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Thread: 4628B curve for Zilch

  1. #61
    Senior Member pos's Avatar
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    You're welcome!

    Yes the DSC260 will be perfect if you stick with 3 ways, but then you will also have to handle the subwoofer(s)...

    The 2470 is not that good, and will not be able to go down to 800Hz in the first place.
    If could be a solution in the 1.2khz-6khz range (the directivity is collapsing quite rapidely) if you keep the 2118H, but then you need a 4way crossover (DSC280 maybe?, or a pair of M553, or maybe some minidsp modules if you are ready for some DIY)

    What horns do you have access to on your local market?

    As for the subwoofers, it is a different problem, and an easier one to solve, once your mains are up and running.

  2. #62
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by pos View Post
    You're welcome!

    Yes the DSC260 will be perfect if you stick with 3 ways, but then you will also have to handle the subwoofer(s)...

    The 2470 is not that good, and will not be able to go down to 800Hz in the first place.
    If could be a solution in the 1.2khz-6khz range (the directivity is collapsing quite rapidely) if you keep the 2118H, but then you need a 4way crossover (DSC280 maybe?, or a pair of M553, or maybe some minidsp modules if you are ready for some DIY)

    What horns do you have access to on your local market?

    As for the subwoofers, it is a different problem, and an easier one to solve, once your mains are up and running.
    Thank you so much!welcome to China and my homeland city: 3100 years old city-Xi'an!
    1.My initial thought is to improve 4628B by simplest way(such as using active crossover without any drivers replacement)is this possible?which is the best crossover points?i want to make full use of 4628B.
    2.the second idea is that in order to improve 4628B's subbass by using two 15' bass drivers,does this work?
    3.which is the best way to upgrade 4628B?add 2407?replace 2118 with 2123 or 2425?
    4.My 4628B's 2404 has no nameplate,how can i identify whether it is -1 or not?
    sorry for so many questions.
    I have JBL 4208.euro L80,but i like 4628B the best.it sounds some old cinema sound.
    in fact, i don't like JBL modern production such as 4429\4338\4348 etc.they seems lack of some taste,they are just studio tools.
    Doing some DIY not all about saving money,maybe just for some fun.if it is too difficult,i'll go buying second hand L300\4344 etc.
    Thank you once more.
    46 lover

  3. #63
    Senior Member pos's Avatar
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    If you like the sound of the 4628B, then why not leave it as it is now?
    You surely you could lead to a more hifi and refined sound with an active crossover and measurement gears (even with the same drivers complement), but maybe you will miss that old ciname sound that you like.

    Why not just add some subbwoofers (spread across the room, not under the 4628's) to augment the bass and call it done?

    Concerning the 2404, I think it is the '-1' variant in this model (but then it seems there are plenty of variants there also...). And it better be: the 3khz crossover point would be really low for a 2405 diaphragm. The only way to be sure would be to open it and check the diaphragm width.

    If you insist on going active, and you are ready to do -lots of- measurements, I think the best two options are to add a horn on top to turn it into 4 way (a 2370 would do, but a 2397 would sure be cooler), or to replace the 2404 by a 2407.
    But then if you ultimately manage to get something as good as a 4348, you will be disappointed as you will miss that 80's sound

  4. #64
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by pos View Post
    If you like the sound of the 4628B, then why not leave it as it is now?
    You surely you could lead to a more hifi and refined sound with an active crossover and measurement gears (even with the same drivers complement), but maybe you will miss that old ciname sound that you like.

    Why not just add some subbwoofers (spread across the room, not under the 4628's) to augment the bass and call it done?

    Concerning the 2404, I think it is the '-1' variant in this model (but then it seems there are plenty of variants there also...). And it better be: the 3khz crossover point would be really low for a 2405 diaphragm. The only way to be sure would be to open it and check the diaphragm width.

    If you insist on going active, and you are ready to do -lots of- measurements, I think the best two options are to add a horn on top to turn it into 4 way (a 2370 would do, but a 2397 would sure be cooler), or to replace the 2404 by a 2407.
    But then if you ultimately manage to get something as good as a 4348, you will be disappointed as you will miss that 80's sound
    Although i like 4628B so much,but I think its crossover is too simple,and even let the E145 go through,why?i think there maybe some room to improve 4628B.
    But in fact,i have not any measurement gearswhat can i do if i use a active crossover?
    If i simplely crossover 4628B at 850hz and 7500hz like DD55000 ,can it work well?
    can 2118 work so high?
    best regards
    Martin
    46 lover

  5. #65
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by pos View Post
    If you like the sound of the 4628B, then why not leave it as it is now?
    You surely you could lead to a more hifi and refined sound with an active crossover and measurement gears (even with the same drivers complement), but maybe you will miss that old ciname sound that you like.

