The Advantages of Floor Coupled Up-Firing Speakers - Page 213 - 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 13th March 2013, 11:52 AM   #2121
graaf is offline graaf  Poland
diyAudio Member
 
graaf's Avatar
 
Join Date: Jun 2007
Quote:
Originally Posted by Elias View Post
None of those links describe the frequency range of the floor reflection that affects the distance perception.
perhaps it is just the same range that generally affects spatial perception - 0.4<4.0 kHz

we don't know of course

but until we know I can't see any reason to exclude the lower midrange a priori
__________________
"high phooey and hystereo" - Yascha Heifetz
  Reply With Quote
Old 13th March 2013, 12:23 PM   #2122
Elias is offline Elias  Finland
diyAudio Member
 
Elias's Avatar
 
Join Date: May 2003
Location: Where you live
Quote:
Originally Posted by graaf View Post
perhaps it is just the same range that generally affects spatial perception - 0.4<4.0 kHz

we don't know of course
That is your assumption. I assume it happens above 1kHz
__________________
Liberate yourself from the illusion of two speaker stereo triangle
Dipole Bass vs Monopole Bass Stereophonic Sound from a Single Loudspeaker 3 Speaker Linear Stereo Matrix Wavelets
  Reply With Quote
Old 13th March 2013, 12:29 PM   #2123
graaf is offline graaf  Poland
diyAudio Member
 
graaf's Avatar
 
Join Date: Jun 2007
Quote:
Originally Posted by Elias View Post
That is your assumption. I assume it happens above 1kHz
that's ok let's call it hypothesis

I gave a foundation for my hypothesis - about 0.6 ms/20 cm, You remember?

So please give any for Yours
__________________
"high phooey and hystereo" - Yascha Heifetz

Last edited by graaf; 13th March 2013 at 12:44 PM.
  Reply With Quote
Old 13th March 2013, 01:37 PM   #2124
Rudolf is offline Rudolf  Germany
diyAudio Member
 
Rudolf's Avatar
 
Join Date: Mar 2003
Location: Germany
Quote:
Originally Posted by graaf View Post
I am trying to understand the results of Elias' test
Without any added data I only see a subjective description (can't be anything else). I don't dare to take any conclusions from that (and wouldn't call it "results" either).
Quote:
it is clear that with 400Hz low pass and also 700 Hz low pass the shifting effect is not that severe - perhaps because ....
just a hypothesis
I would support your argumentation
__________________
www.dipolplus.de
  Reply With Quote
Old 13th March 2013, 01:55 PM   #2125
Banned
 
Join Date: May 2008
Location: Switzerland
Rudolf, you got PM.
  Reply With Quote
Old 13th March 2013, 06:05 PM   #2126
ScottG is offline ScottG  United States
diyAudio Member
 
Join Date: Feb 2003
Location: US
Quote:
Originally Posted by graaf View Post
Are You sure?

Isn't it that for a reflection of a wave to occur the reflecting surface must be no closer than a quarter of a wavelength from a sound source?
What you are describing is a resonant condition - and usually that doesn't happen for a discreet freq.. Now increase that to a pass-band and yes, there could be a *reflective* interference that would change intensity somewhere along the pass-band. An extreme example of this would be an un-damped transmission line (with "peaks" and "depressions" in intensity along the pass-band).
__________________
perspective is everything
  Reply With Quote
Old 13th March 2013, 06:30 PM   #2127
graaf is offline graaf  Poland
diyAudio Member
 
graaf's Avatar
 
Join Date: Jun 2007
Quote:
Originally Posted by ScottG View Post
What you are describing is a resonant condition - and usually that doesn't happen for a discreet freq.
but a standing wave between two walls happens at a discreet frequency, doesn't it? And it is simply a reflective condition not just "a *reflective*"
__________________
"high phooey and hystereo" - Yascha Heifetz
  Reply With Quote
Old 13th March 2013, 07:18 PM   #2128
Elias is offline Elias  Finland
diyAudio Member
 
