CECAA850 Posted February 6, 2012 Share Posted February 6, 2012 I was fascinated when I first saw this thread over at the avsforum, A front loaded horn sub that will get as loud as a THT but go lower. The box is tuned to 20 Hz but the "20" in F-20 stands for cubic feet of box volume. I really had the itch to build a sub, because I hadn't built one in a while plus I had a pocket hole jig I really wanted to try out. The largest obstacle for me would be trying to find a place to put it, as it's not a small box. Let's see, there's an IB in the living room, not going to work there. I built a Tuba-18 for my bedroom system to go with my Lascalas, so I'm good there. My KP-250's needed a sub but I built two ported 18's so I'm covered in that rig. Spare bedroom's too small, not gonna work. Well, if there's no place to put it here, maybe I can find a forum member who needs one. Seems like there was. I should have it up and running this weekend so I'll post some pics over the next few nights of what I've done so far. The end user will end up painting it (I'm sure he'll chime in somewhere along the way) so I'll finish the box appropriately. We decided on MDF for the build. The first pic I'll call Cinema F-20, some assembly required. 1 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 Panels laid out take up most of the floor of my garage, I don't have a shop so the garage gets used for pretty much everything. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 The first thing I normally do is assemble the box with masking tape to make sure all the panels are at least close in dimension. You can normally find glaring mistakes at this stage without actually having assembled anything. I also lable the panels so I don't have to get out my tape measure every time I want to find a particular panel. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 One of my favorite time saving tools, the Jasper Jig. It's perfect for cutting circles. The jig has the ability to cut circles from a little under 3" to 19". All you do is drill an 1/8" hole where you want the center of the hole to be and install the supplied 1/8" steel dowel in the hole. Next you find the corresponding dimension on the jig that you want to cut and put that hole on the dowel. The driver for this build needed a 14" hole. 1 Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 6, 2012 Share Posted February 6, 2012 OMG OMG OMG OMG... i can finally talk about this. i won't steal his thunder and post any of the other build pics i've been sent, but here's some additional information - the driver for this is a Dayton Audio RSS390HF-15 and the amp I chose was the Oaudio 500w plate amp, which I have mounted in my audio rack/closet for short power and interconnect cables. I'll be running thick gauge speaker wire to the enclosure. Due to it's size and my room, I'm pretty limited in placement, but I'm hoping that it's size and output will make that a relative non-issue. it should compliment the rest of my system (noted below) and since I don't have any nearby neighbors i'll be able to air it out regularly. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 3 pics in, that didn't take long[]. Excited???? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 Back to the build. The Jig sets up like this. If you click on the pic and enlarge it, you can see the steel pivot dowell on the bottom. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 Perfect hole every time. The scrap circles underneath are from a previous build. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 The cut it makes is as precise as one would get from a CNC machine. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 6, 2012 Author Share Posted February 6, 2012 Last pic of the night. I'll post some more tomorrow. This is the first panel attatched with pocket holes. I decided to pre-drill and assemble the entire box with screws. After all panels were trimmed and beveled to fit, I'd take it all back apart and do a final assembly with glue. My goal was to try and build a box with ne external screws. More on that later. Quote Link to comment Share on other sites More sharing options...
Mallette Posted February 7, 2012 Share Posted February 7, 2012 Thanks for steering me to this, Carl. You make it look easy... If all the basic cutting and masking tape fit test can be done as quickly as it appears, perhaps sometime I could come over on a weekend and bring the materials such that you could get me to that point? I think I could handle the assembly OK. Right now, I am considering a Titanic III kit from PE for my church organ augmentation project and thought I'd try it at home to see if it would work for me as well. However, I think I'd be a lot happier for my own uses with one of these. Let me know when it's done. I know it's been like the old Jamaican saying "Come REAL soon now, boss," but I still want to come over and hear some serious pipe organ on your systems and perhaps this will be good excuse. Dave Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 7, 2012 Share Posted February 7, 2012 3 pics in, that didn't take long. Excited???? VERY excited. I've been wanting to get my HT into a state of "i'm content for now" before my daughter got here, and this is that last piece. I had been looking at SVS, eD, and many other subs in the $1700 performance range, and after buying a new (old) house, having a daughter, new appliances, etc. it just wasn't going to be possible. Carl threw out the offer to build it for me, and after a quick value prop presentation I received a surprising amount of WAF. So for around 1/3rd the price and a little bit of extra space I'm able to get all of the performance I've been looking for, and then some. I'll eventually go with a pro amp with built in DSP or add a miniDSP. For money and time constraints I went with the oAudio amp - it's very capable and includes some high-pass filters that will let me hit the ground running without risk of overloading my driver. I'm a little concerned about placement, but I really don't have many options in the room so I'll just have to make it work it's best within the room constraints. