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Discussion Starter · #21 ·
I've been modeling all day and just realized I don't really know what to look for. I poked around trying different tunings (since Dan eeked at my 15Hz box :p ) and found that a 300L box tuned to 12Hz with a 6" port looks pretty good and should be safe for the driver with minimal chuffing down to 10Hz, but then I got looking and noticed the FR doesn't look much better than just putting it into a sealed box... How much do you guys general calculate in for room reinforcement down low anyways?



At any rate, I give... what would you guys do with 4 of these and an EP2500?
 

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I would put each one in a ~2 ft^3 sealed box, two in each front corner, and LT/EQ them. Four 12"s with 16mm Xmax is nothing to laugh at.
 

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Quote:
Originally Posted by NEO Dan /forum/post/14072111


You would need an EP series schematic and an amp, I don't have an amp

Is that valid for the EP2500 though? Because I've got one I'm not using right now and could try to tinker with it, though it has been a while since I've had an electronics class.
 

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Wow, I think I need a refresher course. I can't narrow down where the 50 and 30hz HP is at for each channel.
 

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Discussion Starter · #26 ·
I finally decided on the EP2500 with 4 13Kv.2. Total shipped cost of amp+drivers = $500! I decided to try sealed first and see how I like it - each in a 16"x16"x17.5" box (made the cuts easy for Home Depot).


I (finally) got a chance to get to it and start building this weekend (wife and kids were out of town) and found that my woodworking skills could use some work. To start things off I got Home Depot to cut all of the wood for me as I don't have the tools to do so myself. I had them cut one sheet into all 16x16 squares and the second sheet half 16x16 and half 16x14.5. After the guy finished cutting them (it took about 45 minutes to cut it all up) he mentioned that a couple may be off 1/8" or so but most should be right on... yeah right! I don't think a single one of those "squares" were square but I didn't think of that when I started building the first box so the first box looks pretty terrible. For the second, third, and fourth boxes I made sure to make sure all of the pieces I was using were at least the same size before starting drilling/gluing. This helped quite a bit, each box turned out better than the one before it. This was also the case with putting the roundover on the edges (it wasn't a good idea to start on the front baffle of the first box...). All in all they turned out OK.


I read several places not to do a "dry run" test of the subwoofer before it is completely finished but I just couldn't help it, today I installed all the drivers and got a chance to play around with them for a bit in the living room. First impressions are great! I'm replacing an SVS PB12-ISD/2 and the new sub walks all over the old (as it should). I'm getting significantly more output with significantly less distortion for very close to the same price ($100 more than I'm selling the SVS for). I haven't done an official max SPL test but just messing around I did measure a very respectable 115 dB just using the pink noise off my Onkyo 805.


They're not much to look at for now (I still have to smooth them out with wood filler and paint them up with truck bedliner) but here's a pic of them next to the SVS.
 

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Discussion Starter · #27 ·
I got a chance to do some in-room measurements. I don't think this is quite max output but it's definitely as far as I'll be pushing it. These are from my listening position ~10ft from the subs:


Hz dB

10 102

11 101

12 101

13 100

14 102

15 104

16 103

17 102

18 102

19 103

20 102

25 106

30 107

35 110

40 --the test dvd always crashes trying to play 40Hz (maybe that's the resonant frequency of the laser in the DVD player
)

45 120

50 116

55 109

60 109

65 110

70 112

75 113

80 112



Needless to say I am VERY happy with the results! Looking at how it modeled (down ~30dB at 10Hz) I wasn't sure what I was going to end up with (part of why I wanted to try them out before doing the finish work). These results FAR exceeded my expectations of what kind of output I'd see down to 10Hz!


My BFD and sound card should be delivered tomorrow but looking at this I may try re-running Audyssey with the new sub and see if that does anything for the big spike at 45Hz. If so I may have a BFD up for sale...


