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post #1 of 180 Old 09-21-2006, 01:01 PM - Thread Starter
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After reading through a ton of posts in here, it's got me fired up to begin a DIY sub project of my own. Im not new to box building as I've done quite a few in the car audio arena, but this will be my first home theater application. My current set up consists of an svs pc-ultra in my 13x24x8 dedicated theater room. Pics in my sig if it helps any.

I'll try to keep my thoughts as organized as possible.... Im looking for what we all are, deep and powerfull extensions down to the depth's of home theater bass Im happy with my svs, but want more

The drivers: After reading quite a few good reviews here, im leaning towards either a single or pair of the rl-p15's. I'd like to use a pair of them, but if my limitations on box size prevent it, a single would be fine with me. Open to other drivers as well......

The box: I'd like to use a conventional box instead of a sonotube design. If at all possible I'dl like to keep external dimensions at 24x24x48 or less. I plan to use 1" mdf with internal bracing unless 2 layers of 3/4" mdf is required. Using 1" mdf, this gives me 12.88 cu/ft gross volume to work with. Im open to discussing the sonotube design if it's necessary to achive the goals I want.

The port: If at all possible, I'd like to use a 6" port, no longer than 17". This will allow me to use one of the prefab flared ports from thrilleraudio.com. Though if needed, im not against using pvc to get the necessary port length/diameter. Of course I'd like it tuned low, around 15-17hz if possible.

The amp: For overall ease, would like to go with the 1000w plate amp from parts express. If something like the behringer 1500 or 2500 is deemed the better choice, I can live with that as well. I don't have a rack for equipment though, just a prefab audio shelving unit.

Ok, that's all I can think of right now. Im open to any opinions on any of my parameters. I'd like some help deciding if I can make the dual rl-p15 set up work with my box and port limitations.
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post #2 of 180 Old 09-21-2006, 02:15 PM
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Your enclosure doesn't have to be that big, a D2 works well in 260 effective liters. A 6" diameter port will have to be considerably longer than 17" for a ~15hz tune. I'd suggest using sonotube for the port materials due to cost and weight - as for flares, you can either make them yourself with a large roundover bit or you can look into 6" flares that apparently are going to be sold sometime soon......the link is in one of these threads, I forget which.

I'd stay away from the 1000 watt plate amp. Go with a pro amp or the Buttkicker amp.
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post #3 of 180 Old 09-21-2006, 02:38 PM - Thread Starter
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Thanks Steve, I was hoping to hear from you Ok, so your suggesting using a single rl-p15 D2 in 260l (about 9.2 cu/ft if my conversion is correct)?

Im not against using the sonotube as the port material, but I have no idea where to find it locally. Is there a place on the net that sells it and ships it? You mentioned the pre made 6" flare tubes, which is what I was wanting to stay with if possible. I found them here: http://www.thrilleraudio.com/detail.aspx?ID=536 But they are restricted to 17" length, which it doesn't appear will be long enough for my needs. If that's the case, and I have to use the sonotube anyway, would it be better to go up to an 8" port? I just threw out 15hz as the tune, but am not dead set on that. Anywhere from 15-17 or 18 modeled should get even lower in room correct? If you look at my pictures in my sig, the sub will reside in a corner of my room. Unfortunately it does have to be behind the listening position. I get nothing in my listening position if the sub is in either of the front corners.

I'll check out the buttkicker amp along with the Behringer's. How much power would you say is needed for this application? And is it ok to just sit the amp on one of my shelves instead of mounting it in a rack? My only concern is heat issues. Fan noise shouldn't be a problem as I can close the door to my equipment closet and never hear it.
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post #4 of 180 Old 09-21-2006, 03:11 PM
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Sonotube up to about 12" in diameter can be found at the likes of Home Depot and such. They might not carry the Sono brand, so ask for a cylinder concrete form.
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post #5 of 180 Old 09-21-2006, 03:12 PM
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he was referring to 6" flares...which are just the flares...you would attach them to your own port (of any length, as long as the diameter is still 6") There are some links around to these flares...I'm not sure exactly where they are though. I believe they are going to be released soon.
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post #6 of 180 Old 09-21-2006, 03:35 PM
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Ok, so your suggesting using a single rl-p15 D2 in 260l (about 9.2 cu/ft if my conversion is correct)?

260 effective liters, so it will be about 290 raw.

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I found them here: http://www.thrilleraudio.com/detail.aspx?ID=536 But they are restricted to 17" length, which it doesn't appear will be long enough for my needs. If that's the case, and I have to use the sonotube anyway, would it be better to go up to an 8" port? I just threw out 15hz as the tune, but am not dead set on that. Anywhere from 15-17 or 18 modeled should get even lower in room correct?

