The trouble is they are not all flat. KISS is right but keeping the FR flat is not KISS. I am sorry but keeping it flat with the real world components requires a proof of the pudding. I am not getting into a debate. FR was dropped years ago as an overall arbitre. We need to use it purely as a guide and not the be all and end all.
There are those in this thread like the technical considerations perhaps more than the output. Distortion is the big problem. Beat that with fidelity
not so called FR flatness
Boldname,
I also do not want to make this an argument and in reality I actually agree basically with what you are saying. I still think a fairly flat response curve is important but not at the cost of creating other problems that may be worse due to attempts to correct every aberration. My own work has been on lowering the distortion levels in cone drivers with new cone materials and other soft parts and careful motor design. I do believe that the real final frontier in audio is in loudspeaker distortion levels being reduced from what has commonly been acceptable in the industry, that takes a real commitment to quality and alas that is not a major consideration for most commodity speakers built by the millions.
I also do not want to make this an argument and in reality I actually agree basically with what you are saying. I still think a fairly flat response curve is important but not at the cost of creating other problems that may be worse due to attempts to correct every aberration. My own work has been on lowering the distortion levels in cone drivers with new cone materials and other soft parts and careful motor design. I do believe that the real final frontier in audio is in loudspeaker distortion levels being reduced from what has commonly been acceptable in the industry, that takes a real commitment to quality and alas that is not a major consideration for most commodity speakers built by the millions.
Yeah. I think you are right on it. It is great that we can have such excellent sytems and source material, so that if we get the distortion i.e the weakest area of the sound transducer sorted, we will be at some sort of end game rather than a millstone holding it back. One can get so close to reality analogue or digital if done right, that now that we can immerse ourselves in our daily music, theatre, ballet whatever while we still seek to get it even better.
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Numerous studies have shown that "near-flat" is preferred in blind listening tests by virtually all listening demographics. By "near-flat" I mean that a subtle HF fall-off is desired, or not, depending on the total HF power response. The more HF power response the more fall-off is deemed to be neutral. A beaming HF response tends to want something closer to flat.
Individual tastes may vary, but if you find that you "like" something other than "near-flat" then you should ask yourself why you don't seem to fit the "norm". "I have Golden Ears"! - of course! Very few have those!
Individual tastes may vary, but if you find that you "like" something other than "near-flat" then you should ask yourself why you don't seem to fit the "norm". "I have Golden Ears"! - of course! Very few have those!
Since we are talking about Radian drivers here, Vance Dickason tested the Radian bigger 760NeoPB and 950PBs this month...first time ever Radians have been tested by him. Data looks good...though FR isn't as smooth as the factory graphs that don't show the notch in the HF response that is there.
The BBC found this, about 2dB from mid to top but rolling down a bit more with digital. All the Be tweeters coming out now are deliberately rolled off now, and not ruler flat. But much material varies 10 dB or even more about an arbitrary taylored optimum FR. And the sound may recede back or forth as a result . Flicking through a dozen or more live radio stations demonstrates presenters, all with a different treble mid and bass balance. Recording engineers have their own evolved preferences, enough I think, that it does effect our preferences for different labels. Yes it is not quite that simple. Trouble is it takes golden ears to produce pleasing music and golden ears to enjoy. A bit like good and bad wines or no wine at all
Winslow,
Those upper frequency notches and such have been in those Radian drivers since the beginning of time. A friend of mine use to work at Radian and was one of the earlier engineers there. He told me of these problems so long ago and there were fixes and they were never applied. Many engineers have come and gone at that company and yet the situation continues. The real problem at that company is the owner himself, I do know him but haven't talked to him in years. Yes the Be is a nice improvement but the basic motor design, phase plug design and the suspensions used have not changed during all these years. I use to have them make me custom cone drivers and my friend who did network design for my loudspeakers at the time knew exactly where those peaks and dips would be on the Radian compression drivers and he would do what he could to fix the problems in the network but he knew he was trying to cover up a mechanical problem with the drivers. Back then I would look at what he was doing with the networks and wonder what he was doing, it looked rather strange and was nothing like a standard L/R network, it took me some time to see what he was doing with his rather unusual networks. The bottom line was even with the corrections in the network those drivers were just fatiguing over time. that high frequency response would just make you tired after long enough listening to that sound. this was the reason at the time I went to the TAD drivers as a solution, a much better design at the time. Things have not changed much since those days.
