2 Mal-21s in 50 cu ft? Ported to 12Hz? - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 17 Old 01-08-2013, 03:06 PM - Thread Starter
Member
 
MoFinWiley's Avatar
 
Join Date: Feb 2011
Location: Dual Coastin'
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
~50 cu. ft. enclosure with two Mal 21s in a dual opposed fashion, but manifold-like. Ported with a 12Hz tune.

I am considering doing this.

1. I need to use these two Mals.
2. It seems to model pretty well in WINISD.
3. I have talked the wife into this as part of our living room entertainment center.
4. I need to build a frame on this wall anyways, to hold the Black Diamond screen material I "acquired", so this will be "part" of it.

This sketchup was just a quick model to show the manifold placement i was thinking about.

Thoughts?

My concerns.

Manifold width. Curved corner to back of manifold? Angled wall in manifold? In the sketchup the manifold opening is 8x30.


Port size

I modeled it with two 2x20 slots about 19" deep. It show almost 37 m/s with 3200 watts at 11-12HZ

I'll do a model of the room and the entire box/entertainment center idea later today or tomorrow.





Steve
MoFinWiley is offline  
Sponsored Links
Advertisement
 
post #2 of 17 Old 01-08-2013, 03:11 PM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 112 Post(s)
Liked: 615
Yup. Do it!

The Mal-X 21 models pretty good in about 25cuft and tuned as low as you can.

I endorse this build. smile.gif

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is online now  
post #3 of 17 Old 01-08-2013, 03:35 PM
AVS Special Member
 
N8DOGG's Avatar
 
Join Date: Dec 2003
Location: Canada
Posts: 5,580
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 33 Post(s)
Liked: 238
Looks like a coffin for Andre The Giant!!! biggrin.gif

Blasting brown notes for 10 years and counting!

N8DOGG is online now  
post #4 of 17 Old 01-08-2013, 03:48 PM - Thread Starter
Member
 
MoFinWiley's Avatar
 
Join Date: Feb 2011
Location: Dual Coastin'
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Hahaha. "Coffin" build it is.

Scott, would I want to tune lower than 12? It seemed to fall off quite a bit going lower.
MoFinWiley is offline  
post #5 of 17 Old 01-08-2013, 03:53 PM
Member
 
whiskey_face's Avatar
 
Join Date: Feb 2012
Posts: 77
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 17
ermahgerd pls poast many pix.

k thx.


english: oh my god please post a lot of pictures.

smile.gif
whiskey_face is offline  
post #6 of 17 Old 01-08-2013, 03:58 PM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 112 Post(s)
Liked: 615
Quote:
Originally Posted by MoFinWiley View Post

Hahaha. "Coffin" build it is.
Scott, would I want to tune lower than 12? It seemed to fall off quite a bit going lower.

That really depends on you and your desire for whatever cutoff. There will be a tapering off in output but your room will make up for it.

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is online now  
post #7 of 17 Old 01-08-2013, 04:00 PM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 112 Post(s)
Liked: 615
Quote:
Originally Posted by whiskey_face View Post

ermahgerd pls poast many pix.
k thx.
english: oh my god please post a lot of pictures.
smile.gif



biggrin.gifbiggrin.gifbiggrin.gif

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is online now  
post #8 of 17 Old 01-08-2013, 05:32 PM
AVS Addicted Member
 
noah katz's Avatar
 
Join Date: Apr 1999
Location: Mountain View, CA USA
Posts: 20,285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked: 125
If feasible, I'd consider two separate boxes at opposite mid-wall positions to eliminate all odd-order modes, per Welti.

Noah
noah katz is offline  
post #9 of 17 Old 01-08-2013, 06:06 PM - Thread Starter
Member
 
MoFinWiley's Avatar
 
Join Date: Feb 2011
Location: Dual Coastin'
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by noah katz View Post

If feasible, I'd consider two separate boxes at opposite mid-wall positions to eliminate all odd-order modes, per Welti.

I wish, but I am pretty limited with this room. I have the lots of floor space in just one part of the room.

