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Thread: 4343 crossover modifications

  1. #451
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    Quote Originally Posted by B&KMan
    Thanks for reply but I just try without doubt your response.


    1--- in theory, dont matter what code connections or nature of network... the final phase result is all driver have a outward motion right ?? Wrong


    2--- in regard of the theory, I understand your response is according to connection of network : and because the phase of 2121,2420 & 2405 is inverted by circuit network it is important to connect inverted the MF, HF & UHF. See schematic


    3--- All this old drivers have a (+) post = black right?? see JBLPRO Tech Library pahse conventions.


    4--- Manys folks is expose the JBL monitor is load the LF inverted phase for preload the inside speaker by inward motion. so independently the connection what is final motion of each driver ??? all outward ???

    LF inward and all other outward ??? Y


    thanks again for light ...of day


    Jean.





    You have right... this question is delicate set-up and I study hard for control this parameter with my analyser... but it is easy now to perform this test with filters network load... after response , if you wish , I perform pict of this test.

    Ian

  2. #452
    Senior Member B&KMan's Avatar
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    WELL I COMPLETELY CONFUSE....


    actually My old 4343 with original network 3143 is connected exactly same as the shematic representation.

    all drivers of this speaker have a outward motion

    I perform test phase mesure of speaker with new network.

    the LF is outward but all other driver have inward motion if I connect with schematic... the sound is really different and appear more dark than old 4343.

    After connect all in outward motion same acoustic phase , I realise immediately the sound on new is look better same at old speakers but more refined and details.

    Normally all speaker produce final outward motion and because the network processe is invert phase, it is important to re-adjustement polarity in regard of this. But I konw the shema is good and Mr mackensie is write right but real acoustic invert phase is appear really not good in all my books. In JBL site it is really important to final connection is syncro to the input mic... (contractor litterature and all others installation recommandation.) So the final result it is LF inward and other outward ??

    see pict for my test phase:

    1---- set-up direct with big driver (thiel) for expose pulse motion easy perceived on eyes.
    (the driver move half inch motion pulse Yiah baby real pulse test here without doubt... )

    2--- pict expose the result of outward motion : the phase response in botton

    3--- pict expose the result of inward motion :the phase response is upper

    realy easy interpretation and not confusion here...

    So what is what??

    all connection polarity is verified all time... maybe the bigger inductor and caps double the rotation phase and re-align the phase ???

    JBL is perform 4345 speaker with LF Inward and the 4343 is all outward ???
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  3. #453
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    "JBL networks and transducers are designed so that if the red terminal of each transcucer is connected to the appropriate high terminal on the network, the system will be electrically in phase and diaphragm movements will be consistent. However, this arrangement may not result in proper acoustical phasing."


    "The connection resulting in proper acoustical phasing of any combination of components is difficut to determine in advance of assembly. Proper acoustical phasing of low and high frequency tansducers will be that electrical phasing which produces maximum acoustic outpout through the crossover region. In general, if the diaphragms of the various transducers are in the same physical plane or arc, in-phase electrical connection will probably result in proper acoustic phasing. If the diaphragms are not in the same plane or arc, proper phasing should be determined experimentally based on analysis of pink noise or subjective evaluation of program material."

    JBL varies the electrical phasing of drivers in their products to achieve their design acoustical performance from specific combinations of drivers, physical alignments, and network topologies. It is not uncommon to find one or more drivers wired reverse-phase with respect to others within standard systems. JBL's standard wiring is generally considered as comprising the "right" connection. Mileage may vary....

  4. #454
    Senior Member B&KMan's Avatar
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    Quote Originally Posted by Zilch
    "JBL networks and transducers are designed so that if the red terminal of each transcucer is connected to the appropriate high terminal on the network, the system will be electrically in phase and diaphragm movements will be consistent. However, this arrangement may not result in proper acoustical phasing."


    "The connection resulting in proper acoustical phasing of any combination of components is difficut to determine in advance of assembly. Proper acoustical phasing of low and high frequency tansducers will be that electrical phasing which produces maximum acoustic outpout through the crossover region. In general, if the diaphragms of the various transducers are in the same physical plane or arc, in-phase electrical connection will probably result in proper acoustic phasing. If the diaphragms are not in the same plane or arc, proper phasing should be determined experimentally based on analysis of pink noise or subjective evaluation of program material."

    JBL varies the electrical phasing of drivers in their products to achieve their design acoustical performance from specific combinations of drivers, physical layouts, and network topologies. It is not uncommon to find one or more drivers wired reverse-phase with respect to others within standard systems. JBL's standard wiring is generally considered as comprising the "right" connection. Mileage may vary....

    Thanks Zilch for reply but I'm perplex ...

    1--- my 4343 is " same " patern as 4345 ... so the phase is normally same .

    2--- My test phase is realy magnifying the phase response driver but if I put mic on 1 meter and produce pulse and verified phase....

    the result is really evident if one driver is out of phase because the segment corresponding of the response driver is inverted !!! so this type of test is relatively absolute phase response evaluation.

    3--- JBL expose clearly in technote :
    " JBL_TechNoteN1V12C_v5.pdf " and
    " tn_v1n12b.pdf "

    the importance of final result is outward motion to correspond at the real pressure response of mic.... I have doubt is make a opposite way in monitor studio and in same time is expose the importance for contractor, installator to respect the original phase... and expose the problem in technote for respect of multi amp system and active network...

    4--- It is not make sense to invert phase and destroyed the phase response for correction of curve... the unnatural inverted phase expose more trouble than 3 db correction... in fact any good room affect more balance response than 3 db.... pls it is easy to corrected the drop of boomer in start of network by just little displacement....

    strange realy strange...

  5. #455
    RIP 2011 Zilch's Avatar
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    LF driver is wired negative polarity in 3143 network, and the other three are reversed, assuming JBL convention of solid color wire connecting to red terminals of drivers.

    You are reading sound reinforcement technical information, where it is important that everything be in phase with the live instruments. Even then, however, recognize that within individual speakers, the phase of drivers is optimized for performance of that individual box, and the "everything in phase" rule does not apply.

    It matters even less in studio and control monitors, and least in home systems, where the phase of the live instruments is not an issue. No speaker designer is going to compensate for phase cancellation in the crossover region due to driver alignment for the sake of preserving electrical phase integrity.

    It's obvious that JBL didn't, in any case, and that is nothing in comparison to the fact that JBL phase convention itself is the inverse of industry standard, and this extended to its amplifiers as well, up until a few years ago.

    If you believe your system sounds better with the LF driver phase reversed from the schematic, swap the wires and forget about it. At least you didn't decide that all of the others are "wrong." Alternatively, if you want to switch everything to Chebychev filters, have AT it. A "little displacement" is not going to work at 350 Hz....

    Read and weep: http://www.jblpro.com/pub/technote/tn_v1n12b.pdf

    See also: http://audioheritage.org/vbulletin/showthread.php?t=487 where we danced this number nine months ago:

    "This is not sense??? (...)"

    [Same tune....]

  6. #456
    Senior Member B&KMan's Avatar
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    Quote Originally Posted by Zilch

    1---- LF driver is wired negative polarity in 3143 network, and the other three are reversed, assuming JBL convention of solid color wire connecting to red terminals of drivers.

    2---- If you believe your system sounds better with the LF driver phase reversed from the schematic, swap the wires and forget about it. At least you didn't decide that all of the others are "wrong." Alternatively, if you want to switch everything to Chebychev filters, have AT it....

    See also: http://audioheritage.org/vbulletin/showthread.php?t=487 where we danced this number nine months ago:

    Thanks again Zilch,

    Yes the LF on 4343 & 3143Network is invert but the final result is good phase all the way.

    http://audioheritage.org/vbulletin/s...0&postcount=82


    I expose the difference to connect wrong and true polarity and result of phase match... in accord of the schema.

    and I expose if you plug LF in invert (in corrolation of schematic) the final result is foward motion !!! not inward...