My SVS would do a max of 107 dB in my room if I just pushed for max output without caring about distortion. The values for the new subs above are without noticeable distortion (at least not compared to the SVS). I'll post more graphs once I get REW working with the new sound card.
 

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Looks like you have some pretty nice room gain down low.
 

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Discussion Starter · #31 ·

Quote:
Originally Posted by Looneybomber /forum/post/14203309


Looks like you have some pretty nice room gain down low.

No kidding! I'm definitely getting the help I need to run them sealed - I'm glad I tried them sealed before doing anything with creative slot ports to get low tuned in a small enclosure.
 

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Discussion Starter · #32 ·
I received my BFD and new sound card yesterday and finally got some time tonight to learn how to use REW. The initial measurements showed my huge spike around 45Hz along with a MAJOR dip right at 70Hz. After playing around a bit I realized the dip at 70Hz was actually my receiver's crossover taking over, since I had the sub running so much hotter than the mains there was a big drop off there. After setting the crossover for all speakers to 200Hz and the LPF to the max I re-ran the tests and found the dip at 70Hz is completely gone (which was a major relief, I was really bummed about that null). This is my first attempt at using a PEQ of any kind but I think it's pretty good, I tried not to go overboard, I ended up with 3 filters although I could have gotten away with just the 1 at 45 but what's the fun in that
Attached is my output after the EQ was applied - it's more reinforcement that for me this project was a HUGE success! I ended up spending about $230 above what I'm getting for my old sub which happens to be about what the cost of upgrading the drivers in that unit was going to be (the other upgrade path I was considering). Total price (including BFD and sound card) = $730.


Anyone have any ideas for a cheap grill solution? How about cheap binding posts/terminal cups? For now I just have the wire running out the back of each sub but as happy as I am with these results I think I want to go all out and avoid regretting not doing it right the first time.


I still can't believe it, flat to 7Hz at 108 dB!!!

 

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Well done!!!
 

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so they blow the SVS away in SQ and SPL?
 

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Quote:
After seeing the pictures of people who had purchased 4 of those for $4k I just wanted to remind them how far their money could have gone

So true!!!


People always say "Well, DIY isnt for me". LOL, you and I prove that isnt true, your first build is amazing!!! I think people look for excuses not to do the best option.


DIY performance has no limits and those guys just ***** about price, who's product is better, blah, blah, blah.


Your project is just another recent project that has proved to me that multiple sealed subs is the way to go outside if building IBs
 

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Discussion Starter · #38 ·

Quote:
Originally Posted by penngray /forum/post/14218194


so they blow the SVS away in SQ and SPL?

Definitely. The old one could get me 107dB but the distortion was outrageous at that point. These have some head room left at 108dB (probably not between 7Hz and 15Hz but they could certainly play louder above that).
 

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Discussion Starter · #39 ·

Quote:
Originally Posted by penngray /forum/post/14218220


So true!!!


People always say "Well, DIY isnt for me". LOL, you and I prove that isnt true, your first build is amazing!!! I think people look for excuses not to do the best option.


DIY performance has no limits and those guys just ***** about price, who's product is better, blah, blah, blah.


Your project is just another recent project that has proved to me that multiple sealed subs is the way to go outside if building IBs

IB was going to be my next attempt with these drivers if the sealed array didn't work out. I was going to sell the EP2500 and just pipe my subwoofer signal back into the 805 and use the surround back channels as a zone2 powering the IB (it may not have worked as well as I was hoping though, I'm sure the my receiver drops off down low...)
 

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This build sounds like something I would like to attempt as well.


I purchased 2 of the 130v.2 subs a couple months ago and would like to try out the sealed boxes as well.



If you have the time, could you go into a little more detail about the boxes? Type of wood, exact sizes for front/back, sides and bottom, and did you do any type of internal bracing?


I'm not sure how much difference there is between the K series and the O series, but I would think your boxes would be a good starting point.


I would appreciate it.
 
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