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First time DIY SUB advice needed

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diy needed time
2K views 6 replies 2 participants last post by  Mike P. 
#1 ·
I currently have a HSU STF-2 in a 12'x12'x8' tiled room, which I use for 70/30 music and movies. I like the sound quality of the HSU but I find it lacking in depth and output even if I run it hot. I'm currently investigating some DIY options because I live in Hawaii and shipping a VTF3 Mk4 is $362.93, let alone something like a VTF-15H. I've considered getting another STF-2 or a Klipsch 12d while it's on sale, which would cost around $420 shipped, but I'm a little worried about spending more just to end up with upgrade-itis again. I've considered the usual $500-600 range suspects but due to shipping, they become much more than that.

Space-wise I'm looking for a relatively small enclosure. The STF-2 measures 17"x14"x17" and is about the max footprint I can have in my room. I could probably squeeze in a sub that is approximately 6" taller, and another sub approximately the same size in the opposite corner of the room. My budget is around $500-600 for amp, materials, and drivers but is flexible. If there's something noticeably better for $800, I'd consider it.

In short I'm looking for something that is easy to build (ie, sealed cube, sonotube, flat pack), has a relatively small footprint, and would be a significant upgrade from my STF-2. I currently use the system for mainly music, but I do enjoy movies and hard hitting bass. I also have REW and an EMM-6, and have measured the system down to around 25 hz. I don't know how much lower than that I'd like to go, but I do know that 25 doesn't seem to be enough for me.

I greatly appreciate any and all suggestions.
 
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#2 ·
The HSU STF-2 is a 10 inch driver and has a frequency response from 25 hz and up, it was never designed for 20 hz performance for serious HT performance. Testing has shown it will do 106 db at 25 hz and is 9 db down at 20 hz. There are driver/ passive radiator/amp combinations that will do well in small size boxes and give excellent low end extension but you have to pay for it.

Adding 6" in height to your cabinet dimensions would allow a net volume of about 2.2 cu.ft.

The TC Sounds LMS-R12 works well in this volume.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=293-658

You with need a pair of CSS APR12 Passive radiators.
http://www.creativesound.ca/details.php?model=APR12

And a Dayton Audio 1000 watt plate amp.
http://www.parts-express/pe/showdetl.cfm?partnumber=300-809

White is the performance of your current sub woofer.

Purplewould be the performance of the LMS-R12/APR12's/Dayton Audio 1000 watt plate amp.

Text Line Technology Slope Parallel
 
#3 · (Edited)
Oh my, my post got eaten twice due to post count.

Thanks for the reply. Those numbers are truly impressive. I'll keep that in mind for the current sub position. It looks like I need to do some research on passive radiators. Though after looking over my room it appears I can get a much taller sub in the rear. After looking at your post I decided to give Winisd a shot and for my first attempt I modeled a TC Sounds Epic 12 at 400 watts in a 5 ft^3 box with a 20 hz tune.



For simplicity sake, I tried downloading sonosub.exe and got everything looking good at 5.5 ft^3 using a 6" port and 18" sonotube, for a total height of around 4' before the legs. I needed to add the extra .5 ft^3 so the port could clear the driver. I was satisfied with this until I noticed that sonosub.exe doesn't seem to account for port volume. Strange being this program seems to be often recommended but I don't see any posts ever mentioning it.


At any rate, now that I got an idea of how these programs work... it looks like I have way more research to do!
 

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#5 · (Edited)
I think I'm making a simple mistake somewhere but in my pic above it shows a 30"x6" port which should be 1.96 ft^3. It specifies a sonotube cut of 3' 7 1/4" with an 18" sonotube which is 6.36 ft ^3 without the port, driver and endcaps. If I subtract the port volume from the sonotube volume I come out with 4.4 ft^3 before the endcaps and driver.

Can you point out where I'm going wrong?

Edit. Whoops. I got it. Entered diameter for radius. Doh.
 
#6 ·
Ok, so I went out and bought 5' of 18" sonotube on a whim. I know it's been said over and over that these things are shockingly huge in person, but I was still surprised when they brought it out. Now I'm positive 5.5 ft^3 is about as large as I want to go.

Ever since I read the "stubby sonotube" build I've been tempted to go dual opposed, but I'm modeling a ported enclosure with way more output from 40 hz down, while the dual opposed has way more from 40 hz and above. The ported also has a much flatter frequency response, but has much higher group delay below 30 hz. However, I can get by with half the volume in a sealed dual opposed and I don't have to worry about getting the port lengths and flares right.




Aside from the obvious advantage below 30 hz for the ported sub, do the models point to any other subjective differences?

Regarding sealed, is audyssey able to flatten out the response in a typical room? I've read it doesn't boost below f3, and f3 occurs at 45 hz for the dual opposed. How important is the f3 parameter? I know all subs need EQ to be anywhere near flat, but do sealed systems typically need more?

I'm leaning towards the ported with a nu 1000dsp @ 4 ohms bridged for 750 Watts RMS but the smaller box with less extension is still making me unsure. I guess maybe a better question is, are there different drivers that may be better for either application in the same price range? ie, ported < 5.5 ft^3, and small dual driver?

I know I can get slightly better numbers sealed with an LMS-R but going duals is cost prohibitive.
 

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