Lynn
You are asking me to accept your claims of audibility on faith and I am unwilling to do that since they do not coincide with my own experiences. Further your claims of audibilty here are not supported by scientific subjective tests and go against the findings of virtually all tests done on amplifiers that are. Just because something is measureable does not mean that it is audible, just as things that are audible are not necessarily measured. One must close the loop with valid scientific subjective studies to show the level and significance of each and every claim. I do this in my own work as my publications will attest.
We will have to continue to disagree and I will stick by my accusation that you jumped to conclusions when you listened to my system at RMAF.
You are asking me to accept your claims of audibility on faith and I am unwilling to do that since they do not coincide with my own experiences. Further your claims of audibilty here are not supported by scientific subjective tests and go against the findings of virtually all tests done on amplifiers that are. Just because something is measureable does not mean that it is audible, just as things that are audible are not necessarily measured. One must close the loop with valid scientific subjective studies to show the level and significance of each and every claim. I do this in my own work as my publications will attest.
We will have to continue to disagree and I will stick by my accusation that you jumped to conclusions when you listened to my system at RMAF.
Nudging things back on-topic - although post #1062 was a long laundry-list of transistor-amp woes, most of the problems are in the mid/high region. In the LF region, the biggest remaining gremlin is the long reaction time of the Vbe multiplier to the output-transistor die temperature. In dynamic terms, this means the correct operating current is always a few seconds too late - either too much or too little bias. Since beta and Hfe are affected by temperature, this is not a minor point.
It's too bad the LNPA-150 is out of production - that was one of the few Class AB amplifiers that had a fully regulated output, driver, and input section. It sounded noticeably different than any other transistor amp I've heard, despite the audio circuit being outwardly similar to the old Audionics CC-2. I had the opportunity of buying a pair from Daniel Banquer a few years back, and I should have taken him up on it.
Class D/T amplifiers don't measure that well from 1 kHz on up, but look pretty good at lower frequencies, and are free of the thermal-wandering issues of Class AB amplifiers. From the threads elsewhere on the forum, it looks like TriPath has disappeared, so it's Class D from now on.
One things I haven't done is audition some of Nelson Pass' low-power Class A designs with a high-efficiency speakers. I would imagine either a HF horn or the new double-RAALs would reveal the truth about the amplifier in short order.
As for building my Karna amplifier - um, well, that's a big project. They are a long way from being a commercial product with all the bugs chased out. I'm still wrestling with the best way to heat the 45 and 300B DHT's.
Yup, I'm a subjectivist. Must be all that Buddhism I was exposed to in Japan and Hong Kong - kinda hard to shake off after all these years.
(Note about the "avatar" pix - taken in India in 1991, where the folks at the temple were thrilled when I told them I was a Buddhist. Little did I know that Hindus consider Buddhists one of them - they regard it as just another sect of Hinduism. The original pix showed the red dot they put on my forehead - but I thought that was a little over the top, even for diyAudio, so I Photoshopped it out. Still, the whole audio-guru/avatar image is a bit comical in the context of audio, where people fight such mighty battles over such tiny things. I wonder if the model-trains guys wrangle about O vs HO vs S gauge?)
It's too bad the LNPA-150 is out of production - that was one of the few Class AB amplifiers that had a fully regulated output, driver, and input section. It sounded noticeably different than any other transistor amp I've heard, despite the audio circuit being outwardly similar to the old Audionics CC-2. I had the opportunity of buying a pair from Daniel Banquer a few years back, and I should have taken him up on it.
Class D/T amplifiers don't measure that well from 1 kHz on up, but look pretty good at lower frequencies, and are free of the thermal-wandering issues of Class AB amplifiers. From the threads elsewhere on the forum, it looks like TriPath has disappeared, so it's Class D from now on.
One things I haven't done is audition some of Nelson Pass' low-power Class A designs with a high-efficiency speakers. I would imagine either a HF horn or the new double-RAALs would reveal the truth about the amplifier in short order.
As for building my Karna amplifier - um, well, that's a big project. They are a long way from being a commercial product with all the bugs chased out. I'm still wrestling with the best way to heat the 45 and 300B DHT's.
Yup, I'm a subjectivist. Must be all that Buddhism I was exposed to in Japan and Hong Kong - kinda hard to shake off after all these years.
