Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Floor-to-ceiling array vs CBT
Floor-to-ceiling array vs CBT
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 2013, 03:35 PM   #11
Budgie is offline Budgie  United States
diyAudio Member
 
Join Date: Jan 2003
Location: Not were I'm suppose to be......
I am very happy with the performance of my floor to ceiling line array, but I haven't listened to a CBT array yet. I believe the CBT design ignores the problem of ceiling reflections, were a full line does not.
  Reply With Quote
Old 10th October 2013, 04:02 PM   #12
Generic George is offline Generic George  United States
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by Budgie View Post
I am very happy with the performance of my floor to ceiling line array, but I haven't listened to a CBT array yet. I believe the CBT design ignores the problem of ceiling reflections, were a full line does not.
Actually if I understand things correctly (and I may not), it makes better use of them and is part of the reason for the characteristic curve and the power shading on the drivers as they curve. They aren't designed like they are simply because of someone's pet hobby horse as to what makes for good sound reproduction, there does appear to be quite a bit of research and experimentation behind them.

http://www.parts-express.com/cbt36/#
Quote:
Originally Posted by PartsExpress
Specifically Designed to Eliminate the Detrimental Effects of Floor Reflections

The CBT36 has been specifically designed to operate over a reflective ground plane and does not suffer from destructive floor-bounce effects. The curved line array of 72 tweeters extends all the way down to the floor to take advantage of the ground-plane acoustic reflection. Effectively the floor provides a reflective surface that acoustically extends the array below floor level and thus creates an array that is over 10 feet tall and controls vertical coverage and directivity down to below 160 Hz!

The Vertical and Horizontal Coverage of the CBT36 Greatly Reduces Ceiling and Wall Reflections

The above-the-floor vertical coverage of the CBT36 is a narrow 28° which is extremely stable with frequency. This greatly reduces ceiling reflections as compared to a typical box style system. In addition, the horizontal coverage which is very broad narrows as you go around the side of the system, which also significantly minimizes side wall reflections.

Last edited by Generic George; 10th October 2013 at 04:05 PM.
  Reply With Quote
Old 10th October 2013, 05:33 PM   #13
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
A domestic line array or cbt speakers concentrate on vertical directivity but mostly they completely disregard the principles of even horizontal directivity! I simply just don't like the hype around them... First of all, we have our ears placed horizontally for stereophonic localization, we walk - don't fly etc.

Here is horizontal 0¤ vs 30¤ of the Selah Audio CBT lindked above. 6dB dip around 2kHz at 30¤ is really really bad! And the speaker is not symmetrical - I suppose this is the better side!

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


It would be so simple to make these better, it is so hard for me to understand this dilemma. But I don't want this kind of poles in my room... I just keep on nagging about this
__________________
AINOgradient speaker project

Last edited by Juhazi; 10th October 2013 at 05:47 PM.
  Reply With Quote
Old 10th October 2013, 06:34 PM   #14
Generic George is offline Generic George  United States
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by Juhazi View Post
A domestic line array or cbt speakers concentrate on vertical directivity but mostly they completely disregard the principles of even horizontal directivity! I simply just don't like the hype around them... First of all, we have our ears placed horizontally for stereophonic localization, we walk - don't fly etc.

Here is horizontal 0¤ vs 30¤ of the Selah Audio CBT lindked above. 6dB dip around 2kHz at 30¤ is really really bad! And the speaker is not symmetrical - I suppose this is the better side!

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


It would be so simple to make these better, it is so hard for me to understand this dilemma. But I don't want this kind of poles in my room... I just keep on nagging about this
Speakers are inherently flawed devices and that's even before you drop them into a room which is never designed with audio reproduction in mind (Would you want to live in an anechoic chamber?). There are going to be trade offs, compromises, advantages and disadvantages to any set up no matter how much money you spend or how they are designed.

How is it you think they could be made better?
  Reply With Quote
Old 10th October 2013, 06:59 PM   #15
Budgie is offline Budgie  United States
diyAudio Member
 
Join Date: Jan 2003
Location: Not were I'm suppose to be......
What speaker has "even horizontal directivity!"? And at what frequencies? Don't all speakers will become directional at some point, and many highly regarded speakers have narrow radiation patterns, both vertically and horizontally. Electrostatics and planers for example.

Last edited by Budgie; 10th October 2013 at 07:05 PM.
  Reply With Quote
Old 10th October 2013, 07:08 PM   #16
Generic George is offline Generic George  United States
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by Budgie View Post
What speaker has "even horizontal directivity!"?
Well at least according to the marketing information the CBTs are. Have you read any of the technical papers on them?

I believe the SEOS/Gedde style speakers are supposed to as well.

Though they are certainly NOT going to appeal to anyone who cares about how the speaker looks.

This is out of my area of expertise though.
  Reply With Quote
Old 10th October 2013, 10:59 PM   #17
jeno is offline jeno  Norway
diyAudio Member
 
Join Date: Apr 2006
Location: Way up north
The vertical problems are the same when placing drivers side by side whether it is a CBT or straight array. The trick is to get the crossover point as low as possible and the mids as close to the tweeter as possible. It can be done, but that's not the topic of this thread.

I am interested in vertical polars of a floor to ceiling line array. Does anyone have them?
  Reply With Quote
Old 11th October 2013, 12:40 AM   #18
dumptruck is offline dumptruck  United States
diyAudio Member
 
Join Date: May 2010
Location: MN
I'm not sure I've ever even seen a photograph of a true floor-to-ceiling array, now that I think about it, let alone polar measurements.
  Reply With Quote
Old 11th October 2013, 08:33 PM   #19
jeno is offline jeno  Norway
diyAudio Member
 
Join Date: Apr 2006
Location: Way up north
The full height line arrays may be more rare than I new. People talk about them from time to time, but it seems to be mostly theory.

Maybe I will make a quick and dirty prototype with cheap full rangers to have a look at the performance from the mid range and down. We know the upper range from straight arrays will be good from Keele's simulations. It would be interesting to see where in frequency vertical control is lost with an array coupled to a reflecting floor and ceiling, if it would be lost at all.
  Reply With Quote
Old 11th October 2013, 08:37 PM   #20
jeno is offline jeno  Norway
diyAudio Member
 
Join Date: Apr 2006
Location: Way up north
Quote:
Originally Posted by jeno View Post
The vertical problems are the same when placing drivers side by side whether it is a CBT or straight array. The trick is to get the crossover point as low as possible and the mids as close to the tweeter as possible. It can be done, but that's not the topic of this thread.

I am interested in vertical polars of a floor to ceiling line array. Does anyone have them?
I meant of course horizontal problems.
  Reply With Quote

Reply


Floor-to-ceiling array vs CBTHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Alpair 7 used for Keele CBT Array HiroPro Full Range 9 11th March 2016 11:25 AM
Building some CBT clones ... rhubarb9999 Multi-Way 26 11th September 2013 03:30 AM
Driver at floor level or ceiling?? Moondog55 Subwoofers 21 15th April 2012 12:34 PM
Floor to Ceiling ESL ? Borat Planars & Exotics 26 12th February 2010 01:11 AM
HOw close does driver need to be to floor to avoid floor bounce? Kanga Multi-Way 8 24th April 2003 06:09 AM


New To Site? Need Help?

All times are GMT. The time now is 09:38 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki