In regards to felt pads, I've done a number of experiments with felt applications in developing my four omni projects, for various reasons. I took measurements to see the results and this is what I have concluded. It may be common knowledge to experienced DIYers, but might not be to others less experienced.
There is no question that felt has an effect on baffle edge induced diffraction effects. It is easily measured. However, like any application, it can't be done without consideration of what will impacted and at what frequency. For example, felt I added to my recent project, on the baffle edges next to the mid driver did nothing in the passband, but attenuated the break-ups somewhat in the stopband, due simply to the distance from the driver to the felt and therefore the wavelength affected. In my case, the felt was starting at about 2" from the center of the 3” cone and is about 1" wide. It showed up in the FR to have an effect only in the 5000-7000hz or so range, which have wavelengths of between 2 and 3” or so.
I guess what I'm saying is, putting at the baffle edges will have an effect, but that effect depends entirely on the distance from the driver to the edge of the felt application and the width and height of the felt. I tried some EnABL-like applications and did not find them to offer any benefit over felt applied in a standard manner. Also, if you are not careful in respect to these distances and the frequencies affected, you can have a detrimental effect at unexpected frequencies. Willy nilly application of felt is not advisable, IMO.
I hope this is helpful, though maybe off topic a bit.
There is no question that felt has an effect on baffle edge induced diffraction effects. It is easily measured. However, like any application, it can't be done without consideration of what will impacted and at what frequency. For example, felt I added to my recent project, on the baffle edges next to the mid driver did nothing in the passband, but attenuated the break-ups somewhat in the stopband, due simply to the distance from the driver to the felt and therefore the wavelength affected. In my case, the felt was starting at about 2" from the center of the 3” cone and is about 1" wide. It showed up in the FR to have an effect only in the 5000-7000hz or so range, which have wavelengths of between 2 and 3” or so.
I guess what I'm saying is, putting at the baffle edges will have an effect, but that effect depends entirely on the distance from the driver to the edge of the felt application and the width and height of the felt. I tried some EnABL-like applications and did not find them to offer any benefit over felt applied in a standard manner. Also, if you are not careful in respect to these distances and the frequencies affected, you can have a detrimental effect at unexpected frequencies. Willy nilly application of felt is not advisable, IMO.
I hope this is helpful, though maybe off topic a bit.
"... didn't hear any difference with or without the dot but wanted to try and reduce how excited this driver becomes. A dot of rope caulk on the dustcap made piano sound smaller... felt seems to have little or no effect but looks cute)."
http://www.zillaspeak.com/ZillaSpeakFostex103-RS1197A.asp
I knew i tried Moretite on a driver once! It did change the sound but i was not happy with the change.
http://www.zillaspeak.com/ZillaSpeakFostex103-RS1197A.asp
I knew i tried Moretite on a driver once! It did change the sound but i was not happy with the change.
Godzilla said:
This may be expected as a consequence of not verifying the change that any mod to a diaphragm is actually making. Every driver type is unique and reacts differently. Every mod makes a different change, for better or worse. Blindly modifying a driver is extremely problematic. There are no guarantees on any mod to any driver.
I spent a large part of this weekend modding a small driver in a 2-way. I had just set it up to check it out when john k posted his measurements. I had some of what is either Mortite or similar removed from a box with drivers given to me some time ago, used to seal the drivers. So I made some tests of my own, a bit more goal oriented than john, I think, as my intent was also to find the best improvement that I could determine.
I'm working on a lengthy page of measurements and pictures already done and in the computer, but it's going to take a while to do the writeup. I planned to wait until it was complete, but I can show you one set of curves that demonstrates how much variability there usually is with added mass distributed on the diaphragm. The best result will be shown at the end and will surprise many here. It did me.
This is a series of measurements with distributed mass added in deliberate patterns varied on the diaphragm in an organized progressive manner. The changes are dramatic, to say the least. Note that the yellow is the curve with the distributed mass closest to the surround. They all include my first driver mod not related to the added mass.
