4350 Driver Impedance

[Woody Banks]

Howdy All
Are the 2405 & 2440 compression drivers in the 4350 16 ohm. The schematic of the 3107 indicates a 8 ohm load. I am still in the gathering phase of my 4350 hybrid project and would like to at least use the correct diaphragms for the 3107's.

Woody

[Guido]

The 2405(H) measures between 5.7 and 6.7 ohms and is a 8 Ohm Transducer. Doesn't matter what's written on the foilcal.
Right Dia is D16R2405

The 2440/2441 measures between 7.3 and 8.6 ohms and is a ~16 Ohm Transducer.
Edit: Right Dia is D16R2441 (or D16R2440 maybe NLA) = Wrong!
Right Dia is D16R2440 (D16R2441 not with the 3107)

[Mr. Widget]

For the 3107 you definitely want the D16R2440 diaphragms... not because of the impedance but for the proper response curve. The 2441 and 2440 drivers/diaphragms are not interchangeable in this design.

Widget

[Guido]

YEP! Widget is right! NOT with this network.

[glen]

For the 3107 you definitely want the D16R2440 diaphragms... not because of the impedance but for the proper response curve. The 2441 and 2440 drivers/diaphragms are not interchangeable in this design.

Widget

How will 3107s work with 2445 drivers ?
I was planning to use these in my own 4350/westlake style system:
Bass = 2x1601a
active crossover to:
Midbass = 2123H
High = 2445H (with westlake/2397 style horn)
UHF = 2405

Need to modify 3107s?
Start from scratch?

[10 Watt Street]

How about these?

http://cgi.ebay.com/SIERRA-AUDIO-TM-8-STUDIO-MONITORS-TAD-TL-1601A-DRIVERS_W0QQitemZ7377903344QQcategoryZ47092QQrdZ1Q QcmdZViewItem

No affiliation.

[glen]

How about these?

http://cgi.ebay.com/SIERRA-AUDIO-TM-8-STUDIO-MONITORS-TAD-TL-1601A-DRIVERS_W0QQitemZ7377903344QQcategoryZ47092QQrdZ1Q QcmdZViewItem

No affiliation.

That's pretty close to what I was envisioning, too bad I've already gotten all my drivers together.
Don't have the horns (that he's not including).
Maybe I should look into the sierra audio monitors for reference though, thanks for the tip.

[Mr. Widget]

How will 3107s work with 2445 drivers ?
I was planning to use these in my own 4350/westlake style system:
Bass = 2x1601a
active crossover to:
Midbass = 2123H
High = 2445H (with westlake/2397 style horn)
UHF = 2405

Need to modify 3107s?
Start from scratch?Start from scratch.... it is your best option since the only thing your system will have in common with a 4350 is the slot tweeter.


Widget

[Woody Banks]

It seems like the 3107 is going to be the Achilles heel of this whole project. I will put those puppies on epay and purchase active crossovers to relpace them after I complete my gathering process.
To date I have (4) 2230A's , (2) 2202A's and a pair of Westlake style wooden horns (60% complete). I also picked up a pair of ME 120HS drivers from Mr. Bluster that I want to use instead of the 2202A's. The 2202A's are a lot like me: gray and tired looking! The ME 120's should kick some serious ass! If indecision killed, I would have been dead a long time ago.
Mr. Widget's project has inspired me to do a column with curved sides instead of the original wife haters.
Thanks for the help on my crusade.
Woody

[Guido]

I don't think those ME120's will kick more ass than the 2202.

[hapy._.face]

snip:....'Mr. Widget's project has inspired me to do a column with curved sides instead of the original wife haters.' Woody

I dreamed up a four way project that sounds somewhat similar. Where is this thread??

It's based on a 4350 driver array (with a cd substitution). I was thinking of tracing the shape (smith horn curve) from a "top view" perspective onto multiple pieces of plywood(think many 3/4" horizontal cross sections until tall enough). Smith horn curve on the front baffle, straight sides and recess for a screw in rear baffle. Then assemble pieces with glue/clamp/screw until I have a front baffle that mimics the smith horn shape. In decending order (top to bottom): A 2405 slot on top, the smith (resting in a contoured cubby), 2202H midrange below the smith (heavily chamfered to eliminate deflections), and a 2235H side firing sub. A 3107 network modified to accomodate a 2435HPL CD (eventually- custom active crossovers). Lots of shaping/smoothing and a laquer finish. Steamed bentwood frame for the grill cloth.
Any LH members used similar build technique to this? I'd like to hear any supporting or objective arguements.

[Robh3606]

"I was thinking of tracing the shape (smith horn curve) from a "top view" perspective onto multiple pieces of mdf (think many 3/4" horizontal cross sections until tall enough). Smith horn curve on the front baffle, straight sides and recess for a screw in rear baffle."

The stacked and routed sections you describe is how the the TAD SOTA speaker enclosures are done. CNC routed glued with rods like alignment pins if I remember right. Very expensive way to go though. Just do a basic layout on a 4X8 and you will go through lots of them to get the height with lot's of waste as well. It certainly has advantages as you can contour to get damn near any shape you want. Try a search for TAD forget the speaker model number.

