Looking for advice on building new L/R towers - AVS Forum
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post #1 of 17 Old 03-20-2013, 02:12 PM - Thread Starter
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So this is going in the family room, and I have pretty strict guidelines for WAF reasons. For some reason she doesn't mind some big towers, but she hates the idea of putting a couple small cubes around the room even as end tables. So the L/R need to do sub duty as well. Last restriction is no toe-in. I have my current speakers with a fair amount of toe-in, and this apparently drives her crazy. She said she just wants to go turn them every time she sees them. So I am planning to build the angle/toe-in into the cabinet to keep us both happy. I have a pretty small budget for this, although I haven't decided on an exact amount.

This is in a living room and is typically not played very loud. Loud for me is about -10 with my current speakers. Most of the time we are listening at around -30, and I might increase it to -20 to -15 if I am buy myself. This is with mains that are rated at 94db/1w/1m. I am currently using Klipsch SP-1's for L/R with no sub. They have 8" subs built into the cabinets, and they are pretty underwhelming. Whatever I do is likely to be an improvement over what I have.

What I was thinking is Bill's Designer 12 SEOS design. The Designer 12 should just barely fit in a 12.5" wide cabinet with a 30* angle. I like the Designer 12 because it fits, and it is relatively inexpensive. The Delta 12a also fits and is a similarly price, but the Dayton seems to do better in a small sealed box. The 30* angle has the speaker aiming just slightly outside of the seating positions. At 12.5" wide and a 30* angle, I should have a baffle 14.5" wide which is what the design uses. For LF, I was thinking of using the remaining cabinet volume for a sub. With the angle, I won't be able to mount the sub on the front baffle without it hitting the side of the cabinet; however, I should be able to shoe-horn one in the back. A 12" should just barely fit on the back if I don't recess the driver. I don't think mounting the driver on the outside will fly, but I might be able to mount it on the inside. An entertainment console will sit between the two speakers. If I go with a 12" on the back, I was thinking of the Infinity 1260w because it works well in small volumes and it is cheap. If I extend the depth of the tower and use the open space behind the sealed designer 12, I could probably get enough volume to port it. I can probably go about 19" deep on the short side, and about 26.5" on the long side which gives me ~144L volume for the entire cabinet minus bracing, drivers, ports, etc. I haven't decided on what amp I will use for the subs.

So, I am wondering if anyone sees any issues with what I am thinking, or if anyone has any better suggestions.
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post #2 of 17 Old 03-20-2013, 02:19 PM
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After you first paragraphs I was thinking exactly what you described in your second and third paragraph. I think it's a great plan. The designer 12 might provide more bass than you need to cross over to your 12" subs. But you could maybe run them double bass this way for added bass output. If you want to cross the over at 80hz (or even high considering they share the location) you could get away with something more effecient.
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post #3 of 17 Old 03-20-2013, 03:07 PM
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post #4 of 17 Old 03-20-2013, 03:48 PM
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Originally Posted by mobeer4don View Post

Sort of like these....plus sub

http://www.audiocircle.com/index.php?topic=78557.0

Those are the speaker that I instantly remembered when I read what OP'er wanted. That design should fill all of his needs.

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post #5 of 17 Old 03-20-2013, 04:24 PM - Thread Starter
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Originally Posted by tuxedocivic View Post

After you first paragraphs I was thinking exactly what you described in your second and third paragraph. I think it's a great plan. The designer 12 might provide more bass than you need to cross over to your 12" subs. But you could maybe run them double bass this way for added bass output. If you want to cross the over at 80hz (or even high considering they share the location) you could get away with something more effecient.

The reason I was thinking the Designer 12 was because I could cross the sub over at a lower frequency. If I go with a Delta 12A in a sealed box, it looks like I would have to cross the sub at 100hz, or am I looking at that wrong? If so, I am not sure if that is necessarily a bad thing or not. If I use Delta 12A ported, then it would take up more volume than the Designer 12 sealed which would cut into the space left over for the sub. So I guess the question is, is there any benefit to crossing at 60, 80, or 100? It seems as though the added efficiency of the Delta 12a doesn't really benefit me, since the sub won't be able to keep up with it anyway. As a result it doesn't seem as though there is any benefit to the Delta 12a except that I can decrease the cabinet width by 1/2" (the motor isn't as wide).