You cannot add mass anywhere without that mass altering the driver due to the mass alone. Another interesting observation is that in general, when the distributed mass is near to the surround, the low frequency response is barely altered at all. The same distributed mass, moved closer and closer to the former, causes some decreasing sensitivity throughout the whole passband. This for a nominally stiff PP cone. One conclusion is that T/S measurements will not be affected identically for the same mass added, with the possible exception of the stiffest diaphragms. There are others that I will detail in the completed page. I've just started it at this point.
I may run this same series of tests (likely, in fact) on a hard-coned diaphragm to document the differences.
Dave
auplater said:
That you are talking here about Ron Clarke is really quite weird... of all the engineers here, Ron is an engineer's engineer. If it isn't based on real physics it isn't real to Ron.
Ron has seen something in his sims that indicates to him that there is something happening here that is real, is simple, and can be explained. And now that Ron has seen this in the sim, he ihas vollenteered to make the effort, and use his bosses resources to verify what the sim is showing. You will need to be patient, this can't happen overnight. (Canada Post will take 2-3 weeks to just get him the EnABLed drivers)
Ron tends not to be verbose (he doesn't have time). You need to take what he has said and use some imagination to fill things in, as my math professor would say as an exercise... i have no worries about the veracity of the sim Ron uses... we are talking about a serious piece of software here...
dave
An externally hosted image should be here but it was not working when we last tested it.
Sort of looks like it, doesn't it?
I thought you folded in post #2006? You continue to bluff? We don't get to analyse this "energy"? Wow, what a surprise
I never bluff,
Problem is i am using my companies money/manpower to accomplish a study that thay may see as not being profit oriented.
They look upon my group this way, if we cant realize increased profits/productivity/savings then why are we paying for it. I have to account for everyones time and application and every week/day report on expenses and status of assigned projects.
I was trying to hide the expenses under a study on ultrasonic responses of carbon/magnesium migration (segregration) in CS cast slabs and the change in acoustical impedance (Z) at a compressed interface that returns a false signal that rejects an acceptable ,usable plate that passes thru thickness tensile testing. There is many many millions of dollars that are in question and dependant on my findings and solutions. Want to talk pressure?
Time spent on what they consider "my hobbies" will not be spent until i can answer their question.
Again, sorry if i am a bit cranky , i am old and overworked.
ron
I never bluff,
Problem is i am using my companies money/manpower to accomplish a study that thay may see as not being profit oriented.
They look upon my group this way, if we cant realize increased profits/productivity/savings then why are we paying for it. I have to account for everyones time and application and every week/day report on expenses and status of assigned projects.
I was trying to hide the expenses under a study on ultrasonic responses of carbon/magnesium migration (segregration) in CS cast slabs and the change in acoustical impedance (Z) at a compressed interface that returns a false signal that rejects an acceptable ,usable plate that passes thru thickness tensile testing. There is many many millions of dollars that are in question and dependant on my findings and solutions. Want to talk pressure?
Time spent on what they consider "my hobbies" will not be spent until i can answer their question.
Again, sorry if i am a bit cranky , i am old and overworked.
ron
Ron tends not to be verbose
I have no need to. I primarly have to explain things to the upper management in as few words and as simple as possible. They understand that if you hit a nail with a hammer , it goes into the wood. (They question how much did the nail cost and the hammer and the wood and the cost of the employee hitting the nail)
Ron is an engineer's engineer. If it isn't based on real physics it isn't real to Ron.
All i am is a problem solver and a number cruncher, all this is based on nothing more than standard Newton physics(to varing degrrees). We can make it complicated, or simple. I perfer simple.
ron
Why pay attention to their opinions?
Because i respect any input. If you want to know how a tape or broom works, you ask the person using the tape or broom, dont ask the engineer that designed the tape or broom. Theory is all well and good, but it cant replace actual results.
