EnABL - Technical discussion - Page 14 - 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 24th March 2008, 02:33 PM   #131
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
Quote:
Originally posted by john k...
The rings don't do S*%$, nada, nothing, zero, squat, good or bad.
My browser must have the wrong encoding, because I see funny characters.

__________________
Hear the real thing!
  Reply With Quote
Old 24th March 2008, 03:19 PM   #132
diyAudio Member
 
auplater's Avatar
 
Join Date: Apr 2005
Location: KyOhWVa tristate
Default Protocol

In the interest of maybe helping those testing...

Here is a simplistic 4 person test protocol

4 people to determine if EnABL'ing makes a difference by listening

Two possible outcomes

- makes a difference (+) (reject null hypothesis, makes a difference)

- Does not make a difference (-) (do not reject the null hypothesis, no difference)

Sixteen possible results

++++ +++- +--+ --+-
-+++ --++ +-+- -+--
+-++ -+-+ ++-- +---
++-+ -++- ---+ ----

If you set the criteria that the only result acceptable as significant is all respondents report hearing a difference, then only the ++++ result is accepted.

Using this, the probability of an alpha error (rejecting the null, false positive) would be .0625

So, with 4 test subjects using all reporting hearing a difference as a criteria, there is a 1 in 16 chance of saying there is a difference when in fact there is no difference.

John L.
__________________
"...His brain is squirming like a toad..." Jim Morrison
  Reply With Quote
Old 24th March 2008, 03:39 PM   #133
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Default A little more baffle...

Here is an additional measurement. This time, same MG10 driver in same 23" x 25" baffle with same 8 1/2" ring, 1/8" wide, 0.0035" high. But now the mic is flush mounted in the baffle 1" outside the ring. That is, the mic is measuring the impulse associated with the surface acoustic wave as it propagates across the baffle surface. One addition, I also measured the result for a 1/8" wide x 1/8" high ring made of Mortite.

Click the image to open in full size.

White and orange are with and without the Enable like ring. Dark blue is with the Mortite ring. Again, the scale is linear blown up by a factor of 100 vertically. The top of the plot corresponded to -40dB relative to the initial impulse peak. Note that the white and orange are just about identical. No changes greater than approximately -60dB and that may well be in the noise. Also note that the 1/8" high Mortite ring doesn't even have drastic effects. Enable like rings do not effect the wave propagation over the surface in any audible manner. There are no “BL” effects.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 24th March 2008, 03:56 PM   #134
dlr is offline dlr  United States
diyAudio Member
 
Join Date: Mar 2005
Location: Canton, MA
Default Re: A little more baffle...

Quote:
Originally posted by john k...

White and orange are with and without the Enable like ring. Dark blue is with the Mortite ring. Again, the scale is linear blown up by a factor of 100 vertically. The top of the plot corresponded to -40dB relative to the initial impulse peak. Note that the white and orange are just about identical. No changes greater than approximately -60dB and that may well be in the noise. Also note that the 1/8" high Mortite ring doesn't even have drastic effects. Enable like rings do not effect the wave propagation over the surface in any audible manner. There are not “BL” effects.
One of my tests years ago used the hemispherical, plastic, self-stick feet, ones 1/4" and 1/2" diameter at the base. I put them all along the edge of the baffle and also in two successive circular patterns around a tweeter. I gave up that approach when it provided no significant change in the diffraction other than the double circular one making things worse due to close proximity to the tweeter.

I think I still have those measurement files from back around 2001-2002. If I find the files, I'll post them.

Good work, John.

Dave
  Reply With Quote
Old 24th March 2008, 04:01 PM   #135
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Default Re: Re: Baffle diffraction

Quote:
Originally posted by Alex from Oz
G'day john k,

There are a couple of points of difference with what you have tested and my application of EnABL to baffles:
- for a baffle of 23" x 25" I would be using a block size of 1" x 1/2"
- the EnABL pattern would be applied 1/2" in from the edge of the baffle

Cheers,

Alex
I don't think anyone here would argure thaty 1" x 1/2" block of what ever material you are using would have an effect. I certainly never would. But I'd would not place that in the catagory of an Enable process, unless by Enable it is meant any adhoc baffle, port, driver treatment... that migh alter something.

