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Thread: JBL 2226J 2445J 2405 active DSP crossover help

  1. #1
    Member danvprod's Avatar
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    JBL 2226J 2445J 2405 active DSP crossover help

    I've posted about this design before, but am looking for help as I continue to refine the sound and design a crossover topology that best takes advantage of the components in the system that I've built.

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    Design goals:

    • Build a speaker that sounds great with these great components that I can have for years without the urge to upgrade.
    • Build a sensitive speaker that can be powered, in part, to adequate volumes with my 300b amps and sound good in my small listening room.
    • Build a speaker that takes advantage of the MiniDSP for cross-over/EQ duties.


    Background:
    • I had the opportunity to purchase a number of excellent JBL parts for a very reasonable price. These include 2 x 2226J 16 ohm woofers, 2 x 2445J 2" Compression Drivers, 2 x 2405 super tweeters and 2 x 250 Hz tractrix waveguides.
    • I also picked up a miniDSP 4x10 HD for my desire to not spend a fortune on crossover components while I tweak the crossover.
    • Amplifiers include a pair of 300B monoblocks, which power the 2445s, and 2x Crown D45 amps, which power the 2226s and 2405s.
    • I've been living with 2226s built in what I would call "draft" enclosures: ~ 4 cu ft. vented MDF enclosures tuned to 45 Hz with the horns/waveguides and super tweeters mounted on the top on the enclosures. I lift the bass with DSP.
    • They sound pretty good as-is and give me the sense that these components could sound exceptional with the right crossover configuration.


    So that is what the thread is about -- the next steps in putting together this system.

    The drivers:
    • The JBL 2445J is a 2" compression driver with a titanium diaphragm. Part of this build will be to replace the stock diaphragms with the Truextent Beryllium replacement diaphragms. I have these coupled to 250 Hz tractrix waveguides, and mounted on aluminum stands.
    • For woofers, I have the JBL 2226J 15" 16 Ohm drivers. I am pretty happy with their performance in the 4 cu. ft. enclosures, but they could be better -- I think giving them a bigger enclosure, and tuning them deeper could improve their performance. I also have the MiniDSP available to me for tweaking.
    • The super tweeters are 2405s. They are crossed over at 8 kHz and I find them kind of harsh. They may stay in the system or may not depending on the performance of the 2445Js with new diaphragms.


    I am looking for help on how best to measure this system and design the crossover using the MiniDSP.

    Right now I have my crossover is configured as follows.

    Woofers:
    20 Hz LR4
    500 Hz LR4
    35 Hz +8 dB Q 0.8

    Midrange:
    500 Hz LR4
    8000 Hz LR4
    1000 Hz -3 dB Q 1
    400 Hz -4 dB Q 2
    .3 ms delay

    Tweeters:
    8000 Hz LR 4
    1.05 ms delay

    I also have a protection cap network for the MF and HF drivers.
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    So anyways -- looking for some inspiration, ideas, and feedback. If you are interested on where I am taking this, please feel free to follow along. Hopefully I can turn this system into something special.

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    Your system looks good already. Much better than my random stack

    Have you considered throwing a pair of JBL 2123's in there? They're cheap and great. Maybe have them run from ~300-1.2kHz.

    What kind of hardware and software will you be using to take measurements and will you be measuring inside or outside?

    What diaphragms will you be getting for your 2445's?

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    Member danvprod's Avatar
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    Quote Originally Posted by DingDing View Post
    Your system looks good already. Much better than my random stack

    Have you considered throwing a pair of JBL 2123's in there? They're cheap and great. Maybe have them run from ~300-1.2kHz.

    What kind of hardware and software will you be using to take measurements and will you be measuring inside or outside?

    What diaphragms will you be getting for your 2445's?

    Thanks! I'm sure your random stack is nice too! Interesting thought on the 2123s. Mid-coupler might help the crossover between the 15" and the horn for sure. I could put it in a nice, damped sealed box or tube. I'll investigate.

    I have REW for measurement and nice measurement mic and a Focusrite scarlett 2i2 for measurement. I'll plan on doing some outdoor measurements after it cools down a bit here. I've done some measurements inside.

    These are in-room measurements, with crossovers as described in the first post.
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    L/R FR
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    Member danvprod's Avatar
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    More details about the protection crossover

    Here is an annotated picture of my protection crossover. The 2445 is 1.5 octaves below my crossover frequency. The 2405 is 2 octaves below. Both caps are bypassed and there is a 47 Ohm resistor placed parallel to the input, an idea I got from several other threads here.
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    you can start from getting rid of that white horn, and selling it to me
    Semper Fidelis

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    About the 2123, yes, you should def. investigate. It's very efficient and can handle 250W too. The box can be very small. My system is fully active (and I know next to nothing about passive crossover theory). The 2123 is between 2226 & 2446. BW 24dB/oct filters + correction filters and time alignment.