Elias's Avatar
 
Join Date: May 2003
Location: Where you live
Quote:
Originally Posted by lolo View Post
Obviously one is missing, no floor, no ceiling pads. silly me.
I see So without any absorption the first reflection is something like -3dB ?
__________________
Liberate yourself from the illusion of two speaker stereo triangle
Dipole Bass vs Monopole Bass Stereophonic Sound from a Single Loudspeaker 3 Speaker Linear Stereo Matrix Wavelets
  Reply With Quote
Old 13th March 2013, 09:08 PM   #2129
ScottG is offline ScottG  United States
diyAudio Member
 
Join Date: Feb 2003
Location: US
Quote:
Originally Posted by graaf View Post
but a standing wave between two walls happens at a discreet frequency, doesn't it? And it is simply a reflective condition not just "a *reflective*"

Typically not - and least not in relation to a discreet freq.. (..most conditions are simply to complex. That's not to say that there might not be some interference to that wavelength - but that's a bit beyond my interest.)

The point is that it's not really a Reflection.



In any event, we a getting a bit "far a-field" here.

Getting back to a timing que from a more empirical perspective - lets look at the condition for an echo, and derivatives from there..

An echo is a reflection, and an apparent one at that (..in other words a reflection that can be described as a separate source of sound). With that in mind, is a lower freq. echo more easily located at the earliest point (distance/time) that it becomes an echo/(apparent) - or at some multiple of that distance/time?

Now consider a low freq. reflection that doesn't have the distance/time to become an echo (or apparent). Under this condition we have the precedence effect - the direct sound dominates and you get a single localized cue. Of course IF the reflection is sufficiently intense you'll get an alteration to that localization effectively moving the source location a bit closer to the point of the reflection. (..note: this can and does happen in rooms at freq.s below 400 Hz - even in a stereo reproduction context: ex. "pushing" images forward like drum-kits and foreshortening depth as the rear of the loudspeaker gets closer to the "front" wall.) With this in mind, will a closer low freq. reflection have more or less effect on a source's position?

With respect to distance/time and reflections - are the results similar?


Finally lets look at simply the onset of a lower freq.. (or a minute portion of that wavelength). Let's disregard the nature of a reflection vs. that of a resonance. Further, let's disregard the primary condition of the precedence effect.

Just looking at distance/time for our onset to a particular lower freq. wavelength, and factoring-in answers to the questions above, will a really near distance/time reflective condition to our wavelength have much effect?

(..Note: I'm not saying/suggesting the onset of the direct sound doesn't have effect, but rather will a very near distance/time reflective condition to that onset have a substantial effect?)
__________________
perspective is everything

Last edited by ScottG; 13th March 2013 at 09:22 PM.
  Reply With Quote
Old 14th March 2013, 10:33 AM   #2130
graaf is offline graaf  Poland
diyAudio Member
 
graaf's Avatar
 
Join Date: Jun 2007
Quote:
Originally Posted by ScottG View Post
I'm not saying/suggesting the onset of the direct sound doesn't have effect, but rather will a very near distance/time reflective condition to that onset have a substantial effect?
most probably not - not substantial - but also most probably highly depending on the program material

and I ask why not

because only if we know why we can say when it can happen and only the we can consciously take it into account in the loudspeaker design
__________________
"high phooey and hystereo" - Yascha Heifetz
  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
Using a diffuser cone for up-firing speakers tspringer99 Multi-Way 19 23rd July 2014 02:04 AM
Floor Standing Speakers. gurpreetsingh Full Range 11 12th June 2012 06:42 AM
side/ rear firing speakers Good/Bad? mcmahon48 Multi-Way 1 6th February 2009 12:28 PM
How far can the driver of a down-firing sub be from the floor? The Paulinator Subwoofers 11 16th May 2007 08:10 PM
Woofer: side firing pair vs front firing? tcpip Multi-Way 13 9th September 2005 02:13 PM


New To Site? Need Help?

All times are GMT. The time now is 05:23 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