(Note about the "avatar" pix - taken in India in 1991, where the folks at the temple were thrilled when I told them I was a Buddhist. Little did I know that Hindus consider Buddhists one of them - they regard it as just another sect of Hinduism. The original pix showed the red dot they put on my forehead - but I thought that was a little over the top, even for diyAudio, so I Photoshopped it out. Still, the whole audio-guru/avatar image is a bit comical in the context of audio, where people fight such mighty battles over such tiny things. I wonder if the model-trains guys wrangle about O vs HO vs S gauge?)
Earl - you are swimming upstream here.
Lynn believes in different sounding amps - as do a MULTITUDE of other participants on this forum. In fact MOST of this forum provides participation for just this purpose, to improve the audibility of their amplifiers for a given application. With the above, OBVIOUSLY many think that crossover distortion and harmonic distortion are only a few factors relating to the audibility of certain amplifiers, and are perhaps factors of less importance. Just one example is "parts rolling" (or using different parts - without substantial objective changes to currently measurable attributes) in an effort to achieve a better sounding amplifier (to them).
Now this statement:
""Well, this is where individual perceptions enter in. Earl Geddes, ... , believes Costco-quality electronics are good enough to exhibit at the RMAF, and anyone who thinks otherwise is fooling themselves, or worse, trying to sell snake oil to the gullible.""
May not be polite.. and yet it might be VERY polite. Odd, no?
First off - you have only enforced the fact that indeed you DO think Costco-quality electronics are good enough to exhibit at RMAF. (i.e. you found an amplifier from Costco that you thought was good enough to use.) This does not of course mean that ANY Costco sourced amplifier is good enough to use, but at a minimum that the one you used is good enough.
Second - in much the same as Lynn *might* be intimating that you personally think that others are fooling themselves, (and there IS another way to interpret that sentence), you appear to support this very notion by suggesting that perceptually people are doing just that. (i.e. "truth in audio", "elevate our illusions" etc.)
So, indeed that statement was apparently both correct and fair to at least some extent. Now was it polite?
Perhaps it wasn't polite, after all most people don't like generalizations made about them. It is however a common practice, and is useful as a means of communication. Most importantly though, it wasn't abusive in a forum context in that it wasn't a "flame".
Then again.. maybe it WAS polite.
Consider the alternative. What if what Lynn heard wasn't simply a function of the cheap amplifier? (..cheap price wise and in overall materials quality.) What if what he heard was at least in part determined by your speakers? In this sense then, he is being perhaps MORE than fair by suggesting that what he found to be at fault lies not with your speaker, but with the associated equipment.
All of this suggests any number of viewpoints - and perhaps the most telling viewpoint is that you choose to view this one comment in so negative an association to you personally, that you felt the need to defend it here..
Furthermore, ask yourself this question:
Did those who suggested you read this thread, suggest this to defend your "honor" on issues pertaining to amplification?
OR -
Were they perhaps suggesting that you add your knowledge of horns in a productive fashion to this thread?
IMO, its the latter.
Finally..
I don't think Lynn ever asked you to take his "claims of audibility on faith". Rather that he has this perspective, and is giving some basis for that perspective, as well as *trying* to help you understand that a GREAT many others share that perspective.
Again, you are swimming up-stream. Rather than saying "you are wrong" to others, try sticking to those topical areas where you can say
"you are right and this is why.."
OR -
"you are right BUT an improvement can be obtained by.."
(..this follows the cliched yet eminently useful phrase and concept of : "If you don't have anything nice to say, don't say anything at all.")
I convey this to you specifically, (well beyond others), because (IMO):
1. You consistently have this problem communicating in forums.
2. You have a lot of very *useful* information to share that can be greatly appreciated by others.
Well, as always - good luck!
Lynn believes in different sounding amps - as do a MULTITUDE of other participants on this forum. In fact MOST of this forum provides participation for just this purpose, to improve the audibility of their amplifiers for a given application. With the above, OBVIOUSLY many think that crossover distortion and harmonic distortion are only a few factors relating to the audibility of certain amplifiers, and are perhaps factors of less importance. Just one example is "parts rolling" (or using different parts - without substantial objective changes to currently measurable attributes) in an effort to achieve a better sounding amplifier (to them).
Now this statement:
""Well, this is where individual perceptions enter in. Earl Geddes, ... , believes Costco-quality electronics are good enough to exhibit at the RMAF, and anyone who thinks otherwise is fooling themselves, or worse, trying to sell snake oil to the gullible.""
