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Discussion Starter #1
Oh yeah, we're in full swing now!


Started my rendition of lilmike's F-20 today. Obviously the sizes are exactly the same. Picked up the 15" driver on sale from PE.


I went with rabbit joints on the carcass and will biscuit the fold:


I got smart after my last subwoofer build and didn't route the rabbits where I didn't need them:





Starting the fold:





Tim
 

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the biscuits aren't necessary, as the right glue will be stronger than the wood at the edge. i've never even heard of a horn panel "blowing out" when glued in. the weak point is the center of the panels...they will vibrate like drums and suck energy out of your build. the place to go overboard in a horn is the bracing, not the joinery. :)
 

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Quote:
Originally Posted by LTD02  /t/1421690/my-f-20-w-dvc385-88#post_22248428


the biscuits aren't necessary, as the right glue will be stronger than the wood at the edge. i've never even heard of a horn panel "blowing out" when glued in. the weak point is the center of the panels...they will vibrate like drums and suck energy out of your build. the place to go overboard in a horn is the bracing, not the joinery. :)

About two decades ago I did a bit of building.. furniture, cabinets etc. Nothing major, but I have an interest in woodworking. These projects are the first I've done since then (excepting basic trimwork, door hanging etc), so beyond the pleasure of a new sub, the journey is just as gratifying. Some guys spend hours on a piano black finish.. by obsession is joinery!


In short order I will be making a new built-in entertainment center, so getting back into sync with the tools is a good thing.


Besides, the biscuits make it really easy to get the pieces lined up



I have the bracing diagrams for the F-20. I think I may make a few changes, but I'll post them here before I commit.


Probably won't have any more progress until the weekend.


Thanks for checking out my thread!


Tim
 

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"beyond the pleasure of a new sub, the journey is just as gratifying...my obsession is joinery!"


:) if you haven't already, check out member passinginterest's (i think i've got that right) builds. he is one of the best woodworkers around here. i'm sure that you would enjoy reading his threads.


"the biscuits make it really easy to get the pieces lined up"


i knew that you were going to say that...and of course, you are right. :)
 

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Discussion Starter #5
I wanted to add some bracing at the unsupported ends of the folds. I used a single piece of 3/4 ply 2-1/2" wide. The brace goes thorough the second fold (the one that is 90 degrees) and joins to the two outside folds:




Like a glove:




I made a 1/4" recess for the driver so I could line it up properly:




Things are starting to move.. working time of the glues starts to become an issue:




All the folds finished:




Just need to add a brace on the backside and the mouth, cut the access hole for the driver and closer her up.


Tim
 

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You will like this sub. With careful EQ, flat to around 15-17Hz (if your room allows it) will be possible at low THD. If your room does not support much down low, you still have solid 20Hz capability, better than any cinema around, whose -3dB point is 25Hz and falls off the table below that.


The only question will be when will you build a second one to even out freq response at more than one seat?


JSS
 

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Quote:
Originally Posted by maxmercy  /t/1421690/my-f-20-w-dvc385-88#post_22262004


You will like this sub. With careful EQ, flat to around 15-17Hz (if your room allows it) will be possible at low THD. If your room does not support much down low, you still have solid 20Hz capability, better than any cinema around, whose -3dB point is 25Hz and falls off the table below that.

The only question will be when will you build a second one to even out freq response at more than one seat?

JSS

At this point I think I am going to build 3 more. My theater is wired for four. Plywood and labor is cheap



Not sure if I can afford the drivers ATM, but now that my test run is complete I can crank out some more fairly easy. I have a spare Buttkicker amp, so I already have the juice to power them.


I will definitely have 2 in the theater and work from there.


I also have 3 stens and 4 sten II's to make. I have a box full of aura drivers. I need to quit my day job



Tim
 

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Quote:
Originally Posted by NWCgrad  /t/1421690/my-f-20-w-dvc385-88#post_22262043


Nice woodworking, I need to work on my joinery.

Thanks. The rabbits were made with a rabitting bit in the router. It's fairly easy once you get the depth set right (which is the only adjustment you have to make). As 3/4 plywood really isn't 3/4 it took a little while to figure out the right depth. Once I had it figured out I used calipers to make sure I set it correctly each time.


Tim
 

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I picked this set up: CMT 7 pc. Grand Rabbet Bit Set


I have to say I am extremely pleased with the quality of the CMT bit. I've used Freud and Amana before. Freud usually gets high marks, but frankly I'm not terribly impressed. Decent enough, but nothing spectacular. I like Amana better than Freud. This CMT cuts smoother than anything else I've had.


Tim
 

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Quote:
Originally Posted by maxmercy  /t/1421690/my-f-20-w-dvc385-88#post_22262004


You will like this sub. With careful EQ, flat to around 15-17Hz (if your room allows it) will be possible at low THD. If your room does not support much down low, you still have solid 20Hz capability, better than any cinema around, whose -3dB point is 25Hz and falls off the table below that.

The only question will be when will you build a second one to even out freq response at more than one seat?

JSS

I find that I don't need a second F20 to even out FR at all the seats in my living room. Maybe it's because the F20 takes up over 50% of my room...
 

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NICE outdoor build!! It looks almost identical to the pics I took of my f-20 build. Working outdoors is just so much more gratifying!!! You'll love the f-20, I certainly did!!!! I had two with tempest x-2's built in, and they absolutely rocked, I just had a thirst for more systems and with cabs that size, I really had NOWHERE to keep them so I had to offload em' They found a new happy home with another AVS member
 

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Discussion Starter #14
Yeah, working outdoors is nice since I don't have to deal with the dust. The glue also dries extremely fast!


Probably won't get much done this weekend. I ordered the speakon connectors from PE, they should arrive today. I forgot to order the H-Nuts.. I think that I can source them locally.


Currently trying to decide on finish. I think I am going to use General Finishes black tinted WB polyurethane. Hopefully I can get the cabinet sprayed next weekend.


Tim
 

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After being on the back burner for about a month, I pushed ahead. I installed the rest of the bracing:




I had installed a brace at the end of the horn.. but when I went to close up the coffin I found the bottom piece of plywood had warped about a quarter of an inch.. so the brace was too short. Had to pop it out. Made a new one, but decided to finish the coffin BEFORE I install it this time



Also got the t-nuts installed and got the access panel cut. Now I just need to round over the corners, install the speakon connector and get some paint on it.. oh.. and install the driver.


I suspect this will happen in rapid fashion, as the F-20 is now residing in my kitchen. Although I had carried it up and down the basement stairs before I buttoned it up, carrying the complete unit is a different story. I got the completed unit to the top of the basement stairs and said to myself... "uhmmmm.. no."


Just getting it up the 3 steps to the kitchen was a feat.
 

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Thanks, Mike. I wished I had one yesterday!


Maybe you should add that to the bill of materials?



One thing is for sure, this isn't going in the basement until it's done. No way am I carrying it back up.


Tim
 

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Mr. Tim, I was wondering if you could tell me how you measured and marked those angle cuts that were required on the internal horn pieces inside your F-20? Also, what type of tool and how did you go about making the angle cuts themselves? I am relatively new to all of this wood working stuff so please don't think I am an idiot!
 

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Haha I helped a buddy integrate two of those beasts some time back.  One word comes to mind when your faced with those big boys Refrigerator.  An appliance cart would be required if moving by oneself......

 

If you haven't decided on finish I would just mention Duratex if you havent heard about it.  It is very well reguarded and gives a nice durable finish when done.  I do like the finish better when done with a fine sponge roller as opposed to their coarse finish roller but anyhoo thought it worth a mention.

 

Very nice work.
 
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