I am not sure what to make of your post. Could you provide some examples of what you feel is wrong or has been missed with respect to numerical simulations?
> Could you provide some examples of what you feel is wrong or has been missed with respect to numerical simulations?
Hmmm... negative examples rather than positive ones but it is a fair question.
When trying to "do engineering" what is needed is to balance the relevant physical processes to best meet the objectives for the device. Numerical simulations are a direct quantitative evaluation of the relevant physics subject to a set of assumptions (approximated governing equations, numerical error and approximated boundary conditions). If they are a good represenatation of the physics then they are enormously more useful than measurements because they are complete. You can always determine why something happened, what would happen if we tried this, how much would we lose if we had to include this, etc...
So the natural language of people using numerical simulations to do engineering is the physics of whatever is going on plus the assumptions being made. This is absent from the discussions here. If the language of the posts was in terms of the modelling assumptions to represent, say, a ported box or a damped transmission line then a thread like this would collapse. It exists because the posters talk in terms of the mechanism of performing the simulations (FEA, electrical analogy,...) which, I suspect, are only vaguely understood in many cases leading to the projection of a bunch of postive and negative attributes they do not really possess. Then arguing over those plus the usual reasons why people post to forums like this.
Hmmm... negative examples rather than positive ones but it is a fair question.
When trying to "do engineering" what is needed is to balance the relevant physical processes to best meet the objectives for the device. Numerical simulations are a direct quantitative evaluation of the relevant physics subject to a set of assumptions (approximated governing equations, numerical error and approximated boundary conditions). If they are a good represenatation of the physics then they are enormously more useful than measurements because they are complete. You can always determine why something happened, what would happen if we tried this, how much would we lose if we had to include this, etc...
So the natural language of people using numerical simulations to do engineering is the physics of whatever is going on plus the assumptions being made. This is absent from the discussions here. If the language of the posts was in terms of the modelling assumptions to represent, say, a ported box or a damped transmission line then a thread like this would collapse. It exists because the posters talk in terms of the mechanism of performing the simulations (FEA, electrical analogy,...) which, I suspect, are only vaguely understood in many cases leading to the projection of a bunch of postive and negative attributes they do not really possess. Then arguing over those plus the usual reasons why people post to forums like this.
I've never had a signature on an internet forum, but I think I just found one:
"Producing bass is trivial, if you can decide how much of it you want, and what you are willing to pay for it. If you hope to alter the course of the audio business, there are far more important areas to tackle." - Ken Kantor
On a forum like this, most of the participants do not have the fundamental engineering/acoustics training or understanding to debate in purely technical terms. People like the original poster tend to state opinions as facts and then do not possess the capability to re evaluate or defend their beliefs. They cling to the incorrect understanding, even when it is pointed out to be incorrect or physically impossible, because they are not capable of a technically correct exchange of ideas or explanations. This eventually devolves into a ******* contest and then they usually resort to the I'm a victim defense. So the people with the background and understanding try to meet someplace in the middle, sometimes they succeed and sometimes they don't and give up (Kantor's observation about pros avoiding forums like this validates this statement). If you want to initiate a more technical discussion on the topic at hand, be my guest. I am really not sure how else to respond to your post.
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I must stress this is a general observation, and is not directed at any one individual
it is true many people here do not have any fundamental engineering/acoustics training, however i think that there are still many that HAVE engineering degrees and the like, just a lot fewer have acoustic degrees.
therefore many posters quote an engineering question that could affect the acoustic properties of a system, and in some cases they are suppressed by those WITH acoustic qualification, and also sometimes without provocation.
however, the OP, did seem to over step the mark rather often it would seem, almost as if fishing for confrontation. I find it a little sad that some real 'experts' took the bait.
i think that MJKs expletive was unnecessary.
haha although i think with some people, experts or newbies, you are always going to be insert MJKs expletive here into the wind.
I do not think however that the OPs comments were any more constructive than those of an all seeing acoustician, dismissing some partly valid arguement from an engineer, even if in part the arguement shows a lack of deep acoustic knowledge. this does not happen often, but i have experienced it, and im sure it wasnt the first time.
the only real sound reproduction expert here is the man that can say he has doctorates in maths, mech. eng., elec. eng., materials science, acoustics.....
i myself have a degree in elec eng, so im not an expert by any means, but i can theorise, whether right or wrong, and i can explain concepts in simple terms. often my comments have been construed as a slight to the established theory, or that im misguidedly trying to reinvent the wheel. i am not. a scientist questions everything they are confronted with, and by doing this i(at least) am saying, "am i right?" and if im not, "where does my understanding stop, and what do i need to learn". this may be the case with others too.
some very smart people are here, mathematicians, acousticians; but i find very few can explain in simpler terms to another engineer of different background. all this makes for a great scientist, or theoriser; but is awful for anyone actually seeking to learn from the megabrains. lets face it, if the 'experts' wanted a fully conversant tech debate, would they really do it here anyway? and if so, the id expect all the relavent 'experts' to be doing it already. occasionally(maybe rarely even) it seems like this forum can end up a showcase for a particular expert to make claims and refute opposing claims, and also become a tool to stamp down the less expert among us, who are trying to undrestand the idea presented.
"you disagree, so you couldnt possibly have a concept of what im talking about" =arrogance.
black art mentality. "knowledge is power, and while i refuse to explain in terms an engineer can understand, and limit the explanantion to Dr level theory, then i maintain the power."
peace out, hopefully everyone can learn a little more(me included), if some experts can try and come down to our level a little better....it would be benefitial for all im sure.
