Re: Re: Re: Re: My personal opinions of various design philosophies
I have not jumped to any conclusions except that I think it will be hard to find a solution that simultaneously does all these things:
1. Provide smooth amplitude response through the passband
2. Provide constant horizontal beamwidth through the passband
3. Provide constant vertical beamwidth through the passband
4. Small enough that the vertical nulls are outside the vertical beamwidth when combined with another driver
However, I am certain that an elliptical or rectangular waveguide / horn can be made that has a taller forward lobe, i.e. wider angle to the vertical nulls. I am also certain that a very good horizontal pattern can be obtained with smooth response through the pattern. I am certain of this because I've made horns that do this, and I've used others made by vendors I was very satisfied with.
Earlier, I said:
To which you replied:
Well, first I must say you might have misunderstood me. When I say an asymmetrical horn can be made "better", I was talking specifically to the position of the vertical nulls, and therefore the size of the forward clean lobe. I don't believe anyone would argue that closer spacing isn't an advantage in that it grows the size of the forward lobe in the vertical axis.
Second, I would suggest the whole argument is a judgement call, not an absolute. You seem to optimize horizontal at the expense of vertical. I would look for a more balanced design. I mean, I wouldn't throw the baby out with the bathwater - I wouldn't use a horn that had horrible horizontal performance just to gain a little better vertical. But I would trade a little horizontal to avoid having a vertical null too close to the forward axis. People don't move just horizontally, they also sit at different heights.
gedlee said:
I have not jumped to any conclusions except that I think it will be hard to find a solution that simultaneously does all these things:
1. Provide smooth amplitude response through the passband
2. Provide constant horizontal beamwidth through the passband
3. Provide constant vertical beamwidth through the passband
4. Small enough that the vertical nulls are outside the vertical beamwidth when combined with another driver
However, I am certain that an elliptical or rectangular waveguide / horn can be made that has a taller forward lobe, i.e. wider angle to the vertical nulls. I am also certain that a very good horizontal pattern can be obtained with smooth response through the pattern. I am certain of this because I've made horns that do this, and I've used others made by vendors I was very satisfied with.
Earlier, I said:
Wayne Parham said:
To which you replied:
gedlee said:
Well, first I must say you might have misunderstood me. When I say an asymmetrical horn can be made "better", I was talking specifically to the position of the vertical nulls, and therefore the size of the forward clean lobe. I don't believe anyone would argue that closer spacing isn't an advantage in that it grows the size of the forward lobe in the vertical axis.
Second, I would suggest the whole argument is a judgement call, not an absolute. You seem to optimize horizontal at the expense of vertical. I would look for a more balanced design. I mean, I wouldn't throw the baby out with the bathwater - I wouldn't use a horn that had horrible horizontal performance just to gain a little better vertical. But I would trade a little horizontal to avoid having a vertical null too close to the forward axis. People don't move just horizontally, they also sit at different heights.
gedlee said:
Zilch has been an enthusiastic proponent of horns, with over ten thousand posts on the subject on various message boards. He's even featured in Wired magazine this month!
But he never answered my question. If I'm not mistaken, he's never heard one of your speakers. And it doesn't appear that he's heard a truly uncompromised waveguide. (The "progressive transition waveguide" isn't a waveguide, it's a horn.) You've only done a demo in public once, right? Back in 2005 at the RMAF?
There's a handful of people on this thread who've listened to the "New School" waveguides as well as the "Old School" horns. But it's going to be a few years before uncompromised loudspeakers with waveguides are widely available.
Until everyone has an opportunity to listen to the New School, all this hand waving about data is, well, academic.
That's what's so frustrating about this thread. Even the name is silly: "Horn versus Waveguide."
We'd be better off discussing "Republican vs Democrat." Horns and waveguides are two completely different animals. And just as it's possible to have a Republican that leans to the left, it's possible to have a horn that's almost a waveguide.
If there's anyone on the list who wants to listen to one, instead of read about one, there's gotta be an audio club or show in the Pacific Northwest this Summer. I'll throw them in the car and demo 'em, I'd love to convert a few people...
