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In Reply to: Re: Driver operation & E-mails posted by Tomservo on September 13, 2003 at 07:08:28:
Tom -Here we go with more of your double-speak. If you can't make an argument work to buttress your ego, you'll try misdirection instead.
I have been the person that has consistently stated that loudspeaker phase moves throughout its passband. You, on the other hand, claim it to be consistent, using the oversimplifications that you have said many times before. You claim horns have phase of zero, by generalizing them to be perfectly resistive. And you claim direct radiators have phase of ninety degrees, by oversimplifying them to be uniformly reactive. Neither case is accurate, and so both statements are false.
As for the the nonsense you've said about E-Mail's, I'll say it again: Your purpose was to sensationalize and exaggerate, and you've manipulated the issue in order to sway public opinion.
You could claim that everyone in your company was completely stupid if you wish, and that no one there could read the addresses. Or maybe reading your poor grammer and spelling has caused their reading skills to regress. But it is highly unlikely that everyone in your shop misunderstood these letters, when everyone else that has read them did not.
Wayne
Follow Ups:
Wayne, I composed this reply to the post you just removed (must be nice to be able to take back your words like that).
I am posting it here as it addresses many of the same pointsPerhaps if you carefully re-read what I have explained you will come away with more of the gist of what I was saying and the context it is in, instead of the simplistic view you cite.
If anything, one constant message has been “measure them and find out for yourself”.
I have in fact measured horns where the acoustic phase WAS around zero degrees over its operating band and similarly, countless direct radiators that behave as described.
The detailed explanation was to help you finally understand why it is this way (the way outlined in the technical references that seems so hard for you to accept.)
Not only that but I have been involved in several active sound cancellation projects, one with Penn State (that has a good acoustics program) so the idea of producing a specific waveshape and what is needed to do that is not a new concept to me.
Wayne, it was a bad idea for you to have sent the e-mails to the shop.
No one there knew of our discussions and to them it apparently sounded like some "emotional nut case" threatening legal action.
Surely even you can understand there reason for getting a lawyer to look at them and give his “read” (ever heard the expression “better safe than sorry”?) , on the other hand maybe your back to suggesting you didn’t send them?Wayne also wrote:
I'm not the only person that considers you to be a charletan, so you can give up on this crusade you've had for the last few years.Yes, I imagine you do have some friends who think just like you, but I would be surprised if you can find many actual technical people who dispute the operation of what we make and what I do or the argument I made here.
I figure AES and ASA would not have asked me to speak (as an invited speaker) on loudspeakers and transducers etc if they agreed with you on technical grounds. What have they asked you to speak about btw?
On the other hand, largely as a result of side by side demo’s, we are taking away business from a number of larger companies and I don’t imagine they are too happy about that, sour grapes.Also, In your e-mail to me, you accuse me of bashing your products, if your willing to lie about something like that (something where anyone curious can simply go back and look to see what I actually said) , how much of what else you say is also fiction (lies) to
forward Your image in Your market here.
We on the other hand sell NOTHING at all to this market, I am here because I like DIY.
Yes, it did piss me off that you would jeopardize my involvement in DIY here by taking your supposed “problems” to the company I work for.
I did post an explanation here as to why I had to be absent and since it was a 100% a direct result of your e-mails, I told it like it was (without actually saying your name you will notice).
Now that you have tried to slime out of it, it seemed appropriate to fill in the blanks with the missing name, Wayne.
Face it, you farted in Church and now you have to sit in your own pew.
No amount of your arm waving changes what happened as a result of your e-mails.Fwiw, I would also doubt that regardless of your own self image, that you think you can actually speak for everyone else on this as you suggest.
Cheers,
Tom
Tom -Doesn't this kind of thing ever get old to you? Do you enjoy acting like this?
In my first reply to you on this thread, I said "The mass/spring system forms a filter that changes phase with frequency." You, on the other hand, initially described it only partially - inaccurately - speaking only of the mass and disregarding the suspension. You said nothing of cone geometry and the other things that modify system behavior and prevent it from acting as a pure single pole.