    I actually made a thread asking about advice on protection networks yesterday, so the annotated picture of your network was a positive surprise. What is the point of the 47R resistor and the 0.01mF cap, and what voltage rating does that chunky 50mF resistor have, please?

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    Member danvprod's Avatar
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    Quote Originally Posted by DingDing View Post
    About the 2123, yes, you should def. investigate. It's very efficient and can handle 250W too. The box can be very small. My system is fully active (and I know next to nothing about passive crossover theory). The 2123 is between 2226 & 2446. BW 24dB/oct filters + correction filters and time alignment.

    I actually made a thread asking about advice on protection networks yesterday, so the annotated picture of your network was a positive surprise. What is the point of the 47R resistor and the 0.01mF cap, and what voltage rating does that chunky 50mF resistor have, please?
    Do you have a thread about your build? I'd be interested in seeing what you have developed. I'm glad the protections network diagram helps.

    Here was the thread I found the crossover idea on: http://www.audioheritage.org/vbullet...p/t-19613.html

    My 50 uF is 250v btw. The 47 Ohm resistor is to cut the impedance peak at 750 Hz; it's suppose to be a damping resistor. The 0.01 uF cap is a bypass cap.

    Here is the info about the bypass caps: http://www.hawthorneaudio.us/forums/...php?f=1&t=3763

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    Member danvprod's Avatar
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    Quote Originally Posted by ARMED View Post
    you can start from getting rid of that white horn, and selling it to me
    They are nice. 250 Hz Tractrix from StereoLab

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    Quote Originally Posted by danvprod View Post
    Do you have a thread about your build? I'd be interested in seeing what you have developed. I'm glad the protections network diagram helps.

    Here was the thread I found the crossover idea on: http://www.audioheritage.org/vbullet...p/t-19613.html

    My 50 uF is 250v btw. The 47 Ohm resistor is to cut the impedance peak at 750 Hz; it's suppose to be a damping resistor. The 0.01 uF cap is a bypass cap.

    Here is the info about the bypass caps: http://www.hawthorneaudio.us/forums/...php?f=1&t=3763
    Thank you!

    Unfortunately, there's no thread for them as of yet, but I did some research on here a while back which may be of interest to you as it is fairly close to what you're doing. Please look at the DingDing goes DIY thread here.

    It's still a work in progress, but the system is basically 2404, 2446 in 2360A, 2123 and 2226 + subs for the lows. I tried without the 2123, but I could never really get the magic happening from 250-300ish up to around 1kHz until the 2123 was added. That is not to say it's not possible! It just means I couldn't do it, and my experience is not that vast. I've been so happy with the performance that development went sluggish for a while and I've just recently started picking up on it again.

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    Lee in Montreal

    BTW -- I am using Lee in Montreal's suggestions for Bass EQ on the 2226s. It sounds great:

    "Basically, you will need two filters on the woofers. Try the following and adjust to your own tastes.
    a- 12db bandpass at 40Hz w/ Q=1.4
    b- 6db bandpass at 65/70Hz w/ Q=1.1"

    I have my 2226s rolling off at 800 Hz LR, and my 2445s rolling off at 500 Hz, for approximately a 600 Hz LR 4 electrical crossover.

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    Senior Member berga12's Avatar
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    Hi,
    I had more or less a similar setup, starting with my personal suggestions:

    - 2226J --> 16ohm require a HUGE amplifier to have good amount of current, so run up to 500-600W - 8ohm amplifier or a Class D, tuning the 2226 to 38-40-42-45hz is making more ore less the same brake up freq at 40hz, if you want something nicer you can try to go down to 35hz and put a subsonic filter 24db to 30-32hz.

    - 300b --> use them for the FULL high session placing a passive filter between 2445 and 2405 (use it around 9-10khz...), use good component, paper oil capacitors, flat wire coil and autotransformer to attenuate 2445.

    - JABO KH55 --> I don't like this horn, I had for few months used with a 2441.......they sound good but too "wide" and coloured, I prefer JBL2350 style horn, but "degustibus" this is not a "back and white" factor, Just use them, if you can put some damping material on the back (like BRAX noise stopper etc), I've done it and it improves a lot the sound, keep this in mind.

