This seems like it's going to be my next test. Based on the BEM sims, the curves look smooth, quite constant directivity, no complicated intersecting between the SPL lines at different angles. Bassed on the sims of previous configurations, this sim should not be too far off. Pretty hard to describe what curve this is because it started out with an OS expansion throat, but after pulling the lines around in the CAD program and looking at the results, I don't really know what to call it, but it looks somewhat like an AX2 from the pictures I can see.
Attachments
mige0 said:
Michael
I have no idea what that "law" is. Could you supply me a reference in some text somewhere so that I could look it up?
soongsc said:
Soongsc
That is very good, almost too good to be true. Its a simulation right? Is there a mouth?
Im just being honest about all the observations from all the threads I have been involved with Dr. Geddes. My intent was nt to attack but when being honest and talking about the negatives it may just come across as attacks online. I wish it wasn't that way because I think he is doing/has done incredible things and I acutally use his quotes, his papers, his theories to back up any audio opinion I have these days.
Im here to read and learn and to ask questions, post even some subjective conclusions. I do not think this conclusions need to be rip apart, Im okay with them being wrong but there is a proper way to discuss the issues and no one is 100% wrong. Thats just a math 1s and 0s mine set working....I should know I have a mathematics degree from one of th 5 top schools in North America and I know many, many Dr. Geddes. I also live amonst PhDs so again I understand their tendancies.
Sheldon, I believe everyone respects what Geddes has done and many, many are following it now...heck these threads show how much excitement there is about Waveguides, foam, HOM stuff. We have Geddes to thank for that bu that does not give anyone the right to treat others like they are beneath them. I would like to think people can be treated as equals.....If you think all other opinion isnt worthy to what Geddes posts so be it but I can tell that some here get star struck by Geddes becuase simple fact that they defend him at all costs and post Dr. in front of his name. Btw, my wife is a PhD, 4 other couples on the block are PhDs, along with Dentists, Medical Doctors, etc....ZERO.....ZERO of them get referred to as Dr. in a NON-professional situation......we are equals!!
FWIW, even if it seems I attack...I actually promote and support what Geddes is doing in other forums then anyone here would ever believe. I would love to have him sell thousands of speakers because I believe they are superior.
I still want to DIY something cheaper though 😀
Yes, this is still a simulation. There is also a mouth in the simulation. I tried to get the geometry of the driver as close to the real thing as the software would allow. Since the software assumes the diaphragm a rigid body, it does not show the breakup modes.gedlee said:
doug20 said:
Doug, I think the difference here is that Dr. Geddes is acting more as a professional in this particular capacity than a friend. While we aren't necessarily doing business with him, taking a class from him, etc, this is still his work. I too know many many dr's and I know that some preferred to be called Dr. some don't, it's a preference for them.
Then there is the issue of opinion. I wouldn't argue with a dentist over tooth decay. I wouldn't argue with a heart specialist over heart disease. Even if I had studied these things in all the books and websites I could find, I wouldn't feel I have the ability to dispute or argue with the expert. I might query if I thought I had read something contrary, but not out right dispute. A lot of people have been disputing and dismissing his work without fully understanding the science behind it. I can tell you that I too get very annoyed and probably respond more harshley when I'm argued with over issues related to human subject experimental designs, child developed, or any of my other area's of expertise withing my field. I would not argue with my professors so much at this point (I still voice my opinion), but after 4 years of undergrad psychology, 2 years of graduate school, and 5 years as a researcher in the field, I have more expertise than most in these area's. My opinion is far more informed on these issues than someone without my experiences, education, and expertise. I believe that is all that is said when someone, even Dr. Geddes, states that some opinions are worth more than others.
>> law of "non interaction agreement"
I'm pretty sure Michael meant the linear superposition principle, which should be valid at any reasonable SP-level, should it not?
Earl, you are getting lazy😀
- Klaus
I'm pretty sure Michael meant the linear superposition principle, which should be valid at any reasonable SP-level, should it not?
Earl, you are getting lazy😀
- Klaus
KSTR said:
I don't see how you get "linear superposition" out of that, and I guess that I like Michael to agree that's what he meant.
We are talking about linear acoustics here, that is correct.
doug20 said:
I believe we all have an equal claim to humanity. Our opinions on various subjects are not all equal in value. If they were, what would be the point of studying anything? Would you hire someone randomly for a job opening, without regard to their knowledge base?
Just so it's clear, I'm not claiming any special knowledge on the subjects discussed here. I'm at the lower end of the scale.
doug20 said:
I know plenty of PhD's too. I've worked for some. Some have worked for me. Some are brilliant, for some, one wonders how they managed to get any degree. He earned the degree, and has demonstrated proficiency over the course of a career. If he prefers that we use that title, fine, I got no problem.
doug20 said:
This is his profession. Think of it, in some ways, as an informal class. You've never had a professor with a few idiosyncrasies, but was worth the effort for the knowledge they imparted?
doug20 said:
Which is why I said earlier, go ahead and build.
Sheldon
Sheldon said:
Only once did I ever express a preference for Dr. as opposed to Mr. (and that was to make a specfic point), but my preference is Earl. But I'm certainly not going to condem someone for showing some respect for the title. Etiquite says the PhD title of "Dr" is always used in a professional setting and never in a non-professional one (an MD should always be called Dr.). What is this setting? Its probably different for different people.
KSTR said:
gedlee said:
Fine!
So what hair did you find in the soup then, Earl ?