So you merely invented an argument, as you had nothing useful to say. Your comments were out of place because my first post on this thread was a reply to Tom Dawson. It was about quadrature and DSP, and my reply referenced the subject and included links to DSP information. So you simpy derailed the thread and nothing more. You were combative because you wanted the attention, and that's all.
It is this very sort of action that has illustrated your real intentions. Your motives are clearly self-promotional, and you engage in all forms of deception towards that aim. You are manipulative, by inventing arguments and derailing useful conversations to promote yourself or your agenda. You are divisive, by misrepresenting issues such as the one about the E-mails. But the thing that is probably most unattractive is your arrogance, which shows in practically everything you write.
And speaking of the E-Mails, you keep talking about my "sending E-mails to the shop," as if I had sent something to people other than yourself within your little company. The fact is that this comment is another piece of spin - The address used was "tom@servodrive.com" and where this goes is your affair alone.
I pulled my last post and re-submitted it to remove the last sentence, which was "I'm not the only person that considers you to be a charletan, so you can give up on this crusade you've had for the last few years." It's another issue entirely, but I can't help but to wonder how you feel about your peers and suppliers beginning to distance themselves from you. I wonder what happened to Intersonics, and if it is happening again. With your behaviour patterns, you certainly can't be gaining any friends.
Wayne
Hi Wayne,In the time it took to reply , you withdrew your post again.
Here was my reply to it> Doesn't this kind of thing ever get old to you? Do you enjoy acting like this?
Rebutting your feeble nonsense is getting old but the kids are at Gramma’s, Mark has the TEF machine and I am bored.
> You, on the other hand, initially described it only partially - inaccurately - speaking only of the mass and disregarding the suspension. You said nothing of cone geometry and the other things that modify system behavior and prevent it from acting as a pure single pole.
Wayne, go back and read what I said, I describe the spring-controlled region as well as touch on the other effects which come into play well above low cutoff.
What we were discussing was the mass controlled response and the phase shift that goes along with it and what causes it and what you see when you measure it.> So you merely invented an argument, as you had nothing useful to say. My first post on this thread was to Tom Dawson, and it was a list of links to DSP information. You simpy derailed the thread and nothing more. You were combative because you wanted the attention, and that's all.
The post you were replying to was one that included the very things I continued to press with you.
Why in fact did you insert your self in it if it wasn’t for self puffery?> It is this very sort of action that has illustrated your real intentions. Your motives are clearly self-promotional, and you engage in all forms of deception towards that aim. You are manipulative, by inventing arguments and derailing useful conversations to promote yourself or your agenda. You are divisive, by misrepresenting issues such as the one about the E-mails. But the thing that is probably most unattractive is your arrogance, which shows in practically everything you write.
My gosh if that isn’t the pot calling the kettle black, you could probably have a bright future in politics if you want.
Deception, heck I am the one saying measure it for your self and see, some deception sheesh.
Hey Wayne, with all your talk about promotion, perhaps it didn’t occur to you that I don’t sell anything here, I have no DIY products, no one here is likely to buy the companies stuff and we already have a good reputation in our industry. What the heck do you think I am promoting here?
You on the other hand obviously have a great deal of interest protecting your image in your own market so why do you engage in these arguments? Why accuse me of bashing you and your products anyway?> And speaking of the E-Mails, you keep talking about my "sending E-mails to the shop," as if I had sent something to people other than yourself within your little company. The fact is that this comment is another piece of spin - The address used was "tom@servodrive.com" and where this goes is your affair alone.
Spin you say, I would say spin was you trying to make it sound like you didn’t send the e-mails that caused my absence from here.
When you sent your e-mail to me at home, you were sending it to me.
My DIY involvement is not an official part of my job understand, nor do I work at the shop, when you sent them to Tom@servodrive.com, instead, that is at the shop.
Pat at the shop checks all the e-mail and deals with it accordingly, in the process, she read yours and did what she thought was right.
I will get those e-mails Monday fwiw.> I pulled my last post and re-submitted it to remove the last sentence, which was "I'm not the only person that considers you to be a charletan, so you can give up on this crusade you've had for the last few years."
Name calling, calling me a Charlatan, teasing about spelling and grammar, real nice, it highlights what a “very special” person you are.
