JoninCR
Well, this is good, you are forcing me to think, excellent.
The last thought, the one concerning the multiple vent "mesh" with Mamboni treatment, was not intended to dissipate the back wave. Instead my thought was to control the back wave front, on the box inside plates, with Mamboni's infinite edge termination process, applied as if the box faces were those of a driver and between the actual driver and the mesh of ports. I am certain there will be some loss involved, not certain how much, as this is a thought experiment with only a small amount of empirical activity to back it up with.
What I am aiming at is a large area vent, used to create additive sub frequencies, in phase with the front wave emissions, physically stepped back by perhaps 18 inches, to maintain some semblance of emitted phase coherency.
If the Mamboni process can be used to control reflections within the box by controlling the boundary layers of the box interior, we might get that bass EQ without added electronics. I have experimented with multiple small diameter ports for bass reinforcement with considerable success. I have not experimented with more than four, but, I see no reason to assume that many more than four would be less effective. These four holes, and Bass Box Pro will model them quite effectively, rather than one big port. have some added benefits. There is a port flow mass that acts much as a shock absorber. When sized correctly the bass is linearized and without the "boing" character so offensive from more normal ported, closed, boxes.
Oddly these small ports do not chuff until a very high SPL is achieved, 103 dB and higher in my environment and this at 35 Hz, from a single 9 inch Dynavox woofer in an 0.8 cu ft box. Admittedly the woofer has been treated with the EnABL process so that the back wave is quite a bit more orderly than is the usual case. This set up will not charge a large volume, but two boxes will perform very competently in a 20 X15 X 8 volume.
So, what I am after here is bass in phase with the emitted front wave , of lower octave content than the front wave, that has the same dynamic characteristic of the front wave and uses the back wave, through the mesh port scheme, with terminated reflections in the box, to achieve this goal. That the phase coherent energy coming off of an EnABL treated woofer will aid in this is certain, I do not believe the scheme would work otherwise.
So this does fall into one of your two categories that are not monopoles but with a 180 degree, hopefully, twist to the bass that just might eliminate that EQ situation. But, again, there is the Gary Pimm factor and the staggeringly powerful and dynamic bass he has obtained. I will attempt to get him to post here, but he is on sabbatical from audio, specifically due to the lack of intelligent response he encountered on another forum, where that sort of response too often seems to be the norm.
I like your Helmholtz low frequency scheme and am going to put that idea to simmer in the back of my brain, I see considerable parallel to the intent of mesh port idea. Except of course that your idea is working in reality rather than imaginality.
Bud
Well, this is good, you are forcing me to think, excellent.
The last thought, the one concerning the multiple vent "mesh" with Mamboni treatment, was not intended to dissipate the back wave. Instead my thought was to control the back wave front, on the box inside plates, with Mamboni's infinite edge termination process, applied as if the box faces were those of a driver and between the actual driver and the mesh of ports. I am certain there will be some loss involved, not certain how much, as this is a thought experiment with only a small amount of empirical activity to back it up with.
What I am aiming at is a large area vent, used to create additive sub frequencies, in phase with the front wave emissions, physically stepped back by perhaps 18 inches, to maintain some semblance of emitted phase coherency.
If the Mamboni process can be used to control reflections within the box by controlling the boundary layers of the box interior, we might get that bass EQ without added electronics. I have experimented with multiple small diameter ports for bass reinforcement with considerable success. I have not experimented with more than four, but, I see no reason to assume that many more than four would be less effective. These four holes, and Bass Box Pro will model them quite effectively, rather than one big port. have some added benefits. There is a port flow mass that acts much as a shock absorber. When sized correctly the bass is linearized and without the "boing" character so offensive from more normal ported, closed, boxes.
Oddly these small ports do not chuff until a very high SPL is achieved, 103 dB and higher in my environment and this at 35 Hz, from a single 9 inch Dynavox woofer in an 0.8 cu ft box. Admittedly the woofer has been treated with the EnABL process so that the back wave is quite a bit more orderly than is the usual case. This set up will not charge a large volume, but two boxes will perform very competently in a 20 X15 X 8 volume.
So, what I am after here is bass in phase with the emitted front wave , of lower octave content than the front wave, that has the same dynamic characteristic of the front wave and uses the back wave, through the mesh port scheme, with terminated reflections in the box, to achieve this goal. That the phase coherent energy coming off of an EnABL treated woofer will aid in this is certain, I do not believe the scheme would work otherwise.
