The Flex-12, expandable, adjustable subwoofer/mid bass using the MBM-12 kit - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 47Likes
 
Thread Tools
post #1 of 118 Old 09-05-2015, 10:32 AM - Thread Starter
AVS Forum Special Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 2,121
Mentioned: 654 Post(s)
Tagged: 0 Thread(s)
Quoted: 899 Post(s)
Liked: 1733
The Flex-12, expandable, adjustable subwoofer/mid bass design using the MBM-12 kit

Using the MBM-12 kit as a subwoofer / mid bass with adjustable tuning (17hz, 24hz, or 34hz) in an easy to build 3cuft enclosure (14.5"w x 28"h x 18.75"d). Designed for use with the iNuke 1000DSP or 3000DSP with downloadable iNuke DSP settings for each tuning mode for optimal output and sound quality.



With a footprint of only 14.5" x 18.75" it is easily placed in most locations where a larger sub would not pass, but don't let it's size fool you even a single cabinet is capable of some very respectable output. With multiples able to be run off a single amp, up to 3 off a 1000dsp or 12!!! off a 3000dsp you can keep adding them until your output desires are filled or your house starts to fall apart.




This design uses a custom 12" woofer (named Magnum-12 by Erich) designed to excel as a mid bass driver but I found it to be quite excellent as a subwoofer driver in ported enclosures. It very good sensitivity in the upper bass and the strong motor allows it to maintain decent sensitivity down towards tuning in a moderate sized low tuned ported enclosure as well. The sensitivity of the driver >50hz combined with the fairly strong motor strength give it excellent efficiency in the midbass, 10x as efficient as the Ultimax-12 in that range in converting electrical power to sound. This minimizes power compression giving it great dynamics and detail at high volumes very suitable for use with high sensitivity speaker designs.


This design uses two of the 3" precision ports for which the center tube needs to be cut to 10" in order to give the correct tuning. This makes them 16" long and when placed in the enclosure the proximity of the rear port flare to the back of the enclosure allows increases the effective port length to around 19-20" which gives it the 24hz tuning. Plugging one port lowers tuning to 17hz. Taking out the center port extension tubes (leaving just the flares) gives the 34hz tuning. You can tape the ports together using electrical tape which allows you to take them apart if you wanted to experiment with the lower tunings vs. the 34hz tune.


I have designed DSP setting for the iNuke amps that maximize performance for each tuning mode. In the 24hz mode response is +-3dB to 21hz but in room you can expect it to reach to the upper teens. In the 17hz mode response is +-3dB also to 21hz though below that is much flatter and with good room gain usable response can extend down to mid-low teens.


Frequency response of the 17Hz, 24Hz and 34hz modes (outdoors 2m ground plane):



Rough idea of max output for the three different tunings of a single enclosure powered by an iNuke 3000DSP:


Measured impedance of the 17-24-34hz tunings:


Enclosure design, this was designed to be simple to build using the 14.5" x 28" MBM-12 baffle.
There are only three main panel sizes to be cut:
2x 14.5" x 28", These are the same size as the included baffle and make up the rear panel and second layer on the double baffle (the included baffle being the front).
2x 16.5" x 28", These are the two sides.
2x 16.5" x 13", The top and bottom



The bracing I used is just 2" wide strips of left over MDF. Three running side to side, two with strips running front to back and the one behind the driver going from the front to the center. There is also a brace going from top to the bottom made up of several smaller pieces that fit between the others. Looking in at the bracing and damping:





More info to come soon!
Attached Thumbnails
Click image for larger version

Name:	D2H_1228-sm.jpg
Views:	5688
Size:	174.4 KB
ID:	926778   Click image for larger version

Name:	D2H_1226-sm.jpg
Views:	5700
Size:	159.8 KB
ID:	926786   Click image for larger version

Name:	D2H_1206-sm.jpg
Views:	6449
Size:	144.3 KB
ID:	926794   Click image for larger version

Name:	Flex-12 box text.jpg
Views:	5890
Size:	144.9 KB
ID:	926802   Click image for larger version

Name:	flex-12 frequency response 17hz & 24hz outdoors.png
Views:	486
Size:	21.8 KB
ID:	926810  

Click image for larger version

Name:	Max Output 17-24-34 tune iNuke 3000.png
Views:	5520
Size:	25.0 KB
ID:	1024465   Click image for larger version

Name:	Flex-12 impeadance 17-24-34hz.png
Views:	5309
Size:	31.7 KB
ID:	1024473  
Attached Files
File Type: zip Flex-12_iNukeDSP_Settings.zip (2.4 KB, 289 views)
brian6751, cuzed2, Erich H and 6 others like this.

