1 big box Vs 2 small boxes. - 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 6th November 2006, 10:16 AM   #1
diyAudio Member
 
Join Date: Jan 2001
Default 1 big box Vs 2 small boxes.

Any difference putting two of the same sub drivers into one, say 100 litre sealed box as apposed to each driver in its own 50 litre box? Woodwork/bracing issues aside.
Trying to compare what effect it might have on excursion limits, SPL ect in Winisd but you cant model the output of 2 'seperate' boxes.
  Reply With Quote
Old 6th November 2006, 10:35 AM   #2
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Hi,

With 2 boxes you can smooth room response with assymetric placement.
Other than that there is no real diffrence between the two options.

/sreten.
  Reply With Quote
Old 6th November 2006, 10:37 AM   #3
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
Acoustic performance will be identical between the two, as will the load on the amplifier. The benefits will be it's easier to make a stiffer/deader small box, and placement options are more which is beneficial as sreten pointed out. Downsides none that I can think of, other than possible form-factor. Unless you put them so far apart that the acoustic coupling does not happen.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 6th November 2006, 09:28 PM   #4
Collo is offline Collo  Australia
diyAudio Member
 
Collo's Avatar
 
Join Date: Nov 2004
Location: Newcastle, Australia
Send a message via MSN to Collo
If you happened to be looking a ported boxes, going to a single box might give you an extra choice of ports

If your port velocity was excessive with the pair of boxes, you would normally have to go to a larger port, or a pair of ports. This might be more than you actually need, resulting in overly long ports.

With a single box, you have twice the volume, so the port is roughly half the length. You have two drivers, so you need roughly twice the area on the port, which makes it twice as long - getting you back to the original length, only larger diameter.

This might not seem any advantage, but you might end up with a single 6inch port instead of a 4incher in each of the separate boxes.
__________________
Ports rule!
  Reply With Quote
Old 6th November 2006, 10:07 PM   #5
diyAudio Member
 
RobWells's Avatar
 
Join Date: Aug 2002
Location: UK
In the single box you can also mount push push to cancel vibrations.

Rob.
  Reply With Quote
Old 7th November 2006, 01:25 AM   #6
diyAudio Member
 
Join Date: Jan 2001
"Push push", now this is something Im seeing mentioned more and more. It isnt outlined in Vance Dickason's book. (is it isobarik?) Trying to find out more about it. Would this simply be the drivers at each end of a 100L sonotube, one facing in and one out, both wired in phase?
Are the any dissadvantages to it over one single sealed box? Does the basket frame become an issue of crossed at 80Hz?
  Reply With Quote
Old 7th November 2006, 08:46 AM   #7
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
Basically it's as you say, one driver on each end of a tube or opposing sides of a box. It's not isobaric so box volume is still doubled.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 16th November 2006, 03:51 PM   #8
kimado is offline kimado  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
I might be confused but; although the drivers are electrically in phase because they are on opposite sides of the box their cone movement would oppose each other? would that make it isobaric?
  Reply With Quote
Old 16th November 2006, 04:03 PM   #9
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
Isobaric cones don't move opposite, they move together thus doubling cone mass which is why box volume is halved. They also need to be tightly/closely coupled.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 18th November 2006, 01:48 AM   #10
diyAudio Member
 
BassAwdyO's Avatar
 
Join Date: Jun 2004
Location: Illinois
Send a message via AIM to BassAwdyO
Yes there may be some confusion with push push mounting, but basically you are making a bipole(if woofers were directional).

The woofer on the front of the box moves out(with respect to the box) with a positive signal, and the woofer on the back of the box also moves out with a positive signal.... The advantage is in vibration cancelation... instead of the inertia of a single cone vibrating the box, the net inertia is zero(since the two cones inertial forces cancel). The sound pressure remains the same.
__________________
The golden rule of DIY:
Build nice, or build twice!
  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
small-signal (small-power) fast switching complementary transistors Lola Luna Solid State 3 8th April 2010 08:51 PM
Small-signal (or small power) pentode that can handle 400V (or more)? GordonW Tubes / Valves 12 13th June 2008 03:07 AM
PC-speakers + small amp (key words: small, cheap) rho Multi-Way 8 18th May 2006 02:19 PM
Small Monitors, Small Room Seth Smith Multi-Way 0 30th January 2006 06:01 AM
Small case for small boards pcspinheiro Class D 11 4th November 2005 06:20 AM


New To Site? Need Help?

All times are GMT. The time now is 08:24 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