So this does fall into one of your two categories that are not monopoles but with a 180 degree, hopefully, twist to the bass that just might eliminate that EQ situation. But, again, there is the Gary Pimm factor and the staggeringly powerful and dynamic bass he has obtained. I will attempt to get him to post here, but he is on sabbatical from audio, specifically due to the lack of intelligent response he encountered on another forum, where that sort of response too often seems to be the norm.
I like your Helmholtz low frequency scheme and am going to put that idea to simmer in the back of my brain, I see considerable parallel to the intent of mesh port idea. Except of course that your idea is working in reality rather than imaginality.
Bud
Bud,
I'll try to spend some time today looking at the Mamboni and EnABL. I wasn't referring to them in previous post(s). I was talking about posts turning to heavy damping materials inside an open backed box in an effort to absorb some of the rear wave. I doubt constant absorption with frequency, or better, higher absorption with lower frequency, is possible with any material, so that looks like a dead end to me.
Though I'm a relative noob, I'm a quick learner. I've yet to start measuring other than crudely with tones and music, but I will begin measuring a bunch of stuff soon. Guidance is appreciated because I want to do things right, and not waste time with flawed methods. I prefer building new things and listening to music. I believe that all the things I want to measure will be a big help to those less experiences, and even some of the "experts" may learn something new.
My approach has been a very visual one, and "seeing" what happens with both the front and rear waves is what I do.
Please do get Gary involved, and hopefully we can come up with ideas to hold his interest.
I'll try to spend some time today looking at the Mamboni and EnABL. I wasn't referring to them in previous post(s). I was talking about posts turning to heavy damping materials inside an open backed box in an effort to absorb some of the rear wave. I doubt constant absorption with frequency, or better, higher absorption with lower frequency, is possible with any material, so that looks like a dead end to me.
Though I'm a relative noob, I'm a quick learner. I've yet to start measuring other than crudely with tones and music, but I will begin measuring a bunch of stuff soon. Guidance is appreciated because I want to do things right, and not waste time with flawed methods. I prefer building new things and listening to music. I believe that all the things I want to measure will be a big help to those less experiences, and even some of the "experts" may learn something new.
My approach has been a very visual one, and "seeing" what happens with both the front and rear waves is what I do.
Please do get Gary involved, and hopefully we can come up with ideas to hold his interest.
AJ,
You're like a broken record. If you want to learn about waveguides and directivity go here http://sound.westhost.com/articles/waveguides1.htm . Then it will be pretty obvious that I'm controlling directivity to below 1khz. At the sides the sound has good frequency balance albeit at a much reduced level than within the planes of the wg panels, so I must be getting a pretty good match with the transition to dipole. It is much different than any of the flat baffle
As I move around within the soundfield, there is little change in the sound other than the shifting of the image. There isn't the big change in tonal balance as you move and midrange only at the sides that occur with these same beaming 8's on a flat baffle. This is a logical result of the narrowed dispersion of the waveguide, since the midrange energy that would have gone to sides is focused by the WG.
Regarding the HOMs. I picked up that term from reading Geddes. He says they're cause by reflections within a horn. You've obviously never played the same driver on a flat baffle and projecting through a horn shape to really hear the resulting coloration. A perfect waveguide wouldn't have reflections and would only control the expansion of the wave. That means that absorbent material lining the waveguide will attenuate only the reflections. Not only is this logical, but it corresponds with what I hear. Once I start measuring, I doubt HOM's will even be something I can measure, yet my ears can clearly distinguish between colored sound and non-colored using the same drivers, and with the foam and material, the sound is natural like with a flat baffle.
Measurements will only tell us how well I implemented my ideas, not whether or not they are sound, because I only borrowed ideas from the science presented by others who have generously shared their work.
Are they perfect?....definitely not, and that is my reason for posting, to share and learn. When I listen nearfield, as I move out of the plane of the WG's, there is an increase in response, like a noise, that occurs right at the WG plane, so I must be getting some diffraction/reflections despite the 4"dia roundovers, and/or the result of what is making that thick wood vibrate so noticeably.
