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Discussion Starter #1 (Edited)
16 x 12" Sealed sub cabinet...the "Ruptured Spleen"

I'm sick of having a pile of subs and only having a good Dayton 15" and a broke ass 1/10th powered siht 18" to listen to.

I've been reading about how magical the 24 is:rolleyes: and the near field effect being extended over what an 18" can do by the diameter of the cone.

I've got this pile of 12's and figure I can plop 16 of them into a 50.5"x50.5"x24.125"deep box with the baskets touching and covering about 50% of the surface area of the box with cone area.

This should get me optimal coupling between the cones and make it act nearly like a single driver.

I'll use 2 ep4000's to power them and should be able to get 12mm of excursion out of them with 150W per driver.

I'll also be able to do a distributed 16x llt measurement vs a 16x co-located sealed measurement and compare them.


Pics soon


Edit: I'm listening to infected mushroom again, that caused my last rash rant....NEED MORE BASS!!!!!!!!!!!!!!!!!!!


Edit:Just finished it, It's all that.


 

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Discussion Starter #5
I thought you were doing a few LLT's distributed in your room?

Going sealed now?

I'm jonesing for some more bass, and want a little instant gratification.
I can put together an unpainted sealed box in a day. And it'll be small/light enough to move, barely. It should be about 300 lbs empty. I'll put the drivers in when I get it home and have it in place. It should be about 550lbs with drivers.


I have all my wood working tools at another house that a friend is remodeling. The LLT's will be 24"x48"x96" and need to be built in place. I'll build them after I have my table saw and stuff back home. I still have to come to a final decision on box volume and port configuration too.


I'm only using half of the 1260's in this sealed box. I'll still be able to build 4 of the quad LLT boxes with the other 16 subs. Then I'll cannibalize the subs in the sealed box to build the last 4 LLT's. Anyone want to buy a 16x12" sealed cabinet when I'm done with it? Who knows, maybe I'll end up liking the sealed setup and build 3 more of these cabs.


I just got 4 sheets of 3/4 MDF today. I was getting ready to cut it up and had my phone ring with an emergency...bass fix thwarted. I'll cut it up tomorrow and see if I can get the box together. I'm flush mounting the subs in a double baffle, so I'm going to have to cut 32 12" holes with my router...I wonder if one spiral bit will be enough?


I'm still debating what to do with the interior of the box. I'm at least going to put 3 dividers in the box. One between each row of 4 subs to divide the interior into 4 air spaces with 4 subs on 1 amp channel per cavity. What I'm still not sure of is if I want to divide those up further into 16 separate air chambers.


I'm going to have this sub nearfield firing into the back of my couch.
 

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I had a pair of them, sent them about 450 watts and the voice coils fell apart.
The odds are that you sent 450 watts to two subs that is 150watts below RMS and they blow just blew their voice coil apart? Astronomical. Sounds like you wired something wrong or did something.

What amp were you using? How were they wired?
 

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I had a pair of them, sent them about 450 watts and the voice coils fell apart.
Sucks... That's the nature of quality control on a product that is underselling others that compete.

Funny thing is (more like annoying) is the inconsistency in how people rate the sound of them. I know room matters but you hear some people say they sound "off" or "odd" (believe that was on HTShack). Other have said they have used them in many rooms and they are top class sq and top others... Then the dayton Ultimax has a reputation or being only a LF/ULF type... Very tough to pick drivers these days but I am also leaning toward the HO line...Although SI in large sealed... Exactly...
 

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Discussion Starter #9
The odds are that you sent 450 watts to two subs that is 150watts below RMS and they blow just blew their voice coil apart? Astronomical. Sounds like you wired something wrong or did something.

What amp were you using? How were they wired?
I had d4's on a ep4000 wired parallel 1 per channel using about 1/2 the amps capacity crossed at 80hz with the amp plugged into a killa watt that was being watched at the moment the first one went....


Nothing wired wrong or anything like that, never bottomed out. I have a Dayton rss390hf that is run with identical conditions and is just fine.


The glue on the voice coil came apart. The outer layer slides up and down on the inner layers. they still work and have the right impedance but they make a horrible buzz from the voice coil sliding over itself if they get more than 50W.


Crappy quality...but they are cheap.


I will never spend another penny with that company!
 

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The voice coils fell apart.
It's ok... I've thermalled and bottomed every sub I've ever owned. Bassheads be Bassheads. There is no cure and no stepping backwards neither...

Not sure if 2 EP4000 is gonna be enough. Guess you will find out if it clips a lot or not...

By having so many woofers you've increased your thermal handling and displacement considerably. I doubt you will have thermal problems with the array at anything less than ridiculous levels.