May not be polite.. and yet it might be VERY polite. Odd, no?
First off - you have only enforced the fact that indeed you DO think Costco-quality electronics are good enough to exhibit at RMAF. (i.e. you found an amplifier from Costco that you thought was good enough to use.) This does not of course mean that ANY Costco sourced amplifier is good enough to use, but at a minimum that the one you used is good enough.
Second - in much the same as Lynn *might* be intimating that you personally think that others are fooling themselves, (and there IS another way to interpret that sentence), you appear to support this very notion by suggesting that perceptually people are doing just that. (i.e. "truth in audio", "elevate our illusions" etc.)
So, indeed that statement was apparently both correct and fair to at least some extent. Now was it polite?
Perhaps it wasn't polite, after all most people don't like generalizations made about them. It is however a common practice, and is useful as a means of communication. Most importantly though, it wasn't abusive in a forum context in that it wasn't a "flame".
Then again.. maybe it WAS polite.
Consider the alternative. What if what Lynn heard wasn't simply a function of the cheap amplifier? (..cheap price wise and in overall materials quality.) What if what he heard was at least in part determined by your speakers? In this sense then, he is being perhaps MORE than fair by suggesting that what he found to be at fault lies not with your speaker, but with the associated equipment.
All of this suggests any number of viewpoints - and perhaps the most telling viewpoint is that you choose to view this one comment in so negative an association to you personally, that you felt the need to defend it here..
Furthermore, ask yourself this question:
Did those who suggested you read this thread, suggest this to defend your "honor" on issues pertaining to amplification?
OR -
Were they perhaps suggesting that you add your knowledge of horns in a productive fashion to this thread?
IMO, its the latter.
Finally..
I don't think Lynn ever asked you to take his "claims of audibility on faith". Rather that he has this perspective, and is giving some basis for that perspective, as well as *trying* to help you understand that a GREAT many others share that perspective.
Again, you are swimming up-stream. Rather than saying "you are wrong" to others, try sticking to those topical areas where you can say
"you are right and this is why.."
OR -
"you are right BUT an improvement can be obtained by.."
(..this follows the cliched yet eminently useful phrase and concept of : "If you don't have anything nice to say, don't say anything at all.")
I convey this to you specifically, (well beyond others), because (IMO):
1. You consistently have this problem communicating in forums.
2. You have a lot of very *useful* information to share that can be greatly appreciated by others.
Well, as always - good luck!
Man, Scott! I don't think that was called for at all!
Does this mean that if one does not, indeed, share the same opinion as the MANY, they are not welcome here?
This discussion is about loudspeaker design, how about we keep it to that?
For roughly a hundred and 4 pages it was just amazing, let's keep it on track. This discussion could continue to be more and more informative and revealing.
Or, it can degenerate into some kind of name calling because someone has tin ears? Wow, that take a heck of alot of certainty, doesn't it? Or, wait a minute, maybe we're all wrong and it's the many with the tin ears?
Heck, I don't know, but, it appears there are those that do. Pitty!
Does this mean that if one does not, indeed, share the same opinion as the MANY, they are not welcome here?
This discussion is about loudspeaker design, how about we keep it to that?
For roughly a hundred and 4 pages it was just amazing, let's keep it on track. This discussion could continue to be more and more informative and revealing.
Or, it can degenerate into some kind of name calling because someone has tin ears? Wow, that take a heck of alot of certainty, doesn't it? Or, wait a minute, maybe we're all wrong and it's the many with the tin ears?
Heck, I don't know, but, it appears there are those that do. Pitty!
Teh said:
Thats OK.
You can think that if you like.
However,
My intention wasn't to suggest the above statements to anyone but Earl. Nor was it intended to be anything other than constructive to him.
As you specifically mentioned - this thread is primarily about loudspeaker design.. WHO altered that course significantly? Perhaps more importantly, WHO could provide a wealth of information on loudspeaker designs utilizing horns, yet hasn't even broached the subject?
So, no - I don't believe that everyone should "toe the party line" - not by a long shot. But perhaps like you - I do think that the discussion should stay focused on constructive comments, rather then self-defensive posturing on a topic that bears little relationship to the overall thread.
