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 10th October 2009, 03:29 AM   #1
diyAudio Member
 
Join Date: Nov 2004
Location: ga
Default OB or sealed?

This is my first home speaker project.

I would like to build a speaker system based on the JBL E145 and PR170M0s.

#1- I have read most of the work regarding open baffle PR170MO’s here and on ‘High Efficiency Speaker Asylum’. Specifically I would like to replicate the work that Magnetar did regarding the twin OB PR17OMO’s. I believe the last generation had the APT80’s and rear firing Leson TCL1. It seems that the Leson was modified, but how I am exactly not sure. But I thought that I read that he also tried a Beyma CP21's and thought they sounded great. I read that at one point the construction of these speakers was on his web page, but when I did find the link I was unable to open it. It was probably an old link. Does anyone know where I could acquire the specific information regarding his build?

#2- Using the E145, 2123, PR170M0 and horn tweeters. All first order crossovers.

What do you guys think? If I go with choice #1, I need to buy 2 PR170M0 and tweeter. If I go with choice #2, I only need to buy tweeters. The speaker location will be my entertainment center. These will be used for music and some HT.

The E145's will be ported and I have a seperate sub.

Last edited by mitchyz250f; 10th October 2009 at 03:32 AM.
  Reply With Quote
Old 10th October 2009, 03:41 AM   #2
cuibono is offline cuibono  United States
diyAudio Member
 
cuibono's Avatar
 
Join Date: May 2006
Location: City of Angles
I have a clear preference for OB speakers - but the only way to know what you prefer is by trying both...

I might add though, that you might want to think more about 'how' you're going to do this, whatever path you take. IOW, if you're not doing any measurements, you're flying blind. It is much easier to copy someones design - they've done a lot of the work for you. But if you want to go your own way and you can't take frequency response measurements, its likely you won't be satisfied (at least for long), and you won't know why not. Just my two cents...
  Reply With Quote
Old 10th October 2009, 03:58 AM   #3
diyAudio Member
 
Join Date: Nov 2004
Location: ga
Thanks for your response. I have a very good friend who is an EE and getting in audio. We will be doing this project together. He has the equipment to take readings, but I still think my best start would be to copy someone elses design first.

How critical is placement of the OB speakers compared to sealed box?
  Reply With Quote
Old 10th October 2009, 04:49 AM   #4
diyAudio Member
 
Join Date: Sep 2002
Location: Australia
IMO placement is easier. Just keep them out from the rear walls.
  Reply With Quote
Old 10th October 2009, 04:53 AM   #5
diyAudio Member
 
Join Date: Nov 2004
Location: ga
Just to be clear I now have 2 JBL e145's, 2 Audax PR170M0's, and 2 JBL 2123's and a Tempest sub.
  Reply With Quote
Old 10th October 2009, 05:43 AM   #6
diyAudio Member
 
jerome69's Avatar
 
Join Date: Feb 2008
Location: Lyon
Quote:
#2- Using the E145, 2123, PR170M0 and horn tweeters. All first order crossovers
6dB is not recommend if you use a PR170. See Audax application note 600Hz@18dB :
http://www.hautparleur.fr/_audax/pr170m0a.jpg
http://www.hautparleur.fr/_audax/pr170m0b.jpg

also see JBL 2123 : http://www.jblpro.com/pub/obsolete/2123.pdf

JBL E145 : http://www.jblproservice.com/pdf/Dis.../E145-8-16.pdf

Note : OB is not so easy to have a smooth response, the panel should be at least for the PR170 30cm (11.8 inch) width if you want to go as low as 600Hz. It is your first project, I recommend a closed box or better an aperiodic box.

Last edited by jerome69; 10th October 2009 at 06:01 AM.
  Reply With Quote
Old 10th October 2009, 12:17 PM   #7
diyAudio Member
 
Join Date: Nov 2004
Location: ga
Thanks Jerome. I was thinking first order for the 4 way with crossovers at 300, 1000 and 5-6k.
  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
Sealed midbass vs BR, why not sealed ? mbon Multi-Way 4 2nd February 2014 10:23 PM
NSB, sealed? 2litre Multi-Way 1 23rd November 2008 02:14 AM
W8-740 in sealed sub? toseland Subwoofers 2 1st December 2004 07:48 AM
TL or sealed... Chris8sirhC Multi-Way 17 22nd February 2004 12:02 AM


New To Site? Need Help?

All times are GMT. The time now is 05:31 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