    --------
    You have right again for the question of taste : the final word is my ear ( for copy the celebrity word of Mr Mackensie).

    -------

    But for many other members and for the objective question, I stay in my question...


    Do you have feeling because I keep more biggest wire and bigger caps the phase shift 180°

    the problem phase here is weird :

    1--- same box and driver

    2--- I change network;

    3---- result change phase ???

    original design : all driver is push outward

    well, I go to check again my connection

  7. #457
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    Well if you charge couple and have 2 caps in series what is the phase change?? 90 or 180?? Intuition says to add the changes just like 3 pole 18db network. Figure with a charge coupled 18dB network you could get an additional 180 phase change. So from 270 to 450 if I am correct in this assumption. Depending on how many caps are in series to the drivers it could change things a bit. That puts you in the wrong quadrant as far as phasing compared to the original. To end up in the same quad you would have to inverse phase on the driver relative to the original well, I think, phase makes my head hurt


    Rob
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  8. #458
    Senior Member B&KMan's Avatar
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    Thanks Robh3606 for this hurt experiment answer...

    1 --- firstly, it is certain that the phase acoustic measured is obtained
    by comparison with the origin signal. In this direction that requires an apparatus bi-channel with integration of phase. What is the case here. the microphone is 1/4; thus extremely faithful to the signature of impusion of the diaghragm and very faithful to the response in phase.

    with the result that independent of all rotations of phase created
    by the filters, the real final acoustic result of the phase can be evaluated clearly.

    it seems to to me under these conditions, you hold the explanation, it would be interesting to see whether one 4344 mkII with a network in
    DC charges, and by keep in mind the drivers which function according to the
    new convention of polarity reacts is if according to this explanation. For my part, I have difficulty with discern the schema of the 4344 MK II to
    find an answer there.

    In addition, it should be said that in more of producing a circuit in DC charges, I also the concept of cascade introduces.

    In this mess electronic the final result it is a outward motion coherence for all drive in according of original 4343 & 3143 network no ??

    thanks again.

  9. #459
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    Quote Originally Posted by B&KMan
    Thanks Robh3606 for this hurt experiment answer...

    1 --- firstly, it is certain that the phase acoustic measured is obtained
    by comparison with the origin signal. In this direction that requires an apparatus bi-channel with integration of phase. What is the case here. the microphone is 1/4; thus extremely faithful to the signature of impusion of the diaghragm and very faithful to the response in phase.

    with the result that independent of all rotations of phase created
    by the filters, the real final acoustic result of the phase can be evaluated clearly.

    it seems to to me under these conditions, you hold the explanation, it would be interesting to see whether one 4344 mkII with a network in
    DC charges, and by keep in mind the drivers which function according to the
    new convention of polarity reacts is if according to this explanation. For my part, I have difficulty with discern the schema of the 4344 MK II to
    find an answer there.

    In addition, it should be said that in more of producing a circuit in DC charges, I also the concept of cascade introduces.

    In this mess electronic the final result it is a outward motion coherence for all drive in according of original 4343 & 3143 network no ??

    thanks again.
    You appear to be looking too deep that this issue.

    Provided all the drivers have "like"" phase convention the schematics for both the 4343 and 4344 remain true.

    Refer to basic 2nd order crossover theory at Rod Elliotts Sound pages for a thorough explanation of filter phase shifts.

    Ian

  10. #460
    Senior Member B&KMan's Avatar
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    complete phase test result

    Well for manys interesting by more result of phase.

    I send pict of mesure of impulse test and result keeping my mic realy close of driver.

    the first pict is the result of original form of impulse in nyquist presentation.

    the second is the result produce by driver and keeped by mic.
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  11. #461
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    Quote Originally Posted by B&KMan
    Well for manys interesting by more result of phase.