Re: Re: Re: Re: Re: My personal opinions of various design philosophies
And here in a nutshell is our difference of opinion. I would NOT compromise the critical horizontal pattern in any of my designs. That is because the nulls ARE far enough away from the central axis that they are never a problem. Putting them wider may look better on paper, but they are still there and as long as the listener is NOT within one, it isn't very important where they are. We've been trough ALL of this before, but I think that it was worth repeating.
And Wayne, you seem to forget that my speakers ARE NOT designed for axial listening. The vertical nulls are along the speakers vertical axis. There ARE NO nulls along the listener vertical axis at all.
I'm going to start to show my data taken about the listener axis NOT the speaker axis. Floyd Toole encouraged me to do that because he said it was misleading to show the data about an axis that was not the way the speakers were designed to be used. This is what I am going to do the next time that I take data and I WILL show the vertical polars along the listener axis because thats what's important, not some axis that is convenient. What is going to confuse people however is that along that axis the system is not symmetric and may not look CD, even though it is. AL CD means is that all angles are the same, symmetry is not a requirement.
Wayne Parham said:
And here in a nutshell is our difference of opinion. I would NOT compromise the critical horizontal pattern in any of my designs. That is because the nulls ARE far enough away from the central axis that they are never a problem. Putting them wider may look better on paper, but they are still there and as long as the listener is NOT within one, it isn't very important where they are. We've been trough ALL of this before, but I think that it was worth repeating.
And Wayne, you seem to forget that my speakers ARE NOT designed for axial listening. The vertical nulls are along the speakers vertical axis. There ARE NO nulls along the listener vertical axis at all.
I'm going to start to show my data taken about the listener axis NOT the speaker axis. Floyd Toole encouraged me to do that because he said it was misleading to show the data about an axis that was not the way the speakers were designed to be used. This is what I am going to do the next time that I take data and I WILL show the vertical polars along the listener axis because thats what's important, not some axis that is convenient. What is going to confuse people however is that along that axis the system is not symmetric and may not look CD, even though it is. AL CD means is that all angles are the same, symmetry is not a requirement.
Earl (Or any else that might know the answer ....)
What was the process that Electro-Voice used for their old Sentry horns? Those old horns were well damped and had mass to them. Was it a poured system they used?
What was the process that Electro-Voice used for their old Sentry horns? Those old horns were well damped and had mass to them. Was it a poured system they used?
Patrick Bateman said:
The name is fair and the test was fair and reasonable. Some people just didn't like my opinion and that's what led us to where we are now. They see the data one way and I see it another. I explained what I saw in the data, but that was rejected. What I will NOT agree to is that my presentation was not fair or that I had some "alterior motive". Thats just plain insulting. I showed the data just as I got it and I see it as a typical example of the problems with horns.
If horns don't sound bad to you then I guess its a typical example of what's great about them.
Clearly a Horn lover is not going to like what I have to say. None of them have.
Carl_Huff said:
Sorry Carl, I don't really know. I know the current processes that are available, and their strengths and weaknesses, but I'm not up on what people did in the past.
Re: Re: Re: Re: Re: Re: My personal opinions of various design philosophies
You're exactly right, that IS our difference of opinion. I think the vertical nulls should be separated further than you seem to. I also think that it is desirable to limit HF at large vertical angles.
I did not forget that at all. My speakers are like that too, although there is no null straight on axis. It's just that they work best toed in. The cornerhorns require it, and they're really what started me looking at the Hass effect and how it improves imaging when CD speakers are toed-in, crossed in front of the listener. In that respect, we agree.
That's cool, display the data however you want.
I've evaluated a lot of CD horns and what would now be called waveguides over the years. You and I talked about ellipticals back in 2005 at the Great Plains Audiofest. It's all very good stuff to me, moving closer to the ideal all the time. But I still find some little eddy currents in the state of the art, a few things I always seem to come back to. This is one of them.
gedlee said:
You're exactly right, that IS our difference of opinion. I think the vertical nulls should be separated further than you seem to. I also think that it is desirable to limit HF at large vertical angles.
gedlee said:
I did not forget that at all. My speakers are like that too, although there is no null straight on axis. It's just that they work best toed in. The cornerhorns require it, and they're really what started me looking at the Hass effect and how it improves imaging when CD speakers are toed-in, crossed in front of the listener. In that respect, we agree.
gedlee said:
That's cool, display the data however you want.