But the idea that a 0.0035" tall application of paint to anything (Baffle, port, cone, dome or a tweeter) will have any effect at all on the surface wave in the audible frequency range,that is in any way audible is rediculous. Let's put this nonsense about BLs etc to rest once and for all. Applied to a driver it is all the effect of the altered cone properties/vibration and resulting alteration in frequency response, and perhaps, changes in directivity at higher frequencies.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 24th March 2008, 05:12 PM   #136
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
I suspect there might not even be any baffle edge diffraction problem using this driver.
__________________
Hear the real thing!
  Reply With Quote
Old 24th March 2008, 05:26 PM   #137
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Default Re: A little more baffle...

Quote:
Originally posted by john k...
Click the image to open in full size.


Quote:
Originally posted by soongsc
I suspect there might not even be any baffle edge diffraction problem using this driver.

I'm assuming that comment is directed at my result? If so, look at the plot above from my previous post. It is the impulse response measued on the baffle surface. When it gets to the edge it WILL be diffracted, in all cases.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 24th March 2008, 05:39 PM   #138
diyAudio Member
 
auplater's Avatar
 
Join Date: Apr 2005
Location: KyOhWVa tristate
Default Belief and interpretations

Quote:
Originally posted by soongsc
I suspect there might not even be any baffle edge diffraction problem using this driver.
Seems to me there are certain belief systems evidently occurring here that are not going to accept factual data unless supportive of the presumptive improvements being touted.

No amount of empirical data will be deemed adequate to sway such beliefs. That's too bad.

John K.'s data looks pretty definitive.

John L.
__________________
"...His brain is squirming like a toad..." Jim Morrison
  Reply With Quote
Old 24th March 2008, 06:30 PM   #139
Carlp is offline Carlp  United States
diyAudio Member
 
Join Date: May 2006
Location: A New England
John K,

Thanks for the plots. Interesting, and given your application and method, sure doesn't look like an effect as far as my limited understanding of this stuff. I'll continue to listen to the discussion.


Quote:
quote:
Originally posted by Carlp

Here, here. And since we can't speculate on whether or not there is even anything to measure, and theory says virtually nothing will happen, and data we've seen so far says almost nothing happens, this thread will now be closed for lack of anything to talk about...

Carl

No skeptic of the mechanism, not one, has ever said nothing will happen. You're being disingenuous. But your suggestion of what to do is actually closer to the truth than anything else in any of the threads.
Dave, not really disingenuous - more like cheeky, trying to bring some levity. Note the smilie wink! Plus, I didn't say anyone said NOTHING happens, just virtually nothing (relative to audibility), but maybe I've misunderstood what some people are saying. Is everyone saying there IS or COULD BE a dramatic change due to EnABL?

Carl
  Reply With Quote
Old 24th March 2008, 06:37 PM   #140
Carlp is offline Carlp  United States
diyAudio Member
 
Join Date: May 2006
Location: A New England
Quote:
Seems to me there are certain belief systems evidently occurring here that are not going to accept factual data unless supportive of the presumptive improvements being touted.
John L,

I don't really hear anyone saying that Boundary Layer IS the mechanism. All I hear is that some are claiming that they hear a difference, even with it applied to baffles. I certainly don't know where to go next with this, but either you think those hearing a difference with baffle treatment are hallucinating and thus there's nothing more to add to that discussion (and at least relative to John K's plots, that looks true), or you believe they are hearing something and you then have to look at where to look for an explanation. I am interested in Soongc's questions though.

Carl
  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



New To Site? Need Help?

All times are GMT. The time now is 10:18 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