....... Eric, you have to remember that most of the people who read my FAQ and download my ModeCalc program are beginners. They have no idea how to interpret the data your calculator outputs. If you want to think of my program as "dumbed down" a little for the masses, I have no problem with that.
--Ethan
It's just because it ARE beginners that they can easily be mislead.
Experts KNOW it's strongly incomplete. Beginners DON'T.
This is NOT a simplification, it can lead to WRONG interpretation, and only experts know that.
And you even refused (continuously) to mention this limitation.
You present it as a complete room mode calculator, NOT a dumbded down version with limitations.
And only experts know, never beginners who trust this to be A room mode calculator AS IS.
They argue exactly like you did yourself, in that thread with the by you deleted message clearly stating it were tangential modes.
It's not shown in this calculator so it has to be something else, something non-modal. You even explicit stated it couldn't be modes because you calculated them.
You conclude, based on your OWN calculator there are no dominant non-axial modes in YOUR OWN ROOM.
Well there are, AND THEY ARE DOMINANT.
You clearly told at SOS, that you searched, more than once, and never could find any non-axial modes, and you standard shift the proof to others telling otherwise, questioning any related suggestion and reference to whoever and whatever.
Here you get 4 example cases with dominant or significant non-axials.
And you're supposed to be the expert.
And somewhere here at RO the real reason is entered by yourself.
You couldn't find somebody to program a good Room mode calculator calculating all modes for you.
And that's why, and only why, your users only see axial modes.
And that's also why those endless discussions restart over and over again.
Because referring to another guy's calculator must be the biggest sin on earth.
You rather delete a related message, disprove the existence or possible importance of non-axials, and all literature related to it (even without knowing it).
_________________ Best Regards - Eric Desart
Also or Non Respected Past RO Acoustics & Design Moderator?
Ethan Winer Respected Past Moderator
Joined: Mar 19, 2001
Posts: 3209
Location: New Milford, CT USA
> Eric's spreadsheet does not predict a modal response. None of the tools I reviewed above predict the modal response. <
Then what use are they? Why would anyone use a "mere" mode calculator when it won't predict anything useful or give some idea of the response you'll actually get once the room is complete?
> I'm sorry to say you'll have to "do-over" <
Not a problem. Do you think I should put the speaker and test mike in opposite corners as Bob suggested? Or should I do what I did the last time but measure and document all of the positions?
> Acoustic-X is a stand-alone program <
Wow, tough crowd.
You said that program is no longer available, so why mention it now? Pardon me for not being more clear: Of all the programs that you listed or that are free mine is the only one that doesn't require the user to own Excel.
> And you're supposed to be the expert ... You rather delete a related message ... <
It's a waste of my time to continue this sort of discussion with you, so I won't. When you're ready to discuss acoustics without relying on insults, and are prepared to address even half of the points I make, I'll be glad to continue.
> Eric's spreadsheet does not predict a modal response. None of the tools I reviewed above predict the modal response. <
Then what use are they? Why would anyone use a "mere" mode calculator when it won't predict anything useful or give some idea of the response you'll actually get once the room is complete?
That would depend on what information you're looking for. I find mode calculators quite useful in my line of work.
Quote:
Not a problem. Do you think I should put the speaker and test mike in opposite corners as Bob suggested? Or should I do what I did the last time but measure and document all of the positions?
Again, it depends on what you're wanting to look at. Do you want an idea of the "real-world" response at the mix position? Or do you want to quantify the performance of a device in a room in the purest possible sense? The former pretty much gives you free reign to set things up how you'd like. The latter might require a corner/corner setup.
Quote:
> Acoustic-X is a stand-alone program <
Wow, tough crowd.
You said that program is no longer available, so why mention it now? Pardon me for not being more clear: Of all the programs that you listed or that are free mine is the only one that doesn't require the user to own Excel.
Yes, I did allude to Acoustic-X not being available. To be completely honest, I am unsure of its exact status. I do know that it's not very well-supported anymore. Whether you can actually buy it anymore is a question for P-S. I do know that you have to go to great lengths to get it to work on an XP machine.
As for your calculator, just think: If it could predict all the modes, it would in fact be the only free tool that didn't require Excel. If that were the case, it would be completely comparable to the other six Excel tools I listed.