Makes me feel like cutting you some slack, you know what I mean?.> It's another issue entirely, but I can't help but to wonder how you feel about your peers and suppliers beginning to distance themselves from you.
I don’t know, I’ll let you know if it ever happens.
> I wonder what happened to Intersonics,
The focus of the company was on the NASA flight hardware and material sciences.
When NASA hq gave contract authority over our area (containerless processing) to JPL (who was our only competitor) it wasn’t long before the 4.5 M a year flight hardware / research budget went to zero.
The materials side spun off under a new name called Containerless Research Inc, the speaker side was spun off into the hands of a crook from south Africa by the president of Intersonics, then after that disaster Brad took it over and since then we have continued to grow steadily.> and if it is happening again.
No, Servodrive and Sound Physics Labs are a speaker company first and if I do any more gov’t work, it will be on our terms.
> With your behavior patterns, you certainly can't be gaining any friends.
If you were a problem in our market area, I would have to deal with you differently than here it is true.
Here I can saw what I think and not mince words if I choose.
As long as you and the sock puppets that were around here in your absence, are the only antagonistic people that have to deal with, I am not concerned.Cheers,
Tom
OK, Tom, so let me see if I get this straight:You say the letter from John Hancock that was forwarded to you, and my reply that was also copied to you, were misunderstood by you and everyone else in your shop. Copies of the exchange between John and I are here . You say you believed they were written to you, even though one was addressed to "Wayne" and the other to "John."
That's what you're saying? I mean, that is really pretty stupid. Then again, I suppose it might be better than to admit that you intentionally misled the public.
Now let's see; What other nonsense have you written for me to dissect?
You wrote:
> > I describe the spring-controlled region as well as touch on the
> > other effects which come into play well above low cutoff.You didn't mention that for several posts. In fact, you argued against this when I described the behavior of the system in regions of resonance and below-resonance, and the transition from being acoustically small to being acoustically large. That's just a few posts up , and it's all here in black and white, showing your tendency to be combative and invent arguments where none should exist.
Your first posts suggested that the system creates purely a 90 degree lagging phase shift. And frankly, you were quite rude in your demeanor, which gave me the inclination to treat you in kind. Especially since you took the tone of disagreement when I mentioned regions where this was not true. So it was obvious to me that you just wanted to be argumentative.
This is a common strategy that I've seen from you. You will equivocate, using only the part of the truth that you think justifies your position. It's like telling half-truths and choosing which half suits you best. I've even watched you change sides in order to make a different point. But when you buttress an argument with equivocation, the omission makes your statement false.
And speaking of equivocation, lets talk about your usual description of the impedance of horns. They act to increase radiating resistance, but they do have a reactive component. You have minimized this in your discussions of them - just as you did in the link above - and you consistently characterize them as being purely resistive. But even the best horns are nowhere near this ideal.
So how about you commit to something here, and make a definite statement. Tell us how you would describe the real and imaginary impedance of a horn. Tell us how near or how far from cutoff they can be expected to become resistive rather than partially reactive.
Something like this would be acceptable. This shows the acoustic impedance of the horn, with reactive and resistive components clearly visible. Notice that this horn is intended to be used from 40Hz-400Hz, and pay attention to the resistive/reactive impedance in this region:
Horn response and acoustic impedance
Clearly, there is significant reactance in the passband.
-and-
This means that acoustic phase cannot be zero.
Pressure and velocity are not in phase and are instead periodically changing like a series of resonances. That's also why the amplitude response has slight ripples, just like the phase response does.
You might prefer to see this demonstrated with data provided by an unbiased source, perhaps using a real-world horn that can be duplicated. Measurements can be made with the two-microphone method or models can be used instead, I don't care. But there is no denying this fact - No matter what horn is used, this is their very nature so they will all show this type of response.
Or maybe you will show the impedance chart for some of your horn products, to demonstrate their impedance curve and indicate their acoustic phase. It would not be acceptable to see data that was generalized or "doctored." So be careful now, because just about anyone can find this out for themselves.
> > What the heck do you think I am promoting here?
Yourself.
> > Why accuse me of bashing you and your products anyway?