From a technical point of view, I agree that many things talked about here have not been supported by, measurements, neither have they been supported by explanation based on specific music sources. But I do think that we should not criticize a person, but rather either ask for more information and proof, or prove one wrong.
Trying to argue about who is right or who is wrong really brings no improvement to audio. If each of us can be more specific in what we evaluate, then we will see improvements. I know that many people can get offended when they are backed agaist the wall with questions they cannot answer. I guess we should just learn to deal with how not to feel offended.
From a lisnening point of view, very few people try to identify the specific music source they listened to when they came to a specific conclusion; they do not address the changes in individual instruments in the music and and what difference they hear. The general terms generally used to express the their impressons are so relative that unless compared against a known equipment that the readers are familiar with, there is no way one can know how critical a review the writer had performed.
From a technical point of view, explanations are in terms of mathematically derived values rather than basic physical phenomena and physical rules. Most of these are just index specific to one aspect or measurement method, which may not be the critical factor. Most measurement data are only viewed from a particular perspective and not explored in detail to reveal the critical aspects.
It would also be unfair to ask experienced members to throw out all the information without reserve. I think it's a good idea for each of use to contribute something specific enough for others to repeat the evaluation, and if others come to different conclusions, then we can explore what really is going one.
Trying to argue about who is right or who is wrong really brings no improvement to audio. If each of us can be more specific in what we evaluate, then we will see improvements. I know that many people can get offended when they are backed agaist the wall with questions they cannot answer. I guess we should just learn to deal with how not to feel offended.
From a lisnening point of view, very few people try to identify the specific music source they listened to when they came to a specific conclusion; they do not address the changes in individual instruments in the music and and what difference they hear. The general terms generally used to express the their impressons are so relative that unless compared against a known equipment that the readers are familiar with, there is no way one can know how critical a review the writer had performed.
From a technical point of view, explanations are in terms of mathematically derived values rather than basic physical phenomena and physical rules. Most of these are just index specific to one aspect or measurement method, which may not be the critical factor. Most measurement data are only viewed from a particular perspective and not explored in detail to reveal the critical aspects.
It would also be unfair to ask experienced members to throw out all the information without reserve. I think it's a good idea for each of use to contribute something specific enough for others to repeat the evaluation, and if others come to different conclusions, then we can explore what really is going one.
I quite agree with many of the aspects described. This speaker related issue is similar with my findings. But in additional to resonance, the distribution and dissipation of energy stored in the driver is also an important aspect that can result in different sonic signatures of speakers. Differences can be observed via CSD plots over a 4ms range and 0.4 ms range.Lynn Olson said:
I'm actually surprised.
I'm half blind and, as a result, my sense of hearing is hightened. I hear what most around me cannot. My dog can hear better than I but I'm not aware of one human being that can hear as I do.
Still, I'm not nearly convinced of my golden ears as some of you. I'm just wondering if this is some kind of ego thing? How are you so very sure?
The point is very simple! There is a sonic signature that "we", that is you, or you or me seem to prefer. I think the point is very simple; let people have what pleases them.
Correct me if I'm wrong here, but hasn't Lynn identified Earl's work as some of the finest in the world in this thread? Does that make him right, and Earl a genius? I'm not a fan of horns, I still share Lynn's original assessment as "honky". Still, it is merely a preference. I'm really enjoying this discussion as Lynn is opening up to new and previously unacceptable approaches. That is a commentary on one's thirst to know. I admire that.
Also, one last thing, with such a "poor" system driving his speaker system, still, Lynn, and others, find the work done by Mr. Geddes as among the finest avialable anywhere in the world, at any price, right?
So, to get back on track; Lynn, what are you using for drivers for the lowest two-three octaves? What kind of Fs do they have and why are you choosing them verses other drivers? Furthermore, how are you going to drive them? Active Crossovers? EQ'd? Assisted? Transform? Servo? Monoblock amps? Onboard amps? Tube amps? How are you going to handle the real power eaters? How are you going to get them to extend to 20Hz?
How will you achieve the crossover you're looking for? What is it precisely that you are looking for with the low frequency part of the crossover?
I'm half blind and, as a result, my sense of hearing is hightened. I hear what most around me cannot. My dog can hear better than I but I'm not aware of one human being that can hear as I do.
Still, I'm not nearly convinced of my golden ears as some of you. I'm just wondering if this is some kind of ego thing? How are you so very sure?