_________________ ---lovecow---
"You've got to be very careful if you don't know where you're going, because you might not get there." - Yogi Berra
eric_desart Recording Org Pro Audio Forums
Joined: May 23, 2003
Posts: 816
Location: Belgium Antwerp
> ...... You rather delete a related message ... <
It's a waste of my time to continue this sort of discussion with you, so I won't. When you're ready to discuss acoustics without relying on insults, and are prepared to address even half of the points I make, I'll be glad to continue.
--Ethan
I didn't know that facts were concidered insults. You established the facts not me.
The core of my post is clear, but you ignore it once more.
And I tried for 2 years starting with friendly asking and explaining.
Ethan Winer Respected Past Moderator
Joined: Mar 19, 2001
Posts: 3209
Location: New Milford, CT USA
> just think: If it could predict all the modes, it would in fact be the only free tool that didn't require Excel. <
Okay, so what if I added an option to show/hide non-axials? Or maybe show them on a separate line? I'll think about that. I'm still not sure how I'd explain to users when they should consider non-axials or how much weight to give them. But I will think about it.
While looking through Everest's Master Handbook of Acoustics (4th edition) for the formula to calculate non-axials I came across a few other interesting and relevant tidbits.
On page 332 he compares the predicted modes versus what was actually measured in a typical bedroom. (Measured using a slowly swept sine wave, I might add. )
Unlike my test, Everest measured as Bob suggested, with the loudspeaker and microphone at opposite tri-corners. Here too the measured response is not what was predicted, and Everest refers to his attempt to tie the peaks and valleys measured to what was predicted as "disappointing." The disparity shown in Figure 15-9 is not unlike what I showed in my initial post here. Lots of peaks and nulls, with few aligning with any of the predicted modes. So much for opposing tri-corners giving more predictable results...
Also, on page 346 Everest states that "most signal colorations are traceable to axial modes." Which is what I always assumed. However, in fairness, this is in a section titled Simplified Axial Mode Analysis.
Take a closer look at Table 15-1 and then compare to the modal locations in Figure 15-9. I don't think they agree. E.g., there are two (2) axial modes plotted near 60 Hz, yet only the only one close on the table is 67.1 Hz.
Conversely, there is a huge peak at roughly 90 Hz. Take a look at Table 15-1 again and there are two modes - one axial and one tangential - at 90.7 Hz. (And, again, there is no corresponding axial mode on Figure 15-9.)
Unfortunately, this is somewhat typical of the 4th edition of the MHoA. Even more unfortunate for this case, the 3rd edition not only shows the same discrepancies between Table 15-1 and Figure 15-9, but also shows a completely different response graph in Figure 15-9 than what is shown in the 4th edition.
But, I did use one of the above mode calculators to verify the modes were correct in Table 15-1...(edit:) and they weren't - see below...
_________________ ---lovecow---
"You've got to be very careful if you don't know where you're going, because you might not get there." - Yogi Berra
Last edited by lovecow on Fri Mar 18, 2005 11:42 am; edited 1 time in total
Ethan Winer Respected Past Moderator
Joined: Mar 19, 2001
Posts: 3209
Location: New Milford, CT USA
> Take a closer look at Table 15-1 and then compare to the modal locations in Figure 15-9. I don't think they agree. <
Wow, you're right. Man, you're good!
I will now sit back and watch as six people tear Everest a new one for having the nerve to call himself an "expert" after having made such an egregious error!
But, I did use one of the above mode calculators to verify the modes were correct in Table 15-1!
Oops. Check that - I looked a little closer and even Table 15-1 is off a hair. There aren't, in fact, two modes at 90.7 Hz for the dimensions he listed. Nor are their two modes at 122.1 Hz, and there are some other discrepancies above that. Maybe Mr. Everest used the THX calculator!!!
Oh well, so much for that little study.
_________________ ---lovecow---
"You've got to be very careful if you don't know where you're going, because you might not get there." - Yogi Berra
Paul Woodlock Recording Org Pro Audio Forums
Joined: Aug 7, 2001
Posts: 675
Location: Peterborough, UK
> And you're supposed to be the expert ... You rather delete a related message ... <
It's a waste of my time to continue this sort of discussion with you, so I won't. When you're ready to discuss acoustics without relying on insults, and are prepared to address even half of the points I make, I'll be glad to continue.