Because you are, and have been for a long time. That's what this thread is about, and that's what the nature of our relationship has been about from the start. You are so arrogant and self-righteous that you believe you can attack everyone and that they should not argue their points in response.
I see where Mark Seaton got his example, and the things he said in the past were heavily influenced by you. You are the one that drives this thing, and you are solely responsible for the public image of your company.
> > I would say spin was you trying to make it sound like you didn't
> > send the e-mails that caused my absence from here. When you sent
> > your e-mail to me at home, you were sending it to me. My DIY
> > involvement is not an official part of my job understand, nor do
> > I work at the shop, when you sent them to Tom@servodrive.com,
> > instead, that is at the shop.So you don't read your own E-mail's? Try having someone write your E-Mail's then too. Someone who has taken a little bit of remedial English perhaps. Your grammer makes me feel like I'm reading something written with a crayon.
> > Name calling, calling me a Charlatan, teasing about spelling and
> > grammar, real nice, it highlights what a "very special" person you
> > are. Makes me feel like cutting you some slack, you know what I
> > mean?.That's right, Tom. You've always been so kind that it saddens me to see our relationship sour this way.
I noticed that you called yourself a Charletan with a capital "C". I didn't capitalize the word, but your use is fitting and appropriate. I've grown to recognize you as the "P.T. Barnum of the industry."
Wayne
> OK, Tom, so let me see if I get this straight:By gosh, that would be a refreshing and long over due but I will be surprised if you can pull it off.
> You say the letter from John Hancock that was forwarded to you, and my reply that was also copied to you, were misunderstood by you and everyone else in your shop. Copies of the exchange between John and I are here. You say you believed they were written to you, even though one was addressed to "Wayne" and the other to "John."
Wayne, I received ONE e-mail, the one I posted, then my isp was down and I could not receive any e-mail here.
You sent e-mails to the shop (probably because I didn’t respond to yours I would guess) , e-mails which so far I have not seen.
Pat at the office read them and called me about you.
Pat also gave Brad the e-mails and it was decided that “to be safe” the lawyer should see them and I should be absent from here until he makes a call on it.
I have explained this a number of times, get it yet? Probably not.> That's what you're saying? I mean, that is really pretty stupid. Then again, I suppose it might be better than to admit that you intentionally misled the public.
Mislead them about what?
What I described is what happened and while it is true I could have just signed off without explanation, I was angry that you would be the cause of it and did post “why” I was leaving.
Perhaps that made you feel uncomfortable, perhaps people thought you were responsible (as you were) but that is what happened.
Going back and reading the post you sent me, I again ask you to find examples of the bashing of your products you claimed I was doing at the time, you know, the reason you sent me the e-mail in the first place.So far as what I see, misleading the public is what you tried to do by suggesting that you didn’t write the e-mails or that the incident was made up by me.
> Now let's see; What other nonsense have you written for me to dissect?Yes Wayne dissect away, that way you never have to deal with the context or big picture, things that lead to understanding...
You wrote:
> > I describe the spring-controlled region as well as touch on the
> > other effects which come into play well above low cutoff.> You didn't mention that for several posts. In fact, you argued against this when I described the behavior of the system in regions of resonance and below-resonance, and the transition from being acoustically small to being acoustically large. That's just a few posts up, and it's all here in black and white, showing your tendency to be combative and invent arguments where none should exist.
Wayne, you see the combative side because your approach brings that out in me, it is hard to deal with some one like you who, if you could only do some measurements on the real thing would see what I was talking about.
Also, if the discussion was just starting here, I could understand your not being “up to speed” technically but there have been many many past discussion with you about the Unity horn and how the phase of everything matters etc. While you have stopped your “it can’t work” campaign on the Unity, I doubt that you have forgotten all the posts.Acknowledging this argument or that phase / time matters would also make you have to consider the acoustic phase of your designs as well, something you have seemed reluctant to do in the past. I guess this is a “window” that you can’t afford to open psychologically.
> Your first posts suggested that the system creates purely a 90 degree lagging phase shift. And frankly, you were quite rude in your demeanor, which gave me the inclination to treat you in kind. Especially since you took the tone of disagreement when I mentioned regions where this was not true. So it was obvious to me that you just wanted to be argumentative.