You're like a broken record. If you want to learn about waveguides and directivity go here http://sound.westhost.com/articles/waveguides1.htm . Then it will be pretty obvious that I'm controlling directivity to below 1khz. At the sides the sound has good frequency balance albeit at a much reduced level than within the planes of the wg panels, so I must be getting a pretty good match with the transition to dipole. It is much different than any of the flat baffle
As I move around within the soundfield, there is little change in the sound other than the shifting of the image. There isn't the big change in tonal balance as you move and midrange only at the sides that occur with these same beaming 8's on a flat baffle. This is a logical result of the narrowed dispersion of the waveguide, since the midrange energy that would have gone to sides is focused by the WG.
Regarding the HOMs. I picked up that term from reading Geddes. He says they're cause by reflections within a horn. You've obviously never played the same driver on a flat baffle and projecting through a horn shape to really hear the resulting coloration. A perfect waveguide wouldn't have reflections and would only control the expansion of the wave. That means that absorbent material lining the waveguide will attenuate only the reflections. Not only is this logical, but it corresponds with what I hear. Once I start measuring, I doubt HOM's will even be something I can measure, yet my ears can clearly distinguish between colored sound and non-colored using the same drivers, and with the foam and material, the sound is natural like with a flat baffle.
Measurements will only tell us how well I implemented my ideas, not whether or not they are sound, because I only borrowed ideas from the science presented by others who have generously shared their work.
Are they perfect?....definitely not, and that is my reason for posting, to share and learn. When I listen nearfield, as I move out of the plane of the WG's, there is an increase in response, like a noise, that occurs right at the WG plane, so I must be getting some diffraction/reflections despite the 4"dia roundovers, and/or the result of what is making that thick wood vibrate so noticeably.
So you have taken no measurements whatsoever? Just listen then speculate? Ok. Thanks.
cheers,
AJ
Thanks John. I saw that info a while back. I'd love to learn about waveguides. Sounds interesting. Might they be useful with dipoles too?johninCR said:
It will be? If the driver is in it's omni directional frequency range up to 1k, why would you not get controlled directivity on a flat panel?johninCR said:
Must be? You are not sure? This differs from a flat panel dipole how?johninCR said:
Most certainly. You have shifted the resonance peak downward into H-baffle territory. How you are notching this out of the drivers passband without measuring is beyond me. It ought to sound different from a similar width flat baffle, as D has increased.johninCR said:
You've lost me here. The tapered TL of the H-baffle is producing dipole nulls to the side in the omni-range different from a flat baffle? In the non-omni, beaming range, the horn is affecting it how?johninCR said:
Yes, I know, I've been reading his work for years. His work and your work bare little resemblance.johninCR said:
Well, yes and no. Yes I have "played" the same driver (XT19) on a flat baffle and a horn shape. No I have not heard the resulting coloration. I measured a rising response in the drivers low end as dictated by the horn dimensions and corrected the response in the filter design. There was of course no dipole cancellation, as the driver was a monopole.johninCR said:
They will tell me both. I look forward to them.johninCR [/i] Once I start measuring said:
cheers,
AJ
AJ,
I bother to reply to your posts only out of boredom. In the future, please limit your posts to those of a constructive nature, and since I've never seen one from you, what I really mean to say is clearly implied.
When I speculate, I say so.
If you think your dipoles have constant directivity, as you say, let's see the measurements. I'm sorry that you can't understand that a driver's polar response varies with frequency and only by mechanical means can you make it more constant.
The cavities my drivers rest in are too open to create a resonance, so there is no peak to notch out. Why you keep bringing up TL's and H baffles is beyond me. When you come up with a dipole TL or H baffle that you think sounds good with a fullrange driver, let me know.
Only someone like yourself would think that your experience with a compression tweeter is germain to your point.
Haven't you learned by now that your posts only drive people away? Most aren't as thick skinned as I am, or are simply not willing to waste their valuable time responding. I just remembered this forum has an ignore list feature.
I bother to reply to your posts only out of boredom. In the future, please limit your posts to those of a constructive nature, and since I've never seen one from you, what I really mean to say is clearly implied.
When I speculate, I say so.
If you think your dipoles have constant directivity, as you say, let's see the measurements. I'm sorry that you can't understand that a driver's polar response varies with frequency and only by mechanical means can you make it more constant.
The cavities my drivers rest in are too open to create a resonance, so there is no peak to notch out. Why you keep bringing up TL's and H baffles is beyond me. When you come up with a dipole TL or H baffle that you think sounds good with a fullrange driver, let me know.
Only someone like yourself would think that your experience with a compression tweeter is germain to your point.
Haven't you learned by now that your posts only drive people away? Most aren't as thick skinned as I am, or are simply not willing to waste their valuable time responding. I just remembered this forum has an ignore list feature.
