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Lilmike's Cinema F-20 - Page 47

post #1381 of 1589
10/1/12 at 6:56pm
I want to build an F-20. Does anyone have one of the original MFW drivers that they want to sell? Bill
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post #1382 of 1589
10/1/12 at 7:01pm
they are few and far between these days. most of us are building with this driver and having superb results. http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-468
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post #1383 of 1589
10/1/12 at 7:13pm
And this one.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-190
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post #1384 of 1589
10/12/12 at 12:44pm
I had trouble with badly bowed plywood like pretty much everyone else. I fixed some of the smaller ones before installing them, but the big pieces are hard to tell by eye, that is until you install it and realize how bad it is. I just have regular clamps, so I had to come up with another solution for the ones that are bowed in towards the inside of the enclosure. Here's my trick, hope it helps. Just don't forget to put it back in your trunk in case of emergency lol.

DSC01260.jpg
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post #1385 of 1589
10/12/12 at 12:46pm
I avoided this entirely by using MDF. :P
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post #1386 of 1589
10/12/12 at 1:03pm
I used 5x5 BB. No issues with this. Why didn't you use better wood?
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post #1387 of 1589
10/12/12 at 3:55pm
I picked through the wood, and these were the best pieces I could find. I didn't realize how bowed the bottom piece was until I put it into place. I just used cheap plywood because we built a ported box for this amp and driver 6 months ago with mdf, and we didn't want to spend too much money honestly. After this driver's second enclosure, we probably could have bought a decent sub for the price, but it was fun.
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post #1388 of 1589
10/12/12 at 10:39pm
Cheap ply is not a good plan. There are most likely voids all over the place in between the layers and getting all that airtight may prove to be a major pain!!!! Never skimp when it comes to using good ply, it will come back to burn you in the long run. I certainly DO hope that what you have works out, but even the nice pine ply has issues sometimes. Case in point the two sealed 18" boxes I did where i found all kinds of air leaks I had to go back and take care of...
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post #1389 of 1589
10/15/12 at 2:19pm
I used 3/4 cabinet ply from Home Depot.. $35/sheet. They had better grade plywood at $50/sheet (oak, I think? I definitely saw more plys in it). I found the $35 sheets to be fine.

I bought 1/2 CDX ply from HD for some furring (nothing related to speakers) and it was the absolute worst junk I have ever had the displeasure of working with. I usually get CDX from the local lumber yard and the stuff at HD is not even close to the same quality, although it is still "CDX".

Tim
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post #1390 of 1589
10/15/12 at 7:06pm
I used the "cdx" also, it was $30 a sheet. I got it from my local lumber yard though, it was in much better shape then the stuff they had at HD. I'm pretty sure it doesn't have any leaks, because we fired it up on saturday, and the thing is unbelievably loud. It gives your ears the same felling that you get after going to a concert smile.gif
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post #1391 of 1589
10/15/12 at 9:09pm
I would like to thank lilmike for his help. You answered many questions during our build, and it was much appreciated. So thanks for the help, and ofcourse for putting your hard work into the public domain. To those that noticed our mistakes, we thank you also. I'm not the best a cutting wood, but the pl does a good job of fixing mistakes. Quite a few cuts turned out to be 1/8 of an inch off. Out of paranoia, we ended up using 2.5 bottles of pl :O

The hand held planar was usefull, but not perfect. So when we put the final side panel on, I hosed the whole thing down with half a bottle of pl. Then my dad came over and used this "snake cam" thing he has to run it through and make sure we had pl sqeezing out of every seam. Quite the handy tool I might add smile.gif

He than stayed up untill 2am having some drinks with us, and decided we should see how loud we can get the thing going and see if the cops come. They never showed up, and I think we may have all taken a year off of our ears. Never saw the 6am dad sleep till 10am in my life lol. We only had the bash 300 cranked halfway, this thing only needs like 100 watts to really shine.