Wayne, again your dissecting approach prevents you from seeing the big picture.
For example, when I say nominal 90 degree shift, that is not the same as you saying purely a 90 degree shift. So you understand better, “nominal” in this use means approximate or “averages around” and not “is exactly” or “is purely”.I “Want you to be argumentative”, that’s funny, I wonder, can you even “turn it off” when someone disagrees with you? Actually quite the opposite was true, it was nice when you were gone.
> This is a common strategy that I've seen from you. You will equivocate, using only the part of the truth that you think justifies your position. It's like telling half-truths and choosing which half suits you best. I've even watched you change sides in order to make a different point. But when you buttress an argument with equivocation, the omission makes your statement false.
Fine Wayne, normally when I explain something technical to someone, I assume I do not have to explain every thing. Normally I deal with technical people who want to understand something new, not one whose mind has been made up and is unwilling to even consider something different.
> And speaking of equivocation, lets talk about your usual description of the impedance of horns. They act to increase radiating resistance, but they do have a reactive component. You have minimized this in your discussions of them - just as you did in the link above - and you consistently characterize them as being purely resistive. But even the best horns are nowhere near this ideal.
Wayne, the fact is I have measured a number of horns who’s acoustic phase WAS around zero degrees through out a considerable bw.
I have also dealt with systems that HAD TO preserve waveshape so I do have a grasp of what is going on.
Clearly I am unable to put these points into words (that you understand) and without the common ground of measurement, I don’t know how else to fill you in.
I guess if anything I would say that you seem to have a good grasp of the elements in involved but do not have much of an idea where or how much various things come into play.
Your approach reminds me of some one who has read a lot, knows the terms but has never actually built drivers or measured them first hand, that would be my guess anyway.> So how about you commit to something here, and make a definite statement. Tell us how you would describe the real and imaginary impedance of a horn. Tell us how near or how far from cutoff they can be expected to become resistive rather than partially reactive.
> Something like this would be acceptable. This shows the acoustic impedance of the horn, with reactive and resistive components clearly visible. Notice that this horn is intended to be used from 40Hz-400Hz, and pay attention to the resistive/reactive impedance in this region:> Horn response and acoustic impedance
> Clearly, there is significant reactance in the passband.
-and-
> This means that acoustic phase cannot be zero.
Yes Wayne, you are right in the strictest sense, no horn I have seen will have say
a + - .0001 degree acoustic phase around zero.
I have seen horns which were say + - 5 degrees and more that were say + - 10 degrees around zero.
However, to put this in your dreaded concept “context”, in all the discussions so far we have been talking about the difference between direct radiators and horns, direct radiators generally have an acoustic phase which goes from +90 well below cutoff to ~ –90 mid band to ~ +90 well into inductive roll off, with the possibility of hundreds more degrees if operated into cone breakup or non piston behavior. While I didn’t explicitly say so, this also means they traverse zero degrees.One thing you perhaps don’t realize is that by matching the impedance of the acoustic source to the horn’s average Z, the effect of the acoustic impedance variations is minimized so far its effect on acoustic output. This is because when the impedance’s are matched, one has maximum power transfer and shifting one of the two to one side or the other has little impact, one is siting on the top of a curve here..
This is the principal on which antenna power transfer is based and is different than the case when a low impedance voltage source is driving a changing impedance load.
For example in the Bdeap’s (measurements will be on the web site shortly), there is no visible low end ripple in the acoustic output and so, no ripple in the acoustic phase.> Pressure and velocity are not in phase and are instead periodically changing like a series of resonances. That's also why the amplitude response has slight ripples, just like the phase response does.
> You might prefer to see this demonstrated with data provided by an unbiased source, perhaps using a real-world horn that can be duplicated. Measurements can be made with the two-microphone method or models can be used instead, I don't care. But there is no denying this fact - No matter what horn is used, this is their very nature so they will all show this type of response.
