+ Reply to Thread
Page 10 of 13 FirstFirst ... 89101112 ... LastLast
Results 136 to 150 of 182

Thread: 4345 monitor plans

  1. #136
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    6,902
    Golly gee, dood. You made me go take the grills off mine. Amazing. Truly.

    I'm embarrased to admit how many times I've gone through that picture folio of yours. The precision (correction: accuracy) on reproducing those beveled fronts to the cabinet is eye splitting. Wow.

    But, now tell us how they sound, and what is the signal path? I had a (re)peat friend/musician over tonight - I know I'm being used. I hope you are as blown away as you should be for the painstaking effort.

    But excuse me - I have to go right now. Gotta go mark mine with an "Authentic JBL" fire-brand...
    bo

    "Indeed, not!!"

  2. #137
    Senior Member John W's Avatar
    Join Date
    Jun 2004
    Location
    Renton, WA
    Posts
    584
    Quote Originally Posted by boputnam
    The precision (correction: accuracy) on reproducing those beveled fronts to the cabinet is eye splitting. Wow.
    Thanks again,
    The final trim on the fronts was one of the most difficult parts. The beveled angle makes clamping a problem. I installed mine after the veneer,but I might consider adding the front trim prior to the veneer if I did it again.

  3. #138
    Senior Member John W's Avatar
    Join Date
    Jun 2004
    Location
    Renton, WA
    Posts
    584
    Here is the crossover information for the network. It is basically Giskard's equivalent network, without the Lpad on the 2122. Since I am set up for strictly bi-amp I can control this level through the active crossover.
    The 2122 Lpad account for about 3db, so I modified the fixed resistor Lpad on the 2405 and 2425 to have the same impedance, but 3db more gain.
    I used two sources for the parts.
    Parts Express for the resistors and inductors and SpeakerCity.com for the Axon capacitors and Lpads. Axon is basically a re-brand of Solen.
    I built mine using terminal blocks I bought locally. I screwed the components onto the terminal blocks to make adjustments easier down the road.
    Attached Images Attached Images    

  4. #139
    Senior Member John W's Avatar
    Join Date
    Jun 2004
    Location
    Renton, WA
    Posts
    584
    Also,
    The network is only partially biased. I decided to only use bypass caps on the 2122h zobel and other bits of the network that didn't appear to be in the direct signal path. For bypass caps I used WIMA .01 630v MKP10 capacitors from mouser that I bought with the items needed for the crossover card.
    I am open to hearing comments from the crossover experts about this.

    I was able to dial the various lpads in using my Behringer RTA to acheive a nice flat response.
    The speakers sound awesome, very dynamic and engaging. We have the soundtrack to Pirates of the Carabbean II which really came alive with its great dynamics and thundering bass.

  5. #140
    Your Memory Lives On RIP Tom Loizeaux's Avatar
    Join Date
    Apr 2003
    Location
    Baltimore, MD USA
    Posts
    669

    John W

    Great work and wonderful documentation. You've certainly raised the bar!

    The folks at JBL should take a good look at your speakers and let it soak in. That kind of appreciation and care on your part should sober them up to the fact that there is still passion for quality speakers out there.
    You are a credit to this Forum with your pursuit of excellence and willingness to share. You deserve the pleasure you will get from these speakers.

    Tom

  6. #141
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,985
    Quote Originally Posted by John W
    I am open to hearing comments from the crossover experts about this.
    I disclaim "expert" status, but here's the thinking from my experience:

    Though not in the direct path, shunting elements function by subtracting from the signal. If the subtraction is distorted, what remains in the signal to pass is, as well.

    As an economic compromise, I don't bias the LF circuit, just the mid and highs. The large caps typically required are just too bulky and expensive, and it seems the major benefit is to the higher frequencies.

    However, if you're not biamping, the same argument applies. Whatever zero-crossing distortion is generated in the LF is being subtracted from the HF and the remainder passed on thereto; thus the LF should be biased as well.