--Ethan
Ethan please!
I really did think you'd sit down and think about my olive branch posts.
I mean this sincerely in a non combatent way..... you're gonna get nowhere by continuing to have a pre-determined negative view on the tone of Eric's posts.
Eric's post above ( the one with the initial red font sentance ) is NOT insulting you. You are only taking it as an insult because your still locked in defensive mode.
Eric's post above hits the nail on the head FAR WIDER than the scope of the acoustics discussions in this thread.
And that's the 'Expert Issue'
Look, Ethan... You have a lot of qualities I admire in people.
i.e you have a passion for a subject. You're into experimenting and learning about that subject. You're not afraid to question established principles. You like to try and help people and can explain things in a way that's easy for a beginner to understand, etc,etc,
All great stuff!!
However, it seems your pride has some problem with this 'Expert Issue'
Firstly, how do you define 'Expert' ? Is Eric an Expert? Is Jeff an Expert?
Well compared to you and me, and just about everybody else on these forums, YES THEY ARE!!
But I would put money on there being people somewhere in the world who would put Eric and Jeff to shame in the level of, ahem, 'expertness'
So it's all relative isn't it?
In the past I've accused you of not being an expert. To this you have taken umbridge. Fair enough. but let me qualify this.....
You're an intelligent guy. You're NOT an acoustics newbie. You actually have a decent amount of acoustics knowledge compared to most who frequent the forums.
Does this make you an Expert? Well.... to those with lesser knowledge, and for those who are newbies, then YES, you are indeed an Expert! Cool!
But compared to Eric and Jeff, you are not. Just like Eric and Jeff are not Experts compared to those abvoe them in the acoustics knowledeg scale.
Again it's all relative. You know even Eric and Jeff ae STILL students of acoustics.
One of Erics great qualities is that although he has a lifetime's experience of acoustics, he STILL recognises that he STILL has a lot to learn.
All those newbies, beginners, etc who revere your help and knowledge aren't gonna lose respect for you just because there are others ( Eric and Jeff ) around who are more experienced and knowledgeable.
In fact those people are gonna be alot more respectful of you, if you show some humility on the boundaries of your knowledge.
Half the problems of this feud are caused by this 'Expert Issue' and the pride/ego that's fuelling it.
Look at your magazine article in EQ for example. It contained innacuracies. Period. Eric reads it, and is highly bothered by the amount of people ( newbies ) that are gonna be mislead by it. And then what happens? The article fuels the feud.
Just think about there not being a feud for a second and imagine how the article would have turned out if you guys were all friends..... You would have written a draft for the article, run it by Eric and Jeff, who would have corrected the mistakes before it went to print.
RESULT: The article would have been correct. You would have learnt something, and the people reading it wouldn't have been mislead and would also have learnt something. All positive! All Good.
The same principles apply to your Modecalc. Why keep defending it? Why not simply improve it to contain Tangentials and Obliques? If you can't do that yourself ( I thought you were a programmer? ) then find someone else to do it. Pay them if necessary.
It almost seems you're challenging the importance of non-axial modes simply to defend your Mode-Calc? If so this, again, is nothing to do with acoustics. It's to do with personality. particularly the 'pride' aspect of it.
So Ethan, once again I say with complete and sincere 'olive branchness' if only you could drop the pride, be privately AND importantly.. publically humble to Eric and Jeffs higher level of knowledge, and you're gonna get a LOT MORE out of the acoustics side of your life. ALL good! ALL Positive.
A bit more of that and you'll be suprised at how quickly the feud will disappear and you can all work together, rather than causing friction between each other. Which at the end of the day is hurting EVERYONE.
And when I said more and less I did indeed mean EVERYBODY. And YES!that includes Eric too.
I love Eric to bits, but I do see he has built up an automatic negative response to you as well.
You both need to drop it. But bear in mind that it may take a differnt amount of time for different people. Which means that in the future, if Eric 'appears' to still be attacking, then bite your lip AND DO NOT attack back. Doing so only continues the cycle of negativity.
btw- Eric's Red Post above is NOT atacking you. It's simply pointing out ( especially when you read between the lines ) a very important problem that needs to be addressed if this feud is to stop.
People on both sides of the war are not perfect. Including me. but there'[s no other way of saying it....
