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  1. #1
    Dis Member mikebake's Avatar
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    Proper drivers for intended applications"A constant theme

    and undercurrent on this forum.

    Thought I would add my 3 cents and post this in DIY. As always, do as you wish with your own gear, but there seems to be this fairly constant disregard for the driver and application engineering that JBL did. The window of acceptable use is often narrower than people want to think it is for many JBL drivers and products. Indeed, it seems it is the rarer case for a driver to have a pleasantly and suprisingly wider range of applications.
    Considering what JBL designed a specific driver for and attempting to use it in it's proper application, or one in which the variables do not put the dirver/crossover/system outside it's parameters, is what sets some peoples thinking apart from others. They just can't contemplate the value of using a driver/product in some way at odds with or outside it's performance parameters. The beauty is in recognizing and then properly implementing the driver/product in order to revel (no pun) in it's best abilities.
    It is a narrower, more focused pursuit than some realize. The education process here involves understanding this and then asking questions that deal with using the product correctly, not outside it's intended application. There doesn't seem to be much wisdom in bucking JBL's efforts and results, particularly with drivers. There is more going into the design and refinement of JBL drivers than I think most people are aware of. I would say that it would not be unusual for a highly qualified engineer to spend a year of work just getting one driver dialed in, even with all the past knowledge base that exists.

    p.s. this isn't concerning any specific post anywhere else; it has been a theme since about day one on this site

    MBB

  2. #2
    Obsolete
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    Quote Originally Posted by mikebake
    it has been a theme since about day one on this site
    Indeed it has. Thanks for the great post Mike!

  3. #3
    Senior Member spkrman57's Avatar
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    Amen Brother!

    Taking JBL products and using them in other than the JBL intended designs will often lead to less than "optimum" performance.

    If projects using JBL and other components are used, it becomes more of a hit or miss design. I am guilty of doing that also, but I accept the risks with the results.

    My favorite design involves JBL 2226 and Altec 902 on 811B horn crossed over @ 1.6khz 3rd order and single coil on the 2226 is a really nice general purpose system that is good with flea powered tube power up to 300 watt solid state amps. For 45hz to 16khz and simple sound, it is hard to beat, but I would never compare it to a stock JBL system.

    Ron

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    Administrator Robh3606's Avatar
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    Great Post Mike


    Yes I couldn't agree more. You need to use application specific drivers in the same ranges as the original designs to get the best performance out of them. You can go outside these windows however it takes experience using the drivers to get this knowledge. The easiest thing to do is do your home work and use the original JBL designs as a starting point. You at least have a good basic working design model to start with and you get to hear how JBL intended the driver to be used from the outset. You may find that it's what your looking for and stop right there. For the more adventurous you can try your hand at extending the range or trying different crossover points and slope and you have a reference to compare to. Most of the information you need is available right on the JBL Pro sight. Here are a couple of links so you know where to look,

    Vintage Product Information

    This is all the basic brochures for vintage product and gives you driver sets, crossover, and lots of useful information.

    http://www.jblpro.com/pages/obsolete.htm

    Technical Manuals

    This gives you drivers sets, schematics, basic dimensions, cone kits and on and on. Lots of goodies in these sheets

    http://www.jblproservice.com/navigat..._nav_tech.html

    Crossovers

    There are systems not covered in the Tech Sheets and many of the schematics can be found here.

    http://www.jblproservice.com/navigat...chematics.html


    System Reference Charts

    If you don't want all the information in the Tech Sheets and want to do a comparison of different versions say A vs. B you can use these summaries to easilly see what the differences are

    http://www.jblproservice.com/navigat...%20Charts.html



    The Thiele Small Table

    If you use a box program not all come with a database and some will probably be missing the newer drivers

    http://www.jblproservice.com/pdf/Thi...Parameters.pdf

    Rob

  5. #5
    Senior Member spkrman57's Avatar
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    Great info Rob!