    Most fabulous work again, John!

    [I'm still partial to your mod L200t3s, tho.... ]

  7. #142
    Senior Member Ian Mackenzie's Avatar
    Join Date
    Apr 2003
    Location
    The Tardis
    Posts
    5,949
    John,

    Excellent.

    I should have my Solen CC up and going in a few days so we can compare notes.

    Ian

  8. #143
    Senior Member John W's Avatar
    Join Date
    Jun 2004
    Location
    Renton, WA
    Posts
    584
    Quote Originally Posted by Zilch
    Though not in the direct path, shunting elements function by subtracting from the signal. If the subtraction is distorted, what remains in the signal to pass is, as well.
    That makes sense. I guess I have a little tweeking still left to do, which is a good thing.
    First I have to put all that nice grill cloth to good use.

  9. #144
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,985
    Quote Originally Posted by John W
    I guess I have a little tweeking still left to do, which is a good thing.
    Looks like you've got most of it covered; just three more to do, and plenty of room on the board to do it.

    I'll be interested to know if you hear a difference....

  10. #145
    Senior Member Ducatista47's Avatar
    Join Date
    Jul 2005
    Location
    Peoria, Illinois
    Posts
    1,355
    Thank you for sharing your crossover details, John. The cost of your components are quite reasonable and I am quite encouraged.

    Quote Originally Posted by John W
    The speakers sound awesome, very dynamic and engaging. We have the soundtrack to Pirates of the Carabbean II which really came alive with its great dynamics and thundering bass.
    They kind of grow on you. The way I hear it, other speakers might have a better this or that, but the whole presentation of the 4345 is difficult to leave behind. Engaging is a nice way to put it. As for dynamic, does a bear relieve himself in the woods? The only thing you give up is pinpoint imaging and unrealistically deep soundstaging (which seem to be the current mania of the crowd who pay frightening money for speakers).

    Clark in Peoria
    Information is not Knowledge; Knowledge is not Wisdom

  11. #146
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    6,902
    Quote Originally Posted by Ducatista47
    They kind of grow on you.
    Not only that, but the 2245H's truly do get "broken in" with time. The new ones in my 4345 have only gotten better - more responsive and more tonal - after one-year in (routine) service. They are an amazing transducer.
    bo

    "Indeed, not!!"

  12. #147
    Senior Member gerard's Avatar
    Join Date
    Sep 2004
    Location
    Casablanca - Morocco
    Posts
    330

    Talking

    Hello John W

    I was impressed by your work and would be interested to make a similar crossover if you do not mind .

    The only problem is I do not know about anything in electronic but I can assemble the crossover .

    I would like you to answer some questions and forgive me if there are stupid or if I miss something on the thread , english is not my first language :

    1. You use an active crossover for Lf : what type and what freqeuncy and slope .

    2. I have seen on the crossover picture some very small resistance which appear on the schematic but no value : What are they .

    3. There are some conenctions between post I have not seen on the schematic .

    4. what mean the bold line on the posts.

    5 . Which cable or from which post goes to 2122 - 2425 and 2405 ? I can see "+" , "-" , "B" , "3" does not mean anything to me .

    Thank for your support if you can

    Gerard .

  13. #148
    Senior Member John W's Avatar
    Join Date
    Jun 2004
    Location
    Renton, WA
    Posts
    584
    Hi Gerard. Thanks for the kind words and feel free to copy all you want. That is basically what I did too. One thing to note is that I should have charge coupled the three capacitors that show up in the schematic as only being bypassed with the smaller capacitor. See the schematic in the response to question 2 for a proper example.

    I hope I can answer your questions one at a time.

    1. You use an active crossover for Lf : what type and what freqeuncy and slope .

    I am using a JBl/UREI 5235 active crossover. JBL made a special card for these to use with the 4345. Basically it is a 18db 290hz crossover. Here is a link to some additional information, with the schematic for this card:
    http://audioheritage.org/vbulletin/s...hlight=51-5145

    2. I have seen on the crossover picture some very small resistance which appear on the schematic but no value : What are they .

