Twelve 10" NHT Subwoofer Build. - Page 2 - AVS Forum
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post #31 of 274 Old 09-04-2008, 07:30 AM
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Thanks, Jack. I'll double check that I have the correct T/S parameters plugged in!

Jack was right. I was modeling the other drivers...disregard what I said above.

Sorry, Erich!
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post #32 of 274 Old 09-04-2008, 08:26 AM
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Let's try this again:

Looks like your box for 4 is good, your box for 6 should probably be closer to 12 cubic feet (Q is at .814 right now) and your vented box needs to be bigger. Looks like 16 cubic feet tuned to 17 Hz looks good.
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post #33 of 274 Old 09-04-2008, 08:37 AM - Thread Starter
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I'm not sure I could make a box that big for the area they are going in. The only thing I could do would be to go back to 3 per box ported. That would cut the size down to around 12 cu ft I guess? I could make that work.


But I'm not sure of the sound difference between four boxes with 3 subs or 3 boxes with 4 subs each.




Also, I seem to be getting a pretty low wattage needed to reach max excursion in a sealed box. Using 4 per box at 8 cu ft, Unibox is showing max excursion coming in around 35 hz with 600 watts going to that box.

I'm going to keep messing with these numbers.


Thanks for the help so far guys.
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post #34 of 274 Old 09-04-2008, 09:21 AM
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Erich,
#1: 4 in 8'³ sealed is just fine, Jack knows where the "brakes" are on the driver.
#2: 78" x 16" x 20" with a 6" x 25" port. Put the port on the top of the box. needs subsonic filter but it's worth doing. Behringer MIC2200 would do it, and convert you to balanced.
#3 Is not big enough for 6
#4 just let this one go, there's a long list of reasons.


Your models seem a bit wonky, sealed 2'³ per driver series pairs take 96v to hit x-max @~28Hz, but you'll probably never get there, as the suspension stiffens up.

If you want to Model to stay within x-max the ported recommendation with SSF will do just fine and you will get a couple db on the low end.

Regards,
Dan
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post #35 of 274 Old 09-04-2008, 10:27 AM - Thread Starter
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Thanks, I'll go with one of the first 2 then.

#1 looks like the reasonable box to do as a trial I guess. Fairly quick to build too. I surely wasn't second guessing any of you guys on it's output or excursion, I was just curious about the graph I was looking at and whether or not I was reading it wrong.


As for #2, are you guys recommending the ported enclosure over sealed? The 2 programs I used recommended sealed. But I suppose I don't have any real issues against ported.

At 78" tall, with the port on the top, that would only give me about a 4" clearance, would that be too close to the ceiling? The ceiling uses those 2x4' accoustic style panels, not drywall. I wonder if that would cause those panels to flutter above the port?
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post #36 of 274 Old 09-04-2008, 11:27 AM
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Erich,
it is close at 4" but the tuning is low. That combined with the SSF keeps the vent velocity's in check.

What are the ceiling panels attached to? If it's a drop in style setup the port on top probably would be a bad idea.

Regards,
Dan
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post #37 of 274 Old 09-04-2008, 11:30 AM
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If they are drop in tiles you can always put a full width peice of MDF on top of the tile to keep it from moving, that should fix it.

Regards,
Dan
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post #38 of 274 Old 09-04-2008, 11:39 AM - Thread Starter
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Yeh, they are the drop in type. But I didn't use the drop ceiling brackets because I didn't want to lose any height. The corners would be very hard to remove because of the way it had to be installed. Those were the first panels to go up, then it was all power spray painted to "lock" everything together. I'll take a closer look and see what will be involved.
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post #39 of 274 Old 09-04-2008, 06:21 PM - Thread Starter
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Well, I got my Amp and the subwoofers today.

I wanted to show everyone how nice the packaging was from Jack and the speakers as well. By the way, I got these pretty fast coming from California to Ohio. Thanks Jack.

I got 6 of these boxes today. All of them looked good.






I opened them up to see what I was up against.









And last but not least a picture showing one of the corners to be graced by whichever box I end up going with. I'm beginning to think that 4 per box will simply be too big for this area. That light is about 60" off the ground and 22" from the back wall, other measurements are shown.







I'll need to draw up ported box for 3 and see how big that might be.
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post #40 of 274 Old 09-04-2008, 06:43 PM
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Although it’s 10’s (18’s would be even sexier) seeing the multiples of drivers is always a pretty sight!
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post #41 of 274 Old 09-04-2008, 06:54 PM - Thread Starter
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Quote:
Originally Posted by Kubbie View Post

Although it's 10's (18's would be even sexier) seeing the multiples of drivers is always a pretty sight!