The room is our everyday living room on an open floor plan 1st floor.

When I get to do a dedicated HT in the basement the layout will be better (I really want to do a DBA)
MoFinWiley is offline  
post #10 of 17 Old 01-09-2013, 01:07 PM - Thread Starter
Member
 
MoFinWiley's Avatar
 
Join Date: Feb 2011
Location: Dual Coastin'
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
LOL @ my use of "acquired" one of my coworkers said it makes me sounds like I stole the screen material, which I did not, FWIW. I have a friend that installs them. This one is a defect 104 inch one(defect is 4" from corner)...I currently have a cheap 92" screen...All I have to do is build a frame to tension it.




Steve
MoFinWiley is offline  
post #11 of 17 Old 01-11-2013, 10:33 AM
AVS Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: East side of NW Cascades
Posts: 2,485
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 58 Post(s)
Liked: 286
That's like 5 whole 4x8 sheets glued directly together. biggrin.gif Coffin indeed.
BassThatHz is online now  
post #12 of 17 Old 01-11-2013, 11:23 AM
Advanced Member
 
stormwind13's Avatar
 
Join Date: Sep 2011
Location: MN
Posts: 808
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 50
Quote:
Originally Posted by Scott Simonian View Post



biggrin.gifbiggrin.gifbiggrin.gif

Thank you for that.
stormwind13 is online now  
post #13 of 17 Old 01-11-2013, 12:59 PM - Thread Starter
Member
 
MoFinWiley's Avatar
 
Join Date: Feb 2011
Location: Dual Coastin'
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by BassThatHz View Post

That's like 5 whole 4x8 sheets glued directly together. biggrin.gif Coffin indeed.

I have been pondering that fact. I am going to redo this drawing to hopefully be around 6 sheets of 5x5 BB if I can find some in my area. I will have to resort to stick bracing because I would need another 4 sheets if I didn't.
MoFinWiley is offline  
post #14 of 17 Old 01-11-2013, 01:06 PM
AVS Special Member
 
gperkins1973's Avatar
 
Join Date: May 2009
Posts: 1,519
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 13
I wouldn't be concerned with 37 m/s of air speed. I have had higher than that with no issues or chuffing. This is perfect for those drivers
gperkins1973 is offline  
post #15 of 17 Old 01-11-2013, 04:06 PM
AVS Special Member
 
Stereodude's Avatar
 
Join Date: Jan 2002
Location: Detroit Metro Area
Posts: 9,603
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 292 Post(s)
Liked: 377
High port air speeds at subsonic frequencies seems like it would be a significant problem. More so than higher more audible frequencies. You're not so likely to hear the fundamental because reduced hearing sensitivity that low, but the chuffing / turbulence sure will be in your range of hearing and will be that much more obvious.
Stereodude is online now  
post #16 of 17 Old 01-11-2013, 04:30 PM
AVS Special Member
 
Bill Fitzmaurice's Avatar
 
Join Date: Nov 2009
Location: New Hampshire
Posts: 9,218
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 1173
Quote:
Originally Posted by Stereodude View Post

High port air speeds at subsonic frequencies seems like it would be a significant problem. More so than higher more audible frequencies. You're not so likely to hear the fundamental because reduced hearing sensitivity that low, but the chuffing / turbulence sure will be in your range of hearing and will be that much more obvious.
You don't hear low frequency waves passing through the duct at high mach as chuffing, you hear the friction of those waves against the duct, and that tends to be in the midrange.

Bill Fitzmaurice Loudspeaker Design

The Laws of Physics aren't swayed by opinion.
Bill Fitzmaurice is online now  
post #17 of 17 Old 01-13-2013, 01:21 PM - Thread Starter
Member
 
MoFinWiley's Avatar
 
Join Date: Feb 2011
Location: Dual Coastin'
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Thanks guys, I was hoping the ports weren't going to be an issue.

The are of the manifold openings match the SD of the driver, is this acceptable?




Steve
MoFinWiley is offline  
Reply DIY Speakers and Subs

User Tag List

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