AJ,
For those of us on the side lines of what appears to be a long running fray, would you be so kind as to lay out test types, methods and results that would, in your qualitative judgment, either disprove JoninCR's allegations or allow him to move on in his actual physical experiments? For all I know you have already done this in some other thread and pointing us there would be sufficient I am sure.
It does sound as though you have a rather strong bias against qualitative findings. May I suggest that you have a deficiency in training only. The obvious fact that you have ancestors indicates that you have all of the physical equipment needed to make effective evaluations, of the nature of both static and changing sonic signatures, but may have become determined not to use what a couple of million years of threat assessment of a holistic, hostile sound field have selected for.
Please do not take this to mean I am adverse to quantitative measurement, I find it invaluable in my profession. The point I am pushing towards is that our hearing is a very specialized, highly correlated, self protection device.
The semi autonomous correlator that sits on top of the raw sense data, which is not materially different from that received by a test microphone, is scanning for relative data, what is different about the constructed data field that has been rendered, in a 360 degree assessment of threats and non threats. This correlator can, with relative ease block a known benign sound to enable new, unknown and possibly threatening sounds to be addressed. This goes on below the typical level of consciousness 24 hours a day.
The level of discrimination is superior to that of a spectrum analyzer, but it is not an objective discrimination, without training. When I say superior to a spectrum analyzer I am referring to the "information in the grass" and the ability of the correlator to create an understandable and actionable data set from what just looks like noise on a display screen.
Even with training there is not any sort of hard copy printout available. This does not in any way prejudice the results derived from this extremely fine tuned discriminator of all of the values required, to make a correlatable sound field that is understandable to our semi autonomous threat assessment system. Neither you nor I can make any sort of "objective, quantitative " determination of JoninCR's sound field projectors. We have zero quantitative data. And, since we have not heard them, we have no qualitative data either.
Without both, no judgments can be made on the merits of his creations, except those he makes about the recreation of an understandable sound field and qualitative measurements have reliably proven to be a useless guide to what is and what is not a correlatable recreation of an understandable and "pleasing" recreation of a distant sonic event. So, I am skeptical of the value of objective tests without also accepting Jon's qualitative data.
We can, however, listen closely to his qualitative comments to get some notion of his sound field projectors value in recreating a sound field that is intelligible to our correlator based "hearing".
He does after all have the same lineage of ancestors, ones who were able to assess and so left us capable of assessing a very complex threat field, over time, distance and vector, that allowed them to remain uneaten and us to enjoy a mock up of reality, portrayed with enough clues for our correlator to reconstruct a believable event from what would otherwise be meaningless data.
Not useless data, just meaningless. We are, after all of the measurement and analysis is done, the only judge of what is good and what is bad in sound reproduction and that can only be a qualitative judgment.
I also am really tired of the excuse commonly used for tossing qualitative evaluations, "that we all hear differently". This is not correct. We all hear the same, after a few million years of truly excellent predator selection of our species, we must all hear very close to the same. It is only our consciously trained, conscious listening skill set, that varies.
Bud
For those of us on the side lines of what appears to be a long running fray, would you be so kind as to lay out test types, methods and results that would, in your qualitative judgment, either disprove JoninCR's allegations or allow him to move on in his actual physical experiments? For all I know you have already done this in some other thread and pointing us there would be sufficient I am sure.
It does sound as though you have a rather strong bias against qualitative findings. May I suggest that you have a deficiency in training only. The obvious fact that you have ancestors indicates that you have all of the physical equipment needed to make effective evaluations, of the nature of both static and changing sonic signatures, but may have become determined not to use what a couple of million years of threat assessment of a holistic, hostile sound field have selected for.
Please do not take this to mean I am adverse to quantitative measurement, I find it invaluable in my profession. The point I am pushing towards is that our hearing is a very specialized, highly correlated, self protection device.
The semi autonomous correlator that sits on top of the raw sense data, which is not materially different from that received by a test microphone, is scanning for relative data, what is different about the constructed data field that has been rendered, in a 360 degree assessment of threats and non threats. This correlator can, with relative ease block a known benign sound to enable new, unknown and possibly threatening sounds to be addressed. This goes on below the typical level of consciousness 24 hours a day.
The level of discrimination is superior to that of a spectrum analyzer, but it is not an objective discrimination, without training. When I say superior to a spectrum analyzer I am referring to the "information in the grass" and the ability of the correlator to create an understandable and actionable data set from what just looks like noise on a display screen.