A simulated 15hz tune with this design works really well - that would be a 6" diameter port that is 30" long with some flaring or roundovers. My point on the flares was that you be able to just buy the flares themselves. From my point of view, if you are willing to spend the money to buy those flares (which don't be surprised if it comes out to be ~$50), you'd be better off just buying a big roundover bit, as you'll have your flares AND you'll have a big roundover bit

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How much power would you say is needed for this application?

I'd aim for 600-900 watts.
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post #7 of 180 Old 09-22-2006, 06:43 AM - Thread Starter
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Right, 260 liters net...gotcha.

Ahhh, I see what y'all are saying about the flares. I'll have a look to see if I can find the link, but I'll probably use the roundover bit.

Would you think that a pair of the rl-p 12's would work in a similar size box and give me any noticeable gain over the single 15"......worth the extra $$? Which program are you using to model by the way? I've got a copy of bassbox 6 pro, im just not that proficient at using it. I'll give it a try this weekend and post up some more info.

Thanks again for all the tips and help!
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post #8 of 180 Old 09-22-2006, 07:33 AM
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No, RLp12's are geared for small sealed enclosures - car use mainly. I use WinISD Pro and Flare-It.
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post #9 of 180 Old 09-22-2006, 07:41 AM - Thread Starter
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Thanks again Steve. Just for grins and giggles, what would I need to do to have a pair of the rl-p 15's work properly?
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post #10 of 180 Old 09-22-2006, 08:08 AM
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Not sure what you're asking? I think we already covered most of the design.
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post #11 of 180 Old 09-22-2006, 08:23 AM - Thread Starter
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Im wondering what it would take to have 2 of the 15's in a shared enclosure. Two of the rl-p15's in one box.
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post #12 of 180 Old 09-22-2006, 08:50 AM
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Double up the parameters. 520 effective liters, 1200-1800 watts. Instead of two 6" ports that are 30" long, you could go with a single 9-10" that is ~36" long and reduce port velocity even more. That would be the main reason I'd go with a dual driver design. An interesting note may be that Steve nn went from just such a dual RLp15 box to a single RLp15 sonosub and noticed a bit of an increase in sound quality at the same listening levels.
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post #13 of 180 Old 09-22-2006, 09:25 AM - Thread Starter
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Hah, I figured as much. 18+cu/ft is a little larger than I care to go LOL

That is an interesting note on Steve nn's situation. Just going from a box to a sonosub wouldn't have made the difference correct? It's just that one of the 15's work better in 260 liters than 2 of them in 520 liters I would assume? If the tube design in fact works better than the box, I'll reconsider that part.

Would I benefit from using an 8" port versus the 6" in the single 15 box? Or would that make it too long to fit in the box?

Thanks again for all the help!
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post #14 of 180 Old 09-22-2006, 10:00 AM
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If the tube design in fact works better than the box, I'll reconsider that part.

I'd say it is certainly worth looking into. IIRC, Steve has basically said that a single Sonosub using the Rl-p should be enough for most people, in rooms that are not extremely big. Maybe there is something to the sonotube enclosure as opposed to the box, but eitherway, it is lighter (and easier to build?).
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post #15 of 180 Old 09-22-2006, 10:29 AM - Thread Starter
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I'll definetly start looking around for some tube and some tutorials on how to do the end caps and such. Still not sure on how to attach the port to the roundover flare or how to do a flare on the inside end of the port.

Just another quick question, but would using a tc2000 make any appreciable difference?
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post #16 of 180 Old 09-22-2006, 11:48 AM
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Originally Posted by parboy View Post

I'll definetly start looking around for .... some tutorials on how to do the end caps and such.

Patrick Sun has the most details on his site - link

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not sure on how to attach the port to the roundover flare or how to do a flare on the inside end of the port.

Speakerbuilder.net

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Just another quick question, but would using a tc2000 make any appreciable difference?

Probably not. But I do like the extra 4mm of xmax the TC2000 has over the RL-p.

-Robert
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post #17 of 180 Old 09-22-2006, 11:56 AM - Thread Starter
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Hey thanks rlj. Notice your a MS fellow. Im a transplant here in LR by way of Jackson, Hattiesburg, and then Biloxi/Gulfport MS myself Graduated from USM in '97.

So could I use the tc2000 in the same enclosure w/o it changing any of the parameters with regards to enclosure volume, port length, etc.?
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post #18 of 180 Old 09-22-2006, 03:30 PM
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Hey thanks rlj. Notice your a MS fellow. Im a transplant here in LR by way of Jackson, Hattiesburg, and then Biloxi/Gulfport MS myself Graduated from USM in '97.

I moved here from Little Rock almost 6 years ago.

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So could I use the tc2000 in the same enclosure w/o it changing any of the parameters with regards to enclosure volume, port length, etc.?