I've evaluated a lot of CD horns and what would now be called waveguides over the years. You and I talked about ellipticals back in 2005 at the Great Plains Audiofest. It's all very good stuff to me, moving closer to the ideal all the time. But I still find some little eddy currents in the state of the art, a few things I always seem to come back to. This is one of them.
- Waveguides ARE Horns (but horns aren't necessarily waveguides)
gedlee said:
Normally we agree on a lot of stuff, but I don't agree with this.
I was a horn lover, until I heard the Summas.
That's why it was such a "Eureka" moment when I realized that Zilch and Xpert haven't heard a modern waveguide. I was in the same boat that they are in, up until four years ago. If it wasn't for hearing the Summas, I'd probably be building an Econo Wave right now!
I believe you've done a single demo of the Summa in public. Did you know that three of the people who were there that day wound up buying or building constant directivity horns?
Doug listened to your Summas and bought constant-directivity Yorkville Unities, designed by Tom Danley.
Lynn Olson listened to your Summas,
and started a project with waveguides.
I listened to the Summas, bought JBL MP215s because they're similar, then stepped up to 'the real deal.'
And those are just the people who I know by name; who knows how many others had their eyes opened that day?
This might be a stretch, but it reminds me of a famous show by The Sex Pistols. It was at a tiny club in Manchester, but it was so mind-boggling that half-a-dozen people in the audience went out and started bands, or got involved in the music business! Some people claim that this show kick-started The Smiths, Joy Division, The Fall, and the Buzzcocks.
http://www.bbc.co.uk/manchester/content/articles/2006/05/11/110506_sex_pistols_gig_feature.shtml
The point that I'm trying to make is that those people at the Sex Pistols show probably had a mild interest in punk rock, but they walked out raving fans, and started bands.
I see the same thing going on with your customers; they're quite enthusiastic but reading about it is academic. You gotta experience it.
Patrick Bateman said:
Have you heard the Audio Kinesis speakers? It looks like the dds waveguide. Have you played with those at all?
Monger said:
Yep. Duke was there in 2005, along with myself, Lynn Olson, and Doug Kelly. I didn't include him in my previous post because he was already working with Earl Geddes at that point.
In 2005 Duke LeJeune was selling Summas, if I'm not mistaken.
"Waveguide", what's it mean?
Hat's off to you Patrick. You've done a lot of neat projects, I've seen them over the years.
I started to write a reply, then stopped, now I guess I'll start again.
This term "waveguide" gets thrown around a lot, more in the last few years. When I started doing audio, waveguide was reserved for RF work. There were CD horns, and they were designed to put the sound in a specific pattern, so I suppose it might have been appropriate to call them waveguides. They're devices more concerned with pattern control than acoustic loading.
However, Dr. Geddes adds another qualification to the term - the device must not use diffraction as a pattern modifier. I'm cool with that, makes a good way to distinguish waveguides from older CD horns with diffraction slots in the throats.
I think Earl would go further to say the term "waveguide" should only apply to devices with oblate spheroid and maybe prolate spheroid flares. (Note that axisymmetry is not a requirement. Earl likes round horns but that doesn't mean elliptical ones aren't waveguides if they meet certain criteria.)
However, I think by his definition, horns with flat walls would not be considered to be waveguides. Not Quadratics, not Unities. In fact, Unities would have another distinction of having drivers radiating into the side walls, which I think Earl would take issue with as far as HOM were concerned. Please correct me, Earl, but I think that's your position about the use of the term "waveguide".
Myself, I would be OK calling reduced diffraction CD horns "waveguides". It it has a radiused throat to match the driver exit angle to the horn wall angle a la Quadratic, then I'd call it a waveguide. The newer JBL waveguides are like that too. But I'm pretty sure Earl would disagree with that, saying only OS and PS can be called waveguides. That means the device cannot have straight side walls. It is a minimum curve, a catenary, with the desired coverage angle as the asymptote.
Now then, I'm not as keen to obtain the coveted "waveguide" distinction - I want the appropriate behavior but I don't care what you call it. The only reason I mentioned this is I think we may have our wires crossed a little bit. There certainly seems to be some confusion between people on what should be called "waveguide" and what should not be.
