DIY sub advice - End Table Subs - AVS Forum
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post #1 of 27 Old 01-31-2013, 06:28 PM - Thread Starter
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I'm looking for some advice on which direction to go with an end table subwoofer build. I need to build a coffee table and end tables and I want to integrate the subs into the two end tables. The room is my living room and it's quite large in airspace as it's open concept and open to the kitchen, stairwell, hall, etc. I know this is a difficult situation to make proper bass in. Complicating matters I don't want to go super huge on the enclosures, floorspace and WAF are a factor there. I have no place where a 6' tall sonosub or the like would be able to go, hence the end tables. On the bright side I'm thinking the near field placement will help out.

Right now I've got a BIC F12 and it does the job but I'm looking to best that by a decent margin and dig a fair bit deeper. Budget isn't huge (or set in stone for that matter) but figure it in the neighbourhood of $500-$600 for amp & drivers. My initial research has me thinking probably an ep4000 or inuke3000 or the like for an amp and maybe 4x infinity 1260/1262 12" (2 per box in a dual opposed arrangement) or 2x something like an SI 15" (front firing? down firing? I dunno) Ported or sealed is another question too? Usage is mostly HT, but call it 75% HT, 25% music.

I build furniture and stuff do the DIY part isn't a problem, it's more the acoustic side of things. Thanks for any input.
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post #2 of 27 Old 01-31-2013, 07:13 PM
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IMO dual opposed subs make the best end tables because a lot of the box vibration is canceled out.

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post #3 of 27 Old 01-31-2013, 08:11 PM - Thread Starter
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Yea, I was leaning to the dual opposed for the vibration cancelling. Would you do a dual opposed as a sealed or ported?
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post #4 of 27 Old 01-31-2013, 08:16 PM
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Quote:
Originally Posted by fvtalon View Post

Yea, I was leaning to the dual opposed for the vibration cancelling. Would you do a dual opposed as a sealed or ported?

You can do either but I'm going to go on a limb and say 99% of people who make dual opposed boxes go sealed.
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post #5 of 27 Old 01-31-2013, 10:48 PM - Thread Starter
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So if I was to go with a pair of dual opposed Infinity 1260w SVCs, parallel wired for 2ohm in a sealed enclosure what would be the preferred amp?

EP4000, NU3000, or NU3000DSP? Is the DSP worthwhile on inuke? It's about $50 extra. Will it be enough power?

Will the performance in my room be respectable?

I'm on a mac, I will have to dig out an old windows computer and try some winisd modelling this weekend and see if I can't pin down a workable box size...
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post #6 of 27 Old 02-01-2013, 05:29 AM
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Originally Posted by fvtalon View Post

So if I was to go with a pair of dual opposed Infinity 1260w SVCs, parallel wired for 2ohm in a sealed enclosure what would be the preferred amp?

EP4000, NU3000, or NU3000DSP? Is the DSP worthwhile on inuke? It's about $50 extra. Will it be enough power?

Will the performance in my room be respectable?

I'm on a mac, I will have to dig out an old windows computer and try some winisd modelling this weekend and see if I can't pin down a workable box size...

The NU3K is enough power for 4 1260's. In fact it's enough for 8 1262's if you put each one in about 3 cu ft.

The DSP at $50 extra is a no brainer. However, with a big room and only 2 boxes you may want to think about a ported build.

A single SI 15 in a 4cu ft 18hz box will walk all over 2 1260's sealed. Were talking 8db at 20hz difference.
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post #7 of 27 Old 02-01-2013, 05:41 AM
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Quote:
Originally Posted by nograveconcern View Post

The NU3K is enough power for 4 1260's. In fact it's enough for 8 1262's if you put each one in about 3 cu ft.

The DSP at $50 extra is a no brainer. However, with a big room and only 2 boxes you may want to think about a ported build.

A single SI 15 in a 4cu ft 18hz box will walk all over 2 1260's sealed. Were talking 8db at 20hz difference.


How would single and/or duel SI 15's compare to 3 or 4 of the Dayton DVC385's? Or for that matter, how would the single Infinity 1260 or 1262 compare to a single Dayton DVC385?
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post #8 of 27 Old 02-01-2013, 06:12 AM
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Originally Posted by Martycool007 View Post

How would single and/or duel SI 15's compare to 3 or 4 of the Dayton DVC385's? Or for that matter, how would the single Infinity 1260 or 1262 compare to a single Dayton DVC385?