> Or maybe you will show the impedance chart for some of your horn products, to demonstrate their impedance curve and indicate their acoustic phase. It would not be acceptable to see data that was generalized or "doctored." So be careful now, because just about anyone can find this out for themselves.Just as nothing I say to you will ever persuade you of anything (so far as the technical argument) , no measurements YOU come up with would convince me that the measurements I have taken and the stuff I have built based on them are based on fiction.
You caution about “being careful”, is humorously ironic both coming from one who doesn’t measure and as the measurement savvy part of the sound industry has embraced us most readily.
I am counting on the fact that real acoustic measurements ARE the language that our customers deal with. Some have the same measuring equipment I do.
Soon there will be a button on the web site where customers with a tef can download the actual measurement files on our products so they can compare with our products they have if they wish or other people’s products they measured.Further, Heyser’s view of acoustic phase is not a “LAW”, companies that sell MLS based systems often claim their technique shows “true acoustic phase” so there can be a difference in measured results on the same speaker in the same conditions.
Personally, I believe TDS is the way to go and agree with the manual for LSP cad which explains why the MLS systems do not show true acoustic phase ( page 117).
That explanation includes the Hilbert transform, which was in the thread you jumped into.
Such systems would show a horn and direct radiator with identical frequency response as also having identical phase response, which they do not normally have.
This was also part of the thread you inserted yourself into btw.
> > What the heck do you think I am promoting here?Yourself.
Sorry, I’m not for sale
> > Why accuse me of bashing you and your products anyway?
> Because you are, and have been for a long time.
Lets see some examples of me bashing your products, put up or shut up!!.
> That's what this thread is about, and that's what the nature of our relationship has been about from the start. You are so arrogant and self-righteous that you believe you can attack everyone and that they should not argue their points in response.
I see where Mark Seaton got his example, and the things he said in the past were heavily influenced by you. You are the one that drives this thing, and you are solely responsible for the public image of your company.Attack everyone?????, no Wayne, just responding to you..
You say “You are the one that drives this thing, and you are solely responsible for the public image of your company.”
In a way this is true, I do design everything we sell and the performance of our stuff is what we are known for.
> > I would say spin was you trying to make it sound like you didn't
> > send the e-mails that caused my absence from here. When you sent
> > your e-mail to me at home, you were sending it to me. My DIY
> > involvement is not an official part of my job understand, nor do
> > I work at the shop, when you sent them to Tom@servodrive.com,
> > instead, that is at the shop.> So you don't read your own E-mail's? Try having someone write your E-Mail's then too. Someone who has taken a little bit of remedial English perhaps. Your grammer makes me feel like I'm reading something written with a crayon.
I didn’t read my e-mails when they couldn’t be forwarded to me at least this sliver of what you said IS true.
Gee Wayne, I am hurt, your slander and insults make such a powerful argument, such a powerful intellect at work here, clearly, I am out of my league with you (Thank God)..
> > Name calling, calling me a Charlatan, teasing about spelling and
> > grammar, real nice, it highlights what a "very special" person you
> > are. Makes me feel like cutting you some slack, you know what I
> > mean?.That's right, Tom. You've always been so kind that it saddens me to see our relationship sour this way.
I noticed that you called yourself a Charletan with a capital "C". I didn't capitalize the word, but your use is fitting and appropriate. I've grown to recognize you as the "P.T. Barnum of the industry."You caught that, huh, I figured that was too subtle for you to notice.
I used caps because you misspelled charlatan in your post and I thought it was funny that you would harp on spelling and grammar as if it meant anything relevant to the discussion.You say . I've grown to recognize you as the "P.T. Barnum of the industry."
So... that would make you what, either Bozo the Clown or John Wayne Gacey, I suppose..
Cheers,
Tom,
Well, Tom, I see you'd rather talk around the subject than respond to it directly.The E-Mail issue was a fabrication of yours.
And the phase issue is an equivocation of yours.
You rightly discuss that having a resistive load is a requirement for zero phase. That's your argument why horns are better in phase than direct radiators. But when the issue is illustrated - and the reactive component is actually quantified - you backpeddle and use a different argument instead.
So rather than just admitting it and discussing the matter honestly, you go into one of your long diatribes, in an attempt to talk your way around the issue.
