Need help for my first Open Baffle project - 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 21st January 2010, 03:27 PM   #1
anilva is offline anilva  India
diyAudio Member
 
Join Date: Mar 2004
Location: Bangalore
Default Need help for my first Open Baffle project

Hi,

I am in the planning stages for a twin 12" Woofer open baffle speaker with a midrange and a ribbon tweeter.

Being first time to Open Baffle, what should be criteria for selecting a woofer for open baffle. Should it have high Q or what?

Usage is for listening to stereo with vinyl and digital as sources.

I have seen quite a few projects of open baffle, but could not figure out what the basis was for selecting a particular woofer.

Thanks.
Anil
  Reply With Quote
Old 21st January 2010, 03:55 PM   #2
DougL is offline DougL  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Wheaton IL.
Blog Entries: 30
A high Q is a useful feature in an OB woofer.
Low distortion is good.
Large xmax is useful.
High efficiency is always welcome.
Low Fs is welcome (conflicts with efficiency)
Low cost is always welcome.
Depending on xo frequency, cone breakup behavior.

I probably missed a few.

Doug
__________________
Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well)
Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus
  Reply With Quote
Old 21st January 2010, 04:00 PM   #3
anilva is offline anilva  India
diyAudio Member
 
Join Date: Mar 2004
Location: Bangalore
Quote:
Originally Posted by DougL View Post
A high Q is a useful feature in an OB woofer.
Low distortion is good.
Large xmax is useful.
High efficiency is always welcome.
Low Fs is welcome (conflicts with efficiency)
Low cost is always welcome.
Depending on xo frequency, cone breakup behavior.

I probably missed a few.

Doug
Thanks. How do I know low distortion from T/S parameters? Also is large xmax good for OB. Somewhere I remember having read that xmax should be low - may be I am confused with a spec for full range speaker.

Regards
  Reply With Quote
Old 21st January 2010, 05:01 PM   #4
49 - for the 18th time
diyAudio Member
 
c2cthomas's Avatar
 
Join Date: Oct 2006
Location: Near "Music City" (Nashville Tennessee)
Quote:
Originally Posted by anilva View Post
Thanks. How do I know low distortion from T/S parameters? Also is large xmax good for OB. Somewhere I remember having read that xmax should be low - may be I am confused with a spec for full range speaker.

Regards
Nah- for OB bass ya gotta move lots of air - MORE XMAX is a good thing!!!
__________________
DIY audio can be expensive but getting to see things go up in smoke - that's priceless!!!! ..... "whatever - call it brainfart of Mighty ZM"
  Reply With Quote
Old 21st January 2010, 05:51 PM   #5
diyAudio Member
 
jerome69's Avatar
 
Join Date: Feb 2008
Location: Lyon
Hi,

Take a look on this website, you have some OB projects and a lot discussions around this.
Make a OB baffle is very difficult for a beginner but it could be very instructive.
It's easier to make an active OB than a passive one.
You do not have a lot of choice of woofer for OB. With a ribbon forget active crossover.

Have fun
  Reply With Quote
Old 21st January 2010, 06:01 PM   #6
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Quote:
Originally Posted by jerome69 View Post
With a ribbon forget active crossover.
Why ? Just add a safety cap 50-100 uF !?!? No good ?!
  Reply With Quote
Old 21st January 2010, 06:27 PM   #7
diyAudio Member
 
bearberry's Avatar
 
Join Date: Jul 2007
Location: Ottawa
Default OB design guidelines

To learn more:
http://www.quarter-wave.com/OBs/OB_Design.pdf
Music and Design
Issues in speaker design - 2 (and other sections on the same site)

If you are just starting out getting through some of this may be painful and require looking up additional references to understand terminology and concepts. It will gradually start to make sense.
If you just want to build an open baffle (OB) speaker NOW then the quarter-wave.com project by Martin King, and offshoots (especially Jim Shearer's Fostex ff85k and Eminence Alpha design) are probably a good starting point.
  Reply With Quote
Old 21st January 2010, 10:18 PM   #8
DougL is offline DougL  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Wheaton IL.
Blog Entries: 30
Quote:
Originally Posted by anilva View Post
Thanks. How do I know low distortion from T/S parameters? Also is large xmax good for OB. Somewhere I remember having read that xmax should be low - may be I am confused with a spec for full range speaker.

Regards
The only way to know about distortion is to test it.
As someone else mentioned, the more air that you can move, the better.
However, OB is all about compromise. More xmax usually means more distortion or a more expensive motor. Less xmax means lower max SPL and may require more drivers.
I also agree that active is much easier than passive.

If you let us know what you are planning, we could be more specific.

Doug
__________________
Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well)
Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus
  Reply With Quote
Old 22nd January 2010, 12:00 AM   #9
anilva is offline anilva  India
diyAudio Member
 
Join Date: Mar 2004
Location: Bangalore
Thanks for the replies.

My plan is to:

- Have a twin 12" woofers in a open baffle.
- Optionally have a midrange to bridge the gap between the tweeter and the woofer.
- Use a hornloaded tweeter or a ribbon tweeter probably with "L' pads to adjust senstivity.
- Use a simple passive network.

I have made a number of closed and ported speaker systems before, but this is the first open baffle attempt. The reason I am doing this because, I believe open baffle systems have more efficiency and also probably easier to construct.

Cheers.
  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
Question about Open Baffle project gvimhoof Full Range 6 3rd August 2010 08:20 PM
First open baffle project Moondog55 Multi-Way 18 10th August 2008 04:35 AM
open baffle project mastarecoil Full Range 25 29th November 2007 05:08 AM
another Open Baffle project Tomac Multi-Way 1 14th September 2006 09:11 AM
a speaker project : open baffle then_dude Multi-Way 0 28th March 2005 05:33 PM


New To Site? Need Help?

All times are GMT. The time now is 11:37 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