Others need to change too, but...Ethan, you are the one that needs to do some changing, perhaps more than anyone, if this crap is gonna be resolved.
The mantra still needs repeating.....
"You must be the change you wish to see in the world."
Okay, me too. But you have to let me make my points. And you have to read them and at least try to understand them! Please?
> You are only taking it as an insult because your still locked in defensive mode ... I love Eric to bits, but I do see he has built up an automatic negative response to you as well. <
I joined those two statements from opposite ends of your post to show that I'm not the only one who may be responding on automatic pilot. I could love Eric too - I really could! - if only he would act more civil toward me.
> Firstly, how do you define 'Expert' ? Is Eric an Expert? Is Jeff an Expert? Well compared to you and me, and just about everybody else on these forums, YES THEY ARE!! <
Please speak for yourself. Nobody is an expert in everything. Not me, not you, and not Eric. I accept that Eric is a genius with the math and physics, but I also see aspects of acoustics where I am certain I know more. Sorry, but I call 'em as I see 'em. For example, I would never in a million years need to ask about the relation between flutter echo pitch and boundary spacing, as Eric did recently. I understood that relation completely in 1978 when I built a pro studio and we had to treat the floor-ceiling flutter echo.
I see other shortcomings because of Eric's (self-admitted) lack of understanding about electronics and music. Acoustics and electronics are very similar, and a lot of the same principles apply. Likewise for music and musical instruments. So in that regard my extensive background in electronics and music theory, and knowing a lot about how string instruments work, helps me to understand quite a bit about acoustics. My stating this has nothing to do with pride, and everything to do with my point that different people excel in different areas - even within the general umbrella of "acoustics."
So it's not like one person is "more" of an expert than another, but rather which areas of expertise can be applied to a given situation. If anyone is qualified to explain mass-spring resonance it's Eric. But that doesn't mean he knows more about every aspect of acoustics than you or me or whomever. Someone can be an expert brain surgeon yet not know much about opthamology or dermatology, even though all three are in the field of medicine.
> You know even Eric and Jeff are STILL students of acoustics. <
Yep, just like me and you.
> Half the problems of this feud are caused by this 'Expert Issue' and the pride/ego that's fuelling it. <
Yes, but not only me! For a long time Eric claimed that 705 is worse than 703 and not worth the cost difference. He accused me repeatedly of wasting thousands of dollars of other people's money because of my recommendation to use 705. My Density tests showed this is wrong. I just found an earlier ETF test I'd done in a different room that shows the superiority of 705 even more clearly. When I get a chance I'll post that too. In the mean time consider how Eric and a few others responded to my Density report. It was attacked because it disputes what Eric says.
Paul, I have less ego with this stuff than you think, and I have never hid the fact that I've been seriously into acoustics for only three years now. If we could keep the discussion to the facts, and not who's more of an expert, or who deserves to be taken more seriously, much of this would never have been an issue.
> Look at your magazine article in EQ for example. It contained innacuracies. <
Such as?
This is a big problem with you and some of the others, claiming errors in my articles and FAQ, but when challenged never having an answer. Before you reply to anything else I've written in this post, please tell me what's wrong with any of my EQ magazine articles.
> The same principles apply to your Modecalc. Why keep defending it? Why not simply improve it to contain Tangentials and Obliques? <
Because I'm still not convinced that adding them will make my program a better tool! In fact, I fear it will become less comprehensible to the very people who need it most.
> I thought you were a programmer? <
Yes, I am absolutely an expert programmer, proven by my best-selling book (from years ago) that's now on my site as a download. Being able to program non-axials is not the issue at all.
> It almost seems you're challenging the importance of non-axial modes simply to defend your Mode-Calc? <
No, I'm challenging the importance of non-axials because I'm not convinced they're as important as some people say they are. I have already stated here that I don't doubt they account for something. But if they're a problem only sometimes, and even then contribute only a little, why bother? More to the point, how do you explain to a newbie how much weight to give the non-axials?
Suppose someone is designing a basement home theater and they enter their proposed dimensions. Now, when they look at all the modes it might look like the distribution is good when it's really not because the axials, which are far more important, are too widely spaced. Maybe a different type of display could be devised, where axials are shown more darkly, and the others progressively less dark to better show their true importance. Again, I already said I'll consider that. But I need to be convinced they matter enough to include at all. Wes Lachot said here "axial modes are by far the most important modes," and I quoted something similar from Everest. These guys are experts too, more so than you or I. You can't ignore this, or say it's only Ethan who dismisses non-axials!
