EnABL - Technical discussion

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#621
soongsc said:

Prior to the cone vibration module was formally announced, I did put in a wish for one to be able to view the wave front resulting from cone vibration. Don't know whether it will get in there or not. But from the paper, it seems they are possibly looking into it. 🙂

The journey is just as valuable as the result. But we won't have anything to talk about unless you also have something to show. Well, maybe if you pickup the airfare bill...😀
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There's nothing more on FEA worth discussing in this thread. There is no FEA available to anyone here of any relevance, none with any predictive accuracy. If you want to diverge to discuss FEA, I suggest starting another thread. There's nothing but more "if this if that" possible here. But have at it, I'll wait to see if you or anyone else provides any reliable FEA results.

Dave
 
#622
dlr said:


There's nothing more on FEA worth discussing in this thread. There is no FEA available to anyone here of any relevance, none with any predictive accuracy. If you want to diverge to discuss FEA, I suggest starting another thread. There's nothing but more "if this if that" possible here. But have at it, I'll wait to see if you or anyone else provides any reliable FEA results.

Dave
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Is this not good enough?

http://www.caelinux.com/CMS/
 
#623
dlr said:


You missed the point in Klippel's paper altogether. Any bell mode alteration (why assume suppression, why not the more likely addition?) will be inconsequential to the acoustic output of drivers with the enabl tweak.

...
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While not conclusive, it seems we have not been able to find any bell modes that stands out alone, they seem always accompanied by radial modes. Where cone breakup occurs, the bell mode is pretty much non-existent. So it seems that to some extent, the bell modes will help damp the radial modes out if they occur at very close frequencies. It would be interesting to see what would happen of the bell modes were intentionally suppressed.
 
#625
soongsc said:
I thought I'd post this link because it seems quite in line with analysis trend, and explains a few things quite well.
http://www.kettering.edu/~drussell/Demos/MembraneCircle/Circle.html
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The modes in a driver cone have a similar trend. The main difference is that the drum's edge is fixed, whereas the cone's edge is kind of free moving with it's connection to the surround. In the case of the cone, the combination of the bell and radial modes have the most excursion at the outer edge. What the EnABL process seems to be doing is that it breaks up the bell modes close to the outer edge, and the bell modes on the enner side of the pattern seems reduced in amplitude. If you play with the patterns right, there can abe an optimum layout, mass, stiffness combination. The number of patterns relate with the frequency range you are dealing with for a specific cone material. Current pattern seems to handle more or less in the frequency range above 10KHz.
 
#626
After looking at some more analysis, it seems that when the bell modes are reduced, the radial modes are more pronounced, and seem to occur in a lower frequency range. This could be the reason we see a change in CSD distribution with more narrow ridges similar to those measured via CLIO some one posted a while ago.

This part of the analysis using the EnABL pattern was just out of curiousitywhat we will find.
 
#627
dlr said:


You missed the point in Klippel's paper altogether.
Any bell mode alteration (why assume suppression, why not the more likely addition?)
will be inconsequential to the acoustic output of drivers with the enabl tweak.

Dave
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Hi,

Does this not imply that if cone energy can be transferred to bell
modes and disappated that way output will audibly improve as
Klippel's paper implies bell modes do not contribute to output ?

🙂/sreten.
 
#628
sreten said:


Hi,

Does this not imply that if cone energy can be transferred to bell
modes and disappated that way output will audibly improve as
Klippel's paper implies bell modes do not contribute to output ?

🙂/sreten.
Click to expand...
Actually, this is what my patent pending design does. But since this is an EnABL thread, I focus on EnABL discussion and potential.

In reality, bell modes still contribute to some output because of the shape of the cone.
 
#633
Pretty sure they will cause some similar effects. I don't know that indent or "outdent" on one side or the other is important. Disruption of non linear emissions is the goal and I suspect these drivers are clearer with, rather than without. They certainly did not go to the cost of tooling a restrike press to create these because they made no difference in audible performance, or actually sounded worse.

Bud
 
#636
Alex from Oz said:
G'day Carl,

These drivers have not been treated using Bud's EnABL process.
The pattern is not even close to what Bud describes.
I don't think that posting a listening impression on that particular thread would be helpful.

Cheers,

Alex
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Hi,

Completely agree, they are something else altogether.

The indents will affect the termination (mainly bounce back into)
of the tranverse waves within the cone meeting the surround.

Any alleged effects of the indents on the alleged boundary layer
alleged surface wave would be allegations and inseperable in any
subjective impression from the more obvious effects of the indents.

🙂/sreten.
 
#639
Alex from Oz said:
G'day Daygloworange,

Were you able to arrange measurements of EnABL?

I was really keen to see what might come of this.

Cheers,

Alex
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There have been a set of tests done by Danny Richie from GR Research. Although there were no control measurements done on the actual drivers tested prior to EnABL, there is data there that is worth looking at.
http://www.audiocircle.com/circles/index.php?topic=59575.0
I don't know where Al Wooley from RAW Acoustics ended up with his testing. RAW Acoustics have decided to close their doors to the speaker business, so I don't know if their measurements will ever see the light of day.
Originally posted by sreten
Completely agree, they are something else altogether.
Alex
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Those indents around the outer edge of the cone will have a similar effect to bead rolling in sheetmetal. It will stiffen the outer perimeter of the cone close to where it meets the surround.

There is no way painting a series of dashes around the outer edge of a speaker cone will compare to beading the actual cone material.

Cheers
 
#640
Daygloworange said:



There have been a set of tests done by Danny Richie from GR Research. Although there were no control measurements done on the actual drivers tested prior to EnABL, there is data there that is worth looking at.
http://www.audiocircle.com/circles/index.php?topic=59575.0
I don't know where Al Wooley from RAW Acoustics ended up with his testing. RAW Acoustics have decided to close their doors to the speaker business, so I don't know if their measurements will ever see the light of day.


Those indents around the outer edge of the cone will have a similar effect to bead rolling in sheetmetal. It will stiffen the outer perimeter of the cone close to where it meets the surround.

There is no way painting a series of dashes around the outer edge of a speaker cone will compare to beading the actual cone material.

Cheers
Click to expand...


Yes as Denny made note of on Jan 1,09 i closed RAW Acoustics.

AS for the testing I never got into the detailed relay of drivers with Dave D and Bud.I do have the drivers which were to be tested.Before mods then after mods. Dave D will get them on his next trip over to the mainland😉

Without doing a full round of data tests before mods after mods taken several different time frames not just one time this really will never go away. Friend or FOE it will take several hours of testing and I do not see anyone or company who will step forward do the testing, just to make BUD and DAVE more money.😉
 
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