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 1st May 2012, 11:21 PM   #21
diyAudio Member
 
Join Date: Dec 2011
Location: NC
Quote:
Originally Posted by Kjeldsen View Post
Either very large diameter - 30" I'll guess or very heavy membrane = low SPL.

An OB will probably never go lower that 40 Hz, unless you have a very large room, and will need heavy eq., or very wide baffle.
Not sure how that exactly related to my advice of getting a low fs mid qts woofer. I didn't say much about <40Hz and high SPL...unless there was a specific request in the original post that I missed

Quote:
Originally Posted by ScottG View Post
The lower you go, the more excursion you need - a LOT more excursion. OR you need more surface area (..i.e. more drivers). OR of course a combination of the two. (..close-coupling to the floor can also help somewhat.)

There is a tactile sensation that goes somewhat missing with an open baffle design. I prefer a transition from mid-bass to bass at around 70 Hz.
I'm enjoying my 4 21" woofer very much right now (supposed 7mm xmax). I'll be d@mned if I don't have good <30Hz output. The kids watched Transformers 2 the other day and the output was very impressive.

As far as tactile sensation, I complete agree. Once I get everything setup,my two subwoofer towers will play everything <30Hz to give the house good rumble

I have noticed though that at night I can have more bass playing (with open baffles) without disturbing the kiddos. Couldn't do that with the ported subs...
  Reply With Quote
Old 2nd May 2012, 03:14 AM   #22
diyAudio Member
 
Join Date: Dec 2007
thanks guys

those are very informative.

one more question, can i get away with passive xo for open baffle? i have no other choice but to go active xo?

regards,
erwin
  Reply With Quote
Old 2nd May 2012, 04:28 AM   #23
ScottG is offline ScottG  United States
diyAudio Member
 
Join Date: Feb 2003
Location: US
Quote:
Originally Posted by milen007 View Post
thanks guys

those are very informative.

one more question, can i get away with passive xo for open baffle? i have no other choice but to go active xo?

regards,
erwin
You can do this passive. But it's generally more difficult, plus it wastes a LOT of efficiency.

This is a driver reasonably well suited to OB bass (not sub-bass), that has efficiency to burn:
Haut-parleur medium ERS TS38-800PRO

You'd need two though (per loudspeaker) for the xmax vs surface area, maybe more - ask someone to model it with Martin King's worksheets..

..shipping's not going to be cheap though.


If you want to go active there is minidsp for the eq.. That plus a cheap amp with lots of power should work well with just about any driver you can think of.

This is an interesting driver for OB:
http://www.europe-audio.com/Product.asp?Product_ID=4486

You drive one coil "passive" integrated with the rest of your loudspeaker (i.e. just a low-pass filter for the driver as a part of the loudspeaker's crossover), and the other active with eq. for bass boost and room-mode adaption, AND still have a reasonably efficient 1 watt 1 meter output. You still couldn't drive it very low in freq. though at higher spl's.. THAT would require more drivers.
__________________
perspective is everything

Last edited by ScottG; 2nd May 2012 at 04:40 AM.
  Reply With Quote
Old 2nd May 2012, 07:09 AM   #24
diyAudio Member
 
Join Date: Dec 2003
Location: Randers, Denmark
Quote:
Originally Posted by siruis815 View Post
Not sure how that exactly related to my advice of getting a low fs mid qts woofer. I didn't say much about <40Hz and high SPL...unless there was a specific request in the original post that I missed
You need som efficieny to compensate for the OB loss, and since a mid Q woofer with fs below 30 Hz will probably be around 90 dB you will end up with 80-84 dB sensitivity.

A woofer with mid Q and Fs around 40 Hz is easyer to find when high sensitivity is also important. The loss down to Fs will be 6 dB per octave and below it will be 18 dB per octave. You will there for have very good performance down to 40 Hz, and with the correct room also usable information lower than 40 Hz.

I think that most listenings rooms with a OB will not be able to reproduce much lower that 40 Hz anyway because og the cancelation from the rear wall.
  Reply With Quote
Old 2nd May 2012, 07:29 AM   #25
diyAudio Member
 
Join Date: Feb 2005
I used two Eminence Alpha 15 and Supravox.
Bass is active and is very very good.
Attached Images
File Type: jpg 005.JPG (187.7 KB, 652 views)
  Reply With Quote
Old 2nd May 2012, 09:37 AM   #26
diyAudio Member
 
Join Date: Dec 2011
Location: NC
Quote:
Originally Posted by Kjeldsen View Post
You need som efficieny to compensate for the OB loss, and since a mid Q woofer with fs below 30 Hz will probably be around 90 dB you will end up with 80-84 dB sensitivity.

A woofer with mid Q and Fs around 40 Hz is easyer to find when high sensitivity is also important. The loss down to Fs will be 6 dB per octave and below it will be 18 dB per octave. You will there for have very good performance down to 40 Hz, and with the correct room also usable information lower than 40 Hz.

I think that most listenings rooms with a OB will not be able to reproduce much lower that 40 Hz anyway because og the cancelation from the rear wall.
Ah - I think I must've not followed your reply very well. I'd agree with that
  Reply With Quote
Old 2nd May 2012, 09:39 AM   #27
diyAudio Member
 
Join Date: Dec 2011
Location: NC
Quote:
Originally Posted by milen007 View Post
thanks guys

those are very informative.

one more question, can i get away with passive xo for open baffle? i have no other choice but to go active xo?

regards,
erwin
Quote:
Originally Posted by ScottG View Post
You can do this passive. But it's generally more difficult, plus it wastes a LOT of efficiency.
FWIW, I'm running my 21" MCMs passive right now, ~12db/oct 70Hz lowpass via F-mod inline filter - efficiency truly went down the drain. My Behringer EP2000 starts to clip with the drivers still asking for a bit more.
  Reply With Quote
Old 30th May 2012, 12:50 PM   #28
Banned
 
Join Date: Nov 2006
Quote:
Originally Posted by Assesears View Post
Hi

Don't use the alpha 15a only if you want one note bass. The magnet
is to small. I will be selling mine soon hate them

RegardS
I agree.
If you want tight dynamic clean and with all the tonal colours of a bass guitar consider something else.
  Reply With Quote
Old 30th May 2012, 04:40 PM   #29
diyAudio Member
 
Join Date: Mar 2006
Location: SE
What about the Beta 12A ? These have twice the magnet size than the Alphas... I plan to drive them active...

I have 4 beta 12A's which I plan to use with a pair of these Monacor 200x full ranges which I intend to invert so one HF is firing rear, one forwards which I will drive actively with a Behringer DCX2496 Ultradrive when I have worked out how to use it
__________________
John
  Reply With Quote
Old 30th May 2012, 11:09 PM   #30
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Are you not really thinking about an IB, not "open"? There are some very good forums dedicated to IB subs. You will find what parameters are important, then pick the driver. You can't pick by brand.
  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
GRS 15" on open baffle Godzilla Full Range 14 9th March 2011 01:39 AM
Found new open baffle woofer? lenta Multi-Way 8 24th November 2010 07:26 AM
Lab 15 subs on open baffle? Racket Scientist Full Range 3 24th August 2010 05:12 PM
Open baffle Woofer Characteristics Peter Menting Multi-Way 17 22nd November 2003 02:51 AM


New To Site? Need Help?

All times are GMT. The time now is 03:22 PM.


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