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Thread: JBL 4346 DYI with 2123H

  1. #46
    Senior Seņor boputnam's Avatar
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    Quote Originally Posted by lordoflight View Post
    However it seems that something eludes me. It is the sound that is not that clear. As it is a fundamental issue like for example the cables or the drivers are veiling the sound. I was under the impression that the sound of these monitors should be clearer. Is it something that I miss?
    What are you accustomed to listening to, and at what gain, and it what setting? I'm not sure why these would sound "veiled" even if the iPhone mic is presenting an impression of a false boost of the HF - it's not that dramatic.
    bo

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  2. #47
    Senior Member ivica's Avatar
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    Quote Originally Posted by lordoflight View Post
    Dear ivica,

    Please see my comments inline.

    thank you for your answers

    Bogdan
    Hi Bogdan,

    1.
    Using 2308 lenses would reduce higher FR-response due to the spreading off-axis response especially over 4kHz, that would reduce the response , as I have remembered about 3~4 dB.


    so should i purchase the 2308 lenses or not. Would that improve o. the sound clarity?

    I would suggest You to use 2308 lenses when a horn like 2307/2312/2311 is used. The VHF driver would become much more linear FR response, producing less beaming of higher frequency range


    2. Due to the geometrical differences between VHF and UHF drivers, a kind of comb-filter effect would be evident, especially round 8kHz~12kHz when passive network without time delay compensation is applied. Even with the time compensated electronic network, due to the drivers baffle mounting a kind of the same effect can be get, but I believe that all of that would be hard to be recognized by the listener.

    is there anything here that may be improved?

    I think that You do not need to do anything about,
    Remember that for a decades JBL 43xx series were used in the most of audio studios, even though such effect have been present.
    Using more expensive active network with time alignment possibilities, and filters with higher order slopes would make such comb-filter effect less pronounced

    4.
    I think that firstly drivers sensitivity has to be adjusted, and after that I would not expect any great problem at all as any of the used driver is of high quality and very linear, may be the best of any.


    How can I adjust the drivers sensitivity?

    Using L-pads and proper values resistors in the applied network. So a kind of measurement microphone (I think there is USB type from the "MINI-DSP" or other company) and sound card, or proper CD made disk as a source....
    After I would suggest You to make off-axis measurements too. Something about 15~20 deg off-axis is a good approximation, of much more elaborated measurements .

    5.
    I would prefer 2441/45/46/50 & 2311 instead of 242x & 2307, as such combination seems to me more natural sound in the lower VHF FR-spectrum (may be due to the larger diaphragm surface)


    Is there a possibility to improve these 2425's ?


    I do think that any improvements with the mentioned driver & horn combo can be get.

    regards
    ivica

  3. #48
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    I was listening to proac supertowers with the same setup based on my Accuphase E 360.

    The sound was very crisp and clear on my Proacs unlike on the jbl's. The voice for example is very recessed on the jbls and i cannot find that vibrato that is usually present in the voice or in the classic guitars, the breath of the singer, the decay of the chords. The sound is damped somehow. I feel like for example if i change a cable it would clean up the sound. If i put the amp directly on the 2425 without the crossover, the sound seems more crisp and clear, but through the filter the sound gets muddy. I hope I am making myself understood.

  4. #49
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    Is your Proac the Mk1 or Mk11?

    I agree the subjective aspect of the JBL performance is not up to your expectations.

    Can you please elaborate on the JBL you heard at KRS?

  5. #50
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    I have been looking your crossover picture.

    I assume all the filters are on this board?

    But l cannot visualise the capacitors for the 2123 per the 4344mk11 crossover?

    I can see the 3 30uf capacitors for the Low pass filter.

    But I cannot see the 2 36uf. Capacitors, one series and one shunt in the mif filter.

    If l am not following your layout let me know but it look like you have somehow included the capacitor values from the 3155 in the mid filter.

    Again if l am not following your layout let me know.

    But as l commented previously in your measurement of the mid filter, this would explain comments to some extent as the 2123 is overlapping the 2435 horn hence your comment on phase issues.

    The crispness or instrumental clarity comes from the mid cone. If l am correct your mid cone is going too low and too high.

    To validate this Are you about to take clearer pictures and best sketch on a sheet of while paper the layout with the position and values of the crossover parts.

    If we can validate the implementation of he crossover then it much more time efficient to tune the system correctly.

    Below l have attached the 4344mk11 crossover, your crossover layout and the 3155 crossover for clarity.

    The last pic (my dog) l hope will help relieve any frustration.