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 7, 2012 Author Share Posted February 7, 2012 Thanks for steering me to this, Carl. You make it look easy... If all the basic cutting and masking tape fit test can be done as quickly as it appears, perhaps sometime I could come over on a weekend and bring the materials such that you could get me to that point? I think I could handle the assembly OK. You know what they say, looks can be deceiving. The pics are the only thing that I can do quickly. Ask Michael how long I've been dragging my feet on this project (on second thought maybe you better not). Panel cutting takes me a loooong time as whole sheets of MDF are heavy and bulky and it's normally just me working by myself. I also have to borrow a truck to get the stuff to my house. In just a few minutes, I can show you how to cut a panel so straight, it will look like it was done by machine even though you only used a circular saw. I've got some 4" strips of MDF that I had a cabinet maker rip for me. They're 8', 5', and 3' long. All you have to do is c-clamp them to your stock and run your saw along it. As long as you lay it out correctly, you get perfect cuts every time. With my saw, I mark the length of the board plus 1 and 1/2" and cut. Pretty simple. You're welcome to use any or all tools I have for your build. If you REALLY don't want to tackle it, we could most likely do it in a day. I've never had someone help me before, it may go faster. It would be good if you learned though in case you had to make some cuts at the house. Teach a man to fish.......... As a matter of fact, there's one bevel that needs to be cut AFTER several panels are permanently affixed (ask me how I know this). I plan on finishing it up on Saturday, when....., I don't know. After I get the feet on it, I need to round up a couple of people to help me stand it up without buggering up the bottom corners. Sunday may be a good time to have a listen. Carl Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 7, 2012 Author Share Posted February 7, 2012 Dave, I just re-read my last post. Please don't read into it that I won't help you cut your panels, I certainly would. Quote Link to comment Share on other sites More sharing options...
Mallette Posted February 7, 2012 Share Posted February 7, 2012 I have a table saw, router, compound mitre, and circular saw. Every thing I need but confidence... Is MDF really necessary? Seems wood would be better for strength, appearance, and weight. As you say, I think with a few pointers I'd get the hang of it. No rush...give you a chance rest up then perhaps we can discuss. My Sundays are often a wash between church and after church events, but my Saturdays are often open. Dave Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 7, 2012 Share Posted February 7, 2012 I have a table saw, router, compound mitre, and circular saw. Every thing I need but confidence... Is MDF really necessary? Seems wood would be better for strength, appearance, and weight. As you say, I think with a few pointers I'd get the hang of it. No rush...give you a chance rest up then perhaps we can discuss. My Sundays are often a wash between church and after church events, but my Saturdays are often open. Dave the mdf isn't necessary. it was carl's preferred material over plywood and i figured the extra weight would just give some piece of mind against tipping and such. most, if not all, of these builds that i've seen on AVS are using plywood. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 7, 2012 Author Share Posted February 7, 2012 3/4 ply is fine. I'll use either. I used Baltic Birch on my last sub. We went with MDF on this build for a couple reasons. First, you can get 4x8' sheets of MDF for about $30.00 a pop. MDF seems to make a deader cabinet (to me anyways). It's also easier to machine and work once your done. I've stated many times that I'm not a cabinet maker and have only learned what I've taught myself. The cabinets aren't perfect once they're built and require a little "massaging" once complete. Michael also stated he wanted to paint the cabinet and there's no end grain to cover up when you use MDF. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 7, 2012 Author Share Posted February 7, 2012 Dave, don't know if I was clear or even stated the fact that the sub will not be in Beaumont after the 18'th of this month. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 7, 2012 Share Posted February 7, 2012 Michael also stated he wanted to paint the cabinet and there's no end grain to cover up when you use MDF. that too. he's also rounding all the edges for me, which is just a little bit easier in mdf. for what it's worth - there are a whole lot of OEM sub makers that use mdf and charge a ton of money to do so. Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted February 7, 2012 Share Posted February 7, 2012 Carl, Your build is really looking great and it is wonderful that you are doing it to help someone else out.....! That's what it's all about, my friend....! I can't express enough, that the little bit of extra time it takes to layout and dry fit everything before time, pays off exponentially in the end. What you are using to rip your panels is almost as good as having a table saw. It produces very straight and clean cuts, espicially in MDF. Them damn Pocket Screws again......!!!!!!!!!!!!! W. C. Quote Link to comment Share on other sites More sharing options...
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