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Thread: Latest brainstorm! 2435HPL direct radiator?

  1. #1
    Member NewZenith's Avatar
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    Latest brainstorm! 2435HPL direct radiator?

    It came to me in a vision last night, just after I knocked over the wine bottle.
    Would it be possible/practical to convert a 2435HPL compression driver to a direct radiator and what would be the benefits/compromises.
    I am already running 435Be's on my 4345 monitors. Thinking of picking up a pair of used 2435 drivers for experimentation. I believe these drivers have .020 between the phase plug and diaphragm. Above 1 kHz crossover point should allow for a bidirectional Xmax of .030 inches safely.
    Mylar haf rolled compliance is fairly durable, again for above 1 kHz use only.
    My goal would be usable output to 7 kHz or perhaps eight. So I may be able to adequately blend in with a 2405/077 slot in my XPL whatever's.
    It must be possible, however it is beyond me right now, to calculate max SPL at any given frequency with available diaphragm area approximately 7 in.˛ at any given frequency knowing Xmax.
    This experiment would require no permanent modifications to the compression driver.
    A homemade Waveguide could be fixed to the aluminum diaphragm ring with the same fasteners used to hold the back cap on.
    Phase plug may even assist in tuning the lower frequencies for better coupling to a tuning chamber.
    Driver would beam at those high frequencies although I do not know how much.
    Please forgive my curiosity.
    Sincerely your shoemaker newzenith.

  2. #2
    Dang. Amateur speakerdave's Avatar
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    And the purpose would be to have a beryllium dome midrange? Actually, I believe this kind of thing has been done before, with the large format JBL's and the titanium diaphragm (as I remember, in France, by the maker of a studio monitor). I would make one suggestion--stuff something into the compression chamber to absorb the back wave.

    Also, remember while you're horsing around with this, beryllium is very toxic. Personally I prefer mine bolted inside of a back cap.

    David

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    Member NewZenith's Avatar
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    Quote Originally Posted by speakerdave View Post
    And the purpose would be to have a beryllium dome midrange? Actually, I believe this kind of thing has been done before, with the large format JBL's and the titanium diaphragm (as I remember, in France, by the maker of a studio monitor). I would make one suggestion--stuff something into the compression chamber to absorb the back wave.

    Also, remember while you're horsing around with this, beryllium is very toxic. Personally I prefer mine bolted inside of a back cap.

    David
    I was under the impression that beryllium was primarily toxic during the manufacturing process. I have no real intentions on handling the diaphragm directly anyhow. So aside from health risks can you think of any reason why this would be a bad idea?
    I can reason a fiew things that might be quite desirable out of this configuration.
    1. Extended HF response.?
    2. pistonic motion beyond crossover point?
    3. High-efficiency/low distortion.?
    4. Non-break up mode compliance.?
    5. Low cost and investment.
    6. Small enough to fit in many current systems including my XPL experimentals.
    7. Lots of fun.
    Sincerely NZ.

  4. #4
    Senior Member Ian Mackenzie's Avatar
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    I think you are dreaming.

    Please dont be offended but your posts suggest you understand all the issues (which you don't) but want someone else to do all the work.

    You will need to do all your own R & D.

    If you care to do a search on google and understand the engineering of a compression driver it will be come clear that it needs acoustic impediance loading , particularly at resonance and below. You will also need to work out what to do about a rear chamber?

    Hence the Waveguide and all the necessary tailored Eq for a flat on axis response. The Waveguide also assists control of very early reflections, without which the exercide would be a waste of a good driver.

    You are better of buying a the right horn(s) and doing from R & D. If you dont have Clio and all the necessary software tools the odds are it will be crap shoot anyway.

  5. #5
    Member NewZenith's Avatar
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    z

    Quote Originally Posted by Ian Mackenzie;202660[I
    ]"I think you are dreaming."[/i]

    Never said I wasn't, however I believe it to be irrelevant because everything starts as a dream.

    "Please dont be offended"

    The easiest way to avoid being offended is to not be insulted.

    #1 "but your posts suggest you understand all the issues

    #2"(which you don't)"

    #3"but want someone else to do all the work."

    #4 "You will need to do all your own R & D"

    Problem with statements
    #1. I never claimed or Even suggested that I understood all of the issues, if I understood all of the issues I would not post probable questions. I believe that your statement is unfair and unnecessary.

    #2. "(Which you don't)" IMO offensive and redundant, I do not come to Lansing heritage and participate in open forms to be told what I do and do not know, I would rather discover it through open discussion.

    #3. There is no evidence that I desire anyone "to do all of the work" and moreover it is not the behavior I have ever demonstrated here.
    As a matter of fact I contribute in what ways I can, monetarily. I do not give advice, if I believe others can answer the questions more adequately, which is in most cases.
    I have not asked anyone to sacrifice anything of their own, nor do I feel any entitlement to any services that are not freely volunteered.
    All I ask is for an open and fair forum to discuss my ideas, which sometimes are very dream like.

    #4 it is apparent that I will be doing all of my own R&D.