I know one trick that was often used on the older Radian drivers was to punch holes in the Mylar surround used on those Radian drivers, the Mylar is too stiff and non linear in the way it is used. Basically the Radian. Emilar and Rankis Hines drivers are all the same basic design that Algus Rankis designed. I know I am spelling those names wrong but I think you get the picture. All these designs came from one mind and personality clashes created the three companies.
Those upper frequency notches and such have been in those Radian drivers since the beginning of time. A friend of mine use to work at Radian and was one of the earlier engineers there. He told me of these problems so long ago and there were fixes and they were never applied. Many engineers have come and gone at that company and yet the situation continues. The real problem at that company is the owner himself, I do know him but haven't talked to him in years. Yes the Be is a nice improvement but the basic motor design, phase plug design and the suspensions used have not changed during all these years. I use to have them make me custom cone drivers and my friend who did network design for my loudspeakers at the time knew exactly where those peaks and dips would be on the Radian compression drivers and he would do what he could to fix the problems in the network but he knew he was trying to cover up a mechanical problem with the drivers. Back then I would look at what he was doing with the networks and wonder what he was doing, it looked rather strange and was nothing like a standard L/R network, it took me some time to see what he was doing with his rather unusual networks. The bottom line was even with the corrections in the network those drivers were just fatiguing over time. that high frequency response would just make you tired after long enough listening to that sound. this was the reason at the time I went to the TAD drivers as a solution, a much better design at the time. Things have not changed much since those days.
I know one trick that was often used on the older Radian drivers was to punch holes in the Mylar surround used on those Radian drivers, the Mylar is too stiff and non linear in the way it is used. Basically the Radian. Emilar and Rankis Hines drivers are all the same basic design that Algus Rankis designed. I know I am spelling those names wrong but I think you get the picture. All these designs came from one mind and personality clashes created the three companies.
Winslow,
What I remember seeing on some modified Radian drivers was a hole drilled in the center of the center section of the phasing plug with some kind of cotton wadding or similar material stuffed in the drilled hole. It trapped some resonant frequencies that were generated in the assembly. Don't ask me the diameter or depth of the hole but that is something I remember as a fix for at least one of those high frequency problems. This was over 20 years ago so I don't know the details. What seems to get lost in translation with these and most any other compression driver is the fact that most phasing plugs are made of a collection of conic sections that are attached to a secondary conic section in the throat section, not the smoothest way to do things with those transitions. If you think about all the attention paid to matching the exit angle of a horn to the compression drivers exit angle from the throat and the worry about HOMS and other diffraction effects to me it is already to late, the compression driver has these problems build into the basic design. This is all due to poor design and tradition after all these years, there is no reason this situation still exist.
What I remember seeing on some modified Radian drivers was a hole drilled in the center of the center section of the phasing plug with some kind of cotton wadding or similar material stuffed in the drilled hole. It trapped some resonant frequencies that were generated in the assembly. Don't ask me the diameter or depth of the hole but that is something I remember as a fix for at least one of those high frequency problems. This was over 20 years ago so I don't know the details. What seems to get lost in translation with these and most any other compression driver is the fact that most phasing plugs are made of a collection of conic sections that are attached to a secondary conic section in the throat section, not the smoothest way to do things with those transitions. If you think about all the attention paid to matching the exit angle of a horn to the compression drivers exit angle from the throat and the worry about HOMS and other diffraction effects to me it is already to late, the compression driver has these problems build into the basic design. This is all due to poor design and tradition after all these years, there is no reason this situation still exist.
That aren't unobtanium (rare exotica owned by collectors in Tokyo or one-off machine-shop prototypes).
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In reality the answer is no. You have to take your choice of compromises with any compression driver. I do not think that any compression drivers are not designed without some built in problems. What you have to look at is the reasons for these non optimized designs. There are multiple reasons for this over the years but the basic real reason is purely economics. Some of these things could be easily overcome and some of it is just legacy designs and methods. If you look at something like and old Altec or JBL driver the exit angle is made from a cheap piece of tubular steel that has been made by swagging that tube over a simple form and creating that section. This section could have been made with a something other than the conic section there but that would have required a bit more work to produce the mandrel used to form that section. This goes back to the phasing plug sections and it was just easier to use straight walls on each section when the tooling is made than having to produce a curved surface, approximations of expansion rates were just accepted as good enough. Time has not changed these things, we still see the same methods used today that were used when Western Electric and others started the entire process, minor changes of materials, magnets and other parts have been the only real improvements to speak of. Today with modern CNC machinery there really is no excuse for the present situation.