    Your mid filter should have the same equivalent values of all Inductors, capacitors and resisters as in the top section denoted by MF
    Attached Images Attached Images     

  6. #51
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    For comparison I will do a measurement on my 2123 with the 4344mk11 filter this week.

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    clearer crossover picture

    the two 36 microF are in fact pairs of two 18 with a 0.01 bypass. They are near the litz aircoil.

    and thank you for the dog. Its really cute.

    the mid filter and low filter are full 4344mkii. everything should be in there. If I missed
    anything I would be more
    than grateful to point that out for me.

  8. #53
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    and the picture

    here is the clearer picture.
    Attached Images Attached Images  

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    Quote Originally Posted by Ian Mackenzie View Post
    Is your Proac the Mk1 or Mk11?

    I agree the subjective aspect of the JBL performance is not up to your expectations.

    Can you please elaborate on the JBL you heard at KRS?

    It was an mki with titanium hf drivers from MBQuart. However it was very sibilant at times. I had to tMe that sibilance using some copper cables.

    as for the krs speakers, is what i heard on youtube. Never been to Japan But they sounded clear and crisp even in the youtube recording

  10. #55
    Senior Seņor boputnam's Avatar
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    Quote Originally Posted by lordoflight View Post
    If i put the amp directly on the 2425 without the crossover, the sound seems more crisp and clear, but through the filter the sound gets muddy. I hope I am making myself understood.
    You are understood - thanks for the patience.

    I hate to bring this up, but so far Ian is curious about intra-cabinet phase issues. Your post makes me curious about inter-cabinet phasing. So, does this symptom occur with mono (L or R, alone), or only when you are in stereo (L/R) mode?

    And, apologies - a full 50% of the time I inevitably run into systems that are either completely, or by element, unintentionally out-of-phase.
    bo

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  11. #56
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    Quote Originally Posted by boputnam View Post
    You are understood - thanks for the patience.

    I hate to bring this up, but so far Ian is curious about intra-cabinet phase issues. Your post makes me curious about inter-cabinet phasing. So, does this symptom occur with mono (L or R, alone), or only when you are in stereo (L/R) mode?

    And, apologies - a full 50% of the time I inevitably run into systems that are either completely, or by element, unintentionally out-of-phase.

    Thanks for the input. is there any way to put the speakers in phase both intra and inter so to say . the polarity of the drivers and of the filters are a little misleading

  12. #57
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    please check my polarity

    lf red wire - from the - to the red post on the speaker
    mf red wire - from the 2 on the lpad to the red post on the speaker


    hf red wire - from the - on the network to the red post on the speaker
    uhf red wire - from the - on the network to the black on the speaker. beyma has normal polarity.


    lf and mf they are supposed to be in antiphase?
    i'm confused

  13. #58
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    Quote Originally Posted by lordoflight View Post
    It was an mki with titanium hf drivers from MBQuart. However it was very sibilant at times. I had to tMe that sibilance using some copper cables.

    as for the krs speakers, is what i heard on youtube. Never been to Japan But they sounded clear and crisp even in the youtube recording
    Okay

    Apparently the mk11 with a soft dome is far better
    I am sure the Youtube was impressive but you were listening to your pc speakers.

    Subjectivity you are comparing a finished hifi speaker to an in finished pro monitor.

    Without the 2308 lense it is not going to work properly.

    I have a pair of nice metal 2308 if you are interested.

  14. #59
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    Quote Originally Posted by lordoflight View Post
    the two 36 microF are in fact pairs of two 18 with a 0.01 bypass. They are near the litz aircoil.

    and thank you for the dog. Its really cute.

    the mid filter and low filter are full 4344mkii. everything should be in there. If I missed
    anything I would be more
    than grateful to point that out for me.
    Okay but how can we help you validate your implementation if we cannot follow your layout?

    There is a problem some where so if you can sketch the layout that would be great.

    I plan to run a series of measurements tomorrow with the iPhone and the Dayton mic.

    I suggest that you only listen to one speaker and provide feedback

  15. #60
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    Quote Originally Posted by lordoflight View Post
    lf red wire - from the - to the red post on the speaker
    mf red wire - from the 2 on the lpad to the red post on the speaker


    hf red wire - from the - on the network to the red post on the speaker
    uhf red wire - from the - on the network to the black on the speaker. beyma has normal polarity.


    lf and mf they are supposed to be in antiphase?
    i'm confused
    All the mid hi and uhf are in phase with each other.

    The woofer is wired red to red terminal

    The mid hi and uhf are wired red to black terminal

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