Regarding the comment about double-bass, that had crossed my mind because it will be going into a large room. My understanding is that as long as the sub and woofer are in phase, there should be an additive effect with it gradually tapering off as the driver runs out of excursion. If I did this, is there anything that I should do differently with the sub portion of the design?
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post #6 of 17 Old 03-20-2013, 06:11 PM - Thread Starter
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Can anyone help me understand how plugging ports lowers the tuning? I have seen designs that use 2 or 3 ports where one of the ports can be plugged and the tune will be lowered. How does this work, and how can I design for it? When I look at WinISD, the lower the tune, the longer the port needs to be. So I don't really understand how plugging a port lowers the tune, because isn't that effectively decreasing the port length?
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post #7 of 17 Old 03-21-2013, 04:22 AM
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I have always wondered how hard it would be to implement a powered subwoofer into a regular, existing DIY design such as the Seos12/DNA360/JBL2226j. It would be similar to the concept that Definitive Technology uses, but with much better drivers, larger enclosures and more power from better amps.

Who knows, I might very well try that some day!
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post #8 of 17 Old 03-21-2013, 08:29 AM
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Even if you don't need the sensitivity of the delta12a, it would give you that headroom effect and let your run receiver power without issue. And crossing at 100hz should be an issue at all considering the sub and woofer will basically be co-located. I'd only go with the DS12 for cost saving and additional bass output. You could ever go with a 10" model and cross at 100hz, but the 12" model will offer a bit more directivity.

As for the ports, just design the cab with 3 ports. Plug one or two and the tuning changes. Yes, longer ports tune lower. But when you have three ports compared to 2 ports, the ports need to be longer for the same tuning. You'll have to try both in WINISD to see what I mean.
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post #9 of 17 Old 03-21-2013, 10:29 AM - Thread Starter
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Originally Posted by tuxedocivic View Post

Even if you don't need the sensitivity of the delta12a, it would give you that headroom effect and let your run receiver power without issue. And crossing at 100hz should be an issue at all considering the sub and woofer will basically be co-located. I'd only go with the DS12 for cost saving and additional bass output. You could ever go with a 10" model and cross at 100hz, but the 12" model will offer a bit more directivity.

Do you feel that there is any SQ difference between the two woofers? There isn't a lot of information out there on the Delta-12a, and Bill said he thought the Designer 12 sounded richer in the non-bass regions compared to the Eminence drivers. On the other hand, it seems as though you think the Delta-12a is the better choice because of the additional headroom.
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As for the ports, just design the cab with 3 ports. Plug one or two and the tuning changes. Yes, longer ports tune lower. But when you have three ports compared to 2 ports, the ports need to be longer for the same tuning. You'll have to try both in WINISD to see what I mean.

Perhaps I wasn't clear enough in my original question. Is there any way to predict what the FR will look like when one or two ports are plugged, or is this only determined after the fact by measuring? I still don't get the science behind the port plugging. It would seem to me that plugging a port would raise the tuning point and not lower it. Isn't the port length effectively shortened by plugging a port?

BTW, thanks for your input. I appreciate it.
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post #10 of 17 Old 03-21-2013, 10:57 AM
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I haven't used either woofer. I'm also impartial to both. I was just offering an alternative. I'd probably be most inclined to go with the DS12 to get the added bass...

As for the ports, you can see the difference by modelling in unibox or winisd. I wouldn't port if I were you though. I'd just go sealed. Unless you mean on the sub? The port length is decreased, but so is the port area. So it's not as simple as plugging one port shortens the length. The whole port changes.
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post #11 of 17 Old 03-21-2013, 11:19 AM
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BrianJB- I am a bit confused as to how you are talking about implementing this...are you going to use a seperate woofer located on the rear baffle, in addition to the woofer that comes with the Designer12 kit? If so, are you talking about using two different woofers? How would that work out with the crossover?
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post #12 of 17 Old 03-21-2013, 03:20 PM - Thread Starter
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Quote:
Originally Posted by tuxedocivic View Post

I wouldn't port if I were you though. I'd just go sealed. Unless you mean on the sub? The port length is decreased, but so is the port area. So it's not as simple as plugging one port shortens the length. The whole port changes.