I outlined all the underlying mechanisms we have at hand and unless you found a new law, I and all others possibly have missed - HOM *must* be a subset of "diffraction-reflection-delay-interference".
If you still don't agree – give a "low level" (for the "dumb one" please!) explanation *why* not.
Michael
mige0 said:
Oh look! What a surprise, another snarky comment!
Give it a freaking rest. Just pose a question or issue a response and lay off the attitude.
As a simple observer of the discussion it's annoying to have to tease out the substance from posts when people are compelled to bookend it with BS. (I even bolded the BS in case you're having trouble discerning the difference)
This could actually be a reasonable discussion, but I'm frankly embarrassed to even give people links to it because they'd have to weed through so much nonsense to get to the substance.
amiklos said:
No – I *do have* posted constructively throughout and have earned several times no answer to the core questions about the issue of HOM versus "diffraction- reflection- delay - interference" – which basically is the issue what's "new" on HOM.
Until now – *nothing* new under the sun 😉 ! - if you have a look at "my bunch of pretty pictures" and the "non comments" following....
Since being proud to having introduced the double horn my interest - as a noob - in all kinds of things related to horns has gone "through the roof".
What I have focused here - for the ones that didn't notice over the course – is to cut right to the bones of HOM as no one seems to have done that (successfully) before, out of politeness, out of respect, out of fear, out of whatever – actually its become kind a surgery as Earl is protecting this his "HOM" baby from all shades of light over years now!
Looking at the "under the surface" resonance this my intent had - I'd say -there is some general interest in the topic...
As long as Earl is willing to prolong the "question and answer" game – there will be questions to get the answer
🙂
Michael
Michael, I am the dumb one here. And it's not easy for me to try and tease the meaning out of some of your posts. Some of that might be language. If so, that's fine. We'll have to struggle with it. I admire you and all those who make the effort post here in their second (or third, fourth, or fifth) language. Mixing in some purely argumentative asides, just confuses things more. I have to try and figure out if it's a real point you are trying to make, or it's just a rhetorical device.
My understanding (learned here) of the HOM under discussion, is that they are waves, generated by diffraction, that reflect off of the horn surfaces and arrive delayed to the listener, relative to the original signal.
Has this been in dispute (and yes this is a real, not rhetorical question)?
Sheldon
mige0 said:
My understanding (learned here) of the HOM under discussion, is that they are waves, generated by diffraction, that reflect off of the horn surfaces and arrive delayed to the listener, relative to the original signal.
Has this been in dispute (and yes this is a real, not rhetorical question)?
Sheldon
Sheldon said:
Sheldon
This is quite correct and I simply don't see why people find it so mysterious.
Michael
You mistake my lack of discussion as secrecy, its not. I simply do not understand the point that you are trying to make and your tone makes me unwilling to try.
Perhaps you should carefully read the publicly available information Geddes has published, then you could break down your questions and assertions into answerable elements. Right now I find no evidence you have read his stuff and you have no material, therefore, to pursue an intelligent discussion.
You did receive answers but either forgot or ignored them or don't like them, perhaps because they lead into a place which requires huge effort..
Right now, you are working from a base of ignorance which might lead someone to think uncharitable thoughts:
There is no "baby" and no secret. If you google Higher Order Modes you will find over 300000 entries in various areas of science and engineering. As Geddes said, he's applied something well known for a long time.
You did receive answers but either forgot or ignored them or don't like them, perhaps because they lead into a place which requires huge effort..
Right now, you are working from a base of ignorance which might lead someone to think uncharitable thoughts:
There is no "baby" and no secret. If you google Higher Order Modes you will find over 300000 entries in various areas of science and engineering. As Geddes said, he's applied something well known for a long time.
Michael,mige0 said:
I think nobody is obligated to provide answers unless legally binding to do so. In the process of getting into almost everying I focus on, it was very common not to get direct answers. I can still remember the teacher's face when I tried to convince him one exam question was in error.😱
I can't remember whether it was this thread or another thread, but Earl did generally describe HOMs in an understandable manner. For the sake of simpler communication, it is very common to use acronyms, such as HOM or CD. But I would say that your CARA simulation pretty much seems to be what he was trying to describe.
Sheldon said:
Happy not to be lonely as a dumb
To be serious – yes that's exactly been my point .
soongsc said:
Anytime !
Thanks.
gedlee said:
Pfhuhh – what an effort to get such a simple statement from you Earl.
It tells us that HOM in fact is a subset of "diffraction- reflection- delay- interference" which you consistently avoided to confirm when I've come up with .
The logically consequence I did some earlier
( in http://www.diyaudio.com/forums/showthread.php?postid=1848339#post1848339 )
is that HOM in its sonic outcome is – at best – related to specific interaction with the driver (as outlined by Bjorn) or specific masking effects of our hearing ability.
It simply can't be specific to HOM but must apply to all other sound fields of a certain degree of defectiveness / raggedness caused by interference.
Some quite substantial conclusions for now
But maybe we'll go with a "Quite honestly I don't think that you see the point at all."
back to start again...
😉
gedlee said:
Its specific sub-harmonics in my tone you don't like, I assume (probably we would not agree on which sub-harmonics exactly) - anyway - you should be able to listen to your own tone sometimes – ui ui ui....
Well - we are humans after all – different temperament – different background - nothing really serious IMO
FrankWW said:
A matter of the point of view – not to say: pure guess working from your side
soongsc said:
For sure nobody is *obliged* to answer any question – absolutely agree.
Michael