    I send pict of mesure of impulse test and result keeping my mic realy close of driver.

    the first pict is the result of original form of impulse in nyquist presentation.

    the second is the result produce by driver and keeped by mic.

    Next is the result of pict A comared by result of pict B and integration for final difference result Normally called H1

    the first pict is result in in phase and the second is out of phase in look of nyquist plot.

    look the mirror effect ...
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  12. #462
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    Quote Originally Posted by B&KMan
    Next is the result of pict A compared by result of pict B and integration for final difference result Normally called H1
    the next pict is expose maybe the better differential in response in phase and out of phase with nichol diagram.

    the time delay appear in out of phase (pict 2 ) expose the problem of bad phase.

    pict 1 is correct phase time.
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  13. #463
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    Hi

    Quote Originally Posted by robh3606
    Well if you charge couple and have 2 caps in series what is the phase change?? 90 or 180??
    - 2 caps wired end to end ( in series ), retain the expected 90° phase shift of a single cap .

    - Also, a DC bias applied to the junction of those 2 caps , is really beside the point / though ,,,,, see below.

    - I'll let someone else bench test my above assertions if you wish to prove me wrong .
    ( testing for a 180° phase shift "or polarity flip" is easy enough to be labelled simplistic )
    Quote Originally Posted by robh3606
    Intuition says to add the changes just like 3 pole 18db network. Figure with a charge coupled 18dB network you could get an additional 180 phase change. So from 270 to 450 if I am correct in this assumption. Depending on how many caps are in series to the drivers it could change things a bit. That puts you in the wrong quadrant as far as phasing compared to the original. To end up in the same quad you would have to inverse phase on the driver relative to the original well, I think, phase makes my head hurt
    - The rest of this hypothesis ( exra phase rotation within the poles ) falls apart if one can't establish the primary contention found in the first quote ( ie ; 2 caps wired in series = 180° phase shift ). Once again, FTR, the cumulative phase shift is 90° .

    - I'm sure that Jeans' N3145 phase challenges result from some other overlooked area ( though right now, I don't know what that might be / reviewing 12 pages of fractured communications is not my idea of a good time ).

    - Anyone around here with a stock 4345 to test ? If so and if you have the ability to measure relative phases/polarities ( ie with that "Cricket thingy that Bo has previously mentioned ), does the woofer ( 2245h ) move outwards with a positive pulse applied ? Now, what about the 2122h ?

    - Now, how about those of you with your proprietary 4344(s) or 4345(s) . With a positive pulse applied, what is the relative direction of cone travel for the 2235/2245 and 2122h transducers ?

    Thanks <> EarlK

  14. #464
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    Earl,

    Hi,


    In short the woofers move inward, the 2122H outward....yawn.

    I'm going back to bed.....

    Ian

  15. #465
    Senior Member B&KMan's Avatar
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    Thanks Earl for try explanation.

    well, in definitive, Only stock owner have a response and JBL service, so I try to contact service center for this question... but it is twicky because I dont find the color code connection just final acoustic phase response of 4344 or 4345..

    Anyway I perform other test for dissipate question of integration phase in two drivers...

    I put my mic in 1 meter 0° and in between LF and MF for mesure impulse response and analysing phase acoustic response.
    (of course at 1 meter echo is contaminated the original phase so I cut echo response but it is result to cut the original end signal too. so do not put importance to detail amplitude phase just the side is important here...

    I make this set-up for my original stock 4343 and my 4343 with 3145 DC +cascade set-up.

    the first pict expose the phase result (perfect coherence in low (2231 + 2235 diaghram) and mid (2121 +2121 diaghram).

    all driver it outward motion !!! original stock with respect of color code connection 4343 + 3143 network...

    now 3145 DC +cascade set-up plugged no according to schematic expose same result if I plug invert config of schema 3145 mid !!!!
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