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I don't always agree with Kantor and I believe that there is still work to be done as far as deep, powerful bass in small enclosures goes. I'm aware of the well known "laws" however, gains can be made here and there. Many driver companies still to this day do not produce linear motors - there has been very little innovation as I see it.
I am also aware of XBL motors and split voice coils but the fact is that very few companies use these technologies.
I don't understand this response either, it seems a little bitter. Over the years I have tried to share what I have been working on and explain what I can to the best of my ability. I don't get some of these comments, maybe as stated above I am part of the problem. So I think it is time to leave the forums for a while, I have had enough.
Martin, as a newbie here myself, it's obvious you have a lot of fans on this forum. I can see where a newcomer might have a problem with that. But, that doesn't mean there is a problem here. And even if there is a problem, and you are the cause of it, I don't think you're part of it. You strike me as being kind, humble, and patient. Your dedication to sharing your insights with others is remarkable and laudable, and not an easy path to follow.
Lest we forget gentlemen, the internet was originally concieved by scientists looking for a more efficient way to communicate and share ideas with each other. They had it all to themselves - for a while.
I support the idea of a new thread for those with advanced knowledge of acoustics and physics so they can continue here and so we don't loose valuable contributors like MJK. 🙁
Hi Martin,
those who contribute and share are often offended by those who don't .
That seems to happen in life and is not restricted to this forum.
I have to admit that i left other forums, because of bad manners
beeing common there.
I regard this forum high, because there seems to be a good mix of
"amateurs" and "experts", just people with different perspective and
background.
Thereby the form is mostly polite. We all should take care that
this will linger on.
It would be very sad - if not lethal for a forum - to loose
acknowledged contributors.
I cannot imagine, that many of us would bother, if acknowledged
contributors just keep out of troll feeding, even if asked or attacked
directly. You won't loose your backing here, be assured.
On the other hand we cannot want the admins to close every thread
that seems to lead astray ... openness is worthful too.
So we have to live with troll attacks from time to time. I am not
sure whether i have been the troll sometimes as well.
Kind regards
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Urban legend. The oft-mis-cited quote was from a patent commissioner who was trying to expand the patent office.
I agree MJK, I don't usually bother to even read posts like that, but I did and you just have to wonder where people get their perspective. They ought to think before they post that if a question of theirs is being answered by a professional they are getting free consulting. I try to keep my on-line involvement to a minimum, but this was in an area that is one of my specialties and once again it turned into a waste of time.
Martin, if it wasn't for your software I wouldn't know *half* of what I know about front loaded horns and transmission lines. And I've spent weeks/months absorbing the math and the concepts from the PDFs on your web site.
I don't post a lot here, but I am very active in the car audio forums, as the link above demonstrates. Check out the diymobileaudio.com forum, there's a whole new generation of listeners getting interested in horns and waveguides, and I'd like to think that I'm playing a part in encouraging that. If you don't think that your work is making a difference, you should see the stats on that site. There are people all over the world who are following this stuff. There are guys everywhere from Brazil to Slovenia who are learning about horns via car audio. (Not to get off on a tangent, but in my experience, the car audio guys are more receptive to new ideas than the home audio guys, due to the fact that most of them are under 30. Home audio guys tend to be set in their ways.)
And as I said, I couldn't "spread the word" without learning from you.
So don't let the haters get to you, you've educated a lot of us.
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MJK, i have to stress( as i did at the start of the post) that this is not aimed at any individual. the only point i mentioned your good self, was in ref to the profanity you couldnt keep to yourself. THAT i DONT agree with, and it hardly reflects the attitude one would expect of someone like yourself, especially as i have read much of your work and appreciate it fully, and in some ways look up to those who perform such work, yourself included. I have to say i am NOT at all bitter, but it certainly isnt unknown for those experts to 'talk down' to us mere mortals. That was the point. I have a good understanding of elec theory, and a reasonable understanding of acoustic theory, although by no means complete, comprehensive or as good as many here. This doesnt change the fact that many experts here have no desire to explain things to others with lesser knowledge, or simply cannot as they may be incapable of teaching. this ineveitably leads to the impression that the rest of the lesser qualified community are 'too dumb' to understand and arguement, which is lets face it, SOMEtimes at least, explained in technical jargon, which only those already 'in the know' would understand.
It would be like me talking about work, and mentioning performing 'q-axis' tests on an EM machine and expecting all and sundry to understand and accept my explanation.
Truely NO offence was meant to MJK, it was a generalised statement.
I would agree that this is a fair description of what often goes on but I would not agree that the situation is unchangeable. People tend to join in/go along with the community. If they like what is going on they stay and if they do not they leave. The moderators have the initial task of working at what is in or out but over time it becomes largely established.
Unlike say HydrogenAudio, the moderators here have opted to include people that believe in magic (an old fashioned term that will no doubt be denied by the believers). This may raise the volume of posts a lot but it causes problems for the odd technically knowledgeable person that might like to chat or contribute. It is a decision for those that run the site to go for what they want. And the site seems busy.
I have a strong technical interest but have rarely pursued it in online chat forums. My occasional interest here is mainly in people and to a lesser degree information about practical experience that some of the posters here possess. Although I am toying with the idea of performing some numerical simulations on loudspeaker, putting them up on the web somewhere and then chatting about them on a site like this.
I would disagree with this. Smart people understand the basics and how things fit together. What makes people smart and what is required to explain things clearly and logically are very strongly correlated. If you get incomprehensible explanations involving obscure concepts it almost always means the person doing the explaining has an incomplete grasp of how things fit together.
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