    I wonder if this info is in a "sticky" or something like that. Maybe Techbot can arrange for this info to have quick and easy access!
    Ron



    Quote Originally Posted by Robh3606

    Vintage Product Information

    This is all the basic brochures for vintage product and gives you driver sets, crossover, and lots of useful information.

    http://www.jblpro.com/pages/obsolete.htm

    Technical Manuals

    This gives you drivers sets, schematics, basic dimensions, cone kits and on and on. Lots of goodies in these sheets

    http://www.jblproservice.com/navigat..._nav_tech.html

    Crossovers

    There are systems not covered in the Tech Sheets and many of the schematics can be found here.

    http://www.jblproservice.com/navigat...chematics.html


    System Reference Charts

    If you don't want all the information in the Tech Sheets and want to do a comparison of different versions say A vs. B you can use these summaries to easilly see what the differences are

    http://www.jblproservice.com/navigat...%20Charts.html



    The Thiele Small Table

    If you use a box program not all come with a database and some will probably be missing the newer drivers

    http://www.jblproservice.com/pdf/Thi...Parameters.pdf

    Rob

  6. #6
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    Connect a 130A and an LE175/HL87 to an N1200 and tell me that things couldn't be better!

  7. #7
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    130A + LE175/HL87 + N1200 = tell me that things couldn't be better

    Ok! Holy Hand Grenade Batman! Things couldn't be better!

  8. #8
    Senior Member frank23's Avatar
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    Quote Originally Posted by mikebake
    and undercurrent on this forum.

    Thought I would add etc etc

    MBB
    Nice posting. I would never say that JBL does not put a lot of effort into designing their drivers and speakers etc. But to say that using them in another way than intented would not do them justice is a too narrow view.

    When understanding components [or trying to] and accepting their limitations, you can use them in another design very effectively. That is because the design criteria that they were designed for are not necceseraly the ones I need. You could say that I would then not have to use these drivers, but that is not the case per se. I think the main difference between the JBL set of criteria and mine is that for me, speaker do not have to be able to play as loud as is required of studio monitors.

    For instance, I like to use 1st order crossovers, that results in a larger amount of energy going to the driver outside of the passband than with higher order crossovers. So the driver excursion is going to be a factor.

    JBL drivers are designed to withstand high play levels and have to do it for a long time [hanging from the ceiling of a football stadium]. In my living room, I can only feed them 12watts and they probably don't see more than 1watt, but when the see it coming, it might be at a relatively low 250-500Hz.

    I like the sound that way, but I need compression drivers that can handle it and behave up to 15kHz. And so JBL compression drivers are used in a way not intended in their design, but for my goals fit the requirements very effectively.

    frank

  9. #9
    Administrator Robh3606's Avatar
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    "But to say that using them in another way than intented would not do them justice is a too narrow view.'

    Hello Frank

    Well you just missed the boat. It has nothing to do with a narrow veiw. This perspective is from an engineering standpoint not a hobbiest DIY mentality. I can have my friends VW Jeta tow my 3000 lbs boat and it will work fine most of the time, except maybe when I try to stop or get it back up the ramp. It will move it just fine but a Jeta was not designed to tow a 3000 lb boat.

    I can run a 2420 down to 300Hz if I want to using low power. It will sound like crap and the 2nd 3rd harmonic distortion levels will go through the roof but hell it will make music. Jbl would never use it that way.

    Bottom line is you can do what ever you want when you DIY but don't expect to get the kind of resilts these drivers are capable of when you deliberately use drivers in applications they were not designed for or push them beyond their intended passbands. They will work but not up to there potential which is the hole point. Why would you go through the expense of purchasing TOL drivers and ignore the manufacturers reccomendations for use???? Does that make sense to you????