Frequencies above 40hz and below 10hz tend to be bad for the health of voice coils. Single digits have massive power curves and high frequencies have limited air cooling effects.
If you installed fans inside the box pointed towards the coils and/or magnets you might be able to extract some more SPL before bad things happen (a bit unusual and maybe even ghetto, but ya gotta do what ya gotta do!).
 

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Discussion Starter #13
I see. I wonder if your driver(s) was/were defective? Try contacting Stereo Integrity? I have nine of them. All work and sound great. It's too bad yours did not.


Sooo... go for the mega sealed! Will be easy, smaller and extend to the single digits with no need for a HPF.
I'm still planning on the 32 sub LLT tuned to 9hz, I'm not gaining anything with sealed other than smaller size and higher PVL as long as I'm using the EP amps. And size isn't a concern. In the measuring amps test, IIRC, Not said the EP is done by 5-7hz. Output drops and distortion skyrockets.


And I'm losing 16db at 9 hz with sealed compared to the same amount of ported subs.


I just want to throw together a quick sealed box to see what happens with that much cone area packed in as tight as possible nearfield.


The pvl vs spl discussion is very intriguing to me.
 

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Discussion Starter #14
It's ok... I've thermalled and bottomed every sub I've ever owned. Bassheads be Bassheads. There is no cure and no stepping backwards neither...

Not sure if 2 EP4000 is gonna be enough. Guess you will find out if it clips a lot or not...

By having so many woofers you've increased your thermal handling and displacement considerably. I doubt you will have thermal problems with the array at anything less than ridiculous levels.

Frequencies above 40hz and below 10hz tend to be bad for the health of voice coils. Single digits have massive power curves and high frequencies have limited air cooling effects.
If you installed fans inside the box pointed towards the coils and/or magnets you might be able to extract some more SPL before bad things happen (a bit unusual and maybe even ghetto, but ya gotta do what ya gotta do!).
I'm planning on using 4x ep4000's at 4ohm for the 32 subs total. 4x per channel.
I'm going to be dropping a 100A 240V subpanel into the equipment closet and each amp will get a dedicated 20A circuit with 10 gauge wire on a 5 foot run. I don't want any voltage sag.


I had the subs running a 20hz sine wave for an hour the other day. Then changed immediately to a 10hz sine for 10 mins. There was a little clipping at some points and never less power than -.5db from clipping. I only got the coils to 150F. Not much of a difference in temp, if any, between the 10hz and 20hz. Just more excursion. They should be effectively thermal proof set up like that. Each driver can only ever see a max of 160 watts.
 

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I'm planning to build a pair of 1260ws into horns when the weather is warmer, but threw together some quick 1.3 CF boxes for them instead. No regrets at all, they actually work quite well and cover 90% of my usage as-is, in a smaller room used mostly for music at low volume.

Why divide the box internally? For that matter, why make one huge box? Seems like it'd be easier to just make two or four boxes and stack them. And why bother flush-mounting them if it's just a temporary box?
 

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Discussion Starter #18
Why divide the box internally? For that matter, why make one huge box? Seems like it'd be easier to just make two or four boxes and stack them. And why bother flush-mounting them if it's just a temporary box?
I want to get the CTC spacing as small as possible while leaving as much air volume as possible. The outer edges of the baskets will be touching or 1/8" apart. I can't do that with a bunch of boxes, or would have to make them deeper than 2 foot. I'm also going to end up with nearly no scrap after I get everything cut up...99% material usage. The OD on the speakers is 12 1/4" so 4 across is 49". 49.375" with 1/8 inch gaps between them.


2 feet is 1/4 wavelength of 137hz so the box resonance should be out of the pass band. I am dividing up the box for the same reason. It's easier than putting in stick bracing. Also I want this box as heavy as possible to keep it in place. My 15" sub walks across the floor.


The frame and top gasket on the subs happens to be exactly 3/4" so I can just cut a hole right through a layer of mdf and have them flush mounted. I think that should help the speakers couple better and generate a more even wave front than having dips in between each speaker.
 

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Discussion Starter #19
Yeah I would make individual boxes. Much easier to control resonances and bracing. Big panels suck on super subwoofers they flex and you lose output. Plus multiple boxes gives you additional flexibility in placement.

The max panel span on this box will end up being 1'x2'. I don't think there is any worry about vibrations, I'll put an x in each chamber to drop that down to 1'x1'. I don't care about placement other than having the box 8" behind my head. I can use other subs for smoothing if I wanted.


My main goal, other than having more bass now, is to check out the nearfield pvl claims. This box should qualify as extreme nearfield out to a few feet from the surface.
 
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