It has amazing output for music, but it really has to be turned down for movies. Especially with the sound of the house and windows rattling, makes me wish we had a basement with cement walls.
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post #1392 of 1589
10/16/12 at 7:29am
Glad you like it, although I knew you would smile.gif
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post #1393 of 1589
10/17/12 at 8:12am
I definitely like it. The interesting thing is, we used this same driver and amp in a ported enclosure tuned to around 18hz. The difference the f-20 made on the same driver is amazing. Like a complete transformation in the output, especially in the 20hz to 30hz region. Even in the upper teens too, the feeling of the floor subtly moving can make you a little anxious. I see no need for another one, upgrade-itis is finally cured on my end.
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post #1394 of 1589
10/17/12 at 7:55pm
"Glad you like it, although I knew you would"

+1 even from back here in the peanut gallery. ;-)
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post #1395 of 1589
10/18/12 at 6:01am
I just bought some AC/ Arauco to make two F-20's. The plywood was $46.80 a sheet. I tried to find a cheeper alternative like OSB(all 3/4" is tongue n groove and not 4' wide), the CDX ply or MDF. The lumbar yard that I bought from said take a look at their CDX and a high grade particle board that they carry. The CDX ply they had looked like s&%t. Very bad! I guess I can't avoid paying $47 bucks for good AC/ Arauco. I've never seen good ply at Home Depot or Lowes that was less than $45. I'm in S.E. Michigan.
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post #1396 of 1589
10/18/12 at 8:51am
Quote:
Originally Posted by louisdamani View Post

I just bought some AC/ Arauco to make two F-20's. The plywood was $46.80 a sheet. I tried to find a cheeper alternative like OSB(all 3/4" is tongue n groove and not 4' wide), the CDX ply or MDF. The lumbar yard that I bought from said take a look at their CDX and a high grade particle board that they carry. The CDX ply they had looked like s&%t. Very bad! I guess I can't avoid paying $47 bucks for good AC/ Arauco. I've never seen good ply at Home Depot or Lowes that was less than $45. I'm in S.E. Michigan.

Same in the Carolina's. I paid similar for my auruco for the f-20's but was very impressed with the quality. I stepped it up to Lowe's Oak ply for my last build and it had voids running from one end to the other. It is crap... I will be back to the good ole' Auruco for the next builds. I cant find BB anywhere around here anyways, and our only good lumberyard closed its doors not too long ago.
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post #1397 of 1589
10/26/12 at 5:24pm
Why build one when you can build four for 4x the price??? biggrin.gif
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post #1398 of 1589
10/28/12 at 1:06pm
Man, I have not visited this thread in a while knowing I was going to build sealed enclosures for my four MFW-15's. After doing some measuring, I can't get my four subs in the front of the room without compromising my ability to add ample sound deadening and other needed room treatments up front, which are arguably more important than squeezing all four subs up front. No big deal right? Put 2 up front, and the other two in the back to go with my SDX-15 back there…

My dilemma is that I don’t have enough dedicated pre/pro channels (only two) to set the delay and EQ on each sub, or groups of subs (front L/R, rear L/R, and then SDX-15). The original plan was to have the four MFW’s equidistant from the LP up front, thus able to use the same time delay and same EQ’ing, then have the SDX-15 in the back corner with its own time delay, EQ’ing and gain settings. However, if I can’t keep the MFW’s on their own pre/pro channel, this plan won’t work.

The next idea would be to make some F20’s or F24’s, but I can’t get four to fit in my little room, and they’d render my SDX-15 useless…

So my options include,
-Trade my DEQ2496 for DCX2496 and have five individual subwoofers.
-Use my DEQ2496 and suck it up that I can’t EQ and time delay all five separate subs properly.
-Use my DEQ2496, sell two MFW-15s, one SDX-15, and build two F20/24’s…if I can even get those to fit.

For amplification, I have the Crown CE4000 and EP2500. I planned on using one channel of the CE4000 for the four MFW’s (250w/driver) and the other for the SDX-15 (1KW), then the EP2500 on my L/R’s.