Last edited by mtg90; 11-27-2015 at 08:58 PM. Reason: fixed photo links, added files
mtg90 is offline  
Sponsored Links
Advertisement
 
post #2 of 118 Old 09-05-2015, 10:33 AM - Thread Starter
AVS Forum Special Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 2,121
Mentioned: 654 Post(s)
Tagged: 0 Thread(s)
Quoted: 899 Post(s)
Liked: 1733
Reserved for future info.
mtg90 is offline  
post #3 of 118 Old 10-21-2015, 06:14 PM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
The Flex-12, expandable, adjustable subwoofer/mid bass using the MBM-12 kit

These sounded sooooo good at the GTG meet! Great job on this build!!

Last edited by eng-399; 11-27-2015 at 09:27 PM.
eng-399 is offline  
Sponsored Links
Advertisement
 
post #4 of 118 Old 10-21-2015, 08:15 PM
 
More is Better's Avatar
 
Join Date: May 2013
Location: USA
Posts: 1,371
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 620 Post(s)
Liked: 355
@mtg90


What is the max useable excursion on these?
More is Better is offline  
post #5 of 118 Old 10-21-2015, 09:54 PM - Thread Starter
AVS Forum Special Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 2,121
Mentioned: 654 Post(s)
Tagged: 0 Thread(s)
Quoted: 899 Post(s)
Liked: 1733
The Magnum-12 driver will do 10-11mm, the suspension (surround) starts to lock up and make noise around 12-13mm or so.

I need get a video uploaded of one of these blowing out a candle at 8' back. I am sure if positioned right it could do it at 10+ feet.
brian6751 and More is Better like this.
mtg90 is offline  
post #6 of 118 Old 10-22-2015, 05:49 AM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
Im seriously considering using these for LFE. I bet 4 of them in a 2000cft. room would have good output even in the 17Hz tune

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #7 of 118 Old 10-22-2015, 09:10 AM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
in fact, i think they would be perfect for me. I dont really crank up movies that much but I do like to listen to music and concert Blu rays loud sometimes. 4-6 of these gives me the best of both worlds. Im in a basement so Im not interested in ULF anyway. I plan on adding Crowsons for that.

now to sell that Peavey 7500 DSP i just bought LOL!!

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds

Last edited by brian6751; 10-22-2015 at 09:13 AM.
brian6751 is online now  
post #8 of 118 Old 10-22-2015, 09:37 AM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
Quote:
Originally Posted by brian6751 View Post
in fact, i think they would be perfect for me. I dont really crank up movies that much but I do like to listen to music and concert Blu rays loud sometimes. 4-6 of these gives me the best of both worlds. Im in a basement so Im not interested in ULF anyway. I plan on adding Crowsons for that.

now to sell that Peavey 7500 DSP i just bought LOL!!

These would fit you perfect with what your saying. They do get loud to! I have Behringer 15" inch pa speakers for LCR that's talked about in the speaker forum area and with the MBM's complementing those speakers it was really something to hear. I'm going to get two of these to.
brian6751 likes this.
eng-399 is offline  
post #9 of 118 Old 10-22-2015, 10:02 AM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
Quote:
Originally Posted by eng-399 View Post
These would fit you perfect with what your saying. They do get loud to! I have Behringer 15" inch pa speakers for LCR that's talked about in the speaker forum area and with the MBM's complementing those speakers it was really something to hear. I'm going to get two of these to.
It was your thread that helped me choose these. Thanks for all the great reading material. I wish I could have been there. I think they will go great with the 1099's in building
eng-399 likes this.

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #10 of 118 Old 10-22-2015, 10:16 AM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
Glad it helped I was hoping to write down what we heard along with the rest of the guys that there to help out all us diy guys! It's really hard to buy different speakers sight unseen and unheard.
To bad we all live so far away from each other on these forums it would be nice to grab a drink and listen to some of the these speakers and talk shop.
eng-399 is offline  
post #11 of 118 Old 10-22-2015, 10:32 AM
AVS Forum Special Member
 
HFGuy's Avatar
 
Join Date: Jan 2011
Location: Toronto
Posts: 1,004
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 250 Post(s)
Liked: 268
What black paint is that ? This is the exact look I want for my 1099's best buddies.
HFGuy is online now  
post #12 of 118 Old 10-22-2015, 10:40 AM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
Quote:
Originally Posted by HFGuy View Post
What black paint is that ? This is the exact look I want for my 1099's best buddies.
"
The finishing process was three coats of fastprime 2 primer (light sanding between coats):
http://www.menards.com/main/building...4452936804.htm

