Page 12 of 21 FirstFirst ... 21011121314 ... LastLast
Results 166 to 180 of 303

Thread: Discussion Thread JBL 4343 to 4344 upgrade

  1. #166
    Senior Member
    Join Date
    Apr 2003
    Location
    Australia
    Posts
    7,939
    Here are expanded details of the 4343- 4344 Project Upgrade External Hi End Crossover Network.

    The original theme was a high quality passive crossover for use with the JBL 4344 components.

    What evolved from our objectives during the design phase was a crossover network that would be external to the 4344 enclosure, bypass all existing passive crossovers and L Pads and wiring, and use the original equivalent 3145 crossover schematic designed by Giskard.

    The practical realisation of the design is a pair aluminium cabinets that house the passive filters and a system of terminations and wiring that allow routing of both low and high pass biamped speaker signals via a customised cable to the 4344 enclosure. This approach will ensure the passive filters are isolated from internal enclosure vibrations while also providing phase continuity of the four individual signals from the crossover filters direct to the 4344 drivers.

    The enclosures are 9.5 kg each, made from 3 mm aluminium and milled 25mm square aluminium stock. Auricaps and Mills resisters are used in all signal path locations. Pure copper terminations and Welbourne Teflon cable is used throughout. The binding posts are premium grade by Cardas and the 8 pole connector is a heavy duty Speakon. Provision is made for fixed resister values to replace the L pads once the system has been installed and calibrated.

    A customised front panel was arranged to allow precise adjustment of the L pads during set-up and installation.

    It looks deceptively simple, however there is a lot of fine detail and a reasonable degree of difficulty in the implementation.

    In a week or two we will show more details of the installation and set-up.

    Ian
    Attached Images Attached Images     

  2. #167
    Senior Member
    Join Date
    Apr 2003
    Location
    Australia
    Posts
    7,939
    Here are some images of the 4343 internal construction.

    All images courtesy of Subwoofer.

    Ian
    Attached Images Attached Images    

  3. #168
    Senior Member saeman's Avatar
    Join Date
    Mar 2005
    Location
    Near Chicago
    Posts
    624

    4344

    Hello Ian: How's life downunder??? "Talk's Cheap And Whiskey Costs Money". I'm finally getting back to my 4344 project. Thought I'd pop you a few pics of the first cabinet - under construction but assembled dry for fit-up. The baffle layout was altered from JBL original to move the woofer off the center line of the cabinet as recommended by Giskard. I included the recessed area in the rear of the cabinet for mounting the x-over related components (external to the cabinet interior). Giskard commented that the area I provided was a bit generous, but not knowing the size required for the finished electronics prompted me to leave it a bit large (I can keep an emergency pint of Jack and all of my spare money in there). I've been fortunate to locate all of the proper components and will press on to completion. Here's a few pics. Thanks for your continued input on my project. Rick
    Attached Images Attached Images    

  4. #169
    Senior Member saeman's Avatar
    Join Date
    Mar 2005
    Location
    Near Chicago
    Posts
    624

    4344 Pics

    add'l pics
    Attached Images Attached Images   

  5. #170
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,715
    Very nice craftsmanship as always, Rick. I would like to suggest you use KD lumber for your braces though. MDF and particle board are just not structural. I do think you can hear the difference. I have been using braces made out of 1.5" thick birch ply lately, but have also had good results with both KD Fir and domestic hardwoods.


    Widget

  6. #171
    Senior Member saeman's Avatar
    Join Date
    Mar 2005
    Location
    Near Chicago
    Posts
    624
    Hi Wig: Thanx for chiming in. I cut most of the braces this morning and will start fitting them in tonight. They are all 1 1/2" x 2 1/2" KD Douglas Fir. Never thought about using thick plywood on edge for braces - good idea. Where are you getting 1 1/2" thick birch plywood ??? Rick

  7. #172
    Administrator Robh3606's Avatar
    Join Date
    Apr 2003
    Location
    Rocinante
    Posts
    8,163
    "Where are you getting 1 1/2" thick birch plywood ??? Rick "

    Glue and screw 2x 3/4 works like a charm.

    Rob

  8. #173
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,715
    I cut 4" strips from my waste and glue and clamp them... the next day I trim them to 1.5" X 3.5". It works quite well, and uses up the scraps. Sometimes I make it from fresh stock. The cost per cu. in. is about the same as KD Fir in my part of the world.

    I brought it up, because in one of your photos, it looked like you were using some 1" part board. I guess I misinterpreted the image.


    Widget

  9. #174
    Senior Member saeman's Avatar
    Join Date
    Mar 2005
    Location
    Near Chicago
    Posts
    624
    Quote Originally Posted by Mr. Widget
    .I brought it up, because in one of your photos, it looked like you were using some 1" part board. I guess I misinterpreted the image.


    Widget
    No, you're right - 1" P.B. - my mainstay, along with good 3/4" Baltic Birch and proper bracing. I HATE, no I DEPLORE, no I DESPISE MDF for my cabinet making chores. It makes a cloud of dust that gets into every orifice of your body, doesn't glue well and won't hold a screw or glued dowel pin on it's best day. I have used it for cabinet backs and screwed thru to the braces from the outside - OK, but the screws show and I like the clean appearance of no screws. I know this is contrary to the beliefs of many out there BUT are these people just repeating the same thing they hear from others or have they "Walked The Walk" as the saying goes. Proper bracing is the big issue for me - hell, maybe I'll switch to cardboard with some extra bracing.