The point is very simple! There is a sonic signature that "we", that is you, or you or me seem to prefer. I think the point is very simple; let people have what pleases them.
Correct me if I'm wrong here, but hasn't Lynn identified Earl's work as some of the finest in the world in this thread? Does that make him right, and Earl a genius? I'm not a fan of horns, I still share Lynn's original assessment as "honky". Still, it is merely a preference. I'm really enjoying this discussion as Lynn is opening up to new and previously unacceptable approaches. That is a commentary on one's thirst to know. I admire that.
Also, one last thing, with such a "poor" system driving his speaker system, still, Lynn, and others, find the work done by Mr. Geddes as among the finest avialable anywhere in the world, at any price, right?
So, to get back on track; Lynn, what are you using for drivers for the lowest two-three octaves? What kind of Fs do they have and why are you choosing them verses other drivers? Furthermore, how are you going to drive them? Active Crossovers? EQ'd? Assisted? Transform? Servo? Monoblock amps? Onboard amps? Tube amps? How are you going to handle the real power eaters? How are you going to get them to extend to 20Hz?
How will you achieve the crossover you're looking for? What is it precisely that you are looking for with the low frequency part of the crossover?
gedlee said:
Hello,
What type of listening tests have you done to find the audibility of power compression between compression drivers and your direct radiator woofer system? At what levels? Do you find this significant? Why/not?
I ask because I have built quite a few 'hybrids' and all of them seem to fall flat on their face compared to mating the compression driver with a good bass horn. It doesn't really need to be loud to be significant. I have used JBL 2220, 2226, TAD 1601, 1603, EV 15L, 15B, Altec 912B, 416 and 515 as direct radiators crossed electronically to compression drivers in 300 Hz round tractrix horns almost anywhere between 600 and 1500 cycles. The direct radiator bass systems all seem to kill the dynamics compared to a bass horn.
I have not heard your speakers. Do you account for this in your design? How?
Thanks
Hi Scott,
You just wrote;-
>>So when someone comes to a quick conclusion about the sound of something, my first question isn't "can you prove that?" - but rather "whats your experience to make such a conclusion?". <<
I would think it fair to add that there are some who have heard differences in aspects of reproduction and made conclusions about the weaknesses they have heard (or read about in irrefutable reports), who then go on to wrongly apply that same conclusion to all circumstances relating to apparently similar (but not identical) applications, whether their conclusion is directly relevent for all alternative approaches or not.
Some designers take hundreds (thousands?) of hours to create and refine their optimum compromises, often basing new work on prior immeasurable findings which cannot be proved or disproved to have audible consequence until *after* each individual new construction has been fully examined.
Lynn has the hands-on (ears-on) experience to optimise these compromises, and thus I look forwards to reading the outcome of his on-going effort, even though it might not be optimum for me due to the proposed design having a poor signal to WAF-noise ratio!.
Cheers ........... Graham.
You just wrote;-
>>So when someone comes to a quick conclusion about the sound of something, my first question isn't "can you prove that?" - but rather "whats your experience to make such a conclusion?". <<
I would think it fair to add that there are some who have heard differences in aspects of reproduction and made conclusions about the weaknesses they have heard (or read about in irrefutable reports), who then go on to wrongly apply that same conclusion to all circumstances relating to apparently similar (but not identical) applications, whether their conclusion is directly relevent for all alternative approaches or not.
Some designers take hundreds (thousands?) of hours to create and refine their optimum compromises, often basing new work on prior immeasurable findings which cannot be proved or disproved to have audible consequence until *after* each individual new construction has been fully examined.
Lynn has the hands-on (ears-on) experience to optimise these compromises, and thus I look forwards to reading the outcome of his on-going effort, even though it might not be optimum for me due to the proposed design having a poor signal to WAF-noise ratio!.
Cheers ........... Graham.
I think things are back on track and if there even was any personal stuff, it is behind us. I also believe that Scottg's posts were intended to be helpful, as have been most of the other posts. I heartily agree that Mr. Geddes could make some useful speaker observations and Mr. Olsen has twice said that he is respects Mr. Geddes' opinion on the speaker issue, which is what we are supposed to be discussing here.
