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Discussion Starter #1 (Edited)
I need a new project.

I would like to build a tiny sealed subwoofer for music (not a spectacular setup, 2x infinity primus p363). I have some 3/4 mdf lying around, and an old Infinity TSS-450 amp (100 Watt, probably tuned to around 35, 4ohm). I don't listen to music too loud, just want something slightly better.

Any good 8" driver suggestions? How small can I make the cube? I want TINY :)
I live in Canada, so I would prefer local dealers, Parts Express is just not economical here :(
 

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Car audio will be your best bet. Not sure what you have available to you.
 

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Quite possibly you’re wasting your time, skinny. Infinity rates your Primus towers down to 38 Hz to begin with. The limit of most decent 8” subs is only about 40 Hz, and that’s with the typical cabinet about 1 cu. ft. That isn’t even as good as your main speakers.

To be worth the effort you’ll want at least a 1/3-octave improvement in extension from what your mains do, which means the sub needs to get down to at about 30 Hz. There’s no escaping acoustical physics, it’s going to take a pretty exceptional 8” driver with huge excursion (read expensive), along with high amplifier power, to get that low in a 1 cu. ft. or smaller box.

For example, consider a nice off-the-shelf sub that meets your description, the Velodyne Mini Vee. Audioholics tests confirmed that it would get a solid 30-32 Hz. It has a beefy 8” high excursion driver powered by a 1000 watt amp. Street price was ~$750, which shows that exceptional performance in a small package doesn't come cheap. (For example, that same money will get you big SVS 12" sub that can hit 18 Hz.)

Bottom line, it looks like you’re facing quite a challenge to get more bass than you’re already getting for “free” with your main speakers, if your sub options are limited to a tiny 8-incher.

Regards,
Wayne
 

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I know you said no PE, but these are on sale. It has enough xmax that you can achieve some extra depth with an LT. Probably get down to 40Hz if you don't want to play it too loud.

http://www.parts-express.com/tang-band-w8-740p-8-subwoofer--264-854

Too bad you don't want to go big. The 8" in my sig gets down to somewhere between 25Hz, and it's just a cheap Dayton 8" (I should probably replace it with the TB myself). It actually blows me away every time I hear it dig deep. I designed it to take up minimal floor space. And the height is good to put things on, so it's almost space-neutral.

These Sundown's are $170. Pricey, but 32mm peak-to-peak.

 

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I wonder how SVS can rate their ultra's that have dual 8" to dig down to 28hz
 

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You read my post, right? My dismal 8" driver gets down to 25Hz because it's essentially a mini-LLT.

You get to have deep, or TINY. You can't have both.

Instead of hypotheticals, do some modeling in WinISD and see for yourself. You'll quickly get a feel for what the tradeoffs are.
 

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hmm.

So a dual 8" design would be pretty good then.
Yes, but honestly, giving the size of a cabinet needed for dual 8’s to get that low, you could most likely get better performance with a single, bigger driver. I’m no expert though, the guys at our DIY Subwoofers Forum could better advise on this. :T

Regards,
Wayne
 

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Which begs the question: Why didn't SVS use a single 10 :scratch:. Looks like it would fit in the side of that cabinet. Hmmm....
Exactly... considering the SVS was first a sub company you would think so.

But it seems that sealed dual 8" in my Ultras seem to perform faily well once tamed via audyssey correction:

25hz solid.
 

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Which begs the question: Why didn't SVS use a single 10 :scratch:. Looks like it would fit in the side of that cabinet. Hmmm....
Lots of variables, like perhaps something to do with clearances with internal bracing, or added vibration from more extension requiring more substantial cabinet construction (read weight and expense). Or, maybe they just wanted to limit extension so they could sell you a subwoofer! :laugh:

Regards,
Wayne
 

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Lots of variables, like perhaps something to do with clearances with internal bracing, or added vibration from more extension requiring more substantial cabinet construction (read weight and expense). Or, maybe they just wanted to limit extension so they could sell you a subwoofer! :laugh:

Regards,
Wayne
Well... that would still make you smile wouldn't it???
 