Then three coats of Conco 9500 flat black paint:
http://www.menards.com/main/paint/ex...4427301054.htm

Both applied with a fine 6" foam roller. "

taken from post # 415 of this thread

https://www.avsforum.com/forum/155-di...-class-14.html

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #13 of 118 Old 10-22-2015, 10:49 AM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
Guys if anyone has any unanswered questions about these post away I'll see Matt mtg90 tomorrow and ask him what you guys want to know if he doesn't post here post.
eng-399 is offline  
post #14 of 118 Old 10-22-2015, 10:56 AM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
Quote:
Originally Posted by eng-399 View Post
Guys if anyone has any unanswered questions about these post away I'll see Matt mtg90 tomorrow and ask him what you guys want to know if he doesn't post here post.
ask him to design one with the same tuning options but using two woofers!
eng-399 likes this.

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #15 of 118 Old 10-22-2015, 10:58 AM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
eng-399 is offline  
post #16 of 118 Old 10-22-2015, 01:58 PM
AVS Forum Special Member
 
WereWolf84's Avatar
 
Join Date: May 2011
Posts: 1,161
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 425 Post(s)
Liked: 180
@mtg90 ,

can we make those ports on the rear side?
WereWolf84 is online now  
post #17 of 118 Old 10-22-2015, 02:05 PM
AVS Forum Special Member
 
WereWolf84's Avatar
 
Join Date: May 2011
Posts: 1,161
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 425 Post(s)
Liked: 180
Quote:
Originally Posted by eng-399 View Post
I ask him no problem.
ask Matt to design one with the same tuning options in 15" version & 18" version

Last edited by Erich H; 10-22-2015 at 02:46 PM.
WereWolf84 is online now  
post #18 of 118 Old 10-22-2015, 02:15 PM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
The Flex-12, expandable, adjustable subwoofer/mid bass using the MBM-12 kit

Quote:
Originally Posted by WereWolf84 View Post
ask Matt to design one with the same tuning options in 15" version & 18" version

I'll ask when he stops by my house tomorrow afternoon.
Matt works full time and I'm sure he will respond to everyone before I see him tomorrow but if not I'll pass the messages.

Last edited by eng-399; 10-22-2015 at 02:38 PM.
eng-399 is offline  
post #19 of 118 Old 10-22-2015, 02:52 PM
AVS Forum Special Member
 
Erich H's Avatar
 
Join Date: Dec 2007
Location: Cincinnati OH
Posts: 7,461
Mentioned: 345 Post(s)
Tagged: 3 Thread(s)
Quoted: 1943 Post(s)
Liked: 2812
Quote:
Originally Posted by WereWolf84 View Post
ask Matt to design one with the same tuning options in 15" version & 18" version
I hit the wrong button and almost edited your post!

I know your in another country and likely wouldn't be using the Magnum-12 either way, but you could always put two of the 12's in a 3-4cuft enclosure tuned around 42hz. The guys at the GTG will tell you what two of them can actually do. We should keep this thread about the Flex-12 options.

_______________________
The SEOS Waveguide Project
Erich H is offline  
post #20 of 118 Old 10-22-2015, 02:58 PM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
Is there going to be a flat pack for these Erich?

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #21 of 118 Old 10-22-2015, 04:14 PM
AVS Forum Special Member
 
Erich H's Avatar
 
Join Date: Dec 2007
Location: Cincinnati OH
Posts: 7,461
Mentioned: 345 Post(s)
Tagged: 3 Thread(s)
Quoted: 1943 Post(s)
Liked: 2812
It depends on demand. I was going to get the smaller midbass module done first, but I could get this larger Flex-12 done instead. Most people don't think 12" woofers are big enough since the 18" craze, so I didn't make up flat packs for the Flex-12 already. Maybe the GTG from last weekend will change peoples minds a little.

MTG90, now that you have played with these a bit do you think the smaller midbass module could be done with a single 4" Precision Port, versus dual 3" ports? I'm guessing there could be some chuffing, but wouldn't the woofer bei so loud at that point that you couldn't hear it? There's one company that sells an assembled sub with a Lab-15 and a 4" port, so I'm wondering if a 4" would handle this 12" woofer.

_______________________
The SEOS Waveguide Project
Erich H is offline  
post #22 of 118 Old 10-22-2015, 05:07 PM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
well, I'll be sure to do a thread when I build mine

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #23 of 118 Old 10-22-2015, 07:12 PM - Thread Starter
AVS Forum Special Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 2,121
Mentioned: 654 Post(s)
Tagged: 0 Thread(s)
Quoted: 899 Post(s)
Liked: 1733
Quote:
Originally Posted by brian6751 View Post
ask him to design one with the same tuning options but using two woofers!
Just stack two on top of each other!

