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Thread: Some photos of my 4345 clones

  1. #61
    Senior Member edgewound's Avatar
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    Quote Originally Posted by just4kinks View Post
    I left work early yesterday to get these assembled. I am totally pleased! It was worth every minute and every penny, and I haven't even dialed in the crossovers yet. The 2245's are amazing, deep and tight bass.

    Here are a few more pics:

    Note the lack of grill velcro. I have neo magnets embedded in the baffle from behind. I was unsure if I should do this, because the magnets attract dust (and screwdrivers), but now I'm glad I did. The grill attachment is so easy. Turns out that I don't even need the grill guide pin, too bad I drilled it already. Otherwise the baffles would be completely clean.




    And here is a final shot of the corner, to show how it looks finished. I love Baltic birch!
    Stunning craftsmanship. Love the Scandinavian style look...and the outboard networks.

    Congrats on the gorgeous project. I bet the crossovers mounted outside the box improves the performance a bit by cutting down vibration.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  2. #62
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    Congratulations! Very nice work.
    Out.

  3. #63
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    The color helps it blend in so that it doesn't look like a huge 2001 monolith in the living room.

    This is such fantastic workmanship.

  4. #64
    Senior Member Krunchy's Avatar
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    They look really nice!
    Having made some primitive pete style cd racks recently in makeshift circumstances w/a router I can really appreciate how meticulous your woodworking skills are.
    Freshly reconed drivers is basically like having some brand new 4345's. They will bring many many years of pure pleasure.
    Welcome to the club &.... enjoy the hell out of them.

    BTW: did you put a finish on them, clear coat & what kind of music do you mainly listen to?
    Just Play Music.

  5. #65
    Senior Señor boputnam's Avatar
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    Quote Originally Posted by just4kinks View Post
    ... I did locate a polarity problem.
    What was that, and how did it manifest?
    bo

    "Indeed, not!!"

  6. #66
    Senior Member just4kinks's Avatar
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    Quote Originally Posted by boputnam View Post
    What was that, and how did it manifest?
    Well, the 3145 is a 4-way with the upper 3 sections inverted WRT the woofer. Even when the biamp switch is engaged.

    I am biamping, with a 3-way passive crossover, and I wasn't sure about the polarity so I decided to match the 3145, with the upper 3 sections inverted WRT the woofer. When I looked at it with the RTA, I saw a distinct dip at around 300Hz. I flipped the wires going into the crossover and it flattened out. Both channels were the same.

    Now I'm wondering... given the phase characteristics of the 3-way crossover, should the top 2 sections be inverted instead?

    Maybe I'm thinking about it too hard, I probably just screwed up the wiring somewhere.

  7. #67
    Senior Member just4kinks's Avatar
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    Thanks guys!

    Quote Originally Posted by moparfan View Post
    The color helps it blend in so that it doesn't look like a huge 2001 monolith in the living room.
    Too bad, "2001 monolith" is what I was going for!

    Quote Originally Posted by Krunchy View Post
    BTW: did you put a finish on them, clear coat & what kind of music do you mainly listen to?
    I sprayed them with Minwax Polycrylic. It came out alright, but I'll probably just stick with polyurethane next time (I avoided it this time because of the yellow tint).

    As far as music goes, I like rock, but I listen to a little bit of everything. Mostly newer stuff, from the last 20 years or so.

  8. #68
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Titanium Dome View Post
    Congratulations! Very nice work.
    My thoughts exactly!


    Widget

  9. #69
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by just4kinks View Post
    I sprayed them with Minwax Polycrylic. It came out alright, but I'll probably just stick with polyurethane next time (I avoided it this time because of the yellow tint).
    I almost always use one of the water based urethanes when finishing light woods... the satin Polycrylic works pretty well and doesn't yellow.


    Widget

  10. #70
    Senior Señor boputnam's Avatar
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    Quote Originally Posted by just4kinks View Post
    Well, the 3145 is a 4-way with the upper 3 sections inverted WRT the woofer. Even when the biamp switch is engaged.
    Correct.

    Quote Originally Posted by just4kinks View Post
    I am biamping, with a 3-way passive crossover, and I wasn't sure about the polarity so I decided to match the 3145, with the upper 3 sections inverted WRT the woofer.
    Correct.