No. Even though both subs are built on the same platform, they have different T/S parameters. Run both through WinISD or Unibox and see if they are have the same response curve while in the same enclosure. Probably not but I bet they are close.

-Robert
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post #19 of 180 Old 09-22-2006, 03:41 PM
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Just going from a box to a sonosub wouldn't have made the difference correct? It's just that one of the 15's work better in 260 liters than 2 of them in 520 liters I would assume? If the tube design in fact works better than the box, I'll reconsider that part.

Well the use of sonotube can in fact play a role - it's a cylinder shape, and circles don't have any corners, so pressure is exerted equally over the entire surface area. This basically means that the sonotube won't flex or resonate at all. His large box, though braced well, isn't go to be as resistant to flexing, though I never figured it would have resulted in an audible difference. The port area of the single sonosub compared to the dual driver sub is actually less, so it can't be anything port related - well, the port in the large box didn't have any roundovers....but I doubt that was it. The tune on the single sonosub is lower, and that should definitely play a role. The amp is the same, so that's out. The sonosub is downfiring while the box was front firing, so he may be possibly getting less localization. So it would be enclosure, tune, and orientation related I woul imagine. Either way, my suggested designs will now assume sonosubs as the best option.
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post #20 of 180 Old 09-22-2006, 06:14 PM - Thread Starter
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That's a nice way to break it down Steve. Thanks! Sonosub it is! Now I just have to decide if I want the rl-p15 at 260 liters or the tc2000 at 320 liters. Im kind of limited to around 5' tall due to the shape of my room, so that will play a factor as well. I don't mind going with 22" tube, but 24" might be pushing the waf envelope
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post #21 of 180 Old 09-22-2006, 07:07 PM
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Im kind of limited to around 5' tall due to the shape of my room, so that will play a factor as well.

You could accomplish that using the TC-2000 and 22" tube.
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post #22 of 180 Old 09-22-2006, 07:55 PM
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I'd say it is certainly worth looking into. IIRC, Steve has basically said that a single Sonosub using the Rl-p should be enough for most people, in rooms that are not extremely big. Maybe there is something to the sonotube enclosure as opposed to the box, but eitherway, it is lighter (and easier to build?).

If the room is sealed, it should do quite well up to 4000-4500 cu ft or so. My room is right next to 3000 (but very open) and a single puts me in at 112dB peaks uncorrected at just below reference on material like SW II or The MATRIX. Plop in LOTR or WOTW and you'll get there sooner but still at a listening level that most wouldn't dream of viewing at.

As far as the sono being easier to build...I think most would tell you (that have built both) that the sono variety is harder to build. I know the enclosure is already built, but it just doesn't equate out. All subs are a puzzle to a certain extent, but think of the sono as being 750 piece puzzle versus a 500. Also figuring in no fast table saw work, it's a pure router affair because every cut or recess is round.

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post #23 of 180 Old 09-22-2006, 08:05 PM
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If the room is sealed, it should do quite well up to 4000-4500 cu ft or so. My room is right next to 3000 (but very open) and a single puts me in at 112dB peaks uncorrected at just below reference on material like SW II or The MATRIX. Plop in LOTR or WOTW and you'll get there sooner but still at a listening level that most wouldn't dream of viewing at.

As far as the sono being easier to build...I think most would tell you (that have built both) that the sono variety is harder to build. I know the enclosure is already built, but it just doesn't equate out. All subs are a puzzle to a certain extent, but think of the sono as being 750 piece puzzle versus a 500. Also figuring in no fast table saw work, it's a pure router affair because every cut or recess is round.

*sigh*

I just want the damn thing to build itself.
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post #24 of 180 Old 09-22-2006, 09:01 PM
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If the room is sealed, it should do quite well up to 4000-4500 cu ft or so. My room is right next to 3000 (but very open) and a single puts me in at 112dB peaks uncorrected at just below reference on material like SW II or The MATRIX.

I have been trying to wrap my head around statements like this, what does the room size have to do with output capability? Yes, in a bigger room you don't get full room gain, but other than that what is there? I'm not trying to start anything, I have just asked others and tend to get flamed when I do. I don't understand what you are trying to get across with the room size qualifier. Something just isn't clicking in my head. Is it to relate output to outdoor GP measurements?
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post #25 of 180 Old 09-22-2006, 09:48 PM
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Distance from the subwoofer will equate to output you hear as a direct result of what the sub is producing, but there is also room gain and boundary gain. As you mentioned, with a larger room, the sub output won't begin to couple with the room until much lower frequencies than a smaller room, so some low end output is lost in comparison to a smaller room. As for boundary gain, I'm not sure how close the sub has to be to a boundary to get the full 6db gain or some fraction of it, but the smaller the room, the closer the potential boundaries. Mark Seaton or Ed Mullen probably know the specifics on that one. Sub placement along the middle of a wall gives you two main boundaries - the floor and wall, so potential of up to 12db boundary gain that should affect all frequencies in the sub range. With corner placement, you have three. Stick the sub in a cutout, and you have four. With a small enough room, you might possibly be able to get some effects from five or six boundaries - 4 walls, floor and ceiling. Again, Mark or Ed would be a good source on this.
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post #26 of 180 Old 09-22-2006, 10:15 PM
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SteveC, this I understand but it doesn't explain the room size part.

