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Discussion Starter · #1 ·
My brother just had a kid so he's had to shelf his desire for a neat-o home theater for a while. Since his birthday is coming up, I figured I'd make him a sub to get started on. After calling him up and telling him my idea we came up with the following constraints:


$150 budget (total cost, not just driver)

Had to fit behind the tv (corner mounted 50")

Didn't need to be super loud or low, but had to compliment existing small speakers.


Given these constraints, I thought a small (by this board's standards
) 125 liter sonosub would work well. The corner it is going in can accomodate 18" of diameter and 4' of height.


Because it is going to be right behind a rear projection TV I opted to use the Dayton 12" Shielded DVC driver. Power comes from a 70 watt Dayton sub amp (remember the budget!).


Tuned to 26.5 Hz this should provide output like the attached graph. Since the words didn't come out, the peak output is 108 dB and F3 is 25 Hz. Right now construction has started. I'll keep y'all posted as things develop.

 

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Hey wow, great endcaps!! Pretty damn fine work for a $150 sub!
 

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Nice. Please document how you construct the box and how you attach the amp/box the the tube. My father is wanting me to build a small sonosub for him and wants the amp on the tube as well.
 

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Discussion Starter · #8 ·

Quote:
Originally Posted by parboy /forum/post/0


Nice. Please document how you construct the box and how you attach the amp/box the the tube. My father is wanting me to build a small sonosub for him and wants the amp on the tube as well.

I just got back from a business trip so I can plug away at this this weekend. But, to tell you what I have in mind, I've already rough cut a box from the same MDF I routed the caps from. Two of the sides of the box were cut so they touch the hole in the MDF sheet. This gives them a curve that pretty closely matches the curvature of the sonotube. So, I'll put the box together, cap it with the amp and glue it to the sonotube. I'll use some Amazing Goop to plug the hole where the amp's wires go into the sub so the side box doesn't have to be airtight.


So that's my plan. For now . . . sleep.
 

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Discussion Starter · #9 ·
Here is the amp box by itself, and installed. The box is simply glued on. Note the curved surface at the bottom of the box - it matches up with the outside of the tube (actually cut from the other side of the same curve).


I think if I had used a heavier amp I would have screwed it in from the back. Live and learn. Note that I ran two wires through the wall of the sonotube with quick connects. I sealed the hole they travel through with aquarium glue. Doing this, if I ever need to pull the amp or driver out I won't have to reseal the hole. I could have left it unsealed as the amp box is airtight but I didn't know what the effect of having a hole to a second chamber would be.


Anyway, right now this whole thing is drying. Tomorrow I'll put the driver and amp in and see if it runs. If all is well I'll add the carpet and voila!


BTW, if anyone in the Northern Virginia needs 6' of 16" sonotube give me a PM.


 

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Discussion Starter · #10 ·
Other then touching up some areas where the glue oversprayed, I'm done! I plugged it in and started the break in process.


So far I'm actually very suprised with the musicality of the sub. With Bjork, .38 Special and some jazz I have (with lots of upright bass) the low notes are very well seperated. Port noise is non-existant. With only 70 watts this isn't the loudest sub I have, but it fills my 1700 cubic foot room quite well as long as I don't expect party level sound. I don't want to test it with movies until it is broken in some more so I can't comment there.


I would provide a sampling graph but my fiancee's laptop bit the dust yesterday.
 

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Discussion Starter · #13 ·
I moved Stubby up into my office to run a sweep using my office computer. So, here is an idea of output. Please note this room is the top floor of a cape cod style house (sloped roof), about 1800 cubic feet and has no acoustic treatment (hence the massive dips and peaks). Measurement was at about 1.5 meters so hopefully it is not too affected by room gain. An F3 of 25Hz was my designed aimpoint (see graph in first post). Pretty close if I say so myself!
 

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Hey boomie, how does this sub compare to other commercial subs? Thinking of building one myself to replace a cheap 10" RCA sub I have.
 

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Discussion Starter · #15 ·

Quote:
Originally Posted by brandonnash /forum/post/0


Hey boomie, how does this sub compare to other commercial subs? Thinking of building one myself to replace a cheap 10" RCA sub I have.

Honestly, I would consider this a good sub (for the price) for music in an office or small theater. For "serious" HT duty most would probably find it lacking as it gets very unhappy with high output below about 25 Hz. I currently have four subs (this one, a Velodyne CHT-10, an AV123 x-sub and an Yamaha YST-SW160) - the one it is most like is the x-sub. It is very musical but with a bit more laid back sound. Discerning individual notes is very easy and clear. This thing eats up music from Bjork to BB King.
 

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Discussion Starter · #16 ·
Maybe I spoke too soon. As the final part of my testing I moved the Stubby Subby into my living room. This room has higher ceilings and is much more open then my office or theater room. On the plus side, I can actually sit it in a corner. I assumed even with corner loading this would be the hardest test of the "little" 70 watt sub.


Not so.


In my office and theater room I had the gain knob at three lines above min. I had to turn it down a click here. It still does not like the very loud and low bass found in some scenes in some movies (WOTW, "Irene", the Transformers trailer) but I'm not so worried about bottoming out as I was earlier (still haven't done it yet).


I've included a picture of the Stubby subby sitting in the living room. You can see it next to my x-sub (next to the couch) to get an idea of the size.
 
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