More rewarding speaker directivity pattern for in-room stereo listening - Page 2 - 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 31st May 2013, 04:43 PM   #11
diyAudio Member
 
Join Date: May 2010
Location: MN
Let's see a measurement where you set the gate to before those reflections (looks like around the 5.5ms point on the impulse posted).
  Reply With Quote
Old 31st May 2013, 06:36 PM   #12
PRTG is online now PRTG  Latvia
diyAudio Member
 
PRTG's Avatar
 
Join Date: Mar 2005
Location: Riga
Send a message via Skype™ to PRTG
Quote:
Originally Posted by Barleywater View Post
Are you measuring this in room described in #1
Yes. The gating applied to results is 10ms so room interaction with measurements must be significant.

But that's the whole point - if combined direct+reflected measurement follows desired power response according to suggested psycho-acoustical in-room correction, and my ear indeed finds it pleasant, then I see it as a good proof that that's how corrections should be done in general.
  Reply With Quote
Old 31st May 2013, 06:55 PM   #13
PRTG is online now PRTG  Latvia
diyAudio Member
 
PRTG's Avatar
 
Join Date: Mar 2005
Location: Riga
Send a message via Skype™ to PRTG
Quote:
Originally Posted by gedlee View Post
The problem is that when you open with a premise that goes against everything that I know it is really hard to take the rest serious. Stating that the speaker that you made yourself sounds great is such a classic foundation for an entirely erroneous discussion that no one is going to accept it.

Keep the discussion based in non-subjective facts and you might get somewhere. Lead off and follow through with subjectivism and all is doomed.
Dear Earl, with all my respect that's totally up to you. I included some measurements further on plus I don't think it goes "against", rather "along". Or I don't get which statement you mean exactly.

Most room related concepts are based on findings done in anechoic chamber or IEC 268-13 standard room (26' x 16' x 10') or both. Most of people live in smaller rooms and I believe that's a field that asks for more studies towards correction and optimal dispersion pattern of the loudspeakers. Based on my subjective perception I think I found the right direction but you're right that this fact alone doesn't prove it. That's why I looked for explanation and possibly found it in diffuse sound field correction suggested by Zwicker/Fastl. At least it looks reasonably similar to what I got by occasion.

Last edited by PRTG; 31st May 2013 at 07:10 PM.
  Reply With Quote
Old 31st May 2013, 07:09 PM   #14
PRTG is online now PRTG  Latvia
diyAudio Member
 
PRTG's Avatar
 
Join Date: Mar 2005
Location: Riga
Send a message via Skype™ to PRTG
Quote:
Originally Posted by dumptruck View Post
Let's see a measurement where you set the gate to before those reflections (looks like around the 5.5ms point on the impulse posted).
Unfortunately I don't have PIR files anymore just screenshots from analysis window. I'm going to redo them anyway. I believe applied gating on analysis window was 10ms.
  Reply With Quote
Old 31st May 2013, 08:46 PM   #15
PRTG is online now PRTG  Latvia
diyAudio Member
 
PRTG's Avatar
 
Join Date: Mar 2005
Location: Riga
Send a message via Skype™ to PRTG
Quote:
Originally Posted by 6.283 View Post
Hi Jānis,

I haven't read everything here yet. But you may find my suggestion about how to eq. wide dispersion speakers interesting (not sure if you have seen it before).

Interim Conclusions
Excellent, thanks! We came to the same observations but different ways.

"The effects are proportional to the volume setting" - are you sure about this? I guess with increase of reproduction volume (especially in smaller rooms) reflections could build up to be percieved to a larger degree than direct signal so more of attenuation can be required with increased volume.

"What correlation with the HF dip contributes to the sensation that makes you feel as if you are in a larger room" - I guess because high frequencies have faster DD (double-distance) decay rate compared to mids. It was mentioned in Toole's book. That's just how big rooms sound: HF reflections are attenuated as they lose their energy travelling long distances.
  Reply With Quote
Old 31st May 2013, 08:51 PM   #16
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007


When it's my turn ?