    - Crown D45 --> don't use them on 2405...my good.... maybe a small tube amp like 0,5-1W with Real quality, or passive network with 300b like I suggest above.

    - SELL --> both Crown to have a BIGGER AMP (read: more power...) for low bass, Maybe MC2300, you have tons of choice.


    Wonderfull setup, a friend of mine is using 2226h in 90L 45hz, B&C 2" driver in a circular horn and Fostex T500, superb setup, with 300b tamura amp and Hypex UCD400 for low bass.

    below my Old setup, see the Horn treatment.

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  12. #12
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    Hi berga12

    2226 -> Thank you for the detailed response here. This is quite helpful. Good idea on a bigger amp for the 2226. I think my tuning ends up coming up at 40 Hz (both modeled and also measured in-room) and then I end up lifting the response a bit in the bass (which is all the more reason for a bigger, higher-current amp). Right now I have a sub-sonic at 20 Hz, but I might lift that to 30-32 Hz as you've said and experiment with that.

    300B --> Also a good idea here. Are you suggested a 12 dB/octave filter at 10 kHz, for example? Or let the 2445 run all the way unfiltered. This certainly would make a simpler wiring setup, with one fewer amp.

    JABO KH55 --> Thanks for the thoughts here. I've often considered exploring a different horn, maybe a wooden smith horn. Good idea on the noise-stopper. I'll explore that.

    Agree with you about selling the Crown Amps and getting something bigger, and looking at a 2-amp vs. 3-amp setup. Should be a nice improvement.

    If you have any ideas for the XO between the 2445 and 2405, that would be helpful.

    BTW, I did experiment a bit more with the MiniDSP last night. This is where I am at. I decided to loosen the slope on the 2445 to 12 dB an octave. That seems to integrate better with the 24 dB/octave on the 2446 (being that the horn is already falling off pretty quick at about the crossover frequency). I do have a weird bump at 700-800 Hz with the 2226, but I think that is a floor bounce or sidewall bounce. I change the rolloff of the 2445 to 12 dB at 8kHz as well and that seems to integrate pretty good with the 2405.

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    And thanks for the example system. It's very nice.

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    Senior Member ivica's Avatar
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    Quote Originally Posted by berga12 View Post
    Hi,
    I had more or less a similar setup, starting with my personal suggestions:

    ........

    - JABO KH55 --> I don't like this horn, I had for few months used with a 2441.......they sound good but too "wide" and coloured, I prefer JBL2350 style horn, but "degustibus" this is not a "back and white" factor, Just use them, if you can put some damping material on the back (like BRAX noise stopper etc), I've done it and it improves a lot the sound, keep this in mind.
    .......
    Hi berga12,

    What about YUICHI-A290 horn...

    regards
    ivica

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    Senior Member berga12's Avatar
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    Yes YUiICHI or IWATA project I prefer insthead of JABO KH55, but this is Just for my personal Taste

    I still Own a pair of JBL2350, and I would keep them, IWATA I listen several time and they are state of the art for 2" drivers...IMHO.



    About crossover, if you want to try quickly you can easily find 2405 12db schematics looking at every JBL 43XX studio monitor, the filter is more ore less the same for everyone.

    for the 2445 I don't know about their impedance if it's similar to other drivers but I would place a Low Pass 12db at around 8-9Khz (for the 2441 it's around 0,48mH series and 1uF parallel, then you place an LPAD or autotransformer...pay attention with this one, it change CX point)
    for 2405 around 1,5uF series, 0,16mH parallel, 1,5uf series (18db)

    then you can play around with value.

    Low pass for 2226 and hipass for 2445 use the Mini Dsp (Just place a big cap as protection, around 16-20uF series to 2445)

    or you can also decide to have a passive 12db high pass, but the cost will not be so cheap, consider a 16-20uF if i'm not wrong and a 6,6mH parallel .....

    use the DSP for the moment.

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    Senior Member berga12's Avatar
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    Quote Originally Posted by danvprod View Post
    Here is an annotated picture of my protection crossover. The 2445 is 1.5 octaves below my crossover frequency. The 2405 is 2 octaves below. Both caps are bypassed and there is a 47 Ohm resistor placed parallel to the input, an idea I got from several other threads here.
    Name:  Crossover.jpg
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    In case your DSP fail with filter, and you are running good amount of power you will DESTROY your diaphagram with those value.

    2405 is not happy below 6,5khz 18db (not 6!!!!)
    2445 is really not happy below 200hz!!!!!

    pay attention, diaphagram for 2405 are nearly not existing anymore....

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