    Rob

  10. #10
    Senior Member frank23's Avatar
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    hi rob,

    it seems that you see that the goal for the driver is to produce the most sound with the least distortion, which is fine

    my personal goal is to produce the musically sounding speaker for my living room and I don't need 120dB, so I have the room to make other design decisions than the JBL engineers. I don't see why that application uses the driver[s] in an inferior way to the way as JBL used the drivers to great effect in their designs.

    you could even say that the 4430 uses drivers in a way not intended originally. It is just that JBL found a way using a nice horn and crossover to make do without a tweeter, and still produce a very nice 2-way monitor follow-up for the 3-way monitors. Though they did design the 2421 diaphragm but as Zilch shows a 2420 diaphragm [in his LE85] works no less.

    as long as JBL brings out great drivers and horns for me to play around with and this forum exists to share the joy, I'm happy. That is why this is the DIY forum.

    frank

  11. #11
    Dis Member mikebake's Avatar
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    Quote Originally Posted by frank23
    .

    as long as JBL brings out great drivers and horns for me to play around with and this forum exists to share the joy, I'm happy. That is why this is the DIY forum.

    frank
    It still should be a place of trying to employ best practices and sound application, not sloppy implementation. I do understand your point about some flexibility when certain requirements need not be met. Thanks for posting.
    MBB

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    Quote Originally Posted by mikebake
    and undercurrent on this forum.
    Quote Originally Posted by mikebake
    Thought I would add my 3 cents and post this in DIY. As always, do as you wish with your own gear, but there seems to be this fairly constant disregard for the driver and application engineering that JBL did. The window of acceptable use is often narrower than people want to think it is for many JBL drivers and products. Indeed, it seems it is the rarer case for a driver to have a pleasantly and suprisingly wider range of applications.
    Considering what JBL designed a specific driver for and attempting to use it in it's proper application, or one in which the variables do not put the dirver/crossover/system outside it's parameters, is what sets some peoples thinking apart from others. They just can't contemplate the value of using a driver/product in some way at odds with or outside it's performance parameters. The beauty is in recognizing and then properly implementing the driver/product in order to revel (no pun) in it's best abilities.
    It is a narrower, more focused pursuit than some realize. The education process here involves understanding this and then asking questions that deal with using the product correctly, not outside it's intended application. There doesn't seem to be much wisdom in bucking JBL's efforts and results, particularly with drivers. There is more going into the design and refinement of JBL drivers than I think most people are aware of. I would say that it would not be unusual for a highly qualified engineer to spend a year of work just getting one driver dialed in, even with all the past knowledge base that exists. p.s. this isn't concerning any specific post anywhere else; it has been a theme since about day one on this site

    MBB



    Thank you for the post. Points well taken. Coming from an offender- I appreciate the tact you have shown here. As such, I learned a new perspective and it has me learning in a new direction. Which leads me to add my 2 cents (or was it '3'?):



    I understand that this site, with all it's ignorance (not an insult- simply a lack of understanding), can be somewhat taxing on those gifted with the insight on how things JBL/HiFi work. It seems that after a while some of those more knowledgeable tend to project hostility to the ones not more knowledgeable. If I treat my daughter like a moron because she does not have the intelligence of an adult, yet- what would that say about my character? She will likely get a better education than I did and be able to put her talents and skills to better use and surpass me intellectually. No matter how you look at it- this site is a learning module and learning is happening on many different levels. Suffice to say- we all have our specialties in life.

    That being said- factor in the "text effect" and its ability/inability to convey the author's intent. Be it a joke, insult, or what have you- things get misread here every minute. I say it's better to confirm what the person's intentions are before opening up on them. I know it's the consensus to 'shoot first- ask later' for many members, but I hope I'm interpreting that as a joke .

  13. #13
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    Nice post!




    Quote Originally Posted by hapy._.face
    It seems that after a while some of those more knowledgeable tend to project hostility to the ones not more knowledgeable.
    Who are they? By God we'll give them what for! We'll straighten them out forthwith!
    Quote Originally Posted by hapy._.face
    factor in the "text effect" and its ability/inability to convey the author's intent.
    Yeah, there's that...

  14. #14
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    [QUOTE=Giskard]...Who are they? By God we'll give them what for! We'll straighten them out forthwith![/QUOTE]

    '...it was years ago'.

    Thread (post #37): http://www.audioheritage.org/vbullet...ead.php?t=9192

    Giskard- Not you!! Your manner is always mild, pleasant, and forthcoming. Besides you don't know much about this sort of thing anyways. (example of text effect)

    Laugh, please.

  15. #15
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    What was years ago?

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