Even with training there is not any sort of hard copy printout available. This does not in any way prejudice the results derived from this extremely fine tuned discriminator of all of the values required, to make a correlatable sound field that is understandable to our semi autonomous threat assessment system. Neither you nor I can make any sort of "objective, quantitative " determination of JoninCR's sound field projectors. We have zero quantitative data. And, since we have not heard them, we have no qualitative data either.
Without both, no judgments can be made on the merits of his creations, except those he makes about the recreation of an understandable sound field and qualitative measurements have reliably proven to be a useless guide to what is and what is not a correlatable recreation of an understandable and "pleasing" recreation of a distant sonic event. So, I am skeptical of the value of objective tests without also accepting Jon's qualitative data.
We can, however, listen closely to his qualitative comments to get some notion of his sound field projectors value in recreating a sound field that is intelligible to our correlator based "hearing".
He does after all have the same lineage of ancestors, ones who were able to assess and so left us capable of assessing a very complex threat field, over time, distance and vector, that allowed them to remain uneaten and us to enjoy a mock up of reality, portrayed with enough clues for our correlator to reconstruct a believable event from what would otherwise be meaningless data.
Not useless data, just meaningless. We are, after all of the measurement and analysis is done, the only judge of what is good and what is bad in sound reproduction and that can only be a qualitative judgment.
I also am really tired of the excuse commonly used for tossing qualitative evaluations, "that we all hear differently". This is not correct. We all hear the same, after a few million years of truly excellent predator selection of our species, we must all hear very close to the same. It is only our consciously trained, conscious listening skill set, that varies.
Bud
Bud,
No worries. I've been promising measurements for a while. I've been dragging my feet since the company whose active XO/EQ system that I use announced they hoped to have a measurement program, which will tie directly in the XO program, by March. While I was waiting for the new system, I ran across Geddes' Summa, which gave me the dipole WG idea. The program still isn't out, so I may go another route.
When I start measuring, I have a miriad of things and enclosures to measure, so I want to do it correctly and obtain valid results. The last think I want is someone legitimately picking apart methodology, because it will be a lot of work. Also, it seems like work as opposed to building new ideas, which I consider fun, thus my foot dragging. My only real interest is as a test of my tuning by ear.
Advice on proper measurements is welcome. I have a behringer measurement mic, which I know I have to calibrate. My room has an extremely low noise floor, and if something absolutely requires outdoor measurements, I can borrow a laptop and go in the adjacent park area. I downloaded SpeakerWorkshop months ago, but when I heard that it had a very steep learning curve, I never cracked it open. ARTA was suggested by someone on another forum.
No worries. I've been promising measurements for a while. I've been dragging my feet since the company whose active XO/EQ system that I use announced they hoped to have a measurement program, which will tie directly in the XO program, by March. While I was waiting for the new system, I ran across Geddes' Summa, which gave me the dipole WG idea. The program still isn't out, so I may go another route.
When I start measuring, I have a miriad of things and enclosures to measure, so I want to do it correctly and obtain valid results. The last think I want is someone legitimately picking apart methodology, because it will be a lot of work. Also, it seems like work as opposed to building new ideas, which I consider fun, thus my foot dragging. My only real interest is as a test of my tuning by ear.
Advice on proper measurements is welcome. I have a behringer measurement mic, which I know I have to calibrate. My room has an extremely low noise floor, and if something absolutely requires outdoor measurements, I can borrow a laptop and go in the adjacent park area. I downloaded SpeakerWorkshop months ago, but when I heard that it had a very steep learning curve, I never cracked it open. ARTA was suggested by someone on another forum.
JoninCR,
The methodology I would use was taught to me by Miles Nestorovic some twenty years ago, while I was pretending to be his R&D engineer.
Take any useful driver and run it in a number of field modification tests to get a data set of what unknown factors in the field modifying attachments cause alterations in the polar response, phase response, transient decay profile and frequency response of the driver.
Then take one of those attachments and make various alterations to it's size, overall mass, edge step in both curved and flat corners in both depth and follow on shapes. Measure each change and make certain to note all of the physical details.
In parallel, listen to each of these situations in a controlled environment, and any quiet room will suffice. Listen only to music fundamentals and pay as little attention to clues under 250 Hz and above 5 kHz as you can. You are listening for how audible the various attachment and edge terminations are, not what is "best", just what alterations are audible. These should be noted in text with the test data hard copy.