Thanks in advance for addressing the points I've made here, and not injecting ego or pride into the discussion.
I would like to reiterate that I think the book as a whole is quite good. My personal opinion is that the 3rd edition is a better version. But, in all, it's a good book.
(I am willing to give any author the benefit of the doubt having had my own share of "editing" nightmares...)
_________________ ---lovecow---
"You've got to be very careful if you don't know where you're going, because you might not get there." - Yogi Berra
Rod Gervais Moderator
Joined: Jun 8, 2003
Posts: 3275
Location: Central Village, CT
On page 332 he compares the predicted modes versus what was actually measured in a typical bedroom. (Measured using a slowly swept sine wave, I might add. )
Unlike my test, Everest measured as Bob suggested, with the loudspeaker and microphone at opposite tri-corners. Here too the measured response is not what was predicted, and Everest refers to his attempt to tie the peaks and valleys measured to what was predicted as "disappointing." The disparity shown in Figure 15-9 is not unlike what I showed in my initial post here. Lots of peaks and nulls, with few aligning with any of the predicted modes. So much for opposing tri-corners giving more predictable results...
Folks,
I'm going to say this again - because people must have either missed this or dismissed this........
Unless someone can figure out how to calculate the room based on the exact source of the speakers and location of the mic within the space AND INCLUDE THE ROOM CONSTRUCTION - any mode calcs based on room size are going to appear to be "wrong" when the room is subsequently tested.
Room mode calcs are based on the signal beginning at the face of wall (ceiling, floor) - and completing at the other face of wall (ceiling, floor) ............ and it is physically impossible to do this once we reach the real world and begin testing the room.
Place even a small speaker in a room corner - with a mic in a corresponding corner as tight as you can place them - and you will still not acheive the measurements that the mode calculator programmed to work with.
So you take this - add to it the fact that the walls in a mode calculator are assumed to be non-leaking (acoustically speaking) and you should expect to have very different results in the real world that you have in the model.
It surprises me that Mr Everest (being a very bright man) would be dissapointed by the inability to accurately predict reallity in this case for what he considered a "typical" bedroom.
I would be seriously amazed if ANYONE could come up with a mathematical equation that could accurately take into account all of the possible effects that actual construction materials/techniques and speaker/mic placement could do to change the model in the real world.
The concept of that just blows my mind.
Sincerely,
Rod
_________________ Rod Gervais
Acoustics Moderator Sometimes - late at night..... when the wind whips
through the trees........ and the moon shines bright in my
face......... I think deep thoughts.......... and my head hurts.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
For more information on advertising, investing ,
merging
or any other ideas you may have for this community" Feedback
Pro Audio forums, Pro Audio Dealer, audio reviews and all the moderating here is
volunteer. Please remember no-one is being paid to be here or deliver
hot coffee. Play Fair, be polite, patient and considerate to others. Title your
topics properly and do not slander anyone, ever online. Read this before your post here:Recording
Org Disclaimer
This site can be translated into 13 languages. 錄音工作室幫助下，新聞和信息，數位專業音頻論壇, Opname studio helpen, nieuws en informatie, digitale pro audio forums, Studio d'enregistrement à l'aide de nouvelles et d'information, forums de l'audio numérique pro, Tonstudio helfen, Nachrichten und Informationen, digitale Pro-Audio-Foren, Estudio de grabación ayuda, información y noticias, foros de audio digital profesional. help, pro tools, cubase, nuendo, DAW, AD/DA, microphone, preamp, compressor, equalizer, Music Education, Arranging, Composing, collaboration des musiciens,
professionelle Musiker und Ingenieure,
colaboración de músicos profesionales y los ingenieros lo que pensamos acerca de una banda
Our new beta site is now online for testing The New Recording.org CMS
Also or Non Respected Past RO Acoustics & Design Moderator? 
Check that - I looked a little closer and even Table 15-1 is off a hair. There aren't, in fact, two modes at 90.7 Hz for the dimensions he listed. Nor are their two modes at 122.1 Hz, and there are some other discrepancies above that. Maybe Mr. Everest used the THX calculator!!! 