    Why not just add some subbwoofers (spread across the room, not under the 4628's) to augment the bass and call it done?

    Concerning the 2404, I think it is the '-1' variant in this model (but then it seems there are plenty of variants there also...). And it better be: the 3khz crossover point would be really low for a 2405 diaphragm. The only way to be sure would be to open it and check the diaphragm width.

    If you insist on going active, and you are ready to do -lots of- measurements, I think the best two options are to add a horn on top to turn it into 4 way (a 2370 would do, but a 2397 would sure be cooler), or to replace the 2404 by a 2407.
    But then if you ultimately manage to get something as good as a 4348, you will be disappointed as you will miss that 80's sound
    I'm searching Chinese pro audio market these days and find a pair of 4726A(exact same with 4728AP and I725),its horn is 2344A and looks great,but the compressed driver is 2426J,16ohms version.Can i add 2344 to 4628B?then what should i do next?
    Thank you.
    46 lover

  6. #66
    Senior Member pos's Avatar
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    Quote Originally Posted by martin_wu99 View Post
    Although i like 4628B so much,but I think its crossover is too simple,and even let the E145 go through,why?i think there maybe some room to improve 4628B.
    But in fact,i have not any measurement gearswhat can i do if i use a active crossover?
    If i simplely crossover 4628B at 850hz and 7500hz like DD55000 ,can it work well?
    can 2118 work so high?
    best regards
    Martin
    Maybe the fact that the E145 runs without low pass filter is part of the reason why you love the sound of that speaker? The same principle is used in the L100 and the 4312 speakers, and people tend to grow accustomed to their sound and find other speakers dull sounding.

    In any case, if you want to use the DD55000 crossover points (and entier network in fact) you will have to use the exact same drivers and horns, so the only things you could keep are the E145s. In any case, the 2118 will not be able to reach 7khz. Its directivity will colapse, and it will be full of breakups.

    If you feel there are some area this speaker can be improved upon, you need to list them one by one and try to find a way to address them specifically. For example, the bass can easily be augmented with subwoofers. Are there other specific flaws, like harshness or coloration, that annoy you with this speaker?

    Quote Originally Posted by martin_wu99 View Post
    I'm searching Chinese pro audio market these days and find a pair of 4726A(exact same with 4728AP and I725),its horn is 2344A and looks great,but the compressed driver is 2426J,16ohms version.Can i add 2344 to 4628B?then what should i do next?
    Thank you.
    The 2344/2426 is a killer combo, and can be used without the 2404. But you will need measurement gears anyway, even with active crossover.

  7. #67
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by pos View Post
    Maybe the fact that the E145 runs without low pass filter is part of the reason why you love the sound of that speaker? The same principle is used in the L100 and the 4312 speakers, and people tend to grow accustomed to their sound and find other speakers dull sounding.

    In any case, if you want to use the DD55000 crossover points (and entier network in fact) you will have to use the exact same drivers and horns, so the only things you could keep are the E145s. In any case, the 2118 will not be able to reach 7khz. Its directivity will colapse, and it will be full of breakups.

    If you feel there are some area this speaker can be improved upon, you need to list them one by one and try to find a way to address them specifically. For example, the bass can easily be augmented with subwoofers. Are there other specific flaws, like harshness or coloration, that annoy you with this speaker?



    The 2344/2426 is a killer combo, and can be used without the 2404. But you will need measurement gears anyway, even with active crossover.
    I don't konw what it will sound like if cut off 850hz upper of E145,maybe just a try.
    Beside the low end, i also want to make 4628B more smooth and soft,is there any other mothed?Why Mark Gander design 4628B into this way?
    I find out that 2118's range is 70hz-7Khz(3db),2404's range is 4khz-19khz(3db),then which point is the best point to connect them?
    I'v just read a post that a french man add 2404 and 2123 to his 4430,so i think it will be better adding 2426+2344 to 4628B?
    Thanks a lot.
    46 lover

  8. #68
    Senior Member martin_wu99's Avatar
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    By the way,i can open the 'manage attachments' box,i can select files(pics),but i can not upload files,why? there are six pic files remains in the box(i uploaded before) and can not be deleted?
    Thank you!
    46 lover