Then pick one of these attachment modifications, based upon listening for music fundamentals, and begin to alter it's constituents of size, mass and termination of radiation surfaces, informed by the previous wider range of tests. Perform both objective measurements and subjective response with note taking.
Take another driver of similar usage and size and do the same tedious set of tests. Find a third and fourth and do the same thing. You are building a data base library that will inform all of your future experiments.
Once this information is solid and you can repeat it at will, you can begin to add crossovers or surface treatment modifiers that have an effect of noticeable amount, only in the audible tests. Basically unfindable with any reliable certainty in the grass of your measurements. There will be hints in the objective test data, but only years of experience will make them obvious to you.
Miles would take test data sheets and go off to think about their implications, come back to me and ask for specific tests that would answer a decision point about how to progress with his analysis, go away and come back with specific alterations he wanted to try. He always learned from the audible testing, done in concert with every one of these test points. His final decisions about what was and was not acceptable were always based upon his subjective responses to tests that were suggested to him by following a methodological "tree" of decision points. The importance assigned to each of these tests was strictly driven by the qualitative listening done at the same time.
That this method produced some of the finest audio gear ever brought to market will be attested to by the private owners and commercial recording studios that still use his speakers and in many cases his Alpha one amplifiers. Some of you out there in forum reader land will know what I am speaking of here.
I hope this helps you to use both sets of data and will in time give you the ability to take any given cabinet of choice and change drivers, with the uncanny ability to end up with the same sound, by altering how they are diffracted into the air, their relative actual acoustic phase point and how the choices of crossover components and brands affects the drivers performance and brings it into overall sonic compliance with the other drivers in the system.
I have to tell you, my jaw was mostly on my chest watching this skilled design engineer, with his consciously trained "hearing" perform this activity with an ease and fluency I could understand, but not duplicate.
Bud
The methodology I would use was taught to me by Miles Nestorovic some twenty years ago, while I was pretending to be his R&D engineer.
Take any useful driver and run it in a number of field modification tests to get a data set of what unknown factors in the field modifying attachments cause alterations in the polar response, phase response, transient decay profile and frequency response of the driver.
Then take one of those attachments and make various alterations to it's size, overall mass, edge step in both curved and flat corners in both depth and follow on shapes. Measure each change and make certain to note all of the physical details.
In parallel, listen to each of these situations in a controlled environment, and any quiet room will suffice. Listen only to music fundamentals and pay as little attention to clues under 250 Hz and above 5 kHz as you can. You are listening for how audible the various attachment and edge terminations are, not what is "best", just what alterations are audible. These should be noted in text with the test data hard copy.
Then pick one of these attachment modifications, based upon listening for music fundamentals, and begin to alter it's constituents of size, mass and termination of radiation surfaces, informed by the previous wider range of tests. Perform both objective measurements and subjective response with note taking.
Take another driver of similar usage and size and do the same tedious set of tests. Find a third and fourth and do the same thing. You are building a data base library that will inform all of your future experiments.
Once this information is solid and you can repeat it at will, you can begin to add crossovers or surface treatment modifiers that have an effect of noticeable amount, only in the audible tests. Basically unfindable with any reliable certainty in the grass of your measurements. There will be hints in the objective test data, but only years of experience will make them obvious to you.
Miles would take test data sheets and go off to think about their implications, come back to me and ask for specific tests that would answer a decision point about how to progress with his analysis, go away and come back with specific alterations he wanted to try. He always learned from the audible testing, done in concert with every one of these test points. His final decisions about what was and was not acceptable were always based upon his subjective responses to tests that were suggested to him by following a methodological "tree" of decision points. The importance assigned to each of these tests was strictly driven by the qualitative listening done at the same time.
That this method produced some of the finest audio gear ever brought to market will be attested to by the private owners and commercial recording studios that still use his speakers and in many cases his Alpha one amplifiers. Some of you out there in forum reader land will know what I am speaking of here.
I hope this helps you to use both sets of data and will in time give you the ability to take any given cabinet of choice and change drivers, with the uncanny ability to end up with the same sound, by altering how they are diffracted into the air, their relative actual acoustic phase point and how the choices of crossover components and brands affects the drivers performance and brings it into overall sonic compliance with the other drivers in the system.
I have to tell you, my jaw was mostly on my chest watching this skilled design engineer, with his consciously trained "hearing" perform this activity with an ease and fluency I could understand, but not duplicate.