Red = 1260
Yellow = DVC
Lt Blue = SI 15 D2

1ea, Max output, all sealed.


2x 1262's ~= 1 D385 but the Infinitys need 5cu ft (for the pair) to get the same sensitivity down low as the Dayton in 3.5 as well as twice the power. They also end up at about the same cost ratio.

1 SI 15 is~= 2 D385's if you have 1000w RMS to take full advantage of the SI. Not really a fair comparison because if you had that much power then 2 D385's would be 3db over the SI..
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post #9 of 27 Old 02-01-2013, 07:01 AM - Thread Starter
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Originally Posted by nograveconcern View Post

A single SI 15 in a 4cu ft 18hz box will walk all over 2 1260's sealed. Were talking 8db at 20hz difference.

Thanks for the input. My last speaker set was a HTiB with a little, probably 6", mid bass 'subwoofer'. Going from that to better speakers and the F12 is a world of difference but I know in this size room a single entry level 12" is leaving a lot on the table and I know I must be getting little to no response from probably 30Hz and down. Given the room size and aesthetic constraints I know I can't work magic but I'd like to get in on a lot of what I'm currently missing out on. I had originally thought I'd just get a second F12 to even out the room response but since doing some research I think I can do much better for an extra $300-400. I'm not counting the enclosures since I need some end tables anyways.

I will have to do some looking and thinking and see how big an enclosure I can get away with. 4cuft internal ends up being a pretty huge box when you dress up the outside a little for aesthetics. Closer to 3cuft would be much more manageable I think.
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post #10 of 27 Old 02-01-2013, 09:35 AM
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Originally Posted by fvtalon View Post

Thanks for the input. My last speaker set was a HTiB with a little, probably 6", mid bass 'subwoofer'. Going from that to better speakers and the F12 is a world of difference but I know in this size room a single entry level 12" is leaving a lot on the table and I know I must be getting little to no response from probably 30Hz and down. Given the room size and aesthetic constraints I know I can't work magic but I'd like to get in on a lot of what I'm currently missing out on. I had originally thought I'd just get a second F12 to even out the room response but since doing some research I think I can do much better for an extra $300-400. I'm not counting the enclosures since I need some end tables anyways.

I will have to do some looking and thinking and see how big an enclosure I can get away with. 4cuft internal ends up being a pretty huge box when you dress up the outside a little for aesthetics. Closer to 3cuft would be much more manageable I think.

After driver and bracing 4cu ft is about a 21.5" cube which is typical of end table size. 3 cu ft is a 19.5" cube.

I like the Infinities and have 2 1262's that I'm going to put (1 ea ported) into end tables for my non-dedicated-ht family room. However, a .707 flat amplitude box is 2.4 cu ft per driver. DO you end up with 4.8 cu ft. If you’re ok with the small box and making up the difference with eq then fine, but otherwise it's not the best choice for 3 cu ft.
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post #11 of 27 Old 02-01-2013, 10:37 AM
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What about leveraging the coffee table as an enclosure? You could go with a ported build with an 18" driver, or a dual opposed sealed 18" configuration and it should give you more enclosure volume to play with. You could make them down firing as well.

Just something to consider.
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post #12 of 27 Old 02-03-2013, 07:58 PM - Thread Starter
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Using the coffee table as an enclosure had crossed my mind but I don't think I want to go that direction. For one thing it would only be one enclosure which doesn't help the room node situation and it also makes for extremely limited placement. The other thing is we have an Xbox with the Kinect thing and I think I'd like to keep it small and light so it could be moved off to the side easily in order to game. For that matter too I'm not even sure I want a coffee table...

At any rate, I guess I was a little pessimistic in my maximum enclosure volume estimates. I mocked up some coffee tables and I think I can get away with about 19" or 20" wide, up to 30" long (deep) and about 21" high. 20x21x30 is about 7.29 cuft. Now granted the top will eat into that height and I want the top to overhang the sides some to stay away from the giant cube look. Allowing for that and sides I have an internal volume of around 18.25" x 16.5" x 26.5" with a volume of 4.62 cuft. Less 0.19cuft for the SI HT 15 is 4.43 for airspace, port space and bracing which I think I can net 4 cubes for the final airspace right?