The Radian build quality is pretty mediocre. AFAIK they still use the faulty clamping system to mount the diaphragm. It can get way out of wack if you don't adjust the mounting screws with great care. Performance wise the aluminum drivers are OK but not something I could live with in my system or recommend - the Be drivers I have not had but from looking at them they surely aren't built to TAD standards and are the aluminum drivers with a different diaphragm - I;m still enjoying the sound of the Faital HF144s, build quality is again OK but the sound is very much to my liking - dense tone and they are here ease throughout the range I use them
http://www.eighteensound.com/3P-Proprietary-Phase-Plug
Is this a step in the right direction?
The latest 3" drivers from B&C also tested pretty well in voicecoil last year with smooth response out to 18k with only one major resonance peak.
Maybe the Italians will carry the torch moving forward.
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Hi Kindhornman,
Almost the same idea can find in the patent:
Patent US20080192972 - Phasing plug for acoustic compression drivers - Google Patents
regards
ivica
The driver manufacturers re dragging their feet. they can do FEA and modal break up properties now with relative ease. It is better when DIYers start to rework known drivers and make it public. The Chinese then jump in an copy it so the West have to up the game.
A very well designed Mag Al/Mg alloy or other material for driver made to modern practical methods can always be good enough. I would bypass the costly Be and Diamonds until the other state of art but more economic materials really have been expored to their limit. Why do Al diaphragms so often win with the very best digital sound sources.
Because they have been designed and engineered to be the best. This is broadly was true of TAD and still is, albeit they used Be very effectively.
ErnieM,
From that patent it would be real hard to actually see the exact way they are completing the phasing plug but something to notice in the wording of the patent is that it had to be easy, why does everything have to be easy and not just the best that you can do?
ivicai,
Yes that looks like they are using a similar concept of resonant chambers to remove some of the standing resonances that travel across that center section of the phase plug. Just look at the date though and I would assume this patent shouldn't have ever been approved as this is previously known and publicly available information by that time, oh well we all understand that things get by the patent office if not easily found doing a search.
Boldname,
Yes your right, some of the changes needed are so obvious in the drivers assembly that it is a wonder that things just stay the same. The race to develop new diaphragm materials is just part of the marketing story, it is one of the easy things to change and it sounds so exotic when someone reads about using a diamond type material for a dome or some so called exotic material for the diaphragm like some of the plastic diaphragms you see these days. Just grab a commodity plastic resin and use its technical chemical designation and people think it is a big deal like an polyimide, big deal! The majority of non reinforced plastics just don't have the strength to weight ratio that is needed in these applications, that is the obvious reason to me that the top end is rolled of in these designs, the plastic diaphragms will go into breakup mode at those higher frequencies. One thing though about those plastic diaphragms it that the lower flexural modulus of those materials will allow for a wider and lower Q at resonance perhaps making those resonances more benign than the sharp high Q of a metal diaphragm at breakup.
From that patent it would be real hard to actually see the exact way they are completing the phasing plug but something to notice in the wording of the patent is that it had to be easy, why does everything have to be easy and not just the best that you can do?
ivicai,
Yes that looks like they are using a similar concept of resonant chambers to remove some of the standing resonances that travel across that center section of the phase plug. Just look at the date though and I would assume this patent shouldn't have ever been approved as this is previously known and publicly available information by that time, oh well we all understand that things get by the patent office if not easily found doing a search.
Boldname,
Yes your right, some of the changes needed are so obvious in the drivers assembly that it is a wonder that things just stay the same. The race to develop new diaphragm materials is just part of the marketing story, it is one of the easy things to change and it sounds so exotic when someone reads about using a diamond type material for a dome or some so called exotic material for the diaphragm like some of the plastic diaphragms you see these days. Just grab a commodity plastic resin and use its technical chemical designation and people think it is a big deal like an polyimide, big deal! The majority of non reinforced plastics just don't have the strength to weight ratio that is needed in these applications, that is the obvious reason to me that the top end is rolled of in these designs, the plastic diaphragms will go into breakup mode at those higher frequencies. One thing though about those plastic diaphragms it that the lower flexural modulus of those materials will allow for a wider and lower Q at resonance perhaps making those resonances more benign than the sharp high Q of a metal diaphragm at breakup.
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