my guess at the hsu sub that you mention for comparison.

blue would be a ported, 5 cubic footer, tuned to 22hz using the dayton rss390ho:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-469



115db is full reference from the lfe channel and in a real room you will get more bass than in the model.

this ported enclosure would be easy to make. 5 cubic feet net volume and a single 6" diameter port that is 27" long. good bracing and air tight. the particular shape doesn't matter so much. you can build it tall and slim or low and wide, so long as the internal volume and the port stay on plan.

if you really must go sealed, go with the rythmik driver/amp/plan.

good luck with your build whichever way you go.
post #3 of 9
Quote:
Originally Posted by chpwaman View Post

I'm looking at my first subwoofer build and I have a couple of questions. The sub will be primarily for HT (80/20) and be in my basement setup, room is 14x18. I'm considering 2 different driver/amp combos and building corresponding boxes. I wondering if one combo is better than the other for my setup and if either build will provide me with something comparable to a SVS PB1000 or HSU VTF 2.4, either of which I think would be adequate for my needs.

Option 1:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=301-512 - Plate amplifier
http://www.diysoundgroup.com/flat-packs-1/subwoofer-flatpacks-2/3-sub-flat-pack.html - 3 cu.ft flat pack

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-514 - 15" Dayton Audio Ultimax

Option 2:
http://www.rythmikaudio.com/DS1500ci.html - Driver/Amp Combo
http://www.rythmikaudio.com/download/DS1500s_sub_plan.pdf - This enclosure

I will probably build the enclosure for Option 1 to the flat pack specs…I have the tools, materials and I’m pretty handy around the shop. I just don’t know much about the science of sound.
Thanks for any feedback.

The problem with option 1 is that amp has a 30hz HPF built in, making it unsuitable for most sub designs. If you could swing the 1000 watt dayton plate amp the Ultimax 15 would provide some serious potential. An outboard amp like the Behringer EP4000 would give you better value though, and leave an extra channel available for a second sub in the future.

The Rythmik uses EQ to boost the low end for very good extension, but output will be severely limited compared to the UM15 with more power.
post #4 of 9
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

for your room for home theater a ported enclosure would serve you better.

red is 15" um driver in 3 cubes. too small in my opinion. rolls off too quickly. q is too high.

white is my guess at the hsu sub that you mention for comparison.

blue would be a ported, 5 cubic footer, tuned to 22hz using the dayton rss390ho:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-469



115db is full reference from the lfe channel and in a real room you will get more bass than in the model.

this ported enclosure would be easy to make. 5 cubic feet net volume and a single 6" diameter port that is 27" long. good bracing and air tight. the particular shape doesn't matter so much. you can build it tall and slim or low and wide, so long as the internal volume and the port stay on plan.

if you really must go sealed, go with the rythmik driver/amp/plan.

good luck with your build whichever way you go.

Wow...thanks for the info with the graphs. There is no doubt the rss390ho in the graph is the clear winner. I was staying away from ported because I felt adding the port was adding another element that if not done right would really mess with the performance of the sub. Perhaps its not something I should be that scared of doing. But a 27 inch long port, might be the deal breaker, that would mean I would probably need at least one length of the sub to be 30 inches or more? I'm OK with 5.0 cubic feet, but I don't want a long rectangle for a sub. I could see a 22 x 18 x 22, which is just about 5.0 cf on the nose. Whatever I end up building, will need to be made to look like an end table for high WAF.
post #5 of 9
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

for your room for home theater a ported enclosure would serve you better.

red is 15" um driver in 3 cubes. too small in my opinion. rolls off too quickly. q is too high.

white is my guess at the hsu sub that you mention for comparison.

blue would be a ported, 5 cubic footer, tuned to 22hz using the dayton rss390ho:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-469



115db is full reference from the lfe channel and in a real room you will get more bass than in the model.

this ported enclosure would be easy to make. 5 cubic feet net volume and a single 6" diameter port that is 27" long. good bracing and air tight. the particular shape doesn't matter so much. you can build it tall and slim or low and wide, so long as the internal volume and the port stay on plan.

if you really must go sealed, go with the rythmik driver/amp/plan.

good luck with your build whichever way you go.

What if I just used a 4 or 5 inch port, the same tuning and box volume would seem to reduce the length to 11 or 18 inches respectfully...can you just change port diameter like this?
post #6 of 9
the port can be made smaller, but the speed of air goes up. if using winisd, the rear port air velocity tab shows how fast air is moving. too high and chuffing results.

that is why i suggested the port diameter and length that i did.

there are other ported options however, a slot port for example or even a square port. none of these are difficult to calculate.

i was just suggesting the easiest possible solution, a single round port with no bends.

the cross sectional area and length are all that matter.

a 6" port diameter is pi*r^2 = 3.14*3^2 = 3.14*9 = roughly 27 square inches.

a 5.25" x 5.25" square port is also about 27 square inches. so you could make a square port that runs along the bottom and then up the back of the enclosure.

or a 2.62" x 10.5" port of the same length.
post #7 of 9
Thread Starter 
In doing some more research on box sizes, etc and modeling some dimension in my room. Whether I like it or not, size is going to be an issue. I like the size and look of the sub here: http://www.rythmikaudio.com/D15SE.html
My question is, the plans found here: http://www.rythmikaudio.com/download/DS1500s_sub_plan.pdf use the same AMP and same size driver as the D15SE, but the box is much bigger. Is the driver the key here or is there something going on inside the box? The performance of the D15SE (first link) would seem to be all I need for my room. Could I expect to repeat that performance of the D15SE using the CI1501 Driver and AMP combo - http://www.rythmikaudio.com/DS1500ci.html and build a box to the dimensions of the D15SE, which would be smaller than the DIY plans prescribed for that driver/amp combo.
post #8 of 9
Quote:
Originally Posted by chpwaman View Post

I'm OK with 5.0 cubic feet, but I don't want a long rectangle for a sub. I could see a 22 x 18 x 22, which is just about 5.0 cf on the nose.

22 x 18 x 22 using 3/4" material has a gross volume of only 4 cuft. After bracing, woofer, amp, you'd be closer to 3.7 or so. If you put a couple ports in there, you'd be around 3.5cuft net volume, probably less.
post #9 of 9
Thread Starter 
Yes...you are correct..not sure where I got 5 cu ft from. Calculator clearly shows 4.013 cu ft.
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