The way the cabinet is designed the effective port length is increased a good bit from the proximity of the internal port exit to the cabinet walls. A cabinet built for two woofers would need to be carefully designed so that the cabinet volume and tuning ends up the same as the single woofer version so the DSP settings still perform as designed.

Quote:
Originally Posted by WereWolf84 View Post
@mtg90,

can we make those ports on the rear side?
Yes if placed in the same vertical plane just on the rear panel.

Quote:
Originally Posted by Erich H View Post
MTG90, now that you have played with these a bit do you think the smaller midbass module could be done with a single 4" Precision Port, versus dual 3" ports? I'm guessing there could be some chuffing, but wouldn't the woofer bei so loud at that point that you couldn't hear it? There's one company that sells an assembled sub with a Lab-15 and a 4" port, so I'm wondering if a 4" would handle this 12" woofer.
A single 4" port has just a bit less cross sectional area then two 3" ports, but less port wall surface area so yes it will work well.
WereWolf84 and eng-399 like this.
mtg90 is offline  
post #24 of 118 Old 10-23-2015, 03:08 AM
AVS Forum Special Member
 
brian6751's Avatar
 
Join Date: Mar 2006
Location: Canton, MI
Posts: 7,156
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1753 Post(s)
Liked: 1784
I was just worried about having the ports facing a screen if stacked but I guess they are so small I could just turn them sideways

--------------------------------------------------
FOR SALE:
Lots of stuff. Check the Audio Gear Classifieds
brian6751 is online now  
post #25 of 118 Old 10-23-2015, 07:22 AM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
Matt do you have custom settings in the Inuke 3,000 DSP for the Flex-12. I'm guessing you measured outside and made changes to get it flat, Or did you just set the High pass.
eng-399 is offline  
post #26 of 118 Old 10-23-2015, 01:57 PM - Thread Starter
AVS Forum Special Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 2,121
Mentioned: 654 Post(s)
Tagged: 0 Thread(s)
Quoted: 899 Post(s)
Liked: 1733
I'll upload the iNuke 3000DSP settings in the first post once I double check that everything is set correctly for both channels.
mtg90 is offline  
post #27 of 118 Old 10-23-2015, 07:41 PM
AVS Forum Special Member
 
corradizo's Avatar
 
Join Date: Aug 2009
Location: near Chicago
Posts: 3,487
Mentioned: 83 Post(s)
Tagged: 0 Thread(s)
Quoted: 1552 Post(s)
Liked: 1635
Quote:
Originally Posted by mtg90 View Post
I'll upload the iNuke 3000DSP settings in the first post once I double check that everything is set correctly for both channels.
Was curious about this too, wouldn't you use REW and eq flat in the room?
corradizo is offline  
post #28 of 118 Old 10-23-2015, 07:52 PM
AVS Forum Special Member
 
eng-399's Avatar
 
Join Date: Sep 2013
Location: Plainfield IL.
Posts: 5,605
Mentioned: 597 Post(s)
Tagged: 0 Thread(s)
Quoted: 2476 Post(s)
Liked: 5153
Talked to Matt today and yes once the MBM is in the spot were you want it you have to run REW to get it flat. He put in the filters before the meet to have it ready for that day. It probably needed a little more eq in the room but from what we heard I don't think I would of been a lot.
corradizo likes this.
eng-399 is offline  
post #29 of 118 Old 10-23-2015, 10:09 PM - Thread Starter
AVS Forum Special Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 2,121
Mentioned: 654 Post(s)
Tagged: 0 Thread(s)
Quoted: 899 Post(s)
Liked: 1733
The settings I designed give it a smooth anechoic response to start out with and also optimize performance. I spent a good bit of time playing with the high pass, limiter and DEQ settings to get the most from both the amp and driver which is why they sounded as impressive as they did.

All the normal EQ settings are unused (well 1 is used for the 17hz mode) those that are free can be used to EQ for the room.
mtg90 is offline  
post #30 of 118 Old 10-24-2015, 04:25 AM
AVS Forum Special Member
 
corradizo's Avatar
 
Join Date: Aug 2009
Location: near Chicago
Posts: 3,487
Mentioned: 83 Post(s)
Tagged: 0 Thread(s)
Quoted: 1552 Post(s)
Liked: 1635
Nice. What kind of curve would you then employ in room? I ask because it seems like Mikes @eng-399 subs have a pretty big house curve on them.
corradizo is offline  
Sponsored Links
Advertisement
 
 

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off