You're really a piece of work.
Wayne
Hi Wayne> Well, Tom, I see you'd rather talk around the subject than respond to it directly.
If it were anyone else, what I have said in many posts would have been considered responding directly. There are speaker designers on this list that have picked up technical things from my posts to you, or at least that’s what they say.
Unfortunately, I apparently don’t speak “Wayne speak” I guess, so I doubt I could even convince YOU the Sun would rise in the morning..The E-Mail issue was a fabrication of yours.
This is rich, you could choose to admit that it was your e-mails that caused me to be absent rather than try to make it sound like there was no issue, that I made them up or you didn’t send them.
This is pretty funny watching you try to slime out of it though.
> And the phase issue is an equivocation of yours.Ok Wayne, maybe things ARE different in Wayne’s world, maybe phase and physics are different too in your special “land without measurements”, clearly we are on different pages here.
Maybe the references I cited are wrong in your special place too.
If I were you, I would proceed at maximum magnitude in whatever vector you think is best. You are entitled to your own view of things after all as am I and I am perfectly content to know you’re off designing your boxes in your own special way.> You rightly discuss that having a resistive load is a requirement for zero phase. That's your argument why horns are better in phase than direct radiators. But when the issue is illustrated - and the reactive component is actually quantified - you backpeddle and use a different argument instead.
No, not a different argument at all, if you were paying attention or “wanted” to understand you might have at many points on this journey. You choose “not to see” which is different than ignorance, you are simply one very stubborn / proud fellow who desperately wants to be in the speaker business (my take)..
> So rather than just admitting it and discussing the matter honestly, you go into one of your long diatribes, in an attempt to talk your way around the issue.Yes, the posts are longer than you deserve, I keep having this glimmer of a suspicion that you really do want to understand rather than just be the root of a technical Monty Python argument sketch.
If you were interested though, you would have already done enough homework to know how drivers and horns work at this level. Sadly, if I were to waste more time and words trying to clarify it, you would simply call it more diatribes or pick one or two words to focus on.
I see you also carefully avoid mention of the “product bashing” you insist I was doing after I asked you to “put up or shut up”
This was the issue you wrote me and the shop about wasn’t it?, the e-mails that were the problem remember.
Again “put up or shut up”, you accused me of bashing your products a number of times (read your e-mail) show the examples of what you wrote about and stop lying.> You're really a piece of work.
Thanks Wayne, coming from you that is re-assuring.
Just as I am willing to let my posts stand on there own, I hope the readers of your posts here also gain an added appreciation for the “depth” of your personality, I know I have.
TaTa.Tom
Honestly, Tom, I'm expecting an apology.You need to acknowledge the manipulative tactics you used in this E-Mail thing . It was entirely a fabrication of yours, and you need to be held accountable for it.
You also need to be taken to task for the spin you've placed on technical matters . Especially when you become combative and argumentative just for the sake of self-promotion.
You've badgered me this way for years, and you've always been wrong to do so. Sometimes I've reacted to you and responded similarly. Sometimes not. But in general, I think this kind of thing is bad and don't care for it at all.
When disparate results are obtained using different measurement systems, one must consider the possibility of ambiguity. But there is no ambiguity in the correlation between phase and the ratios of real and imaginery impedance. You can easily find phase when resistance and reactance are known.The relationship between phase and impedance is determined by the following formula:
θ = ArcTan i / r
where,θ is the phase angle
i is the imaginary or reactive impedance, and
r is the real or resistive impedanceConsidering this, you can easily find the phase where impedance is known.
So let's look again at the response chart for a horn:
You can see that the horn is intended to be used from 40Hz to 400Hz, so that's the region of interest. You'll notice that the device is quite reactive, meaning that it has non-zero phase. And it isn't trivial - It is a significant amount. For example, phase θ = 65 o at 55Hz, 45 o at 110Hz, 30 o at 200Hz and 20 o at 400Hz, where the horn has reached upper cutoff. Phase isn't consistent either, but instead is a series of ripples representing large closely-spaced changes in phase.
Wayne
Hi WayneI don’t know the dimension of the horn you have modeled but there are a few things one can tell about it from the curves.
