4350 Monitor Plans - Discussion Thread

[boputnam]

Fellow Forumites...

Rick has asked that we open things for discussion. I don't want to muddy his "documentation" archive thread, and so suggest we do all the discussing, questions, ideas, lusty memories chat, here.

NB: If any discussion noise gets inadvertently posted in the "documentation" thread, I will endeavor to move it all here.

Thanks to Rick for this excellent opportunity to study the 4350!

[saeman]

Attached are some pics of early 74' vintage 4350's. These sold on ebay a couple of years ago. I think they went to Japan (too bad). For those who have not seen the first offering in this model, you'll see quite a difference. Early white aquaplas coated 2230's are the big difference. Note the blank plates covering unused holes are mounted on the outside of the cabinet. The 2405 is the early style that required the split ring for cabinet mounting. I'll be waiting for a long time for a pair like this to come my way. Rick

[boputnam]

Hey, Rick...

On the "Plans" thread, you are right now talking about using the plexiglass templates for cutting the baffle. Why not just use a "Jasper Circle Jig" or like tool?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=365-250

[johnaec]

Why not just use a "Jasper Circle Jig" or like tool?I will say that if you're doing more than a few holes of the same size, using a jig that uses a router guide for cutting holes can be FAR faster than a Jasper Jig. The Jasper is great for making these jigs, though, and if you're only doing a couple holes, it's probably not worth making a router-guide jig.

BTW - while plexiglass is nice, it's just as useful making one out of wood. At Hard Truckers, that what we did, though positioning was automatic with baffle guides - plexiglass could be useful to see positioning if you're just doing one-offs. We also had additional jigs with metal "insert" guides for drilling the speaker mounting holes - you just run a drill, (or drill press, depending on the situation), right through them into the baffle. In no time at all you have the speaker hole and mounting holes.

John

[saeman]

Hi Bo and John: I have a Jasper Jig and I use it to cut all of the templates but I have found it to be too time consuming to cut all of the holes for a project with just the Jasper Jig. There is also more margin for error/slip ups using the jig. With templates the router is inside the guide edge and the router can't go anywhere past the desired edge of the hole. For a one time project it's probably not worth the time and $$$ to make templates but I've had some of mine for many years. Every new project may add one or two more to the pile. Most of JBL's cabinet holes are standard size and can be used over and over - 15" and 12" woofs, 2405's, H91's and x-over cutouts. I only had to add one new template for the 4350 project for the baffle ports. As John said, you can see thru the plexi and that's why I chose it over wood. It also wears well from the router base going around and around year after year. Just my choice - not the only option.

[saeman]

On the subject of templates but off the subject of JBL. I recently started building two pairs of SAE Mark XIV Electrostatic Speaker cabinets, one pair in walnut and one in rosewood - the two options offered by SAE in the 70's. I have been looking for a pair for over 5 years with no luck. Finally found a beater, non-restorable pair of cabinets that will serve as only a model to build the new cabinets. After that they'll be useless. This project has turned out to be a Template Nightmare and I'll certainly burn up a 4 x 8 sheet of plexi in the process. Without templates this project would be a total disaster. I posted some pics to show some of the work. They may give some of you some ideas of how to tackle your own special projects. Although JBL didn't offer anything quite as crazy as this SAE design they did offer some enclosures that had curved bases and non-parallel surfaces. L212's would be a good example with their sloped base.

My goal on this project is to accurately produce 4 cabinets that are identical in every detail to the originals produced by SAE. Templates are mandatory to achieve uniformity, piece to piece. I cut a large template, table mounted to cut the dado recesses into the side panels, another to cut the sloped side faces and one more big one to cut the groove that that the grills slide into. It took 2 more templates to cut the recessed hole that the 12" Gauss woofer mounts in. 3 more were required for the recessed mounting of the 5" mids and their rear mounted enclosure tubes and one more for the electronics cutout on the cabinet back. When the project is done the templates will sit and collect dust as I doubt I'll ever use them again. If anyone out there wants to take this crazy project on, let me know and I'll loan you the templates.

A good pair of JBL's will blow these SAE's away but I've always wanted them. There is something to be said about the high end on electrostatics and I want to give them a listen. Rick www.lubecentersys.com/mark14 (http://www.lubecentersys.com/mark14)

[Ken Pachkowsky]

There is something to be said about the high end on electrostatics and I want to give them a listen. Rick

Yes, that is a fact. I had a buddy back in the seventies that had a pair of Magnapan Tympani 3A's. The high end was very nice.

Ken