  9. #69
    Senior Member martin_wu99's Avatar
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    Measured
    sensitivity (SPL at I m (3.3 ft) with I W input. swept 500 Hz-2.5 kHz) shall be at least 97 dB on axis
    and 94 dB 45 degrees off axis. As an indication of electromechanical conversion efficiency, the BI
    factor shall be at least 11(H), 15(J) newtons per ampere. The half-space reference efficiency shall
    be 2.1%. Usable frequency response shall extend from 70 Hz to 7 kHz. On-axis response,
    measured at a distance of 1.8 m (6 ft) or more under free-field conditions. shall be ± 3 dB from
    200 HZ to 4 kHz. Acoustic loading shall further extend the low frequency response.
    Highest Recommended
    Crossover Frequency: 3 kHz

    from 2118 PDF

    Maybe add 2425+2344 to 4628B and let it work on 3khz-7khz is a way, is that right?
    46 lover

  10. #70
    Senior Member pos's Avatar
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    1.5khz or so would be much better. You also need to match the horizontal directivity at the crossover point. The 2344 is 100° from 1khz up. The 2118 shall be 100° maybe around 1.8khz, so that would be the maximum crossover point. It would be the ideal crossover point with steep slopes. Anywhere between 1.2khz and 1.6khz should be good with shallow crossover slopes.
    But keep in mind that the 2344 needs specific compensation, because it is a pure constant directivity design in the frequency range you are considering.

  11. #71
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by pos View Post
    1.5khz or so would be much better. You also need to match the horizontal directivity at the crossover point. The 2344 is 100° from 1khz up. The 2118 shall be 100° maybe around 1.8khz, so that would be the maximum crossover point. It would be the ideal crossover point with steep slopes. Anywhere between 1.2khz and 1.6khz should be good with shallow crossover slopes.
    But keep in mind that the 2344 needs specific compensation, because it is a pure constant directivity design in the frequency range you are considering.
    I just studied Gold Sound Speaker Kit11,and found out that its crossover points is 300hz&5000hz,maybe 5000hz is the point,i'll try it first.but i like 2425 and 2344 very much,i will try it sooner or later.
    Freq Response:
    Power Range:
    Efficiency:
    Max. Volume:
    Crossover
    Controls
    Dispersion
    Distortion
    Woofer
    Midrange
    Tweeter
    Cabinet
    Satellite
    Subwoofer

    28-21kHz+/-3dB
    5-300 WRMS 8 ohm
    93dB
    118dB
    300 & 5000Hz
    midrange & tweeter level
    100 deg to 20kHz
    < 1% 3rd harmonic at 100 dB
    JBL 15" 2235H; 80 oz mag
    JBL 8" 2118H, 30 oz magnet
    JBL 2404H biradial horn
    6 cf, 44x18x17" -OR-
    0.4 cf, 16x10x8" &
    6 cf, 44x18x17" (2 req'd)
    46 lover

  12. #72
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by pos View Post
    1.5khz or so would be much better. You also need to match the horizontal directivity at the crossover point. The 2344 is 100° from 1khz up. The 2118 shall be 100° maybe around 1.8khz, so that would be the maximum crossover point. It would be the ideal crossover point with steep slopes. Anywhere between 1.2khz and 1.6khz should be good with shallow crossover slopes.
    But keep in mind that the 2344 needs specific compensation, because it is a pure constant directivity design in the frequency range you are considering.
    What kind of specific compensation does 2344 need?
    46 lover

  13. #73
    Unabashed Speakerholic cosmos's Avatar
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    4628B with subwoofers.

    Here is the system in my workshop. I think it sounds pretty good and can be heard over most shop noise.. :-) An added benefit is that the critical drivers are high enough to be near ear level when standing and can shoot over most of the equipment..

    There is (2) 2245H per channel crossed over at about 100 Hz.
    Attached Images Attached Images  

  14. #74
    Administrator Robh3606's Avatar
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    There is (2) 2245H per channel crossed over at about 100 Hz.
    Sure you have enough woofer down there. I bet they kick some serious butt!!

    Rob
    "I could be arguing in my spare time"

  15. #75
    Unabashed Speakerholic cosmos's Avatar
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    Quote Originally Posted by Robh3606 View Post
    Sure you have enough woofer down there. I bet they kick some serious butt!!

    Rob
    Rob,

    Yeah, they can be a little overwhelming if you let them...

    It's amazing how effortlessly they can produce deep bass. If you watch them work, you can barely see them working. You hear the boom, but just barely see them move. Amazing I tell ya!!!

    Further, they are just about a perfect bottom for 4628B. I think in a pair they're about the same efficiency.. and they integrate with the E145 so well.. It is a much better sounding system than many, many knowledgeable people would think. No, it's not leading edge.. but damn it makes nice music and it sounds live and dynamic!

    Before I found these, I had a pair of SR4718 that sounded great, but was looking for a pair of 4518. These came along and I am really pleased with their performance. The funny thing is, with them on casters and stacked up that way, it really doesn't take that much floorspace and they're easy to move around. I have Metal and fabric grills for the front to protect the drivers from accidentally putting a board through a cone.

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