It would appear to be a horn that is 1 / 2 wl or longer vs the minimum 1 / 4 wl length (a guess based on the spacing of the ripples).
Based on the frequency response ripples, I would guess the driver is not a good match and / or the mouth is not large enough. This would not be a high efficiency horn.
Response ripples in the output can be caused by a mis-match at either end of the horn IE: mouth too small or driver not suitable. The latter is where the M.L. math is useful.
Fwiw, simpler models (like spice models or the transmission line model I use) also tend to over state the “Q” of such ripples compared to measured results (suggesting there are un-accounted acoustic losses).While this model show ripples in the output up to the high cutoff, it is not necessary to have them when everything is right.
The thing is, whatever the horns impedance is, it is not the definition of what comes out the mouth of the horn.
The horn has an acoustic “impedance” curve, which changes most rapidly in the range near the lf cutoff. Driving that horn is a driver that also has an acoustic impedance and reactance.
When the source and load (driver and horn) are matched, there can be a considerable change in either with a minimum effect on the output.
For example with a nominally matched source and load, one can change the load to 2X or 1 / 2 the original and see less than a 2 dB change in output power. Contrast that to the 6 dB spread when a voltage source is used on a changing load.
Since the driver’s impedance is in series, the effects of phase shift are also reduced (like any reactance in series with an R compared to just the reactance).
The driver also has reactance, however it is customary to make this a conjugating quantity, either by proper sizing of the driver properties and rear volume and / or adjusting the horn flare hyperbolic constant which shapes the rate of change of resistance and reactance (reactance annulling)Anyway, I have to help with some homework so I have to keep this short.
Since you have a way to model horns, how about if I see if I can find parameters which result in little or no ripple in the response. I will post the specifics (since I can’t post images) and you take your program or Mc Beans and see how it looks. Conversely, if this is a real horn you have, let me know the specifics and I will see if I can find a driver which is a better fit.40 to 400 Hz is wider bandwidth than most of the single horns I do but I think flat response in that range would be possible.
Without ripples in the output, there will be no ripples in the output phase as well.
With a horn that is more resistively dominated, the phase will be around zero at the output (after all the fixed delays are removed ala Heyser) and the result is also a more efficient horn
Remember it is only the efficient horn which is resistively dominated and having an acoustic phase around zero degrees.Shortly at the new web site there will be measurements for the Bdeap, while narrower BW than your example, acoustic phase is around zero from somewhat above low cutoff through its operating band.
Also if I recall, the BT-7 response curve also has the acoustic phase plotted.
Got to runTom
Perhaps you will post some examples of horns that have zero phase throughout their passbands. You have promoted time alignment as one of your main marketing strategies, so I can see that you are zealous about it. But I don't find it to be particularly accurate to state the generalization that horns are resistive and therefore phase is zero. Frankly, I always considered your "zero-phase" assertion to be a generalization at best.Horns do become more resistive at higher frequencies, and so there is some reason to mention this general trend. But the fact is that they are not purely resistive, and really aren't even predominantly resistive. So for you to say "horns are resistive" in an argument about phase or acoustic impedance is an overgeneralization that leads people to an inaccurate conclusion.
So I suggest that you back up this assertion with some demonstratable facts; Even when modeling hypothetical infinite horns there is a large reactive component, so it will suprise me to see evidence to the contrary, particularly on a finite horn. But you'll excuse me if I won't accept your measurements as evidence.
Dimensions and specifications would be acceptable, so that they can be used for modeling purposes. Or independent measurements from an impartial lab would be fine. But I think you can understand why I might be a bit skeptical of data coming from you after the comments you've made on this thread and others.
You might not accept my measurements either. I typically don't publish measurements for this very reason, and would prefer that anything we use as evidence come from an independent and impartial source. But anyone interested can use these discussions as "seeds for thought" and do their own analysis. Below are measurements of several horns connected directly to an amplifier without any crossover or electronic reactive components in the circuit, not even a protective capacitor.
Amplitude response is shown in black, phase is gray.
Altec 811
Edgar 650
Eminence H290
JBL 2370
Martinelli 17"
Peavey CH-3
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