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Discussion Starter #15
Lots of great responses here guys... Thanks. I may actually try and build a small 10, maybe the CSS SDX10. What would be the smallest box for that guy? I'm thinking 12" cube?
 

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A bit late to the party, but given the constraints and expectations in the OP, I would take this approach for operating the sub below resonance:

1. Find an 8" driver with the biggest Xmax and power handling that fits the budget, without worrying about Fs.

2. Build sealed boxes for them which meet the domestic acceptance factor.

3. Measure the impedance curve of the woofer in the box to determine resonant frequency and Q, using the procedure outlined at http://www.linkwitzlab.com/images/graphics/f0Q0.gif.

4. Apply a Linkwitz "biquad" transform eq by building an op-amp based circuit such as outlined in Part 3, Fig. 25 at http://www.linkwitzlab.com/Removed pages/x-sb80-3wy.htm, or using a miniDSP for the sub crossover and eq. This flattens the sub response below resonance down to an arbitrary cutoff frequency.

The Eq parameters will be f0/Q0 = exact conjugate of the results from step 3. fp/Qp determine the lower cutoff, f=19Hz and Q=0.5 work nicely.

For a Canadian purchase, check Solen: https://solen.ca/pub/index.php?s1=1&a=2.
Something like the Peerless SLS 830667, 8" Paper Cone Woofer for around $70 is a possibility, but it's worth checking the advice of whomever suggested looking at car sub drivers.

I used this approach with a pair of EVM15Ls in 3 cu ft sealed boxes, Fs=70Hz, and sub crossover at 70Hz so operating below resonance but flat to 20Hz, the results were the best I've ever heard. Bag End used this approach.

With 8" drivers, you can't go loud, but you can go low at modest volume levels. Conjugate eq is your friend.

that was a long 2¢ reply, hope it gives a different perspective
 

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I have the mini vee from Velodyne and it does go low and loud. It will do 28hz but down probably 4-5db as it is quite loud at the 31.5hz track on the stereophile test cd.
The sub is not cheap but son of a gun it does work well and blends with speakers for music almost like magic.
 

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Wayne,

I stumbled on this thread while googling for a small sub for office. You really know the ropes!...You either saved "skinny" from wasting a bunch of money...or encouraged him to spend a lot more! <grin>

I have previously purchased 2 subs, and despite the rave reviews, was disappointed with both.
(Polk PSW 111: 8" ported, 150w)
(Pioneer SW-8MK2: 8" ported, 100-Watt)

Both sounded weak and woofy. They certainly did not have the punchiness and tight bass I expected.

I thought you might also save/cost me some money while picking your brain/experience for my situation:

  • small, sheetrock enclosed office 9' x 10' floor with 8' ceiling
  • music only (jazz, pop-rock), no movies
  • cabinet size not important
  • priority: tight, accurate, punchy bass rather than deepest frequency capability
  • small desktop stereo amp (Class T type, ~50wpc)
  • mains: Pioneer SP-BS22 bookshelf pair
I'm not looking to shake the walls, but would like to feel bass in my chest a bit. I will mostly be listening to jazz at moderate volume.

Looking either to purchase off-the shelf...or perhaps build my own if the sub will meet expectations...

Money: flexible...hopefully under $500

Can you recommend a solution?


Carl Perez, Cobleskill, NY
 

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I agree with Wayne that 8in sub is somewhat useless.

At 10in you can get either the CSS SDX-10 or Dayton RSS-265HF/HO. Both will fit into 1cu ft sealed. Both are available from Solen, the CSS also directly from creative sound. IIR you music preferences + don't listen loud, you can EQ as "pmcmullin" suggested and get extension to 25-30Hz without too much risk of over-excursion. Relieving your mains for low bass will clean-up their sound. If you really want to stick with 8in, then the Peerless SLS 830667 is a classic.
 
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