Oh sorry, I posted the explanation (pic) of my example on another thread
Floating speaker enclosures

Last edited by picowallspeaker; 31st May 2013 at 08:56 PM.
  Reply With Quote
Old 31st May 2013, 09:00 PM   #17
diyAudio Member
 
Lynn Olson's Avatar
 
Join Date: Jul 2004
Location: Northern Colorado
Without gating out the room reflections, you have no idea what the first-arrival (anechoic) response is, which makes crossover design impossible.

Set the left edge of the time window a bit to the left of the initial rise-time, and the right edge just before the first room reflection. That might only give you 3 mSec, which in turn only gives about 300~400 Hz frequency resolution, but that's good enough to see if the drivers are reasonably flat and if the crossover is flat.

The rule-of-thumb in crossover design is to use sharp enough slopes so that severe ripples are at least 15 to 20 dB below the average response level. Since this is a difficult requirement to meet without 24 dB/octave (or steeper) slopes, it's an incentive to use drivers that have smooth rolloff regions, at least for an octave above the intended crossover frequency.
  Reply With Quote
Old 31st May 2013, 09:06 PM   #18
PRTG is online now PRTG  Latvia
diyAudio Member
 
PRTG's Avatar
 
Join Date: Mar 2005
Location: Riga
Send a message via Skype™ to PRTG
Quote:
Originally Posted by picowallspeaker View Post


When it's my turn ?

Oh sorry, I posted the explanation (pic) of my example on another thread
Floating speaker enclosures
Sorry, I missed your initial post. Thanks for suggestion! I don't think it is related to vibrations, and foam layers I used provides a certain degree of decoupling.
  Reply With Quote
Old 31st May 2013, 09:17 PM   #19
PRTG is online now PRTG  Latvia
diyAudio Member
 
PRTG's Avatar
 
Join Date: Mar 2005
Location: Riga
Send a message via Skype™ to PRTG
Quote:
Originally Posted by Lynn Olson View Post
Without gating out the room reflections, you have no idea what the first-arrival (anechoic) response is, which makes crossover design impossible.

Set the left edge of the time window a bit to the left of the initial rise-time, and the right edge just before the first room reflection. That might only give you 3 mSec, which in turn only gives about 300~400 Hz frequency resolution, but that's good enough to see if the drivers are reasonably flat and if the crossover is flat.

The rule-of-thumb in crossover design is to use sharp enough slopes so that severe ripples are at least 15 to 20 dB below the average response level. Since this is a difficult requirement to meet without 24 dB/octave (or steeper) slopes, it's an incentive to use drivers that have smooth rolloff regions, at least for an octave above the intended crossover frequency.
Right. Still I like to use 1-st order if possible for its excellent transient response and lack of ripple at crossover point. Unfortunately there aren't many midbass units around that doesn't exhibit sharp peaks on upper midrange. I was lucky to get these old paper units. Here is one of them measured alone with whizz cone still in place, then removed, and then improvised phase plug added. Green line is where I stopped tweakings.
Attached Images
File Type: jpg 03_1_4gd32A_risinam_problemas_virs_6k_mehaniski.jpg (130.8 KB, 258 views)
  Reply With Quote
Old 31st May 2013, 09:39 PM   #20
diyAudio Member
 
Join Date: May 2010
Location: MN
That's another measurement you need to be gating properly, like Lynn is describing. Thinking about in-room sound and measuring it is all well and good, but you need to measure the direct output without reflected sound to do the sorts of things you're posting about, like finding flaws in the crossover and messing with phase plugs.

Last edited by dumptruck; 31st May 2013 at 09:41 PM.
  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
What is the ideal directivity pattern for stereo speakers? keyser Multi-Way 2645 16th April 2014 01:26 PM
Black Hole in your listening room; room treatment dfidler Everything Else 5 29th March 2011 12:02 AM
I need a soft (for location speaker stereo) in a room mati1979 Software Tools 1 7th November 2009 08:19 AM
Driver pattern, directivity and other confusing issues mefistofelez Multi-Way 2 19th January 2006 03:56 AM


New To Site? Need Help?

All times are GMT. The time now is 10:43 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