So.... let's drop any amplifier discussion for now, and any discussion of any possible personal issues,
and get back to speakers. I'm as eager as the rest of you to keep learning from our amazingly knowledgable members here.Variac
Chief Moderator
OK, deep breath, everyone. Visit this site to get turned on and inspired. Karna just showed it to me, and wow, a glimpse of the future! I want one of those - I'll take the personal UFO, too. Just gotta get better so I can enjoy it fully.
Just so we all hear it loud and clear: Earl has done things with horns I've never seen done before. LeCleac'h has done things with horns I've never seen done before. Alexander is taking ribbons in a new direction. Bud Purvine's EnABL is doing things for cones that have not been done before. ScottG, Magnetar, and lots of others in this forum have paid their dues with horns and are generously sharing what they've discovered over many years.
I believe in giving credit for breakthroughs to the people involved, and making their names known. This is personal for me: part of the reason I left Audionics was a decision by management to suppress credit for the work that Bob Sickler and I did. I later found this is common practice in the high-end industry, and the prime reason for the turnover of good, talented people. That's why the industry has such a long, sad record of two steps forward, and two steps back.
OK, my spiritual side is sticking out here, but I feel the Open Source model is essential if we're going to make any forward progress in audio. Mainstream high-end has been spiralling downward to irrelevance and extinction, controlled by the self-appointed gatekeepers of the Big Two review magazines, while genuine innovation is crowded out by slick marketing PR and a decadent boutique esthetic.
The DIY movement is only partly about doing it cheaper, for some of us, it's about breaking out of the CES exhibition -> paid-for-review -> dealership straightjacket. If you know any hifi dealers, they'll tell you they can't afford to sell anything other than magazine-endorsed products, end of story.
I began in hifi in 1973 by working as a commissioned salesman, one of the most degrading jobs I've ever had. I have some sympathy for these guys; it's a brutal business, combining the worst aspects of carrying high inventory costs with a fashion-driven product mix. They just don't have the freedom to take a chance on anything the magazines don't endorse - the buyers by now have become almost totally brainwashed by the inane reviews, and are just looking for "component of the year" at a discount. Very few audiophile buyers even know what a live acoustic concert sounds like; they buy idiotic "audiophile CDs" instead, complete with track-by-track listening instructions, telling them in the liner notes what sound effects to listen for.
Yes, this is a cry from the heart. You read that right. I'm not trying to prove anything here - I just want to get this big dumb beast to move forward again, and pull itself out of the swamp of indifference and decadence. My technique for the last fifteen years has been to tease the reader, draw them out a little bit, and get people to think about things a little differently. Sometimes I slyly put in a little spiritual tidbits, disguising them as I go. Some readers catch the little Easter eggs, while most miss them. That's OK, it's what I intended.
The most effective method has been to actually build the things, rather than write rants like this one. Before I started the Ariel, there was a weird prejudice that transmission-line speakers had to be inefficient. Wrong. Before I started the Amity, Aurora, and Karna, people thought that transformer-coupled amplifiers had high distortion. Wrong.
With this speaker, I want to move into the space between prosound and audiophilia. Not one, not the other. There are a few players there, but not many. The long recovery period from the accident - God, has it been since January 7th? - has been an opportunity to throw the project open to the diyAudio community, who have been nothing less than extremely gracious and hospitable to me.
I thank all of you.
This project is going to get built. By me, and I imagine, by some of the readers following this immense thread. I expect there are going to be many variations, some compact and leaning towards the Linkwitz direction, others going for ultimate dynamics and top-quality prosound horns, and others for new options we have with the RAAL ribbons commissioned for this project, and now available to the DIY community.
I thank all of you. This is your project too.
Just so we all hear it loud and clear: Earl has done things with horns I've never seen done before. LeCleac'h has done things with horns I've never seen done before. Alexander is taking ribbons in a new direction. Bud Purvine's EnABL is doing things for cones that have not been done before. ScottG, Magnetar, and lots of others in this forum have paid their dues with horns and are generously sharing what they've discovered over many years.
I believe in giving credit for breakthroughs to the people involved, and making their names known. This is personal for me: part of the reason I left Audionics was a decision by management to suppress credit for the work that Bob Sickler and I did. I later found this is common practice in the high-end industry, and the prime reason for the turnover of good, talented people. That's why the industry has such a long, sad record of two steps forward, and two steps back.