Patrick Bateman said:
Hat's off to you Patrick. You've done a lot of neat projects, I've seen them over the years.
I started to write a reply, then stopped, now I guess I'll start again.
This term "waveguide" gets thrown around a lot, more in the last few years. When I started doing audio, waveguide was reserved for RF work. There were CD horns, and they were designed to put the sound in a specific pattern, so I suppose it might have been appropriate to call them waveguides. They're devices more concerned with pattern control than acoustic loading.
However, Dr. Geddes adds another qualification to the term - the device must not use diffraction as a pattern modifier. I'm cool with that, makes a good way to distinguish waveguides from older CD horns with diffraction slots in the throats.
I think Earl would go further to say the term "waveguide" should only apply to devices with oblate spheroid and maybe prolate spheroid flares. (Note that axisymmetry is not a requirement. Earl likes round horns but that doesn't mean elliptical ones aren't waveguides if they meet certain criteria.)
However, I think by his definition, horns with flat walls would not be considered to be waveguides. Not Quadratics, not Unities. In fact, Unities would have another distinction of having drivers radiating into the side walls, which I think Earl would take issue with as far as HOM were concerned. Please correct me, Earl, but I think that's your position about the use of the term "waveguide".
Myself, I would be OK calling reduced diffraction CD horns "waveguides". It it has a radiused throat to match the driver exit angle to the horn wall angle a la Quadratic, then I'd call it a waveguide. The newer JBL waveguides are like that too. But I'm pretty sure Earl would disagree with that, saying only OS and PS can be called waveguides. That means the device cannot have straight side walls. It is a minimum curve, a catenary, with the desired coverage angle as the asymptote.
Now then, I'm not as keen to obtain the coveted "waveguide" distinction - I want the appropriate behavior but I don't care what you call it. The only reason I mentioned this is I think we may have our wires crossed a little bit. There certainly seems to be some confusion between people on what should be called "waveguide" and what should not be.
Sorry for going off topic, but this point made me chuckle a bit. You decide to reference a "real sports car" and then select a car that probably wouldn't fit the definition of a "real" sports car. Not only that, but you pick one of the most fundamentally flawed performance cars on the market. It's an engineering marvel to be sure, but only because it can attain the performance it does with such a flawed design. I wish they would just allow the 911 to die off and put the same kind of effort into the Cayman which has so much more potential to begin with.
I'm not comparing the fundamentally flawed 911 to the Summa waveguide, btw.
Patrick Bateman said:
As long as you are itemizing the list of listeners. I heard Geddes' Summas in his homes some 3 or 4 years ago. I purchased a pair of his 12" waveguides coming up on a year ago and I am still working on building the speakers to use them (almost, but home renovations get in my way).
I have also heard the Summas, a pair of massive unity based speakers made by Nick (with the later changes to the throat to improve the FR anomalies) and have heard at least 8 different iterations of the PT Waveguides. The Summas are excellent and clearly better to my ears than the PTs. However, I don't necessarily think that clear difference couldn't be accounted for with crossover work. All of the versions I have heard showed some of the promise that CD offers but all outside of one used a generic low pass. I suspect that with some work, and a proper subwoofer implementation, the clear differnce could quickly turn into a miniscule difference. The horn I didn't mention was the unities. The were the horn that provided me with my epiphany moment for horns, the Summas provided a similar level of performance and probably better overall because of the settings. I couldn't realistically compare the summa to unity system the way I heard the two, but I consider them the two best systems I've heard to date and that includes some very high end speakers from JBL, Wilson, and more.
This whole thing sort of reminds me of the CD vs Vinyl debate, where in the end, the mastering is what will have the biggest impact. Similarly, the speaker as a whole will have more impact than the form of "waveguide" used. The key should be teaching people about the merits of Constant Directivity moreso than the profile used to acheive it. An entry level modern CD horn still sounds superior to a high end vintage horn to my ears.
This whole thing sort of reminds me of the CD vs Vinyl debate, where in the end, the mastering is what will have the biggest impact. Similarly, the speaker as a whole will have more impact than the form of "waveguide" used. The key should be teaching people about the merits of Constant Directivity moreso than the profile used to acheive it. An entry level modern CD horn still sounds superior to a high end vintage horn to my ears.
