SW-12-08 sandbox

dvenardos · « **on:** 15 Mar 2009, 02:02 am »

Based on Brian's recommendation of 4.4 ft^3 for (2) SW-12-08 and an A370PEQ:
http://www.audiocircle.com/index.php?topic=65660.msg602551#msg602551
It looks like you could double the width of the internal box for SW-12-04 sandbox and increase the internal box height to 17" to get 4.42 ft^3 (28.5" w x 17" h x 15.75" d) and then just make a larger external box for sand fill.

This would give you two side by side front firing SW-12-08. Comments?

Danny Richie · « **Reply #1 on:** 15 Mar 2009, 02:25 am »

It would be a really solid box and sound really great too. One of the best things about this DIY thing is the flexibility to make it the way YOU want it.

fcraven · « **Reply #2 on:** 15 Mar 2009, 03:25 pm »

That sounds mighty tasty.

One caution, as you start to poor in your second or third 60 lb bag of sand just remember that you are adding to the weight of your sub

. So, I strongly recommend wheels.

dvenardos · « **Reply #3 on:** 15 Mar 2009, 08:15 pm »

I am having lots of fun. I don't think I will ever buy a speaker pre-made again.

I believe in the original sandbox thread that Danny said that it didn't take that much sand to fill the sides. Three sixty pound bags would definitely be a problem.

If I go this route I would like to incorporate it into a component rack and center channel stand by adding shelving on top. I think the dual forward firing SW-12-08s would give a lot of flexibility to the crossover on the center channel. Just need to test the intended location before building to make sure there aren't any room acoustic issues.

fcraven · « **Reply #4 on:** 15 Mar 2009, 09:45 pm »

The amount of sand depends on how much space you need to fill up. I had a 3/4" gap, and Danny had a 3/8" gap. either way if you double your size you will be doubling your sand.

But I must say, I love my sand box... which is on wheels.

dvenardos · « **Reply #5 on:** 15 Mar 2009, 10:45 pm »

Would it be better to make these side firing like stereodude which would reduce vibration and increase efficiency? Also, I assume that would justify a smaller cabinet.

Stereodude · « **Reply #6 on:** 16 Mar 2009, 12:00 am »

Quote from: dvenardos on 15 Mar 2009, 10:45 pm

Would it be better to make these side firing like stereodude which would reduce vibration and increase efficiency? Also, I assume that would justify a smaller cabinet.

It won't increase efficiency. I arrived at the box size I have mostly because of the excursion limits of the drivers at 10Hz with 370W with a moderate amount of polyfill.

m-fine · « **Reply #7 on:** 16 Mar 2009, 01:26 am »

Quote from: fcraven on 15 Mar 2009, 09:45 pm

The amount of sand depends on how much space you need to fill up.

FYI, typical sands seem to take up about 17-19 cuin per pound, or 90-100 lbs per cuft.

dvenardos · « **Reply #8 on:** 17 Mar 2009, 05:52 am »

Quote from: m-fine on 16 Mar 2009, 01:26 am

Quote from: fcraven on 15 Mar 2009, 09:45 pm
The amount of sand depends on how much space you need to fill up.

FYI, typical sands seem to take up about 17-19 cuin per pound, or 90-100 lbs per cuft.

Just roughing it, I get 90 lbs for 1" which would be 68 lbs for 3/4 and 34 lbs for 3/8.

dvenardos · « **Reply #9 on:** 24 Mar 2009, 01:05 am »

Okay, Eargasm a birdie told me you are building one of these so fess up.

EARGASM · « **Reply #10 on:** 24 Mar 2009, 05:18 am »

Removed by member.

dvenardos · « **Reply #11 on:** 24 Mar 2009, 06:49 am »

This thread is worthless without pics.

Opposing or adjacent drivers?

dvenardos · « **Reply #12 on:** 24 Mar 2009, 05:46 pm »

Quote from: EARGASM on 24 Mar 2009, 05:18 am

And, what's this with 4.4 cf internal volume? 1.5-ish cf/each is perfect for the GR Servo Subs. Maybe 4.4-ish is correct for a pair of the Rythmik units?

Okay, keep in mind that I haven't done the calculations myself, but my understanding is this. 1.5 cf is based on 370w powering the woofer. If you went with the new high power amp then that would remain ideal. The 4.4 cf creates more air space to lessen the load on the 370w amp when powering two drivers instead of one. Steredude came up with 3.5 cf for his dual based on using the 370w amp and taking into account the excursion limit of the drivers at 10hz. Again, I didn't do any of these calculations so YMMV.

madpoet · « **Reply #13 on:** 24 Mar 2009, 09:56 pm »

Heh, we'll see what Eric hooks me up with! I need to make sure to have some furniture dollies or something once I'm done filling this monster!

madpoet · « **Reply #14 on:** 25 Mar 2009, 07:11 pm »

So Eric and I decided on 17.5 tall x 29.5 deep x 31 wide. Gives me a couple orientations I can use it in.

dvenardos · « **Reply #15 on:** 25 Mar 2009, 07:35 pm »

Quote from: madpoet on 25 Mar 2009, 07:11 pm

So Eric and I decided on 17.5 tall x 29.5 deep x 31 wide. Gives me a couple orientations I can use it in.

One of your dimensions has to be wrong because that is 9.26 ft^3.
Are you doing adjacent or opposing drivers?

madpoet · « **Reply #16 on:** 25 Mar 2009, 07:43 pm »

Adjacent drivers. That does include the grill frames, so there's some extra there (but not that much). Let me pull out my abacus and check again

dvenardos · « **Reply #17 on:** 25 Mar 2009, 07:48 pm »

Quote from: madpoet on 25 Mar 2009, 07:43 pm

Adjacent drivers. That does include the grill frames, so there's some extra there (but not that much). Let me pull out my abacus and check again

For front firing adjacent drivers your width and height looks good, it is your depth that is wrong.

EARGASM · « **Reply #18 on:** 25 Mar 2009, 07:51 pm »

Removed by member.

madpoet · « **Reply #19 on:** 26 Mar 2009, 05:19 pm »

Well, 600 lbs of sand would be one absolutely imovable box

Really looking forward to playing with this. I'm going to stand it on end to start, sort of like a double stack. Should be a lot of fun.