*Side note* My wife won't care if I have five small sub enclosures since they will be in walnut, curved side walls, and piano black front/backs. The large horn subs might cause her to drink heavily.
*Side note #2* My 2 y/o won't be able to climb on top of the horn subs, but will be able to climb on top of the little sealed subs. I guess not too long ago he was on top of my Infinity Beta50 after using the infinity sub next to it as a step stool. He also knocked over the Beta-50, my Dynamic 4T's, Cerwin vega towers, bookshelfs on stands, fingers through tweeters, ball point pen on woofer cones, and small scratches on plasma screen using plastic sword. This guy is a hellion because his mom doesn't watch him while he's alone downstairs in my HT room. Ok done venting.
Edited by Looneybomber - 10/28/12 at 1:16pm
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post #1399 of 1589
10/31/12 at 10:26am
Go with the DCX. It was one of the best investments I have ever made, audio-wise. I use 5 of the channels for varying delays, EQ, etc....amazing piece of gear!
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post #1400 of 1589
10/31/12 at 9:18pm
I had a quick question, I wanted to use a plate Amp like the bash 500. Can I mount that to the box (if so where) or will the vibrations affect the components on the back of the amp.

Thanks

Also, is the link broken for the bracing info on the first page? Can someone please repost...

Off to the lumber yard wink.gif
Edited by stang725 - 11/1/12 at 5:40am
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post #1401 of 1589
11/1/12 at 5:56am
Quote:
Originally Posted by stang725 View Post

I had a quick question, I wanted to use a plate Amp like the bash 500. Can I mount that to the box (if so where) or will the vibrations affect the components on the back of the amp.
Thanks
Also, is the link broken for the bracing info on the first page? Can someone please repost...
Off to the lumber yard wink.gif

1 post. Joined 08/2007.
So that was your first post and took you five years. Unfortunately I don't have good answers for any of your questions other than many dowel rods could work, but may not be the best solution.
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post #1402 of 1589
11/1/12 at 6:19am
Quote:
Originally Posted by Looneybomber View Post

Man, I have not visited this thread in a while knowing I was going to build sealed enclosures for my four MFW-15's. After doing some measuring, I can't get my four subs in the front of the room without compromising my ability to add ample sound deadening and other needed room treatments up front, which are arguably more important than squeezing all four subs up front. No big deal right? Put 2 up front, and the other two in the back to go with my SDX-15 back there…
My dilemma is that I don’t have enough dedicated pre/pro channels (only two) to set the delay and EQ on each sub, or groups of subs (front L/R, rear L/R, and then SDX-15). The original plan was to have the four MFW’s equidistant from the LP up front, thus able to use the same time delay and same EQ’ing, then have the SDX-15 in the back corner with its own time delay, EQ’ing and gain settings. However, if I can’t keep the MFW’s on their own pre/pro channel, this plan won’t work.
The next idea would be to make some F20’s or F24’s, but I can’t get four to fit in my little room, and they’d render my SDX-15 useless…
So my options include,
-Trade my DEQ2496 for DCX2496 and have five individual subwoofers.
-Use my DEQ2496 and suck it up that I can’t EQ and time delay all five separate subs properly.
-Use my DEQ2496, sell two MFW-15s, one SDX-15, and build two F20/24’s…if I can even get those to fit.
For amplification, I have the Crown CE4000 and EP2500. I planned on using one channel of the CE4000 for the four MFW’s (250w/driver) and the other for the SDX-15 (1KW), then the EP2500 on my L/R’s.
*Side note* My wife won't care if I have five small sub enclosures since they will be in walnut, curved side walls, and piano black front/backs. The large horn subs might cause her to drink heavily.
*Side note #2* My 2 y/o won't be able to climb on top of the horn subs, but will be able to climb on top of the little sealed subs. I guess not too long ago he was on top of my Infinity Beta50 after using the infinity sub next to it as a step stool. He also knocked over the Beta-50, my Dynamic 4T's, Cerwin vega towers, bookshelfs on stands, fingers through tweeters, ball point pen on woofer cones, and small scratches on plasma screen using plastic sword. This guy is a hellion because his mom doesn't watch him while he's alone downstairs in my HT room. Ok done venting.

