Isobaric 8” subs - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 31st August 2011, 05:51 PM   #11
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by PressureFM View Post
Thanks for the measurements, I am currently trying to work out a "compact" design around 50 to 66 Liters for portable needs (outdoors use) with a high output to match the "Boominator" design, when a little more 'uupmh' is needed.

Not sure it is doable with only 100 Watt (Tripath TAA4100A based) available though.
The advantage of an Isobaric design is smaller size for a given F3.
The disadvantage of an Isobaric design is they only have the same output of a single driver, rather than the 6 dB gain when cone area and power is doubled.

If you are looking for the most bass "umph" with low power, in a relatively small enclosure, the SS15 or THAM or similar tapped horn would probably be the best bet.
  Reply With Quote
Old 31st August 2011, 08:46 PM   #12
ODougbo is offline ODougbo  United States
diyAudio Member
 
Join Date: Aug 2011
Location: Maryland USA
Default Finish Measurements:

Finish Measurements:

Wood is 3/4” MDF

11 1/2 Wide 17” Tall 19” Deep.

The port is 10” wide x 13-1/2” deep x 11/16” high (slightly less than 3/4”).

It’s fairly easy to build, rip 10” boards for front, top, bottom and port. The tunnel can be make with 10” square slabs with a 7” hole, laminate them together. Obliviously the cone should not hit the back of the magnet of the front speaker.

I do recommend a table saw, router and several clamps. Take your time building the tunnel, the box will assemble quickly.

What I like about this cabinet design is the tuning, both “humps” are equal and the dip is at 31hz. The emphasis for this box is super low, quick response bass, all at a good price (-; (-;

Yes I do know the pic is 1” MDF, 1” is hard to handle and it’s expensive, these are dimensions for second box that I built using 3/4 material.



Quote:
Originally Posted by PressureFM View Post
I was reading a book (the old "The Secrets of Car Audio") the other day that suggested an isobaric design.

It clearly stated that an isobaric alignment will have lower resonance because the air space between the woofers will act as a buffer of sorts.

What size is the box, port length and how much air do you have in the air space between the woofers?
  Reply With Quote
Old 31st August 2011, 09:02 PM   #13
ODougbo is offline ODougbo  United States
diyAudio Member
 
Join Date: Aug 2011
Location: Maryland USA
The output may be the same as one, however the air coupling allows the speakers to handle gobs of power and the box is half the size. These are not expensive drivers; “floppy cone” is the best description. They can be driven with a modest 60 watt stereo amp.

One driver will sound great in a 2cf box, easy-to-listen music maybe; not for HT, action scenes with explosions. I’ve had plenty of big boxes, multiple boxes; so clunky to have around, end up cutting them up after a while.

I do have a question for you, I have no idea, can a tapped horn box be tuned?
  Reply With Quote
Old 1st September 2011, 12:13 AM   #14
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by ODougbo View Post
1” MDF, 1” is hard to handle and it’s expensive
And not as suitable or as stiff as 18mm BB ply (actually about the same stiffness as 15mm BB)

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 1st September 2011, 01:21 AM   #15
ODougbo is offline ODougbo  United States
diyAudio Member
 
Join Date: Aug 2011
Location: Maryland USA
Default BB grade plywood

Not sure what BB ply is, BB grade plywood over here in the US would not be a good choice for a speaker project. The 1” MDF is nice, I use it for smaller satellite speakers, often add additional lead lining for damping. I’ll try to attach a photo.



Quote:
Originally Posted by planet10 View Post
And not as suitable or as stiff as 18mm BB ply (actually about the same stiffness as 15mm BB)

dave
Attached Images
File Type: jpg HDS Kit 2.JPG (617.2 KB, 322 views)
  Reply With Quote
Old 1st September 2011, 01:33 AM   #16
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Quote:
Originally Posted by ODougbo View Post
Not sure what BB ply is,
Baltic Birch.

jeff
  Reply With Quote
Old 1st September 2011, 02:47 AM   #17
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by ODougbo View Post
Not sure what BB ply is, BB grade plywood over here in the US would not be a good choice for a speaker project. The 1” MDF is nice, I use it for smaller satellite speakers, often add additional lead lining for damping. I’ll try to attach a photo.
Actually, BB is excellent material for a speaker project -- especially for woofers. Far better than MDF IMO. I won't use MDF for building a speaker (except some small amounts in some very specific areas).

There has been considerable dicussion on this subject already. Start here: Discussion on what materials to build speakers out of

... and what do you mean by over here in the US?

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 1st September 2011, 03:54 AM   #18
TerryO is offline TerryO  United States
diyAudio Member
 
TerryO's Avatar
 
Join Date: Nov 2002
Location: Seattle,Wash.
Quote:
Originally Posted by planet10 View Post

... and what do you mean by over here in the US?

dave
He means "way" over here in the USA, where it's always sunny and bright and the fruit falls off the trees into your lap.

Have you guys in the Far North started building fresh Igloos yet? It should be snowing up there by now.


Best Regards,
"Tropical" TerryO
__________________
"If you have to ask why, then you're probably on the right track."
quote from Terry Olson's DIYaudio Forum application
  Reply With Quote
Old 1st September 2011, 05:28 AM   #19
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by TerryO View Post
He means "way" over here in the USA, where it's always sunny and bright and the fruit falls off the trees into your lap.

Have you guys in the Far North started building fresh Igloos yet? It should be snowing up there by now.
Hey Professor Olsonovitch... you only got a couple degrees on us, you have a little more rain and a lot more smog. Make sure you change the filters in your gas mask

Click the image to open in full size.

Hope the proper units don't confuse you....

dave

BTW: Ruth says she is going to get a new foamy for your next visit.
Attached Images
File Type: gif Ave-weather-seattle-v-Vic.gif (61.3 KB, 593 views)
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 1st September 2011, 06:02 AM   #20
TerryO is offline TerryO  United States
diyAudio Member
 
TerryO's Avatar
 
Join Date: Nov 2002
Location: Seattle,Wash.
Quote:
Originally Posted by planet10 View Post
Hey Professor Olsonovitch... you only got a couple degrees on us, you have a little more rain and a lot more smog. Make sure you change the filters in your gas mask

Click the image to open in full size.

Hope the proper units don't confuse you....

dave

BTW: Ruth says she is going to get a new foamy for your next visit.
It's amazing, but those graphs exactly match the settings on my equalizer!

The proper units? Are those in metric inches, or feet?

There was nothing wrong with the old foamy, other than the claw marks and blood stains from the Grizzly Bear attack that I suffered (or was it actually one of those Giant Canadian mosquitoes?).


Best Regards,
Terry
__________________
"If you have to ask why, then you're probably on the right track."
quote from Terry Olson's DIYaudio Forum application

Last edited by TerryO; 1st September 2011 at 06:08 AM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Isobaric HELP subs Subwoofers 4 4th April 2010 02:03 AM
Convert floor standers to subs with Tang Band 8" subs? prerunnerv6 Subwoofers 3 26th February 2006 12:44 AM
2 subs one box/2 subs 2 boxes vetkilr Subwoofers 5 22nd February 2006 09:27 PM
isobaric 6.5" subs - newbie johsti Subwoofers 4 18th February 2006 04:17 PM
Isobaric for subs only? speekergeek Multi-Way 8 13th January 2004 03:15 AM


New To Site? Need Help?

All times are GMT. The time now is 09:24 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2