OK, my spiritual side is sticking out here, but I feel the Open Source model is essential if we're going to make any forward progress in audio. Mainstream high-end has been spiralling downward to irrelevance and extinction, controlled by the self-appointed gatekeepers of the Big Two review magazines, while genuine innovation is crowded out by slick marketing PR and a decadent boutique esthetic.
The DIY movement is only partly about doing it cheaper, for some of us, it's about breaking out of the CES exhibition -> paid-for-review -> dealership straightjacket. If you know any hifi dealers, they'll tell you they can't afford to sell anything other than magazine-endorsed products, end of story.
I began in hifi in 1973 by working as a commissioned salesman, one of the most degrading jobs I've ever had. I have some sympathy for these guys; it's a brutal business, combining the worst aspects of carrying high inventory costs with a fashion-driven product mix. They just don't have the freedom to take a chance on anything the magazines don't endorse - the buyers by now have become almost totally brainwashed by the inane reviews, and are just looking for "component of the year" at a discount. Very few audiophile buyers even know what a live acoustic concert sounds like; they buy idiotic "audiophile CDs" instead, complete with track-by-track listening instructions, telling them in the liner notes what sound effects to listen for.
Yes, this is a cry from the heart. You read that right. I'm not trying to prove anything here - I just want to get this big dumb beast to move forward again, and pull itself out of the swamp of indifference and decadence. My technique for the last fifteen years has been to tease the reader, draw them out a little bit, and get people to think about things a little differently. Sometimes I slyly put in a little spiritual tidbits, disguising them as I go. Some readers catch the little Easter eggs, while most miss them. That's OK, it's what I intended.
The most effective method has been to actually build the things, rather than write rants like this one. Before I started the Ariel, there was a weird prejudice that transmission-line speakers had to be inefficient. Wrong. Before I started the Amity, Aurora, and Karna, people thought that transformer-coupled amplifiers had high distortion. Wrong.
With this speaker, I want to move into the space between prosound and audiophilia. Not one, not the other. There are a few players there, but not many. The long recovery period from the accident - God, has it been since January 7th? - has been an opportunity to throw the project open to the diyAudio community, who have been nothing less than extremely gracious and hospitable to me.
I thank all of you.
This project is going to get built. By me, and I imagine, by some of the readers following this immense thread. I expect there are going to be many variations, some compact and leaning towards the Linkwitz direction, others going for ultimate dynamics and top-quality prosound horns, and others for new options we have with the RAAL ribbons commissioned for this project, and now available to the DIY community.
I thank all of you. This is your project too.
Lynn, nice commentary!
One thing though, about your Easter Eggs "while most miss them". I doubt you're looking to be engaged on some of your "isms". Besides, I'd be willing to bet that most readers of this thread have been fortunate to see your humor throughout. You are an amazing writer as well. But, don't think what you're saying is being missed.
Back to your project; the crossovers? How do you intend to cross the drivers over? I know that depends upon the final driver choices but you must have at least some framework your working towards? Or are you looking more toward the Bastini's as an exemplar? How are you going to compensate for the baffle losses?
One thing though, about your Easter Eggs "while most miss them". I doubt you're looking to be engaged on some of your "isms". Besides, I'd be willing to bet that most readers of this thread have been fortunate to see your humor throughout. You are an amazing writer as well. But, don't think what you're saying is being missed.
Back to your project; the crossovers? How do you intend to cross the drivers over? I know that depends upon the final driver choices but you must have at least some framework your working towards? Or are you looking more toward the Bastini's as an exemplar? How are you going to compensate for the baffle losses?
Teh said:
Wait a moment while I do a writer-persona switch <click>, ah, all betta now.
Overall system topology:
1) Servo monopole bass, 60~80 Hz LPF. Rythmiks look like best candidates.
2) Midbass/Bass driver array. Independently powered and equalized for room and response ripples. EQ in the boost direction kept to an absolute minimum. Optional 60~80 Hz HPF, 200~300 Hz LPF. The simplest MB/B array is a single 21" driver; more complex variations are a group of three 12 or 15-inch drivers.
3) Widerange driver. This shares a high-quality amplifier with the tweeter; both use a passive crossover in the 1.2~2 kHz region. The passive WR/tweeter crossover has a design target of 10 degrees or better phase-match in the crossover region. A HPF in the 80~200 Hz region is optional - the degree of overlap with the MB/B array to be determined by measurement and audition.