Patrick Bateman said:
The combination of hearing the Summas and the AudioKinesis left a strong - and very favorable - impression at that RMAF show among many listeners. Unlike so many old-school horns, both speakers were flat, and free of the gross colorations that typically comes with high-dynamic-range systems. This was a major breakthrough, and I was glad to be there to see and hear it.
The most-talked-about buzz at that show - and the ones that followed - were the innovative open-baffles, but the new-generation horns and waveguides left an impression as well. My previous favorable impression of horns was hearing an Altec A5 at the San Francisco Audio Club, but that was more of a "listening-through" experience, where I was mentally subtracting the heavy colorations and focussing my attention on what the system did really well - most of all, why it sounded so different than the Altec A7 sound I had heard (and disliked) many times before. Hearing Christian Rintelen's Blue Thunders in Zurich a couple of years later reinforced the impression - there was something there, and the trick was dealing with the colorations while retaining the virtues of high dynamic range.
That was also the show where I bought a copy of Dr. Geddes' book, which I strongly recommend to any reader of this thread. With any luck, the bad old days of PA and theater horns with intentional diffractors in the throat may be behind us.
Patrick Bateman said:
Yes, Duke was selling Summas and we were doing all the designs together. Duke wanted to offer a more WAF loudspeaker and so he made his own, but still very much along the lines of my designs. I even did a crossover design for him. But then it became clear that his selling speakers that competed directly with mine that the conflict of interest was going to be a problem.
I think that Duke would contend that the Summa line is the better sounding speaker, and I agree that his have a better WAF. Can't have both and my priorities are clear.
dnewma04 said:
And all used the "entry level" Selenium drivers, too, no? DE250 with the Selenium throat adapter certainly sounds better to me, though I haven't done more than a cursory listen thus far. Also, the regular resonances Earl shows in his measurements may well be generated by the Selenium drivers rather than the waveguides. That they appear in all of the planes is certainly suggestive.
dnewma04 said:
That is the primary intent of EconoWave, and for many of those building them, it represents a significant paradigm shift in their appreciation of audio, and a gateway to DIY adventure, none of which is well served by vested interests gratuitously characterizing it as "crap."
Re: "Waveguide", what's it mean?
Wayne
Just so we are all clear on the term "waveguide" here is how it came about.
In 1991 when I found a new and different way to analyze flared conduits, and that this new method predicted some fundamentally different contours, I realized that calling them "horns" was a misnomer since it was exactly "Websters Horn" equation that I discarded when I did my analysis. To be clear on this distinction I used the term "waveguide" to mean a device that is based on a seperable coordinate system. I was aware of the terms usage in RF as well as Bose usage for the "wave radio", but I did not feel that this prior usage would be a conflict with mine. Hence, you can see that the term does mean "seperable coordinate conduits" because that's what it was first used for.
This can all be verified since the documents are all in print. The widespread use of the term to mean "anything" is not of my choosing, you can be sure of that.
Wayne Parham said:
Wayne
Just so we are all clear on the term "waveguide" here is how it came about.
In 1991 when I found a new and different way to analyze flared conduits, and that this new method predicted some fundamentally different contours, I realized that calling them "horns" was a misnomer since it was exactly "Websters Horn" equation that I discarded when I did my analysis. To be clear on this distinction I used the term "waveguide" to mean a device that is based on a seperable coordinate system. I was aware of the terms usage in RF as well as Bose usage for the "wave radio", but I did not feel that this prior usage would be a conflict with mine. Hence, you can see that the term does mean "seperable coordinate conduits" because that's what it was first used for.
This can all be verified since the documents are all in print. The widespread use of the term to mean "anything" is not of my choosing, you can be sure of that.
dnewma04 said:
A little rash perhaps, but you are actually quite correct. The basic design of the 911 goes back to about 1942 or thereabouts. It is not so much flawed as it is dated. Porsche tried to pull this car from the marketplace but the reaction was so seveer that they kept it, and raised the price! Its a highly refined automobile, but in terms of technology I would bet on the Acura NSX as being the better car. I take either🙂
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