I would buy a couple of those plastic kids gates and stack them in the doorway, so he could not get into the HT room.
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post #1403 of 1589
11/1/12 at 6:20am
Mounting the bash to the enclosure is fine, mounting it INSIDE the box somewhere is not the best plan though, and it doesnt really fit in the driver cabinet. Not sure what's up with the bracing link, but I will say I built mine before any bracing was suggested and it sounds perfectly fine....Welcome btw, good you came out of the dark! 5 years is an aweful lot of lurking.
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post #1404 of 1589
11/1/12 at 8:05am
Quote:
Originally Posted by stang725 View Post

I had a quick question, I wanted to use a plate Amp like the bash 500. Can I mount that to the box (if so where) or will the vibrations affect the components on the back of the amp.
Thanks
Also, is the link broken for the bracing info on the first page? Can someone please repost...
Off to the lumber yard wink.gif

http://www.avsforum.com/attachments/8782

post 977 in the thread.
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post #1405 of 1589
11/1/12 at 8:18am
Yeah, I went back and read the whole post again, knowing I missed someone asking this question (amp placement). I will prob just locate it in separate box... good to know that I don't need bracing.... as far as my lack of posts... sorry was in the Navy for ~10 yrs, attached to various submarines w/o Internet... finally got out and have more time for projects like this...

Thanks for the quick responses... Anyone near Austin, TX area, that might be of some help in construction if I throw a few dollars your way... I just moved here (San Diego) and don't have any woodworking tools yet and will prob be cheaper to just have someone cut the wood for me... Plus would like to benefit from someone's experience, as I am a noob when it comes to speaker box construction. I did build a mame cabinet once upon a time... but that's the extent of my wood working experience...
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post #1406 of 1589
11/1/12 at 12:30pm
Thread Starter 
Embedded links in post #1 appear to be broken. Sorry...it wasn't me, honest. If I can figure out the new editor, I will try to fix post #1, but until then:

Bracing discussion is here:

http://www.avsforum.com/t/1329971/lilmikes-cinema-f-20/960#post_21160972

5X5 Cutsheet is here:

http://www.avsforum.com/t/1329971/lilmikes-cinema-f-20/420#post_20501440

Edit:
Fixed links in first post.
Edited by lilmike - 11/1/12 at 10:13pm
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post #1407 of 1589
11/3/12 at 7:53pm
I recently completed a THT build driven by a Dayton Audio HF 15" and a spare channel of a QSC GX-3. The THT replaced 2 Polk PSW505 subs. I plan to add an F-20 with a Dayton RF 15" in a corner opposite of the THT using one of the PSW505 amps then sell the other PSW505 to finance the plywood. wink.gif I currently have no way to test LF response and dial in other than YPAO (sucks) but hope to get a proper testing setup once the F-20 is compete. If I have read correctly I will require a Behringer laptop sound card, REW software, with a mic. Yes?
Edited by BIG INJUN CHIEF - 11/3/12 at 8:06pm
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post #1408 of 1589
11/4/12 at 6:56am
Or you can use the Radio Shack SPL meter, analog or digital, with the proper calibration file applied in REW. It works reasonably well and is uber cheap.
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post #1409 of 1589
11/4/12 at 6:09pm
It's been a long time since I read about a build, this one was quite the thread. I was a lurker here a couple years ago but never posted. I had to post after actually reading it.
Excellent work lilmike.
I have not done any building for a long time and my son asked me to build a Sub for his house because is wife was encouraging him to build a HT room.
Last time I built a Sub for him he was a kid with a beat up honda living in my basement many years ago.

Looks like fun!
definitely on my top list for a build.
I was going with with an IB but this is eliminates all the IB hassles.
One box and one plate amp..... easy.

Thanks for all your hard work and all the questions you answered.

All the best.

Gexter
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post #1410 of 1589
11/5/12 at 8:25am
Quote:
because is wife was encouraging him to build a HT room.

Now this...

This will possibly upset some folks. Haha, I am in the same camp however, the lady LOVES the theater.
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