Bud
Hi Bud,
Thank you (and also so many others above) for posting from your long gained experiences. Also apologies for this post not adding more to the discussion, but I smiled when reading the truth contained within your sentence;-
>>When I say superior to a spectrum analyzer I am referring to the "information in the grass" and the ability of the correlator to create an understandable and actionable data set from what just looks like noise on a display screen.<<
Cheers ......... Graham.
Thank you (and also so many others above) for posting from your long gained experiences. Also apologies for this post not adding more to the discussion, but I smiled when reading the truth contained within your sentence;-
>>When I say superior to a spectrum analyzer I am referring to the "information in the grass" and the ability of the correlator to create an understandable and actionable data set from what just looks like noise on a display screen.<<
Cheers ......... Graham.
Down the years did anyone ever get to listen to a 'Beveridge' loudspeaker?
http://www.beveridge-audio.com/Technology.htm
http://www.beveridge-audio.com/Technology.htm
BudP said:
Bud - your last sentence is reminiscent of what Harvey Rosenberg used to describe (in his own very entertaining way), as our individual "cumulative aural matrix"
Except for those unfortunate few with physical impairment or nerve/brain damage, we do all hear more or less the same.
However, from the moment they become functional, (i.e. before we become "conscious" ) each of our auto-correlators are subjected to a unique stream of multi-sensory data ( including audio ), that throughout our life continues to shape both the wiring and programming of how our "wet-ware" interprets this raw data into "reality".
All of us playing with this hobby for any length of time have heard someone say "but, I don't have a trained/golden/critical ear - I couldn't hear the difference......."
everyone's "ears" are trained, just not all of the training is intentional
Even though I'd like to get back talking about designing a new OB speaker, I'm not sure I agree about hearing being equal. Similar sure based on evolution, but actually quite different, and more than just taste. I find that our sensitivities vary quite a bit in different frequency ranges. eg One of my employees gets dizzy any time I run low frequency tests, and not even than low. He says it's actually painful. I am very sensitive, probably overly sensitive, in the range around 3khz. Even at only moderate volumes, peaks in that range literally hurt my ears.
I some people like speakers with an uptilted response, and I believe it is more than just taste or taste in music.
The differences in our hearing have nothing to do with how valueable a tool our ears are in speaker building. In many respects our ear/brain combo are more useful and sensitive than the most expensive equipment, and the relatively crude measurements to which I will be restricted will only help quantify what I hear.
AJ will get his measurements, but in the meantime he should gather the measurements of other speakers including his own, especially in the area of polar response, so he has some basis for comparison. Otherwise mine won't be of much value. Until then he can choose to accept my descriptions or not. I'm not trying to sell anything, and I do try to be as objective as possible, since I have no interest in fooling anyone, including myself.
I applied some science available online to come up with what I think is a unique design. They are designed to achieve some very specific things, and the results tell me the science is sound. While some of these goals are in contradiction to Mr. Olsen's views, the concepts seem to work in my room, so I want to follow through and take the design as far as possible.
I some people like speakers with an uptilted response, and I believe it is more than just taste or taste in music.
The differences in our hearing have nothing to do with how valueable a tool our ears are in speaker building. In many respects our ear/brain combo are more useful and sensitive than the most expensive equipment, and the relatively crude measurements to which I will be restricted will only help quantify what I hear.
AJ will get his measurements, but in the meantime he should gather the measurements of other speakers including his own, especially in the area of polar response, so he has some basis for comparison. Otherwise mine won't be of much value. Until then he can choose to accept my descriptions or not. I'm not trying to sell anything, and I do try to be as objective as possible, since I have no interest in fooling anyone, including myself.
I applied some science available online to come up with what I think is a unique design. They are designed to achieve some very specific things, and the results tell me the science is sound. While some of these goals are in contradiction to Mr. Olsen's views, the concepts seem to work in my room, so I want to follow through and take the design as far as possible.
I agree, I think our non-belligerent attitude around here attracts people like Lynn, so I would appreciate everyone keeping that in mind. Also let's not get off into general comments about perception and other topics that typically don't lead anywhere....
