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Thread: replaced my 2420 + 2344A with 2435 + PT-H1010HF

  1. #1
    Senior Member frank23's Avatar
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    replaced my 2420 + 2344A with 2435 + PT-H1010HF

    Hi,

    I'm sorry I am not posting too often, but with two small children my JBL hobby only gets so much time...

    I just wanted to let you know I have finally hooked up the 2435 + 100x100 waveguide (the 338785-002, or PT-H1010HF). I have had this combination boxed in my garage for years. I have done much effort to get the right horns and then I had 2 children (or, my wife did actually) and then, nothing.

    I have hooked it up to the existing crossover that my 2420 + 2344A combination has been playing on the past few years.

    Out of the box it sounds fine, but the drivers have been in my garage for the last few years so they probably get better (or different) when they come up to room temperature and everything has setteled down a bit.

    I'll try to see how they develop over the next days. I know there are threads about this driver / horn combi, I was following them a few years ago and decided to buy this combination. So now I'll be able to hear them for myself.

    regards, Frank

  2. #2
    Administrator Robh3606's Avatar
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    Hello Frank

    I did the same change out a couple years back. Curious to see what you think.

    Rob
    "I could be arguing in my spare time"

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    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by frank23 View Post
    ...and then I had 2 children (or, my wife did actually) and then, nothing.
    Then nothing audio related or nothing in your marriage?

    Quote Originally Posted by Robh3606 View Post
    Curious to see what you think.
    Yes, please let us know how it turned out.


    Widget

  4. #4
    Senior Member frank23's Avatar
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    Hi,

    After this one day I would say that:
    + stereo image is a little better
    + larger dynamic range
    + better pace
    - the sound is a little harsher
    - there are problems with S, T and F sounds

    As things are now I'd prefer the old setup as it is nicer to listen to, but remember that I have just "plugged and played" this setup on the existing crossover, so perhaps it is not all fair to say so.

    But I don't know how the slight harshness and STF problems would go away by changing the crossover values. They are quite obvious and in the old setup I got rid of them totally (and I mean totally, the Van den Hul The First Ultimate carbon interlink does wonders). Does anyone know the frequency range these problems occur in?

    BTW I am a "high end" follower with class A amps, high end cd/da and carbon interlinks etc. Not from the "another 500W is better" school.

    Regards, Frank

  5. #5
    Senior Member frank23's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    Then nothing audio related or nothing in your marriage?

    Yes, please let us know how it turned out.

    Widget
    Audio related! Although I did change components. But I didn't have time to rebuild my speakers as I liked.

    Frank

  6. #6
    Senior Member spkrman57's Avatar
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    CD/horn efficiency differences???

    You might need to attenuate the HF section a little to better match the overall efficiency of you system.

    Just a thought......

    Regards, Ron
    JBL Pro for home use!

  7. #7
    Administrator Robh3606's Avatar
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    - the sound is a little harsher
    - there are problems with S, T and F sounds
    Sounds like there is a peak in there. There may be a sensitivity issue as well I don't know if the 2435 on a 1010 is the same as a 2425 on a 2344??

    Do you have any measurement capabillity like an RTA??

    When I get a chance I will run a stock 2435 in LEAP with a 4430 crossover and see what it looks like. I have measurements of uncoated 2435's and Imp runs on the horn in the "library" so to speak so it should be a quick work-up to see what's up.

    What components are you using from the 4430 network?? Is it stock or are you just going with the compensation in an active set-up??

    When I did my own networks using that combo I needed a couple of notch filters to flatten things out.

    Rob
    "I could be arguing in my spare time"

  8. #8
    Senior Member frank23's Avatar
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    hi,

    I don't use any components from the 4430 crossover. It is a setup of my own design combining an 8" kevlar ticonal magnet woofer with a 2420/2344A combination all through a 1st order crossover with compensation for the 2344A high end fall off and an attenuation network for lowering the sensitivity to match the woofer.