    "If you care to do a search on google"

    This is over the top! I read at least two hours a day about speakers including hundreds if not thousands of posts here on LH.
    It has gotten to the point where I often run over the same posts while doing searches for completely different things realizing that I'm often rereading subject matter, that is saying something considering the size of the library here.

    "and understand the engineering of a compression driver it will be come clear that it needs acoustic impediance loading , particularly at resonance and below. You will also need to work out what to do about a rear chamber?"

    You are asking me my own question?

    I think I made it clear in my first post, which I reread just to make sure, I am aware that the diaphragm needs to be loaded. I have already experienced similar problems with my composite T030 drivers, which I solved.

    "Hence the Waveguide and all the necessary tailored Eq for a flat on axis response."

    I believe you may be over complicating the issues, my reference to a waveguide was an inaccurate statement, I would like a radius transition from the aluminum ring around the diaphragm to the baffle board. However lots of drivers successfully operate without waveguides that have a similar configuration, remember it is already a speaker. My job would be to fool it into thinking it was on a horn.

    "The Waveguide also assists control of very early reflections, without which the exercide would be a"

    "waste of a good driver."

    Please explain to me the waste part, if the driver does not function as I intended to or expected it to then I can, within a few moments, converted it back to a compression driver. no harm done, no money lost. Only some time, which is all we really have any way.


    "You are better of buying a the right horn(s) and doing from R & D. If you dont have Clio and all the necessary software tools the odds are it will be crap shoot anyway."
    This is the part that remains to be seen.

    In conclusion, simply put, humbly and honestly.
    Tell me something I don't already know.
    Sincerely newzenith.

  6. #6
    Member NewZenith's Avatar
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    Da! No good at working controls.

  7. #7
    Member NewZenith's Avatar
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    [quote=NewZenith;202677]This is the part that remains to be seen.

    Quote Originally Posted by speakerdave View Post
    1. Hey, you know? It's crazy enough--it just might work!


    2. You're good at asking for advice and not great at taking it.


    1. I shall take that as your sincere endorsement, pioneering spirit.

    2. It sure looks that way, but it is not always true.

  8. #8
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by NewZenith View Post
    can you think of any reason why this would be a bad idea?
    25 years ago I had the same thought when I listened to my LE85s with the back cap off as I replaced the diaphragm. Without the fog horn on it the 1.75" aluminum dome sounded far more natural. I considered designing a system based on this as a mid then decided it was stupid to use the driver in this fashion. Most of the expense of the driver is in the tight tolerances in the throat and phase plug. Why throw those out to get a dome mid? I decided to buy a high quality domed mid that was purpose built instead. At the time JBL didn't make anything like it, but others did. Today you can get these used JBLs or if you want a SOTA DIY project look into ATC. They make an excellent 3" mid dome.


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  9. #9
    Administrator Mr. Widget's Avatar
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    Or... just go ahead and do it. It isn't a smart thing to do, but you may have fun.

    It's somewhat like taking a brand new car and tossing the body so that you can put one of your own design on it. It may work and it may be fun, but it isn't the smartest thing to do and probably won't work as well as going with it as it was originally designed.


    Widget

    BTW: It is beryllium dust that is the health issue.

  10. #10
    Member NewZenith's Avatar
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    Mr. widget

    I have looked long and hard at the ATC dome midrange, very nice and intriguing. However will not work for my desired application.
    I must cross my midbass drivers at 1 K. or above, I would like to cross my dome out at 7K or above to a slot.
    My experimental domes, you have to take my word for now, work extremely well. I have beautiful stock 093ti,s and choose not to use them.
    After doing some major surgery on 2435HPL compression drivers I was enormously impressed with their design and resilience.
    Cost on used compression drivers is low enough, just low enough, to warrent potential experimentation on one unit.
    In my humble opinion, which isn't always that humble.
    I do not believe I can currently buy, at any price, exactly what I'm looking for. the ATC goes into non-pistonic motion above 4.5 kilohertz if I recall correctly. It is primarily designed to be crossed at lower frequencies, which is inapplicable to my current application. Also it's claim to fame.
    I will someday own a pair of ATC supra domes, as soon as I peel out the $1500.
    Think of the potential benefits should the driver be tuned properly for low frequencies and controlled excursion, 2 Tesla gap, ultra low weight motor and diaphragm assembly, crossed high enough and with aggressive crossover slopes I believe it would be capable of usable SPL.
    This is however a guess.
    How would it sound?, in my estimation, should it be tunable and capable of high enough or usable SPL's it would sound awesome.
    Like it does on a good horn, without any horn anomalies.
    Sincerely newzenith.

  11. #11
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by NewZenith View Post
    the ATC goes into non-pistonic motion above 4.5 kilohertz if I recall correctly.
    Doesn't the 2435 do that below 4KHz?

    Take pictures when you are done... would be interested in seeing them.


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  12. #12
    Member NewZenith's Avatar
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    2435 remains pistonic, according to what I have reaed, to beyond 15K.