I'm not so sure my house could handle twelve 18's!
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post #42 of 274 Old 09-04-2008, 07:37 PM
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I like the shot of robertcharles build in progress with the 4 18's and 8 18 pr's, I'll follow your's as well...

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post #43 of 274 Old 09-04-2008, 08:19 PM
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Ahh, line array's always look nice!

YID DIY
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post #44 of 274 Old 09-05-2008, 07:31 AM
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Jack or Dan (or anyone really )

Could you help me understand the advantage of going with 6cuft for 3 drivers over 4cuft for 3 drivers? Is it the resulting higher Q (.895 vs .773)?

Also, I'm trying to model the different options and I'm not sure if I'm entering the correct power/driver. Right now I'm using 150W/driver which looks like too much for the 2cuft box. It looks like 60W/driver is just right for the 2cuft box (which results in exactly the 96V Dan stated above...). I'll have to do a bit of reading as I didn't see any input on my earlier question of what kind of loads can be created out of 3 of these drivers in a box...

Any input would be appreciated
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post #45 of 274 Old 09-05-2008, 11:35 AM
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Quote:
Originally Posted by Kubbie View Post

I like the shot of robertcharles build in progress....

I wish it had a scale reference in that pic though. When I scrolled down, I thought it was a pic of the 12 10" drivers for this thread!
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post #46 of 274 Old 09-05-2008, 10:05 PM
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Quote:
Originally Posted by Jim Hef View Post

I wish it had a scale reference in that pic though. When I scrolled down, I thought it was a pic of the 12 10" drivers for this thread!


Jim,
How tall are you? Those woofers are a bit over 6'

Regards,
Dan
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post #47 of 274 Old 09-06-2008, 06:42 AM
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Realized that after I saw the post that described them! It would really show their size if something was placed in the pic that gave a reference...perhaps a person or even a shoe???
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post #48 of 274 Old 09-06-2008, 09:10 AM - Thread Starter
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Okay, time to impress.....well sort of. I'd like to get thoughts and ideas for this final design. Box sizes may vary just a bit to get the correct cu/ft.


As a newbie to Sketchup, this took me longer than I would like to admit.










It keeps the area for my center channel clear and I can put teh Behringer amp up there too. Also it doesn't go up too high on the sides to get in the way of my lighting.

Each side will actually be 2 boxes for weight issues. Bottom box of 4 and one side box of 2. Wired as Neo Dan mentioned.

Box depth? Depends on sealed or ported I guess. I can make them maybe 15" deep fro sealed, or go 20" deep for ported.


Could I port the 2 side boxes out the top and then the bottom 4 out the front? Or will I have enough of these to just go sealed and be done with it?
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post #49 of 274 Old 09-06-2008, 11:46 AM
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Erich,
I recommend you do a bit testing:
Do your eD subs sound better with the baffles 20" out into the room, or 4" out from the corners(pointing to the side walls)?

Your gonna have to pull the mains out to 2.5-3' into the room

Regards,
Dan
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post #50 of 274 Old 09-06-2008, 12:08 PM - Thread Starter
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I'm going to start testing that today. As of right now, and after many many sub placements, the front seemed to give me the best and most natural sound.

But, I haven't pushed them any closer to the side walls because I wasn't sure if they would cause issues with the mains. I will find out and let you know.
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post #51 of 274 Old 09-07-2008, 09:12 AM
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Do you have any plans to replace your center channel speaker? Some of the newer models are quite large, and you may want to allow enough room for a future speaker.
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post #52 of 274 Old 09-07-2008, 10:26 AM - Thread Starter
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Quote:
Originally Posted by Jim Hef View Post

Do you have any plans to replace your center channel speaker? Some of the newer models are quite large, and you may want to allow enough room for a future speaker.

I figured on leaving about 2' between the subs. Do you think that would be enough? If I ever get another center channel, it might be a DIY model.
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post #53 of 274 Old 09-07-2008, 11:17 AM
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Well, the Paradigm Reference series center channel speaker is about 38" long. Perhaps you can adjust each side boxes for about 42" between them, and then have enough room for an equipment cabinet for the amps spaced side to side.
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post #54 of 274 Old 09-07-2008, 11:29 AM
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Jim,
Perhaps he could set up his mains to create a proper soundstage and solid center image, thus allowing him to run without a center. That is unless he has listeners sitting outside the sweet spot.

Regards,
Dan
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post #55 of 274 Old 09-07-2008, 11:40 AM
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Quote:
Originally Posted by NEO Dan View Post

Jim,
Perhaps he could set up his mains to create a proper soundstage and solid center image, thus allowing him to run without a center. That is unless he has listeners sitting outside the sweet spot.

But how many people watch movies alone? There's usually atleast one more, sometimes nine.

YID DIY
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post #56 of 274 Old 09-07-2008, 12:01 PM - Thread Starter
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I just did some more measuring to check. I have a 110" screen and have considered going with a 100".....maybe. It's a cheap DIY out of designer white laminate, so it's changable. With a slightly smaller screen and moving a bit higher would allow me to put the center channel up above the sub boxes and still stay away from the screen, allowing for any width if it's ever needed. That's figuring the sub if I keep the boxes around 15" in width.


Okay, I gotta admit, I'm tired of measuring! I've been staring at my room and fooling with SketchUp for over a week. I gotta get this thing started!


This is the best I can do here: I just don't think I can scrape up much more cu/ft than the following.


4 identical sealed boxes:

15"x19"x48" gets me right around 6.36 cu ft. After the extra baffle, braces and driver displacement, it should be really close to the 2 cu ft per driver you guys recommended. Figuring driver dispacement in the range of .03 cuft.



OR


4 identical ported boxes.

Largest I can go to have everything fit (and still look reasonable):

15"x22"x48" which would give me about 7.45 cu ft prior to subtracting ports or anything else.


Modeled in Unibox, that ported box isn't half bad tuned to around 15 - 17.


The BIG question, which of those 2 makes the most sense? I'll have to get an EQ for the sealed or an filter for the ported, so that part doesn't matter.



I'm down to the final day before I go nuts! Any strong ideas on which of those 2 boxes I should go with could possibly save me a trip to the looney bin later this week.


I have a need for a cloud of flying MDF dust!!!!
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post #57 of 274 Old 09-07-2008, 01:16 PM
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Neo or Looney: Does it make any sense to have two boxes tuned to a very low frequency, and then build the other two boxes as sealed? Seems to me that a hybrid with this many drivers could give very good results with that alignment...the two 2 driver boxes on each side tuned to 14-16 Hz varying the height for volume instead of depth??? I agree, it will be interesting to see how the overall sound quality varies with the left/right channels now moved 3' closer to the listeners.
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post #58 of 274 Old 09-07-2008, 01:46 PM - Thread Starter
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Jim, if anyone does think that makes some sense, I can do the sealed horizontal boxes with 3 in each one as mentioned above.

The side vertical boxes you are talking about could go up to about 56" tall. If I do something like 15x21x56, that would give me about 8.3 cuft prior to braces, ports and subs. Depth would be different between the 2 boxes, but not too big of a deal.

I can't go any higher because I have a light at 60" high and 22" from the wall.



I have decided to try and keep 4 boxes of 3 for reasons ranging from too much output with all 12 going at one time for music, to the ease of mtching boxes, and 4 Ohm loads per box. It may not be ideal, but it just seems to work better for me in this scenerio.

I don't mind building 2 ported at one size and 2 sealed at another size though. Each pair can then be run on it's own seperate channel and adjustable as well. Even the ability to select ported for movies, then sealed for music. Or run all at the same time. I like those options.
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post #59 of 274 Old 09-07-2008, 06:20 PM
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I don't have great feelings for what your about to do by putting your subs out into the room.
Collecting data now makes for much more predictable results greatly increasing the chances for a successful outcome, foolish to pass on the opportunity IMO.
So I ask again. Have you measured the difference between the response from the box pointed out into the room at the proposed 21" verses facing sideways into the corner at ~4"?

Regards,
Dan
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post #60 of 274 Old 09-07-2008, 08:43 PM - Thread Starter
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No, I guess I haven't done the actual sound measurements with equipment. I have compared just by listening for quite a while. The ED's up on the front give me the most natural sound in the main listening area and the 2nd row as well. Those boxes are 15" deep and about 3.5" off the front wall. If I ended up doing the sealed 19" deep boxes, I figured they would be pushed up and toughing the front wall.

When you mention facing sideways 4" out from the corner, are you talking about the drivers facing left to right out into the room, or firing at the wall?


The front is not where I get the most bass, but it sounds the nicest. The left rear corner gives me the most, but I can pinpoint their location and they are also sitting 2' away from the 2nd row and the bass isn't as good in that position. The 3rd best place is about 10' back from the screen on the left wall. But again, it's easy to locate as it's just 2' from the main listening area, second row isn't as good either.


I was siding my house today and didn't have much time to move things around and test. I will try out multiple sub postions on Monday with both pairs of subs I have.
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