    So it is a little out of the ordinairy, certainly on this forum!

    I'll post the crossover layout and values tomorrow.

    Maybe the 2435 has peaks in different areas than the 2420 and the crossover match isn't optimal.

    Regards, Frank

  9. #9
    Administrator Robh3606's Avatar
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    Maybe the 2435 has peaks in different areas than the 2420 and the crossover match isn't optimal.
    Well lets see what you have.

    Rob
    "I could be arguing in my spare time"

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    ...Hey - I've owned many systems over 30 years and I am from the "500 watts is better" camp! ...Anyway, I would say this is not necessary for a high sensitivity system like most Altecs but for JBL big power is usually much better!

  11. #11
    Senior Member frank23's Avatar
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    hi,

    here is my crossover layout, the drivers are simplified by only a resistor which is about right for the bass driver as it has a very, very low induction, but of course is not right for the 2420/2344 combination

    I know the real impedance can also be modelled, but I don't know how...

    the 2420/2344 crossover can be highered or lowered in the graph by changing the resistor values around the opamp on the left, I don't exactly know what the right value should be, but this is how the setup sounds great

    I just substituted the 2420/2344 for the 2435/waveguide now and found the sound a little harsh.

    In the graph below the green is my current crossover. The red is the current, but without the high compensation. The blue is what could also be done as a simple alternative to the more complex green, but as you see there is a difference of a few dB's between them. But I could try it as I have the components [always difficult with paper-oil capacitors].



    Frank

  12. #12
    Senior Member frank23's Avatar
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    Hi,

    Instead of taking a simple resistor to represent the driver I have now found out how to simulate the driver impedance peaks and have made a graph of the crossover-driver interaction for the 2425/2344A combination. Just to see what the calculated effects would be. Of course, I don't have a 2425, but I couldn't find impedance curves for the 2420 on the 2344A.

    The impedance curves of the 2435 on a H9800 horn that I found showed very low impedance peaks. Does anyone know the impedance peaks for the 2435/waveguide combination?

    In the graph below the green line is the crossover vs a 6ohm resistor. The blue and red graphs represents the impedance simulations for about 500Hz and about 1200Hz peaks.

    The graphs show that the impedance peak causes the level at 1246Hz to be about 1.4dB louder than with a normal resistive value. It also shows that the rising impedance due to self inductance causes the high compensation to come out about 2dB louder at 20kHz which isn't a bad thing.



    Frank

  13. #13
    Senior Member Beowulf57's Avatar
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    Quote Originally Posted by frank23 View Post
    h
    I just substituted the 2420/2344 for the 2435/waveguide now and found the sound a little harsh.

    In the graph below the green is my current crossover. The red is the current, but without the high compensation. The blue is what could also be done as a simple alternative to the more complex green, but as you see there is a difference of a few dB's between them. But I could try it as I have the components [always difficult with paper-oil capacitors].



    Frank
    You found the sound harsher with the 2420/2344? Below you noted that the 2435/waveguide was a little harsher...which is it?

    Do you get the same STF problem using the setting without compensation (Red)?

    I found the 2420/LE85/HL92 combo a bit harsh/hard/glaring and sibilant until I added the 2405H HF drivers with 3106 (8000Hz) crossovers. The upper response (above 8KHz) of the 2420's was ragged and the sound improved noticeably when they were rolled off above 7KHz and the 2405H's took over.

  14. #14
    Senior Member frank23's Avatar
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    I had the 2420/2344. When I changed it to the 2435/PTwaveguide the sound became harsher.

    Frank

  15. #15
    Senior Member Beowulf57's Avatar
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    Quote Originally Posted by frank23 View Post
    I had the 2420/2344. When I changed it to the 2435/PTwaveguide the sound became harsher.

    Frank
    Okay...now I got it. So, does the STF problem decrease without the HF compensation?

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