Lynn, when you want to start making your decisions, please feel free to start another thread that is limited to comments about your design only, as it is developed. We can keep this thread more for "Brainstorming"
Variac
Lynn, when you want to start making your decisions, please feel free to start another thread that is limited to comments about your design only, as it is developed. We can keep this thread more for "Brainstorming"
Variac
OB with Fertin 20EX and Eminence Kilomax Pro 18A
Thinking of an OB with front baffle 24-28" wide at the base tapering asymmetrically to 12" at top, 48-52” tall (ala apogee). Edges of the front baffle would be rounded 1-2" rounding. Side supports behind the front baffle would start at 12-15" at base and taper to 2-3" at top. Active Deqx for crossover (80-160 Hz?) and room equalization with solid state amp for the Eminence and 300B SET for Fertin 20EX. My room is 20' W x 32' D x 8' H. Listening seat is 11' from speakers if they are 6' from rear wall.
Questions:
1. How's the Eminence KW Pro 18A for this application? Seems to be good from TS standpoint (FS=33, 95db, Qts=.6 Xmax=10mm peak, hi power handling). Seems to be very rough though beyond 200 Hz – due to cone break up or heatsink? Are there others that work better? (move as much air, cost less, go lower, transition smoother, etc.) Can this driver be equalized with the deqx to a reasonable in-room bass response (shooting for 30 Hz or less?) assuming that the driver and amp have enough headroom?
2. My thinking for the baffle shape is that the asymmetrical shape would decrease undesirable baffle interaction. Is it better to have the angled side of the trapezoid to the outside or inside edge?
3. There's been a lot of discussion regarding baffle diffraction. Does this also apply to the rear of the baffle as well or is rear baffle diffraction unimportant from a time window perspective?
4. What are the best techniques for minimizing baffle vibration? My worry is that the 18” Eminence will rattle the daylights out of the Fertin.
5. How important is it to secure the drivers from the rear to supplement the basket mounts?
6. I always liked the idea of using the same type of amp for bi-amping. Would I get satisfactory results from the Eminence with the right 300B SE amp? My feeling is that it would quickly run out of gas due to the equalization necessary for extending the low end.
7. I would like to run the Fertin down as low as possible without endangering it or creating a hole in the response that has to be artificially equalized - using more of my top end amps headroom. Any ideas on where to start are welcome. I assume that I would just run a response curve on the Fertin by itself and put the cross over ½ to one octave higher than where it starts to roll off naturally.
8. Anyone have comments on experience using the Deqx in this type of application?
Thanks
Thinking of an OB with front baffle 24-28" wide at the base tapering asymmetrically to 12" at top, 48-52” tall (ala apogee). Edges of the front baffle would be rounded 1-2" rounding. Side supports behind the front baffle would start at 12-15" at base and taper to 2-3" at top. Active Deqx for crossover (80-160 Hz?) and room equalization with solid state amp for the Eminence and 300B SET for Fertin 20EX. My room is 20' W x 32' D x 8' H. Listening seat is 11' from speakers if they are 6' from rear wall.
Questions:
1. How's the Eminence KW Pro 18A for this application? Seems to be good from TS standpoint (FS=33, 95db, Qts=.6 Xmax=10mm peak, hi power handling). Seems to be very rough though beyond 200 Hz – due to cone break up or heatsink? Are there others that work better? (move as much air, cost less, go lower, transition smoother, etc.) Can this driver be equalized with the deqx to a reasonable in-room bass response (shooting for 30 Hz or less?) assuming that the driver and amp have enough headroom?
2. My thinking for the baffle shape is that the asymmetrical shape would decrease undesirable baffle interaction. Is it better to have the angled side of the trapezoid to the outside or inside edge?
3. There's been a lot of discussion regarding baffle diffraction. Does this also apply to the rear of the baffle as well or is rear baffle diffraction unimportant from a time window perspective?
4. What are the best techniques for minimizing baffle vibration? My worry is that the 18” Eminence will rattle the daylights out of the Fertin.
5. How important is it to secure the drivers from the rear to supplement the basket mounts?
6. I always liked the idea of using the same type of amp for bi-amping. Would I get satisfactory results from the Eminence with the right 300B SE amp? My feeling is that it would quickly run out of gas due to the equalization necessary for extending the low end.
7. I would like to run the Fertin down as low as possible without endangering it or creating a hole in the response that has to be artificially equalized - using more of my top end amps headroom. Any ideas on where to start are welcome. I assume that I would just run a response curve on the Fertin by itself and put the cross over ½ to one octave higher than where it starts to roll off naturally.
8. Anyone have comments on experience using the Deqx in this type of application?
Thanks