  10. #175
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,715
    Quote Originally Posted by riessen
    I HATE, no I DEPLORE, no I DESPISE MDF for my cabinet making chores. It makes a cloud of dust that gets into every orifice of your body, doesn't glue well and won't hold a screw or glued dowel pin on it's best day.
    I agree, I agree, I agree... unfortunately it actually sounds better than particle board or solid lumber. The two hard faces with the dust core make a self damping material that is relatively inexpensive and coincidentally about the best material going for speaker boxes.

    As for assembly, I use a narrow crown stapler... fast and secure... don't screw up though, the joint will not come apart.

    I wear one of these, with a half face mask... I've used it for years while painting, and it keeps the handkerchief clean it you know what I mean.


    Widget
    Attached Images Attached Images  

  11. #176
    Administrator Robh3606's Avatar
    Join Date
    Apr 2003
    Location
    Rocinante
    Posts
    8,163
    Hey Rick

    Those are nice looking cabinets!! Bet they weigh a ton! You have your drivers all lined up???

    Rob

  12. #177
    Senior Member
    Join Date
    Apr 2003
    Location
    Australia
    Posts
    7,939
    Rick,

    Any thread like this without pics is worthless.

    Nice work.

    I suggest you follow the JBL designations for tactical bracing per earlier drawings. Also there is are two front to rear braces that skirt the dog box to the rear panel. They make is big different to the rigidity of the front panel.

    Ian


    Quote Originally Posted by riessen
    Hello Ian: How's life downunder??? "Talk's Cheap And Whiskey Costs Money". I'm finally getting back to my 4344 project. Thought I'd pop you a few pics of the first cabinet - under construction but assembled dry for fit-up. The baffle layout was altered from JBL original to move the woofer off the center line of the cabinet as recommended by Giskard. I included the recessed area in the rear of the cabinet for mounting the x-over related components (external to the cabinet interior). Giskard commented that the area I provided was a bit generous, but not knowing the size required for the finished electronics prompted me to leave it a bit large (I can keep an emergency pint of Jack and all of my spare money in there). I've been fortunate to locate all of the proper components and will press on to completion. Here's a few pics. Thanks for your continued input on my project. Rick

  13. #178
    Obsolete
    Join Date
    Apr 2003
    Location
    NLA
    Posts
    12,193
    Quote Originally Posted by riessen
    No, you're right - 1" P.B. - my mainstay, along with good 3/4" Baltic Birch and proper bracing. I HATE, no I DEPLORE, no I DESPISE MDF for my cabinet making chores. It makes a cloud of dust that gets into every orifice of your body, doesn't glue well and won't hold a screw or glued dowel pin on it's best day. I have used it for cabinet backs and screwed thru to the braces from the outside - OK, but the screws show and I like the clean appearance of no screws. I know this is contrary to the beliefs of many out there BUT are these people just repeating the same thing they hear from others or have they "Walked The Walk" as the saying goes. Proper bracing is the big issue for me - hell, maybe I'll switch to cardboard with some extra bracing.
    Alrighty then!

    Yeah... I've walked the walk and killed a few trees in my time. I used Novaply for many, many years but switched to MDF in the late 90's. The dust is deplorable and I'm always cleaning filters for my shop-vacs. Bracing has always consisted of select pine.

    They do look nice as usual Rick.

  14. #179
    Senior Member saeman's Avatar
    Join Date
    Mar 2005
    Location
    Near Chicago
    Posts
    624

    4344 Bracing

    Ian - Giskard - Wig: I'm planning on starting to install braces tonight but after your comments I thought I'd bounce my ideas off you guys. Since my 4344 cabinet is a deviation from factory and also from Ian's plans, the bracing has to be different in my view. I pushed the mid-base box clear to the right against the cabinet side. This was to allow installation of the mid driver, thru the woofer hole, without providing a removable rear access panel. The side of the mid-base box will be glued/screwed to the cabinet side and eliminate a side brace at that point. My rear panel is in three sections and the dividers are 1" x 4" P.B. They essentially act as left to right back braces across the back panel. They are dado/glued into the cabinet sides. All other braces shown on my pic are 1 1/2" x 2 1/2" doug fir. I also provided a lateral brace across the baffle just above the woofer cutout. The line shown in red is a possible brace befween the mid-base box and cabinet back. Thought I'd assemble the cabinet and then decide if that brace was needed. Take a look at my attached pic and comment if you will. Thanx - Rick
    Attached Images Attached Images  

  15. #180
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,715
    I would definitely add the red brace(s) too. I have found tying the middle of the baffle to the back and the middle of the sides to each other really stiffens up the box and the bass response. Having braces crossing the central cavity of the box can make it difficult to install networks etc., but when possible I try to do it... it just sounds better.


    Widget

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. How to Upgrade your JBL 4343 to a 4344
    By Ian Mackenzie in forum Lansing Product DIY Forum
    Replies: 3
    Last Post: 09-08-2005, 10:33 PM
  2. 4350 Monitor Plans - Discussion Thread
    By boputnam in forum Lansing Product General Information
    Replies: 6
    Last Post: 05-28-2005, 09:54 AM
  3. Upgrading a 4343 to 4344 components
    By porschedpm in forum Lansing Product Technical Help
    Replies: 9
    Last Post: 10-29-2004, 10:45 AM

Posting Permissions

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