I understand room and boundary gain and how they work, but I don't understand why people add the room size figures. Without a seating distance the comparisons are meaningless.

As long as you are +4ft from a wall, boundary gain isn't much an issue (~2db at 4ft if I remember right). Also boundary gain is 3db max at 10hz per wall right?
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post #27 of 180 Old 09-22-2006, 10:26 PM
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Say you have a 2000 cu ft room. You have the sub placed in the middle of a 13ft wall, at 9ft you get 110db at 65hz.

Now you move to a 4500 cu ft room. You place the sub in the middle of a 26ft wall, and at 9ft you get 108db at 65hz.

Now you move outside. You place the sub in the middle of a 45ft exterior wall, and at 9ft you get 107db at 65hz.

What does this tell you? It don't get it. This is the way I see it.

(This is an over simplified example. Changing the distance from the walls also effects the gain slope as well. I did not do the math for that. If you are scratching your head check out this post from Evil Twin )
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post #28 of 180 Old 09-23-2006, 08:21 AM - Thread Starter
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Played around in bassbox 6 pro and got these graphs. The driver was not in the database, so I hope I entered all the values correctly. This is using a sonotube that is 22x56.25 which gives me 11.3 cu/ft effective. This is with a 6" port, 27" long which gives a 14.6hz tune.
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post #29 of 180 Old 09-23-2006, 10:27 AM
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I have been trying to wrap my head around statements like this, what does the room size have to do with output capability? Yes, in a bigger room you don't get full room gain, but other than that what is there?

Distance from the sub comes up much as you know, but something I don't see very often is how close is your seating to a boundary. When I'm in the den just 5' away from my sub, I need to turn up the gain more in my 12 X 12 because I'm basically sitting in the middle of the room. Take the same sub out to the main and increase the distance and sq ft over double and it still takes pretty close to the same gain to come in calibrated due to my seating is up against the right boundary.
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This is using a sonotube that is 22x56.25 which gives me 11.3 cu/ft effective.

I think 320 (base) liters seems to be the magic number with the TC.

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post #30 of 180 Old 09-23-2006, 12:17 PM
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SteveC, this I understand but it doesn't explain the room size part.

Sure it does. I mentioned room gain - the smaller the room, the earlier the onset of room gain, the more "free" output one gets. I mentioned boundary gain - the smaller the room, the more likely the sub is going to interact with boundaries, the more "free" output one gets.

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Without a seating distance the comparisons are meaningless.

Seating distance should be included, but in regards to low end output benefitting from room gain, or overall output benefitting form boundary gain, room size should also be included. If Steve nn can get those 112db peaks at say 14hz in his wide open room, that says something, cause he isn't getting as much room gain as someone with a much smaller, closed off room.

Let's look at the Rythmic sealed 12" Servo unit. Crackyflipside has one in a corner of his 7'x10'x8' room, it is setup to be relatively flat to 10hz, and he is getting sufficient output. Crackyflipside then paid Chuck a visit and brought his sub - Chuck's listening room is 16'x24'x8' AND open to other rooms in his house. After setting it up to be flat to 10hz in a corner, and trying to do an 85db sweep from 9' away (which is pretty typical), it bottomed. Now distance to the seat in both of these circumstances is needed to make a valuable comparison, and I don't know cracky's, but let's assume an extreme case and say only 3'. A typical room isn't an anechoic chamber, so we'll assume 4db loss every doubling of distance, giving cracky 6db more headroom due to seating distance.

Now, 6db difference alone isn't going to make much of a difference with bottoming occuring at 85db. 91db isn't very loud for subwoofers. What's happening is that room gain is setting in much earlier (at a higher frequency) in cracky's room than Chuck's, and if we assume typical room gain to be 4-8db/octave, getting the onset of room gain at what I think calculates to be 56hz in cracky's room will play a VERY big role. Chuck's room, not taking into account the fact that it is open to other rooms in his house, wouldn't start seeing room gain until around 23hz - considering it is open to other rooms, that onset point will probably drop down into the teens. So even assuming worst case scenario of only 4db/octave of room gain, cracky is gonna have at least ~7db more gain in the teens than Chuck. Realistically, it's probably gonna be more like ~14db.

Finally, if a room was infinitely large, it would behave like an anechoic chamber, with NO room gain and little to no boundary gain - that definitely affects output levels seen at the seat.
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