Bandpass Woofer/Midrange? - 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 24th March 2006, 10:26 AM   #1
m@ is offline m@  Thailand
diyAudio Member
 
Join Date: Nov 2004
Location: bangkok
Default Bandpass Woofer/Midrange?

I've been playing around with dipoles, full rangers, and tri-amped systems, but have recently been researching more conventional closed box, passive two and three way systems.

I've been wondering what people have experienced using bandpass loaded (sub)woofers, esp from around 100 to 20. For the lowest octaves, it seems ideal as it could eliminate the more complex and expensive part of a crossover network. In my sims, it also reduces overall volume by 25% or more, while maintaining an optimal alignment.

I've also read that they have better transient response than a standard BR when tuned properly.

I guess this is technically a subwoofer, but i'm talking about integrating it into a floorstander with a forward firing port.

Most complaints I've found were about 'boomy, one note bass.' But most complaints about BR cabinets are the same - and i've heard plenty of good speakers with BR loading.

And does anyone know how a bandpass enclosure actually works? I've read 'acoustic cancellation' on a couple of sites, but I'm not sure what that's supposed to mean. Do they mean the high frequencies are coming through the cone and cancelling? That doesn't seem accurate to me. Doesn't it just mean that you're containing the front wave (as well as AS loading the cone) and you get the normal BR thing going on in the port side?

Also, has anyone every heard of a mid or midbass that was bandpass loaded?

Any experience/opinions on this?
  Reply With Quote
Old 24th March 2006, 11:57 AM   #2
diyAudio Member
 
Join Date: Nov 2004
Location: sk
Send a message via AIM to ocool_15 Send a message via Yahoo to ocool_15
I have never seen a midrange in a band pass I would think they would wreck the imaging. PA systems could use it for effiecieny but I think horns are far more common.

If you model it: For efficiency they will have 1 note but you can build them for more bandwidth giving up efficieny and probably having 2 humps.
  Reply With Quote
Old 24th March 2006, 12:20 PM   #3
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Hi,

in hifi something is only rarely new.

In a typical bandpass the lowest frequencies use sealed box loading,
hence "better than reflex transient response". By enclosing the front
of the driver and adding a port you get a 2nd order low pass function.

This does save on crossover components for an add on subwoofer.

The add on AB1 sub for the LS3/5a is a good example of a stand/sub.

/sreten.
  Reply With Quote
Old 24th March 2006, 05:15 PM   #4
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
Bandpass designs are good for maybe an octave range at best. Sort of a double tuned BR design. Efficiency is good as the pass bandwidth is narrowed. Suffers from max SPL as all the air has to be moved through the ports. Used as subs are not good for people that are looking for so called "bass slam" effect.
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 24th March 2006, 05:52 PM   #5
RJ is offline RJ  United States
diyAudio Member
 
Join Date: Oct 2004
I experimented with bandpass subs. Only the bass drums sounded any good. Other bass instruments didn't.
It did get me to research bass drums on other enclosures. Well, it's not the box but the drivers. Turns out the low Le (voice coil inductance) drivers were the key in obtaing good clean & fast bass.
Enclosures were then matched to the driver.

Also, the slope in simulation programs don't match real world frequency response. You don't get a 24 db slope front or back, especially the back portion. The back slope also has a secondary resonance that has to be mitigated with a crossover, You can kill some of the midrange and tame that resonance with stuffing, but I found a plate amp was the best. The midrange coming through the port sounds really hollow, as if the band is playing in a cave.
  Reply With Quote
Old 25th March 2006, 02:10 AM   #6
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

The LS 5/8 BBC monitor's midrange is technically BP loaded, albeit very modestly: http://www.bbc.co.uk/rd/pubs/reports/1979-22.pdf

Of course all compression midrange horns are BP loaded.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  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
Suitable midrange cone, for bandpass mid in Unity horn. Puggie Multi-Way 1843 Yesterday 09:25 PM
Bandpass Woofer Box Design alloyskull101 Subwoofers 11 5th January 2005 10:54 AM
bandpass enclosure woofer selection Opie Multi-Way 1 21st September 2002 07:57 PM


New To Site? Need Help?

All times are GMT. The time now is 05:03 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