(Things should be as simple as possible, but not to simple: Albert Einstien)
I have no need to. I primarly have to explain things to the upper management in as few words and as simple as possible. They understand that if you hit a nail with a hammer , it goes into the wood. (They question how much did the nail cost and the hammer and the wood and the cost of the employee hitting the nail)
Ron is an engineer's engineer. If it isn't based on real physics it isn't real to Ron.
All i am is a problem solver and a number cruncher, all this is based on nothing more than standard Newton physics(to varing degrrees). We can make it complicated, or simple. I perfer simple.
ron
Why pay attention to their opinions?
Because i respect any input. If you want to know how a tape or broom works, you ask the person using the tape or broom, dont ask the engineer that designed the tape or broom. Theory is all well and good, but it cant replace actual results.
(Things should be as simple as possible, but not to simple: Albert Einstien)
I hear ya, I deal with this all the time. The problem most the the time with engineer's and architect's that I deal with is that most just have the books smarts without the hands on and common sense. This can be frustrating but most of the time talking logical with them in real world conditions terms seems to help out but some just don't get it.
I've always had this problem with math teachers. Whenever I ask how or where certain methods are applied in real application, I always get a blank look and annoying remarks.ecir38 said:
Are we done yet?
Anyone else want to join the whine-in?
Still not even a hint of magnitude of effect. Not even an educated guess, based on the "boundary layer hypothesis". Still looks like a "tweak", maybe works, maybe not.
I've got to get back to my humble non important work, helping to save kids lives, build microwave plumbing for surveillance and communications, atmospheric greenhouse gas evaluation, non-useful stuff like that, dumb engineering pursuits, eh?
John L.
Anyone else want to join the whine-in?
Still not even a hint of magnitude of effect. Not even an educated guess, based on the "boundary layer hypothesis". Still looks like a "tweak", maybe works, maybe not.
I've got to get back to my humble non important work, helping to save kids lives, build microwave plumbing for surveillance and communications, atmospheric greenhouse gas evaluation, non-useful stuff like that, dumb engineering pursuits, eh?
John L.
Get real guys. Welcome to the planet amateur-DIY!
Bud introduced us to this. If it wasn't a successful tweak then interest would probably have petered out by now.
He went a bit OTT with his enthusiasm all that zero hash, too much detail to bear, perfect transducer, EnABLing everything in the house that has an edge etc - but hey that's how DIY enthusiasts' minds work. A kind of semi-informed brainstorming. Don't knock it - we all do it to some degree.
Re his (and other's) theories - it is a bit like my own profession anaesthesia. Unless you are a SPECIFIC specialist in the field, you struggle to really understand the detailed practical application of the scientific principles involved. That's modern science for you.
And even if you are involved in another branch of engineering - it only helps you to a point: my surgical colleagues are sometimes staggeringly ignorant of important principles of anaesthesia ...
So no whining from me. What's the point?
Bud introduced us to this. If it wasn't a successful tweak then interest would probably have petered out by now.
He went a bit OTT with his enthusiasm all that zero hash, too much detail to bear, perfect transducer, EnABLing everything in the house that has an edge etc - but hey that's how DIY enthusiasts' minds work. A kind of semi-informed brainstorming. Don't knock it - we all do it to some degree.
Re his (and other's) theories - it is a bit like my own profession anaesthesia. Unless you are a SPECIFIC specialist in the field, you struggle to really understand the detailed practical application of the scientific principles involved. That's modern science for you.
And even if you are involved in another branch of engineering - it only helps you to a point: my surgical colleagues are sometimes staggeringly ignorant of important principles of anaesthesia ...
So no whining from me. What's the point?
Here you got more to fight about. Rename this thread to "Speaker kindergarten" Or put your CV's on the net, boys!
http://gboers.xs4all.nl/daisy/home/g3/139/g1/loudspeakers/refiningreplikon.html
http://gboers.xs4all.nl/daisy/home/g3/139/g1/loudspeakers/refiningreplikon.html
Well said, Alan Hope!