    Quote Originally Posted by just4kinks View Post
    When I looked at it with the RTA, I saw a distinct dip at around 300Hz.
    Now that there, is interesting. The crossover from the 2245 to the 2122H is 290Hz - nominally where you've seen this anomaly with your measurement gear.

    Quote Originally Posted by just4kinks View Post
    I flipped the wires going into the crossover and it flattened out. Both channels were the same.
    Interesting solution, but it might have dealt with the symptom and not the problem.

    Quote Originally Posted by just4kinks View Post
    Now I'm wondering... given the phase characteristics of the 3-way crossover, should the top 2 sections be inverted instead?
    As we tend to say in these instances, "you can do whatever pleases", but this would be different from the OEM engineering.

    Quote Originally Posted by just4kinks View Post
    Maybe I'm thinking about it too hard, I probably just screwed up the wiring somewhere.
    Possible.

    Clearly, you're deeply steeped in all this. However, may I be so bold as to humbly ask if you're aware of JBL's unique polarity convention? Unless you are, this could explain the anomaly (cancellation) you noted, right where you noted it. But, if, as I expect, I get enlightened by your reply, we'll have to dig a little deeper...
    bo

    "Indeed, not!!"

  11. #71
    Senior Member just4kinks's Avatar
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    Clearly, you're deeply steeped in all this. However, may I be so bold as to humbly ask if you're aware of JBL's unique polarity convention? Unless you are, this could explain the anomaly (cancellation) you noted, right where you noted it. But, if, as I expect, I get enlightened by your reply, we'll have to dig a little deeper...
    If you mean positive on black, yes I am aware of it.

    Quote Originally Posted by boputnam View Post
    As we tend to say in these instances, "you can do whatever pleases", but this would be different from the OEM engineering.
    This got me thinking, what did JBL do in the 3155? The answer is that all 4 sections have the same polarity:
    http://www.jblproservice.com/pdf/Network Schematics/3155 Network.pdf

    I started searching for an explanation, and the answer has been in front of me the whole time:
    http://www.audioheritage.org/vbullet...l=1#post240082
    http://www.audioheritage.org/vbullet...l=1#post240590

    Sorry, Mr. Widget, but I bet you knew it wouldn't be "for the last time" when you wrote that

  12. #72
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by just4kinks View Post
    I started searching for an explanation, and the answer has been in front of me the whole time:
    http://www.audioheritage.org/vbullet...l=1#post240082
    http://www.audioheritage.org/vbullet...l=1#post240590

    Sorry, Mr. Widget, but I bet you knew it wouldn't be "for the last time" when you wrote that
    OMG. Not that thread again!
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  13. #73
    Senior Señor boputnam's Avatar
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    Quote Originally Posted by just4kinks View Post
    If you mean positive on black, yes I am aware of it.
    I guessed you would. But it's all in how you use that knowledge...

    Quote Originally Posted by just4kinks View Post
    This got me thinking, what did JBL do in the 3155? The answer is that all 4 sections have the same polarity...
    Correct. But that is not what JBL did with the 3145.

    I have not experienced the dip you described, and my networks are stock - so wiring is easy the OEM way. I'm suspicious that with your gorgeous networks and JBL's inverted polarity there is some unintended wiring snafu. But it doesn't matter, so long as you have resolved the anomaly and have your motors firing the way (i.e., direction) you want them to on (+) signal.

    Quote Originally Posted by BMWCCA View Post
    OMG. Not that thread again!
    It was good to re-read that stuff. 3-yrs ago... Whoa.
    bo

    "Indeed, not!!"

  14. #74
    Senior Member DavidF's Avatar
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    Quote Originally Posted by 4313B View Post
    Love the color! Well done!

    Crazy aren't they? I wish I still had the twenty cubic feet available for a pair.
    The big-baffle enclosures are always appealing to me. An outmoded preference, no doubt. But an old-fart is as an old-fart does.

    Very well done.
    David F
    San Jose

  15. #75
    Senior Member maxwedge's Avatar
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    I think their ugly!




























    NOT!!!!!!!!
    Nice work

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