I was just talking about the sub. I was thinking of using 2 or 3 tubes and having the option to plug one. The left tower will be up against a wall and about 2 feet from a side wall. I am concerned about the bass getting a little boomy from the corner, so I thought it would be a good idea to have the option to plug one of the ports to get a more gradual slope from the sub.

I am definitely keeping the Dayton woofer sealed, because as you said, it already has more than enough extension like that.

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BrianJB- I am a bit confused as to how you are talking about implementing this...are you going to use a seperate woofer located on the rear baffle, in addition to the woofer that comes with the Designer12 kit? If so, are you talking about using two different woofers? How would that work out with the crossover?

I am going to buy all the parts that are needed for Bill's Designer 12 design, from Erich if he has them or from PE if he doesn't, and build a 40" tall cabinet. The components from the Designer 12 design will go in the top half of the cabinet. I will then seal off the bottom half of the cabinet to use for a subwoofer, and it will likely be an Infinity 1260w. I may also consider the Dayton HO 12, or maybe the TC Sounds Epic 12 if I can stretch my budget. The waveguide, compression driver, and Designer 12 woofer will be attached to the front baffle. The sub will be attached to the rear of the cabinet toward the bottom. I am mounting the sub on the back for no other reason than it will not fit in the front, since I am angling the front baffle. I will have two speaker connections on the back. One for the upper area which will be connected to my receiver, and one for the bottom sub which will be connected to a separate amplifier. It will look pretty similar to the speaker in the link posted earlier, except it will be 1.5" wider, and have the bottom sealed off for the sub. I hope that makes it a little more clear for you.
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post #13 of 17 Old 03-22-2013, 08:38 AM
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This sounds like a very novel idea, Brian! I have considered doing something similar with a Seos15/BMS4550/JBL2226 with a good woofer, but I have scrapped that idea in order to be able to put my funds towards a Radian 951PB. I can't wait to see how yours turns out, though!
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post #14 of 17 Old 03-22-2013, 08:46 AM - Thread Starter
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Alright, I think I decided on the sub portion of the design. By increasing the depth to the maximum, I can get about 94L/3.3cu.ft. for the sub after subtracting port volume, bracing, driver, etc. I will have to build a box or run a tube for the wires of the top section. I think I will just cut a hole out of the bottom of the top portion and run it behind and under the sub and out the back. Using that space behind the woofer is complicating the build, but I think it will be worth it for the extra sub volume.

Anyhow, now that I have the volume, I decided on a 24hz tune with two 3" ports at 18.5" long using the Infinity 1260w. Plugging one of the ports should drop the tune to 17hz. I think that will make a nice compromise between output and extension. If things work out like I am expecting, I will probably plug one of the ports on the corner placed speaker, and leave the other speaker with both open. Any thoughts about what I am planning to do with the sub either positive or negative?

Unfortunately the space between the designer 12 and the side wall is only going to be about 3/32". I am a bit nervous about that, but I don't really want to go any wider on the cabinet. My cuts will have to be spot on or it could end up hitting the wall. I will have to think that through some more.
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post #15 of 17 Old 03-23-2013, 05:58 AM
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How will you be implementing the crossover on the subs and waveguide/mid?
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post #16 of 17 Old 03-24-2013, 03:41 PM - Thread Starter
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How will you be implementing the crossover on the subs and waveguide/mid?

I will be using Bill's crossover from here http://www.diysoundgroup.com/forum/index.php?topic=10.0 for the compression driver and woofer. I will then use the crossover on my receiver for the subwoofer. I don't know if I will run the Designer 12 full range or cross it with my sub. It all depends on whether or not I need the extra bass or not, and I won't know until I get them completed and in my room. Think of the subwoofer as one speaker, and the wrest as another. They happen to share the same cabinet, but the way it is designed there is no reason they couldn't be in completely separate cabinets.

I drew something up in SketchUp. It's only my second time using the program, and there is a lot I don't know so it's the best I could do. The upper-right portion is completely sealed off from the rest. The rest of the enclosure is for the subwoofer.

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post #17 of 17 Old 03-25-2013, 04:21 AM
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That is very cool looking, Brian! I would think that the crossover for the front part would need to be slightly modified because of the angled front baffle. Wouldn't the original crossover be somewhat different due to this?
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