I put winisd on my old laptop and I've been playing with it. I'm not sure how to interpret the results I'm getting. With 2 1260w in a 4.3cuft sealed box, I have the gain already -1.46 @ 80Hz then rolling off to -9.75 @ 20Hz. A vented 17Hz 4 cuft SI HT 15 is only -0.19 @ 80Hz and -6.46 @ 20Hz which seems much better.

But then on the SPL graph the 1260s @ 300W which I assume is per driver are 119dB @ 80Hz and 111dB @ 20 Hz vs 115db @ 80Hz and 109db @ 20Hz with the 1260s also doing 103dB vs 95dB @ 10Hz. Which I guess you'd EQ down the higher Hz values on the infinitys and then have a flatter, louder, output? The 15" is at 600W in that model too. Assuming I've modelled it correctly I'm not sure which is the better result?

Some confusion on port sizing too... How do you figure out an optimal port size? If I did a slot port it seems like it needs to be huge, 1.75" x 16.5" is mach 0.10 but it's 59" long which is ridiculous. Yet 3x2" ports are 20" long and mach 0.1 which is much more manageable.

I've been reading and modelling for most of the day and it's quickly becoming a 10 new questions for every answer situation. rolleyes.gif
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post #13 of 27 Old 02-04-2013, 08:24 AM
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Quote:
Originally Posted by fvtalon View Post

Using the coffee table as an enclosure had crossed my mind but I don't think I want to go that direction. For one thing it would only be one enclosure which doesn't help the room node situation and it also makes for extremely limited placement. The other thing is we have an Xbox with the Kinect thing and I think I'd like to keep it small and light so it could be moved off to the side easily in order to game. For that matter too I'm not even sure I want a coffee table...

At any rate, I guess I was a little pessimistic in my maximum enclosure volume estimates. I mocked up some coffee tables and I think I can get away with about 19" or 20" wide, up to 30" long (deep) and about 21" high. 20x21x30 is about 7.29 cuft. Now granted the top will eat into that height and I want the top to overhang the sides some to stay away from the giant cube look. Allowing for that and sides I have an internal volume of around 18.25" x 16.5" x 26.5" with a volume of 4.62 cuft. Less 0.19cuft for the SI HT 15 is 4.43 for airspace, port space and bracing which I think I can net 4 cubes for the final airspace right?

I put winisd on my old laptop and I've been playing with it. I'm not sure how to interpret the results I'm getting. With 2 1260w in a 4.3cuft sealed box, I have the gain already -1.46 @ 80Hz then rolling off to -9.75 @ 20Hz. A vented 17Hz 4 cuft SI HT 15 is only -0.19 @ 80Hz and -6.46 @ 20Hz which seems much better.

But then on the SPL graph the 1260s @ 300W which I assume is per driver are 119dB @ 80Hz and 111dB @ 20 Hz vs 115db @ 80Hz and 109db @ 20Hz with the 1260s also doing 103dB vs 95dB @ 10Hz. Which I guess you'd EQ down the higher Hz values on the infinitys and then have a flatter, louder, output? The 15" is at 600W in that model too. Assuming I've modelled it correctly I'm not sure which is the better result?

Some confusion on port sizing too... How do you figure out an optimal port size? If I did a slot port it seems like it needs to be huge, 1.75" x 16.5" is mach 0.10 but it's 59" long which is ridiculous. Yet 3x2" ports are 20" long and mach 0.1 which is much more manageable.

I've been reading and modelling for most of the day and it's quickly becoming a 10 new questions for every answer situation. rolleyes.gif


This site is the only place I have found, though there may be others, that correctly calculates slot ports. WinISD does not. Hint: a slot port ends up being shorter than a square tube port of the same area.

http://www.carstereo.com/help/Articles.cfm?id=31

It also will calculate the minimum port area based on driver size and xmax.

As far as the SI 15 vs 2x1260, the ported SI has both more sensitivity at 1 watt and more max output.

The place where the sealed 12's beat the ported SI is below 14hz where the ported box begins to unload and should be high passed. However, if your goal is to play that low loud you will need 16 of the 1260's. wink.gif
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post #14 of 27 Old 02-04-2013, 08:31 PM
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I've done over a dozen of these types of builds for both myself and friends. While I understand the principles behind dual opposed, I see no need for it in an end table build and have done downfiring ported on all of them, taking advantage of the larger volumes of air. The Infinities like big boxes ported, and a pair would certainly be considered a capable subwoofer system.

