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Stereo Integrity's new HT Subwoofer - Page 19

post #541 of 2212
Quote:
Originally Posted by beastaudio View Post

just get the behringer ep4000 and have the other channel as backup when you inevitably build the OTHER endtable smile.gif they are about $275 right now from Walmart last I looked.
Get dual 2 ohm voice coil config and you can run them stereo 4 ohm and be golden at a little over 650 watts per driver once all is said and done

or make a 4ft^ box, wire a dual 4 ohm as a 2 ohm load and run 950 watts into it off one channel of a ep4000

Gear mentioned in this thread:

post #542 of 2212
Quote:
Originally Posted by brian6751 View Post

or make a 4ft^ box, wire a dual 4 ohm as a 2 ohm load and run 950 watts into it off one channel of a ep4000

A 21" cube would yield about 4.2 cuft so subtract driver and bracing and you a little under 4cuft. This would be fine with 950 watts sealed
post #543 of 2212
Quote:
Originally Posted by beastaudio View Post

Pics or it didn't happen!!!!!!!









Computer crashed as soon as I posted last. I am on another computer now. Hope this works


Keep cranking,

Robert
post #544 of 2212
Haha, Lookin real good dude! We are gonna be seeing an awful lot of the drivers about to be built out smile.gif
post #545 of 2212
I like what I see so far. The only thing that caught me really quick was the diameter of the opening in the motor. It is very small when compared to the LMS, but it is also a smaller motor. Otherwise, they look fantastic! By the way, the wife cleaned up all the Christmas and New Years stuff today and was readying me to redo the front of the house, and well, 2 big boxes showed up as soon as it was cleared out- Ironic to say the least!


Keep cranking,

Robert
post #546 of 2212
Quote:
Originally Posted by zheka View Post

I followed these instructions for the gain structure set up.
So what happens with extreme ULF content most subs/amps cannot come close to reproducing even if there is enough headroom at 20Hz ?



The obvious is that there is clipping.
A quote from Rod Elliot:
Quote:
There is no doubt that a clipped asymmetrical waveform will generate a DC component in the output of an amplifier.

The main answer to your question is that the sound effect is (as Elliot describes above) an asymmetrical waveform and is almost always comprised of many frequencies across 5 octaves. The clipped waveform is not frequency specific, it's level specific, so all frequencies are affected. Lots of harmonic content and a DC component will be added as well.

When you buy a commercial EQ'd sealed sub, it's prevented from this severely clipped, potentially mechanically damaging scenario by use of aggressive limiters (which will prevent the amp being pushed beyond 500W) or HPF, a la the JL Audio and Epik stuff.

Here's a real world example of a sealed EQ'd system that employs aggressive limiting to keep the system healthy when the sonic booms hit. Seaton set up 4 SubMersives for an AVS member a few years back. Once set up, Seaton ran prog sweeps, measured @ the LP and posted the results, which I scaled to a REW graph:



You can clearly see how the limiters restrict the boosted low end of the system as the power demand increases. As a result, the FR changes from F3 in the low teens Hz to F3 in the low 20s Hz. The dashed traces are inserted to illustrate that such a system really has infinite responses since real program is dynamic and soundtracks are to the tune of 30dB in range, far more than the range shown in the measured sine sweeps from minimum to maximum. Seaton has since added 4dB of reserve power to the SM, so the results would reflect that if he repeated this exercise with the added power.

The alternative is to pre-empt the excessive demand down low when pushing the levels up by lopping off the low end from the start with a HPF.

With a DIY sub, you won't have either unless you plan for it and implement it properly into the system you build.

Josh's tests revealed that this driver is not designed to 'soft bottom', but that the bobbin will strike the back plate and that max in 4 cubes down low is under 1KW. I'm confused by his test results in that it appears to me that he fed it far more than 1KW with no bottoming and his measured Re doesn't look like it jives with the impedance trace, so you'd have to ping him to explain anything further about this particular driver.

If you have any further comments on this subject, I suggest you start a thread. I don't want to continue in this thread since we're OT.
post #547 of 2212
Thank you very much, Dave.
This is very educational. I probably will have more question. I will keep them for the new thread.
post #548 of 2212
Actually Dave, as you did allude to the 18HT in that post, it is still a good post for those contemplating a build. I am looking at a little under 4 cuft per driver off the LG which would yield about 1100watts per driver at 4ohm stereo, assuming the specs are spot on with the amp. I will assume they are a little lower than stated unless someone has evidence that this is not the case. Thanks for the input dood biggrin.gif I would ideally use a LITTLE less wattage for them, but I already have the LG and it is a solid choice for 8 of these guys smile.gif
post #549 of 2212
My pair arrived today:


Nice simple packing








Mine don't show any evidence of poor stitching as was reported on an earlier prototype in this thread


post #550 of 2212
Oooh, that is bootyfull. smile.gif

Hurry up Fed Ex. biggrin.gif
post #551 of 2212
im contemplating picking one of the 18"D2 up to put in the Elemental Designs a7-450 with the LT 1300 amp. the box is 4.8 but i dont know how much space bracing and the woofer is, the amp is around .37 cu ft.
post #552 of 2212
Quote:
Originally Posted by amik View Post