I wish more here had the same understanding as you & stopped wasting bandwith with constant nit-picking.
Just let this develop in a natural way & it will either be seen as a tweak with no guarantee of success (and hence disappear) or some real understanding of it's fundamental operation will emerge & it will indeed be an invaluable benefit.
I wish more here had the same understanding as you & stopped wasting bandwith with constant nit-picking.
Just let this develop in a natural way & it will either be seen as a tweak with no guarantee of success (and hence disappear) or some real understanding of it's fundamental operation will emerge & it will indeed be an invaluable benefit.
EnABL data
I especially appreciate the way the time scales are unequal when results are presented to prove the improvement after treatment.
That's pretty weak...🙄
Phase plug + EnABL actually looks worse than Phase Plug alone, if CSD is the method of enlightenment, when you normalize the charts wrt each other.
We were taught in intro chem lab (10th grade I think) that the x/y/z axes should be equal when comparing graphs.
c'est la vie .. and please, let's get past the whining...
John L.
I especially appreciate the way the time scales are unequal when results are presented to prove the improvement after treatment.
That's pretty weak...🙄
Phase plug + EnABL actually looks worse than Phase Plug alone, if CSD is the method of enlightenment, when you normalize the charts wrt each other.
We were taught in intro chem lab (10th grade I think) that the x/y/z axes should be equal when comparing graphs.
c'est la vie .. and please, let's get past the whining...
John L.
Re: EnABL data
http://www.diyaudio.com/forums/showthread.php?postid=1347196#post1347196
dave
auplater said:
http://www.diyaudio.com/forums/showthread.php?postid=1347196#post1347196
dave
peterbrorsson said:
Yep. Before = really bad response above 1k Hz.
After = really bad response above 1k Hz.
(Do we need to qualify how bad bad is?)
Let's see, a 14 year old patent for a silver bullet that generated no commercial licensing agreements. Who was it that said the market will decide? Bud? Seems the market has already spoken.
auplater,
This emphasis on testing is a good thing. So far it has shown only that something is happening. Certainly not what nor how important it might be. Just that we can find a difference.
However, if you are going to base your audio experience strictly upon a measurement graph you can see, on a piece of paper, why have one? Not picking a fight here. Perhaps a better way to say this is here.
http://www.diyaudio.com/forums/showthread.php?postid=1423388#post1423388
The two large quotes on the bottom of the page are actually relevant to EnABL. These "quality" factors are exactly what people who have correctly applied the process are experiencing. Everyone of them. And yes, yet another sweeping statement, but one I am quite confident of.
Now, I too must return to my day job, the design of transformers that cannot kill people, even in the bath. And guitar amp powers and OPT's that allow musicians to express their art at the highest levels they could hope for. Yet another sweeping statement, and again, one I speak with confidence.
AJ should be able to get in here and on to this sweeping thing pretty quick, dontcha think?
Bud
This emphasis on testing is a good thing. So far it has shown only that something is happening. Certainly not what nor how important it might be. Just that we can find a difference.
However, if you are going to base your audio experience strictly upon a measurement graph you can see, on a piece of paper, why have one? Not picking a fight here. Perhaps a better way to say this is here.
http://www.diyaudio.com/forums/showthread.php?postid=1423388#post1423388
The two large quotes on the bottom of the page are actually relevant to EnABL. These "quality" factors are exactly what people who have correctly applied the process are experiencing. Everyone of them. And yes, yet another sweeping statement, but one I am quite confident of.
Now, I too must return to my day job, the design of transformers that cannot kill people, even in the bath. And guitar amp powers and OPT's that allow musicians to express their art at the highest levels they could hope for. Yet another sweeping statement, and again, one I speak with confidence.
AJ should be able to get in here and on to this sweeping thing pretty quick, dontcha think?
Bud
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