I always approach these builds with ergonomics in mind, where the table dimensions come first, and then work backwards with the available internal volume. For 12" long throw woofers, I use 1/4" the diameter as the limit for ground clearance, or 3" for these. Figure on the comfortable height for placing and retrieving items while seated and other dimensions to balance with the size of the space and other furnishings.
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post #15 of 27 Old 02-05-2013, 05:55 AM
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I've done over a dozen of these types of builds for both myself and friends. While I understand the principles behind dual opposed, I see no need for it in an end table build and have done downfiring ported on all of them
Dual opposed has its benefit in eliminating the tendency for a sub to move across the floor at very high levels. But it does nothing to eliminate vibration of the cabinet panels, and more than a few potential builders mistakenly think that it does. If the intent with a table sub is to keep the panels from vibrating, so that objects placed on the sub won't rattle and dance, adequate bracing is all you need, while downfiring will keep the sub from moving about at high output levels. Not that there's anything wrong with dual opposed, but the box has to be twice as large, which may make it too big to work as an end table.

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post #16 of 27 Old 02-05-2013, 07:58 AM
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I've done over a dozen of these types of builds for both myself and friends. While I understand the principles behind dual opposed, I see no need for it in an end table build and have done downfiring ported on all of them, taking advantage of the larger volumes of air. The Infinities like big boxes ported, and a pair would certainly be considered a capable subwoofer system.

I always approach these builds with ergonomics in mind, where the table dimensions come first, and then work backwards with the available internal volume. For 12" long throw woofers, I use 1/4" the diameter as the limit for ground clearance, or 3" for these. Figure on the comfortable height for placing and retrieving items while seated and other dimensions to balance with the size of the space and other furnishings.

Exactly what I'm planning to do with my 1262's. cool.gif

Got any pictures of your builds?
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post #17 of 27 Old 02-05-2013, 07:16 PM - Thread Starter
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In the case of the ported 1262ws what kind of output are you expecting based on the models? What kind of bottom end extension are you expecting?

I tried modelling one in 4cuft with a 17Hz tune and the results don't look like I'd expect. Huge spike at 17Hz with a dip at 30hz? I think I might have made a typo in the sub specs when I inputed the infinitys.

As much as I like the idea of the 2 ported Si 15s I did all the math and by the time they're shipped the 2 15s are worth as much as 8 1260/1262ws. Are 2 1262s in larger (3.5-4cuft) ported enclosures going to provide better output than 4 1260ws in a sealed dual opposed configuration?
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post #18 of 27 Old 02-05-2013, 07:44 PM
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Sadly, I haven't kept an accurate log of the builds, and lost quite a bit to last years Hurricane Irene flood........but I did escape damage from superstorm Sandy. Mostly Mission style lending towards F.L.W. I like using tenons with opposing stains for contrast. Red Oak and Maple worked well together for me.
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post #19 of 27 Old 02-05-2013, 07:50 PM
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Quote:
Originally Posted by fvtalon View Post

In the case of the ported 1262ws what kind of output are you expecting based on the models? What kind of bottom end extension are you expecting?

I tried modelling one in 4cuft with a 17Hz tune and the results don't look like I'd expect. Huge spike at 17Hz with a dip at 30hz? I think I might have made a typo in the sub specs when I inputed the infinitys.

As much as I like the idea of the 2 ported Si 15s I did all the math and by the time they're shipped the 2 15s are worth as much as 8 1260/1262ws. Are 2 1262s in larger (3.5-4cuft) ported enclosures going to provide better output than 4 1260ws in a sealed dual opposed configuration?

If you have available enclosure volume and you're on a budget, ported will always produce better results than sealed. As I mentioned earlier, all of these inquiries aren't really the way to proceed.....best to determine the individual enclosure volume based on your table design, and work from there. In lies the beauty of DIY, allowing for a system to work within the constraints of environment and budget.
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post #20 of 27 Old 02-05-2013, 10:33 PM - Thread Starter
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Buried in one of those previous posts I had determined the size; 20"W x 30"L x 21"H overall. To allow for aesthetics, top overhang, legs or panel detail etc lets call the internal box volume a maximum of 16.5"W x 26.5" L x 19"H, I suppose more like 16" H in a down firing arrangement on 3" legs. So around 4.8cuft for a front load or 4.0cuft for down firing. A single 12", bracing and a port should account for what, 0.5cuft? So 3.5cuft airspace.

