Multi-driver, horizontal center speaker with TB-871? - Page 3 - 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 16th October 2004, 04:15 AM   #21
diyAudio Member
 
thomas997's Avatar
 
Join Date: Feb 2004
Location: Vancouver
I use two of the W4-657.


You could go for the W4-656 used in MarkMck's mods (and of course do his mods).
  Reply With Quote
Old 17th October 2004, 06:47 PM   #22
diyAudio Member
 
acenovelty's Avatar
 
Join Date: Aug 2004
Location: SF Bay Area
Quote:
Originally posted by Timn8ter
Well, that's one down. How about having one speaker above and one below the picture? I think I tried that once but it's been a while. I think the WAF factor was about zero which is why I abandoned it rather quicky.
Hello Timn8ter,
Not having the Wife Factor you speak about, (mine always wants more, bigger, higher fidelity), I built horizontal center channel speakers for above and below the monitor over 10 years ago. They are driven by an old Lexicon CP-3. Monitor is 36" wide, center channel speakers fill that space above and below. Bottom center channel is at your ear level, top center speaker is aimed downward to your ear level. Use a piece of string. Self built cabinet for monitor/speakers was designed around this idea.
According to all the experts, this is heresy. Granted I'm not an electronics engineer or an acoustics engineer. The single vertical center channel I started with just did not sound right to my ears.

The sound stage for the center channel is about 12 feet wide in my little room and stays locked on the screen no matter where you sit.
Volume control on the Leach amp that drives them allows me to tinker with the final output.
I'm a happy camper.

Prosit
  Reply With Quote
Old 18th October 2004, 05:01 PM   #23
morbo is offline morbo  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Guelph, Ontario
Out of curiosity, has anyone actually built a bessel array center as described on this thread, that is an array of 5 drivers wired in the bessel arrangement? If so, can you tell us how far away you needed to be for the 'effect' to work?
  Reply With Quote
Old 18th October 2004, 05:11 PM   #24
diyAudio Member
 
Timn8ter's Avatar
 
Join Date: Jul 2003
Location: Seattle, WA
Quote:
Originally posted by acenovelty


Hello Timn8ter,
Not having the Wife Factor you speak about, (mine always wants more, bigger, higher fidelity), I built horizontal center channel speakers for above and below the monitor over 10 years ago. They are driven by an old Lexicon CP-3. Monitor is 36" wide,
The WAF came into play because we have a 65" rear projector so the lower speaker had to sit in front of the console. I'm glad to hear positive results and will keep that in mind when I trade up to the front projector. Thanks.
  Reply With Quote
Old 18th October 2004, 05:29 PM   #25
diyAudio Member
 
Join Date: Apr 2004
Location: Costa Rica
Send a message via AIM to johninCR Send a message via MSN to johninCR Send a message via Yahoo to johninCR
When I was experimenting with bessels I played with the 5 and 7 unit arrays, but mostly the 7 because the middle space was 0 power and perfect for a tweeter. I dropped it because an array pair had zero imaging, just a wall of sound from between the speakers. I don't recall any big difference in SQ related to distance, but I didn't really do any nearfield critical listening.

The wiring posted earlier was just from memory. I was about 6 months ago and the link I had doesn't work any more. I'm certain there was 1 ea of the -2 and -1, but I'm not certain if the -1 was on the end or the driver next to the end.

The bessel "effect" is related to dispersion outside of the plane of the array and it does work even in the very near field.

The old link I had was to a copy of a page from Don & Carolyn Davis's book "Sound System Engineering" which included wiring configurations for a number of different bessel arrays, so if anyone has this book, please post a copy of that page.
__________________
Everyone has a photographic memory. It's just that most are out of film.
  Reply With Quote
Old 18th October 2004, 05:47 PM   #26
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally posted by johninCR
Don & Carolyn Davis's book "Sound System Engineering"
This book has a very good description and formulas for deriving any size array. Attached are an extract from the above that describes 5 & 7 (really 6) driver arrarys.

dave
Attached Images
File Type: gif bessel5n7-wiring.gif (8.8 KB, 212 views)
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 18th October 2004, 05:51 PM   #27
morbo is offline morbo  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Guelph, Ontario
Quote:
The bessel "effect" is related to dispersion outside of the plane of the array and it does work even in the very near field.
Thats interesting... I have read in several places from fairly well respected people that the Bessell array only sounds like a point source from a great distance away. The only quote I could find offhand is from the LDSG:

Quote:
One final note: Sooner or later, many people's research into arrays leads them to Bessel arrays. A Bessel array is a specially wired vertical array whose apparent vertical size varies with frequency, thereby avoiding the ragged vertical polar response of a normal vertical array. This appears to be an attractive design. However, most references to Bessel arrays fail to mention that they're only effective at listening distances equal to, or greater than, approximately ten times the array length. This makes them unsuitable for most home application, although they're used to good effect in many stage and professional systems. For more information, a good source is the Meyer Sound web site.
However I have seen Jim Griffin and others mention this as well. I hope you're right, as it would be ideal for my application.
  Reply With Quote
Old 18th October 2004, 05:55 PM   #28
diyAudio Member
 
Join Date: Apr 2004
Location: Costa Rica
Send a message via AIM to johninCR Send a message via MSN to johninCR Send a message via Yahoo to johninCR
Thanks Dave, this time I saved a copy.
__________________
Everyone has a photographic memory. It's just that most are out of film.
  Reply With Quote
Old 18th October 2004, 06:55 PM   #29
diyAudio Member
 
Join Date: Apr 2004
Location: Costa Rica
Send a message via AIM to johninCR Send a message via MSN to johninCR Send a message via Yahoo to johninCR
Quote:
Originally posted by morbo


Thats interesting... I have read in several places from fairly well respected people that the Bessell array only sounds like a point source from a great distance away. The only quote I could find offhand is from the LDSG:

However I have seen Jim Griffin and others mention this as well. I hope you're right, as it would be ideal for my application.
My testing was pretty crude. I was using vertical arrays and even at distances less than 1 meter the dispersion was totally different than with a normal array. With a normal array, the line of the plane is very clear and once above it the SPL reduction is very very significant. With the bessel, this clear line doesn't exist. I think this may be another case where the theory conflicts with the real world in small rooms and short arrays, because I find that issues of lobing, near field/far field transition, etc aren't very significant for in-home arrays.

Another alternative would be a normally wire array but on a convex baffle to give you good horizontal dispersion. That way you would also get the full sensitivity increase of multiple drivers. You may want to look at JBL's papers for J and Spiral arrays.
__________________
Everyone has a photographic memory. It's just that most are out of film.
  Reply With Quote
Old 18th October 2004, 07:06 PM   #30
morbo is offline morbo  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Guelph, Ontario
Quote:
You may want to look at JBL's papers are J and Spiral arrays.
Thanks for the reference, I'll have a look at these.
  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
Horizontal MTM Center channel: avoiding off-axis nulls DcibeL Multi-Way 27 10th October 2009 05:57 PM
Vertical/Horizontal 2 x JXR6 Linear Array as central speaker ? fvaille Full Range 6 11th January 2009 10:20 PM
horizontal digital media center blue934 Parts 3 12th August 2008 02:54 PM
Horizontal speaker alignment - 2way, 2.5way fb Multi-Way 2 11th August 2008 09:12 PM
Multi driver TLs mashaffer Subwoofers 9 8th August 2006 01:21 AM


New To Site? Need Help?

All times are GMT. The time now is 01:50 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