    I am thinking with the low weight diaphragm, high power magnet gap, The kicker will be keeping the diaphragm movement limited. The 2435 and other compression drivers are not really, in my estimation, that different from many direct radiators, especially UHF drivers. It is not that much of a stretch to convert a compression driver, in my approximation, to direct radiator HF duty. Considering that many domes, we little 1 inch domes, can be crossed at 1.8k and give usable output, my shoemaker brain thinks a 3 inch dome, will be happy at 1.3K even considering its limited Xmax.
    Now I will gladly post photos and any technical information that I derive.
    However the photos will be rather boring, all I am going to do is make a baffle adapter and hopefully a simple chamber to load the diaphragm.
    I would like the driver to stay out of trouble well below its intended crossover point.
    NZ.

  13. #13
    Member NewZenith's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    This type of pea body discussion is not going anywhere,.

    A freakin 3 inch dome is not going to work up to 8000 cycles.

    Again, work the math and apply the diameter of the device to the frequency bandwidth.

    The penny drops, what is a phase plug for! Doooooooooooooooooooooa!

    Go what the movie Flight of the Phoenix

    http://www.imdb.com/title/tt0377062/

    Seriously, physics says it just wont work, the best you will get is 4,000 hz if that after which it gets very messy. A smart designer would then look at a Ribbon driver above 3800

    I would suggest scrap the idea of the 2435 and buy a Scan Speak Ring Radiator .


    Its all been done before.

    See the Solen site for details of the ATC dome incorporated into a 4 way setup using a 2245 as a woofer.

    Okay cool, close to a real answer! I had my curiosity about phase, I do not understand phase exactly as it relates to how sound is radiated off of a surface.
    Are you saying that phase cancellation would leed to uneven or jagged frequency response, unusable.
    I cannot transcend the laws of physics, whether or not I'm aware of them.
    However, so many Cone drivers are used in that frequency range and beyond, I figured it would work for a dome to?
    Anyway with all the blah blah blah that goes on every day in every form, including this one, I cannot understand why it would be so painful for someone to answer such a simple question in a legitimate way.
    As I have done for other people in my area of expertise, tens of thousands of times with nothing expected of them.
    With patience, with grace, and good will.
    Maybe I should stick to asking about what's the best brand RCA cables.
    or do tight knit rugs sound worse than shag carpets?
    I can guarantee you there would be no objection to that discussion, ad nausea!
    I'm thinking of upgrading the power cords on my hafler amps, what do you think, which color with sound best?
    I hear read is better for bottom end and green has smoother midrange?
    Sorry off-topic.
    It sounds like, back to the drawing board for me.
    NZ
    PS.
    JBL claims usable response to 8K on T030 domes.
    They must be as confused as I am.

  14. #14
    Senior Member timc's Avatar
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    2435 remains pistonic, according to what I have reaed, to beyond 15K.

    No. The breakup modes are above 15Khz, not the pistonic charateristic.



    -Tim
    2213 + 2435HPL w/aquaplas + H9800 (Matsj edition)

  15. #15
    Member NewZenith's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    This is the part that remains to be seen.

    In conclusion, simply put, humbly and honestly.
    Tell me something I don't already know.
    Sincerely newzenith.

    Okay

    I will be straight up with you.

    You know sweet FA.

    And you need need to read up wisely a good text ad stop pulling our chain about your understanding of the freakin serious BASICS and come back with some real specifics. As I said you are pioneering.

    I suggest you post on AudioKarma for a few clues.


    Okay, I am glad you'll be straight up with me, I have been straight up with everyone since I have been involved here in LH, without exception, so thank you.

    "You know sweet FA." ?? I know less than that, I don't even know what you're talking about?

    If this is an attempt to humiliate me, it is completely unnecessary. I put so many disclaimers as to make anyone's attempt at telling me that I knew something or claimed to know something a ridiculous and unwarranted criticism.

    If people are not interested in respectfully explaining why something will not work, I would rather they simply not comment at all. I think just about any mature human being would feel the same way regardless of subject or context!

    Let me ask anyone who reads this thread a simple question, how many times do people say things that they really have no business saying. Ever rant about politics? About food? Or music? Religion? Any subject you can think of, has anyone who's ever talked about anything, really know what they're talking about?
    What if you had a recording of everything you ever said to this point, do you think you might find fault with many of the things that you have proclaimed? I can guarantee you the answer is yes! This is why being truly humble is the only reasonable solution to the overwhelming amount of unknowns that we are surrounded with. Even the smallest and most mundane things around us have infinite complexity.
    It Is irrelevant that I, do not have all the answers, I am seeking information, of course I do not have all the answers.

    I'm not going to take this information, and make tens of thousands of dollars with it. I am not a pirate, I am a sincere hobbyist.
    I have, in general had good success with my audio meandering, I know it will only take me so far, and that I must become serious about the science.
    My whole reason for posting before attempting this project was to gather information, to help me decide whether or not it would even work!
    What I got were general criticisms and you shouldn'ts. I do not respond to that type of information, I do not like authority. If you are not my equal, don't bother talking to me!

    Sincerely NZ

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