Thanks again for any input. smile.gif
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post #21 of 27 Old 02-06-2013, 06:15 AM
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Buried in one of those previous posts I had determined the size; 20"W x 30"L x 21"H overall. To allow for aesthetics, top overhang, legs or panel detail etc lets call the internal box volume a maximum of 16.5"W x 26.5" L x 19"H, I suppose more like 16" H in a down firing arrangement on 3" legs. So around 4.8cuft for a front load or 4.0cuft for down firing. A single 12", bracing and a port should account for what, 0.5cuft? So 3.5cuft airspace.

Thanks again for any input. smile.gif

Driver displacement should be about .15 and bracing another .1-.2.

Ported will give you a flatter response with more output below 25hz. The dual sealed will be louder above.
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post #22 of 27 Old 02-06-2013, 01:47 PM
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I know you're primarily considering a single sub per end table, but I think you really ought to consider buying some lightly used SSD 15s like I did and going with a build similar to what I did.

http://www.avsforum.com/t/1428124/ssd-15-dual-opposed-vertical-sub-build

Granted, I haven't yet gotten top plates because the glass cutter didn't inspire confidence that they can do what they said they can (prolly going granite now), but it fits all the right notes and it's not too expensive - around a grand for both. The results are spectacular, too!

If you have any questions, feel free to PM me and I'll get back with you.
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post #23 of 27 Old 02-06-2013, 02:07 PM
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Just wanted to throw in my experience with an "end table sub". I'm currently using a Dayton 15 HO in a 3cu ft sealed box powered with a crown xls1000. The box is pretty heavily braced and final wall thickness is about 1". I used it as an end table for about 2 days, then realized that during heavy bass notes there was too much vibration to set anything on it. I added more internal bracing, but still ended up with the same problem. Now it's just a piece of furniture with nothing on it - which for me made placement easier and I don't mind, but is no longer an "end table".

So... long story short, I would take any and all advice about reducing box vibration. The dual opposed sub idea sounds interesting.
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post #24 of 27 Old 04-13-2013, 10:15 PM
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I was in the same situation had a f12, I am currently building a table tuba. Pretty big for a end table though. I plan on doing a concrete top for it like I did for my kitchen cabinets when I built them
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post #25 of 27 Old 04-14-2013, 06:52 AM
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A word of warning. I built a couple downfiring 12" end tables. The WAF worked out really good. They blend right in. But they love to wander around. I need to find a way to control them. They'll walk more than 6" in a movie. Sometimes bumping into the wall making an annoying sound. And putting my hand on the top why playing they vibrate viciously. Compared to my third sub which is dual opposed (same drivers) which is nearly dead to the touch and doesn't move an inch. If I did it over again, I'd have to think hard about doing it differently. They are adequately braced!
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post #26 of 27 Old 04-15-2013, 07:56 PM
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Tux are yours on hardwood or carpet? Spikes should keep them from sliding around on carpet. if they are on something like hardwood you could try the sticky stuff you put under area rugs to see if that will help keep them in place
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post #27 of 27 Old 04-17-2013, 12:05 PM
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Originally Posted by tuxedocivic View Post

A word of warning. I built a couple downfiring 12" end tables. ... But they love to wander around. ... If I did it over again, I'd have to think hard about doing it differently. They are adequately braced!
My build is not quite done, and owe the group a write-up, but this applies here.

I vibration isolated the subwoofer in my end table sub. Single, down-firing Tempest X and it's rock solid at any power level. Here's a link to the theory...
And a cross-section of the design, showing only the rails, subwoofer capsule, and support system. Legs are not visible in the diagram; it's just floating in thin air, like any good cross-section.


The idea is to create a spring-mass system with a resonant frequency below the lowest expected driving frequency. As you can see from the link, transmissability falls like a rock above resonance. They suggest a 70% margin to driving frequencies; I aimed for an octave... and assumed a 10Hz driving frequency. I targetted a 5Hz resonance empirically, by adding small springs until I got 10 cycles in 2 sec on the stopwatch.

The only tricky part is finding springs with the right spring rate and rest length. I wanted to support 85lb. with only 1/3 deflection (concerned with creap over time), but I had a lot to choose from (thanks to my employer). I varied placement to get equal deflection from all the springs, so it sits level. At this point, the only thing that happens when I send it a 20Hz sine wave is a whistle where the leads enter the box; nothing moves at all.

I expect a glass of water on the table would jiggle much less than one on the floor next to the sub, but that's what's missing - the table top has a BIG hole in it.

HAve fun,
Frank.
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