2 bass drivers in a TL - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 3rd October 2012, 02:05 PM   #11
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: London/Bangkok
For a TL subwoofer, going Isobaric definitely has benefits, if it really works.
  Reply With Quote
Old 3rd October 2012, 02:14 PM   #12
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
I don't really think so .
Try isobaric
Try TL
different worlds

In the Aj-horn manual there's mentioned the use of a second speaker at some point of the TL , just for fun ...
  Reply With Quote
Old 3rd October 2012, 08:41 PM   #13
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally Posted by philipc View Post
So basically I would end up with a bigger box if I use 2 drivers instead of 1 box?
Hi,

Inevitably a box with two drivers will be twice as big as one with one.
With twin drivers you can make the box narrower and deeper than
using a single larger driver.

rgds, sreten.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow
  Reply With Quote
Old 3rd October 2012, 09:02 PM   #14
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by mondogenerator View Post
..........though normally we dont use the volume in TL designs.
How else do you know how big to make it?

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 3rd October 2012, 09:08 PM   #15
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally Posted by Bill poster View Post
I thought about this for a sub, does it work?
Hi,

Isobaric is simply a compound driver made from two drivers. The resultant
parameters of the compound driver can often be found in other single drivers.

e.g. the parameters of two 8 ohm 6.5" bassmids used isobarically become more
similar to the parameters of a 4 ohm 6.5" designed specifically as a subwoofer.

It works, but there is no magic, which why they are quite rare.

Often good for repurposing cheaper drivers into something they were
not really designed for, and the typical clamshell arrangement will
cancel any magnetic and suspension assymetry of cheaper drivers.

Compared to one driver, two isobaric have :

Double the cone mass, half the Vas and hence the same Fs.
Half the impedance (or double), the efficiency is halved.
The same sensitivity for parallel and - 6dB for series.
The same maximum SPL.

Essentially your halving box size at the cost of half the efficiency.

rgds, sreten.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow
  Reply With Quote
Old 4th October 2012, 01:22 AM   #16
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by Bill poster View Post
For a TL subwoofer, going Isobaric definitely has benefits, if it really works.
It's worked for me. Without it, making [ML] TLs with some of the ultra high Vas drivers I've used [~15 -30+ ft^3] would have resulted in unacceptably large cabs with just one woofer and due to their typically low linear excursion capability, dual drivers/channel were often required anyway to get sufficient dynamic headroom down low.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 4th October 2012, 01:40 AM   #17
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Hi,

Clearly isobaric works for silly Vas drivers, your just creating a compound
driver with more sensible parameters. That does not validate isobaric as
a principle that works, its more a useful technique for parameter shifts.

You can always build a single driver equivalent to a compound pair.

rgds, sreten.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 4th October 2012 at 01:50 AM.
  Reply With Quote
Old 4th October 2012, 02:37 AM   #18
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
True and it worked as predicted, so if this doesn't validate the principle, then what does?

Well, manufacturers can, but it's beyond the capabilities of the vast majority of DIYers, so we work with what's available and when high acoustical efficiency combined with a low tuning is a performance goal, then 'silly Vas' drivers is the way to go if a lot of low efficiency drivers and the high power required to drive them isn't an option for whatever reason.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 4th October 2012, 04:33 AM   #19
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
GM: I think you know what i meant. In my TQWT the line CSA, taper and length are calculated, but volume isnt per se. I COULD calculate it, but i dont need to.
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson
  Reply With Quote
Old 4th October 2012, 11:05 PM   #20
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally Posted by GM View Post
True and it worked as predicted, so if this doesn't validate the principle, then what does?

GM
Hi,

Sorry, I meant validate the principle as being better/beneficial (re cost),
obviously the principle works, and is effective in some circumstances.

rgds, sreten.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow
  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
Onken bass box with 2 Eminence Deltalite ll 2510 10" bass drivers albertli Multi-Way 35 11th May 2011 12:05 PM
Need Help w/ Bass Cabinet for TAD TL-1102 & TL-1601a. Use w/ TD-4001 & Yamamoto Horn HP8903B Multi-Way 11 22nd February 2011 07:20 PM
Why no high efficiency bass drivers for sealed bass channel? hasselbaink Multi-Way 48 19th October 2010 02:24 PM
tl, tl with other drivers or no tl at all? beamnet Multi-Way 14 20th January 2006 03:10 PM
6.5" Bass TL? bhg41088 Multi-Way 7 16th May 2004 03:55 AM


New To Site? Need Help?

All times are GMT. The time now is 10:24 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