4) Tweeter. Either an advanced-profile horn+CD with the best-possible impulse response and very low distortion in the 1~5 kHz region, a new-generation AMT from Beyma or Mundorf, or the new RAAL double-ribbon tweeter. Passive HPF in the 1.2~2 kHz region.
Although I'll probably use a Behringer or similar utility-grade digital crossover/EQ for the rough setup and measurement, I plan to use a passive crossover for the WR/Tweeter crossover in the finished system. The requirement for room EQ in the MB/B region implies that separate amplification and EQ (digital or otherwise) is desirable.
The main design goal is a high-dynamic-range system that is dipole over most of the audio range. The biggest challenge will be system coherence, something designers of 3 to 4-way horn systems have to struggle with.
There is a reasonable chance the dipole-to-horn transition will be a little easier than it is with a conventional monopole-to-horn transition, which goes all the way from omnidirectional (in the bass) to the 90-degree conical radiation pattern of the horn.
The 15" + horn combination goes all the way back to the 1937 Bell Labs Iconic. The Iconic has a distinguished history, but we don't need to keep copying the format of a seventy-year-old design.
A dipole radiation pattern is similar to a pair of 90-degree conical patterns placed back-to-back. If we use a reverse-phase rear horn, well, the difference between the two becomes even smaller. We're no longer talking about the latest iteration of an Iconic any more.
Managing the radiation pattern of the Midbass/Bass array will need attention, although not as difficult as the WR/tweeter, since the MB/B array works at much lower frequencies - and in a range where the radiation pattern merges with the room characteristics. The things to watch for are the driver-to-driver phase angles and the radiation pattern in the 80 to 500 Hz region.
As mentioned earlier, the simplest - and most compact - way to realize the MB/B is a single 21" driver. The biggest drawback of the 21" is poor response above 200 Hz, since these are designed as subwoofers, not woofers, and certainly not midbass drivers. This implies a steeper slope for the LPF for the 21", making integration with the WR driver a bit more challenging, not to mention side issues of different driver colorations.
My esthetic favorite is the quad array of 12" drivers - one for WR, one for MB, and two for Bass. These can be mixed-n-matched for best integration driver-to-driver and well-behaved rolloffs at higher frequencies. If BudP's EnABL does the wonders for these that it does for the Lowther, that's going to make things easier all around.
As for the 20~80 Hz range, it's a choice between EQ'ed vs servo subwoofers. In this frequency range, where excursion distortion dominates, I think servo is the easy and obvious choice. Considering the depth of engineering that goes into the Rythmiks, the choice is even more obvious.
There is a reasonable chance the dipole-to-horn transition will be a little easier than it is with a conventional monopole-to-horn transition, which goes all the way from omnidirectional (in the bass) to the 90-degree conical radiation pattern of the horn.
The 15" + horn combination goes all the way back to the 1937 Bell Labs Iconic. The Iconic has a distinguished history, but we don't need to keep copying the format of a seventy-year-old design.
A dipole radiation pattern is similar to a pair of 90-degree conical patterns placed back-to-back. If we use a reverse-phase rear horn, well, the difference between the two becomes even smaller. We're no longer talking about the latest iteration of an Iconic any more.
Managing the radiation pattern of the Midbass/Bass array will need attention, although not as difficult as the WR/tweeter, since the MB/B array works at much lower frequencies - and in a range where the radiation pattern merges with the room characteristics. The things to watch for are the driver-to-driver phase angles and the radiation pattern in the 80 to 500 Hz region.
As mentioned earlier, the simplest - and most compact - way to realize the MB/B is a single 21" driver. The biggest drawback of the 21" is poor response above 200 Hz, since these are designed as subwoofers, not woofers, and certainly not midbass drivers. This implies a steeper slope for the LPF for the 21", making integration with the WR driver a bit more challenging, not to mention side issues of different driver colorations.
My esthetic favorite is the quad array of 12" drivers - one for WR, one for MB, and two for Bass. These can be mixed-n-matched for best integration driver-to-driver and well-behaved rolloffs at higher frequencies. If BudP's EnABL does the wonders for these that it does for the Lowther, that's going to make things easier all around.
As for the 20~80 Hz range, it's a choice between EQ'ed vs servo subwoofers. In this frequency range, where excursion distortion dominates, I think servo is the easy and obvious choice. Considering the depth of engineering that goes into the Rythmiks, the choice is even more obvious.