    The small resistors here are ¼ watt 3million ohm resistors that are part of the charge coupling in the network. I copied the basic schematic of the crossover from this post by Giskard.
    http://audioheritage.org/vbulletin/s...&postcount=124
    He does a better job of showing how these resistors fit into the plan.

    3. There are some conenctions between post I have not seen on the schematic .
    I hope not. You may be seeing the red and black wires I used to link up the three channels to the single input + and -.

    4. what mean the bold line on the posts.
    The bold lines signify soldered connections between various nodes on the terminal strips. These were soldered on the back out of view. Often more than one capacitor or resistors needs to link together so these show these connections

    5 . Which cable or from which post goes to 2122 - 2425 and 2405 ? I can see "+" , "-" , "B" , "3" does not mean anything to me .

    Check again, I tried to mark which section goes to which driver. “+” and “-“ are the inputs from the binding posts, and “R” and “B” are the red and black posts on the individual speakers. Where there is a “3” it means that the connection is to the third tab of the L-Pad, level adjustment.

    Hope this helps and let me know if you need some further clarification.

  14. #149
    Senior Member gerard's Avatar
    Join Date
    Sep 2004
    Location
    Casablanca - Morocco
    Posts
    330
    Hi John W .

    Thank for your info.

    I will go back to item 3.

    A- it seems the + red wire on 2122 post ( horizontal ) is going from (+ left ) to extreme right ( number 10 ) and there goes to the vertical post + on 2425 !.

    B - It seems the red wire going from the battery to the 2122 post ( 2nd horizontal ) is then connected to a black wire to first 2122 post ( number 8 from left ) ? .

    Than for info .

    Gerard

  15. #150
    Senior Member John W's Avatar
    Join Date
    Jun 2004
    Location
    Renton, WA
    Posts
    584
    Quote Originally Posted by gerard
    Hi John W .

    Thank for your info.

    I will go back to item 3.

    A- it seems the + red wire on 2122 post ( horizontal ) is going from (+ left ) to extreme right ( number 10 ) and there goes to the vertical post + on 2425 !.

    B - It seems the red wire going from the battery to the 2122 post ( 2nd horizontal ) is then connected to a black wire to first 2122 post ( number 8 from left ) ? .

    Than for info .

    Gerard
    A - I see your confusion when looking at the picture. The terminal strips are elevated slightly off the plywood. The red wire does go from the + post on the 2122 to the + post on the 2425, but it goes underneath the right side of the top terminal strip. The camera angle makes it appear to be connected when it isn't.

    B - In the layout, the small 1/4 watt 3m ohm resistors are used for the charge coupling. The + side of the 9v battery needs to link to each of these resistors. This isn't displayed in the drawing of the layout, but it is what you are seeing in the picture.
    I have a big roll of fine black wire that I used for wiring these together. I probably should have stuck with red, but switched to black when linking these together.
    Attached Images Attached Images  

+ Reply to Thread

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. 4343 VS 4345 network?
    By tv506 in forum Lansing Product Technical Help
    Replies: 21
    Last Post: 08-17-2011, 08:12 AM
  2. NEW 1.5 inch horn for 4345 / 4343
    By subwoof in forum Lansing Product DIY Forum
    Replies: 114
    Last Post: 07-23-2008, 05:47 AM
  3. Ian's (& Bo's) 4345 project
    By Ian Mackenzie in forum Lansing Product DIY Forum
    Replies: 176
    Last Post: 08-31-2007, 06:24 PM
  4. 4345 Foilcal
    By Guido in forum Lansing Product General Information
    Replies: 8
    Last Post: 01-05-2005, 12:49 PM
  5. 4345 Crossover with an 8 ohm Compression driver???
    By Robh3606 in forum Lansing Product Technical Help
    Replies: 3
    Last Post: 06-17-2003, 06:32 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts