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Just bought 2x SI HT15D2 & Behringer amp. What do?

2310 Views 8 Replies 4 Participants Last post by  corradizo
Hello, folks!

I have been lurking here for a little while, and watching all of the amazing stuff going down,
I thought I would like a piece of that action.

Basically, I am trying to build 2 big honking subwoofers. (The rest of my system is satisfactory for me, but my powered Klipsch 12 just doesn't get it done.)
Based on the general recommendations of this board, I jumped on a pair of B-stock Stereo Integrity ST15D2 woofers, with plans of building 2 individual sealed enclosures, and placing them on either side of the couch. I like bass, and more to the point, I wanted to really have some significant SPL at and below 20Hz.

Here's what I have done so far:
-Bought the 2 woofers.
-Last night (drunk amazon.....) I grabbed a Behringer Europower ep2000 (750x2 @ 4ohm)

I am not at all concerned about form factor. I can build the room around the subs, that makes perfect sense to me. (I have no less than 2 VW engines and multiple transmissions in spare bedrooms. I need a girl.... But, until then, let's have at it!!)

Two questions:
1) I am pretty set on the drivers (at least for now) but the amp was a bit of an impulse purchase. I think it should be better then the inuke line, and I don't really care about a crazy low THD on a sub amp. It is cleaner than the driver will be, so no worries right? I was going to wire the drivers to show a 4 ohm load per channel, and run the amp in 2 channel mode. The amp is rated at 750wpc, and I know the HT15D2 likes about 600wpc, but sealed enclosure should mean that I can feed her some extra power without ejecting voice coils, right?

2) Help with the enclosure. I have always liked sealed enclosures, at least in the car. Tighter, punchier bass, although you will need more power to get the same spl. One of my questions is down firing (a concern given the significant throw of this woofer?) vs front firing. I was assuming that I would prefer a front, so I could rotate it to play with standing waves and whatnot. I considered building one, but the cost of buying required tools meant I would not save anything. I looked at the flatpacks, they were about $90 ea, that was pretty good. Then I met a guy on Craigslist who said he could bang out (2) 3ft^3 enclosures for me for $100 ea. Seems like a no-brainer, since he agreed to put a few braces in, and cover it with black carpet. Long term, I will plan on doing a nicer enclosure, but for now, it is proof of concept, and something to play with that I don't care too much about. I am assuming I will need to play with the location of the subs to get optimal response, and after I have a settled design, I would likely have him re-make me another pair, covered in a nicer fabric or something. Would you guys help me design the enclosure? The kid can build a box, but I am not sure about modelling an enclosure, that's a little beyond what most do.

Unfortunately, I have a copy (bought from Parts Express in 1996) of Vance Dickason's Loudspeaker design cookbook, but I can't find it, and I believe there are lots more resources on the web. I downloaded WinISD, but could not really get it to cooperate with me.

What other info can I provide to help you help me?
Room is 18' x 14', with a slightly vaulted ceiling. The floor is terrazzo, with an area rug in the middle. I can put it on a piece of carpet, but would prefer to cover the box in carpet and have it sit on the floor. If it moves, I'll throw rubber pads underneath.
I put all of my equipment in the 'about me' page, if you want to know anything about my (mostly craigslist) rig.

LOL. Yeah, I want to do this, please: :hsd:

Thanks so much!
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Are there any more SI 15's around?

I know they are going to be making 18's again but I dont think they are making 15's anymore. Have you seen this guys cabinets before?
Availability? Don't know. I bought these a month ago, and they were considered 'B' stock (as in not perfect), but if there are defects, I did not notice. The drivers weren't on the website, I just emailed Nick.

Yeah, I have seen pictures of his (random CL guy) boxes, and they are better then average. Not to the point of rabbet joints and the like, but good looking boxes. Better than I would make, or would assemble from a flatpack. And I just want to cover it in black carpet anyway. As long as it is structurally sound, aesthetics are not yet important.
I just want functionally unlimited bass. I miss it. It won't fit in any of my cars now, so I need ludicrous bass at home.
Are there any more SI 15's around?

I know they are going to be making 18's again but I dont think they are making 15's anymore. Have you seen this guys cabinets before?
As stated the 15's were b stock. I snagged one myself.

Not sure if they have any more, but they are a phenomenal deal, but once they are gone they are gone.

They do have enough extra parts for a long time.

So if you can grab one or two, make some phone calls :)
Amp arrived today. (EP2000)
Wow! It's a beast! easily 40 pounds...

Now all I need is a cabinet design and I'm in business.
I'm working through WinISD pro, with limited success.

Can anyone confirm that there is a difference or benefit to down firing vs front firing? That is my sticking point before moving forward.

In some case you can gain a 1/2db by down firing your woofer. Other than that there are not a LOT of benefits to down firing verse front. More of a personal choice. I have seen a few builds with down firing dual opposed and it turned out well.
Cool, thanks for the reply.

I guess I'll keep hacking at WinIsdPro, and see what I can make of it.

OK folks, we are now up and running, and I was hoping for an equipment audit / sanity check.

I built a 3 ft^3 sealed enclosure. It is basically 18x18x18 internal, which is just over 3 ft^3, less the woofer displacement. It is 3/4" MDF, with a double thick front baffle, and I used Liquid Nails construction adhesive and screws to hold it together. It is tight, and I feel no air leaks at all. I will be building a second identical cabinet in the upcoming weeks or months.

When I hooked the amp (Behringer EP2500) up, I was barely able to get any sound at all (all gains maxed, it was still quieter than my 12" klipsch). I bought an ART CleanBox Pro, to adapt -10dB to +4dB. Instantly, I had a LOT more noise. (Can anyone confirm / deny that the newer CleanBox Pro's do not roll off hard under 20Hz?)

I have the sub output for my receiver (Yamaha RX-V2400) set just above half way (+2dB), and the CleanBox gain maxed out. I am running the Behringer at about 75% gain, with the knob set at 3 O'clock. I regularly see the clip lights flashing when I am listening to it very loud. Is this a cause for concern? I have clip limiters ON and filters OFF.

Lastly, I fixed the Behringer's fan. I tried a different 24v fan, and it was quieter, but not quiet. Then, I got an LM7812 voltage regulator, and ran it between the 24v output from the amp and an 80mm computer fan. It is silent, and I have 11.8VDC going to the fan consistently. The Voltage regulator gets a little hot, so I dropped it in front of the cooling fan, and it keeps the temp of the voltage reg quite reasonable.
(Anyone with particular experience in the Voltage Reg department? My uncle (electrical engineer) says I needed to put caps on the incoming and outgoing legs of the reg, so I soldered .33uF caps on each side, and then the fan would not run. Went back to just the voltage reg, and it runs fine. Any advice?)

Thoughts? Opinions? Ideas?
Thanks so much for your time, gents!

After we get this sorted, and get the second cabinet built, It will be time for REW!
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Congrats! I have the inuke3000dsp. It has three orange clip lights and a red. I learned that the first two light up all the time at high volume. When the third goes off the red is soon to follow and at that point the amp protects the sub. So I'm usually seeing my irangle lights flickering during big bass hits. In bass heavy music the first light usually just stays on. So if your is similar and your not hitting the red light, I think you've got it tuned right.
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