Mine don't show any evidence of poor stitching as was reported on an earlier prototype in this thread

I believe bdaniels, who won the woofer pictured in question, replied a few days after the accusations about the erroneous surround stitching were made saying that there was no error in the stitching...only a few people over-analyzing a picture (I don't think we need to get into bossobass's now heavily edited/erased posts about micro-holes in the cone, etc). eek.gif The surrounds are stitched by humans, not robots, but the results are very satisfactory. PS: There is a glue behind the stitching on the cone that would negate any of the latter "issues" with the stitching.
Quote:
Originally Posted by baniels View Post

For what little it may be worth, the stitching on my 18" D2 is fine. It stays on the surround all the way around. There is some fluctuation in the distance from the edge of the seam to the edge of the surround, so I can see that if whomever/whatever is doing the stitching loses focus, it could turn out wrong.

To end on a good note, the pre-ordered woofers are being shipped out at a stead-fast rate! Most of the 18" woofers have been sent out and a few 15" woofers have been sent out at this point. cool.gif
post #553 of 2212
Quote:
Originally Posted by amik View Post


That is a good picture! Care if we use it for the site?
post #554 of 2212
Quote:
Originally Posted by Mikullla View Post

im contemplating picking one of the 18"D2 up to put in the Elemental Designs a7-450 with the LT 1300 amp. the box is 4.8 but i dont know how much space bracing and the woofer is, the amp is around .37 cu ft.

Should be fine, just be a little "safe" with the drive levels. at 4 cuft you should be pretty safe.
post #555 of 2212
Quote:
Originally Posted by Electrodynamic View Post

That is a good picture! Care if we use it for the site?

I was thinking the same thing about that very pic, Nick! I don't know if it's the lighting or what, but that is an epic pic for sure! Also, mad props on the shipping boxes. They look 10x better that what the prototype was shipped in.

So I gotta ask, are there any differences between the prototype and the production driver?

I shot you an email yesterday, so let me know the external dimensions of the shipping boxes and when the order is going to be ready for pickup!

Happy New Year all! I'm thinking this is going to be a big year for SI...wink.gif
post #556 of 2212
You can use that pic if you'd like, but I can take some better pics with no junk in the background if you are interested and then give you a link to the full resolution versions. Those were done pretty hastily in my den which is in disarray. Let me know if there are specific shots or angles you'd like.
post #557 of 2212
Well well well. just got a FedEx email. appears i have approximately 156 pounds of bad ass drivers on my doorstep!!! cool.gif

i have to say. i am totally impressed with how this pre order went down. I wasnt expecting them for a couple weeks. Good work SI!!

i can hear my wife now. "WHAT THE HELL DID YOU BUY?!!!!!!!!!!!!!!!" HAHAHAHAHHA!!!
post #558 of 2212
Quote:
Originally Posted by brian6751 View Post

i have to say. i am totally impressed with how this pre order went down. I wasnt expecting them for a couple weeks. Good work SI!!

+1
post #559 of 2212
weird thing is, i dont remember getting a shipping notice.
post #560 of 2212
Quote:
Originally Posted by brian6751 View Post

weird thing is, i dont remember getting a shipping notice.

None here, but kind of good that way.
post #561 of 2212
Quote:
Originally Posted by robertcharles View Post

None here, but kind of good that way.

yeah. it was a nice surprise i guess. as long as your not out of town for a while and have them sitting on your porch.
post #562 of 2212
I received a shipping notice and delivery notice.

In the past some of those notices have occasionally been caught by spam filters. Had to teach gmail using the "not spam" button.
post #563 of 2212
i looked in the spam filter. didnt see one.
post #564 of 2212
FedEx should be visiting my house tomorrow - I'm getting the automated notifications
post #565 of 2212
All four of mine made the trip just fine. Wow they are big!

If these things sound as good as they look ill be floored.

Now to get these cabinets done!
post #566 of 2212
some pics






post #567 of 2212
How many subs could I run with (1) Crown Itech 8000?
post #568 of 2212
Quote:
Originally Posted by bodhisafa View Post

How many subs could I run with (1) Crown Itech 8000?

A bunch!




No seriously, it depends on the resistance, box sizes and the voltage to the amp, mostly. Lots of variables with that amplifier. Also, bridged or stereo?

Keep cranking,

Robert
post #569 of 2212
Thanks for sharing the pics Brian! These driver really do look amazing.

Chris
post #570 of 2212
Mine are definitely not going to be a drop in replacement and let it rip. I am going to need to do a little work on the front of the baffle in order to get the clearance for the surround and the cloth. I have a few ideas, but the time is not there yet. I am going to mount one though. Maybe later.


Keep cranking,

Robert
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