Rob:)

[hapy._.face]

[QUOTE=Robh3606The stacked and routed sections you describe is how the the TAD SOTA speaker enclosures are done. CNC routed glued with rods like alignment pins if I remember right. Rob:)[/QUOTE]

RATS! :banghead:
As humanity ages- our collective ideas are becoming realized. As a result- there seem to be fewer and fewer original ideas left in the world these days.
Well, at least I know my concept has some merit...
Thank you!:)

[Mr. Widget]

The stacked and routed sections you describe is how the the TAD SOTA speaker enclosures are done. CNC routed glued with rods like alignment pins if I remember right. Very expensive way to go though. Just do a basic layout on a 4X8 and you will go through lots of them to get the height with lot's of waste as well. It certainly has advantages as you can contour to get damn near any shape you want. Try a search for TAD forget the speaker model number. For anyone considering this approach... the folks at TAD have had so many production problems with this technique, that they came out with an alternate lower cost design that did not require this technique. Fabrication isn't the main problem, it is what happens at all those glue joints as the wood naturally expands and contracts.


Widget

[hapy._.face]

snip'....it is what happens at all those glue joints as the wood naturally expands and contracts.'
Widget

Thank you Mr Widget; Excellent information, as usual. ;)
I'm planning a scaled down model in reinforced cardboard
I wonder if threaded rods (running vertical) bolted with threadlock would help? Those same rods could be extended on the bottom to create spiked feet. In addition- I could slap a few thin sheets of liquid fiberglass reinforcement to the outside- forming a skin to hold the joints secure (a $50 cost). I'm not bound by the large scale manufacturing roadblocks that TAD must have encountered. Look at the complexity of that design!!!

http://www.6moons.com/industryfeatures/ces_2003/tad6.jpg
:crying: :crying: :crying: :crying:

My concept is far more primitive by comparison.
I already have a stack of 20+ sheets of 3/4" marine grade plywood just sitting (home reno project never realized). That should give me a good $$ headstart. I love the 2397- but I cringe at the deflections- evident when perched atop a square cabinet. Also, the deflections evident by the radius protruding from a flat baffle. I'm currently obsessed with finding an ideal, contoured front baffle technique...
People must think I'm nuts for taking on such a huge project, and my wife would agree. But consider this: The 4350 is a given performer. That is a non variable. A few simple tweaks and a far superior cabinet design- I think it's worth the effort. I may end up with something better- maybe worse. I can always re-use the drivers!

The 4350/3107/M552 might work for this configuration initially, but it's obvious that I'll have to rework it all to correct for the 2435. That should be fun...(:bs:)


The more I incorporate my architectural education into audio- the more I see the K2 (9800) as an ideal enclosure. JBL really burned pencils on that one!!:)

[edgewound]

For anyone considering this approach... the folks at TAD have had so many production problems with this technique, that they came out with an alternate lower cost design that did not require this technique. Fabrication isn't the main problem, it is what happens at all those glue joints as the wood naturally expands and contracts.


Widget

The whole TAD structure is clamped together from top to bottom with threaded rod. Waste becomes less of a problem if you use a CNC/router technique that maximizes the yield of your material by using open "C" sections stacked with a few closed sections as braces for a plank style baffle. It will be REALLY heavy. Why not try it? It just might be spectacular. And you'll have gained an experience in the process.

Have a look here: http://tadhomeaudio.com/

[hapy._.face]

snip'...by using open "C" sections stacked with a few closed sections as braces for a plank style baffle....'

Exactly as I envisioned it. The "C" section cut-outs could even interlock and share a "side" cut to maximize on material usage. Isn't 'heavy' what you want in enclosure design?? :D
It may not end up exactly like I have it arranged in theory- but I just gotta try the concept out....

[Mr. Widget]

The whole TAD structure is clamped together from top to bottom with threaded rod.Those threaded rods are for assembly... they are removed once the cabinet is built. The point of my post mentioning the problems that they have had with this technique is a cautionary tale... That technique can certainly be used, and several people are doing it. I only mentioned the downside as the two people that I have talked to that have built speakers using this technique, Andrew Jones of TAD and Alon Wolf of Magico, have both told me of the nightmares they have had getting successful cabinets made.

One thing to be very careful of is that every interior surface be completely sealed in epoxy resin... otherwise moisture will get into the wood and your glue lines will pop, or even the original plywood glue lines will pop if your cabinets aren't completely sealed inside and out. I've seen them this way even after they thought they were sealed... it isn't pretty.

Widget

[edgewound]

Exactly as I envisioned it. The "C" section cut-outs could even interlock and share a "side" cut to maximize on material usage. Isn't 'heavy' what you want in enclosure design?? :D
It may not end up exactly like I have it arranged in theory- but I just gotta try the concept out....

Yes....heavy/dense is good. Fire-up that router, baby. Before you start making all that sawdust....please.....get yourself a good industrial respirator mask with replaceable filters. Not just a dust mask...a respirator. Give your lungs a break. Saw dust smells good, but it wasn't meant to inhaled....especially MDF or plywood. You can find them at Lowe's or Home depot....Around $30-$40.

[edgewound]

Not me, dude! I'm shooting the moon here- might get the tree branches at best. But at least I'm grounded in that reality. And hey- I might even learn something, or perfect a previously abandoned technique!

I like your thinking.

[Earl K]

- I recommend a quantity of appropriately sized test boxes be used to mock up any prospective project .

- They will save a lot of future grief and become useful mules for other projects .

- Make a baffle-plug ( that accepts a 10" ) that goes over the cutout for your preferred 12 incher. With a pair of 2122/3 mids on hand you can determine for yourself , if the acoustic handoff between 12" & a 15" is to your liking ( or not ).

[hapy._.face]

snip '....get yourself a good industrial respirator mask with replaceable filters'

Agreed. Thank you. I wouldn't be without mine. I did some (illegal) asbestos removal to save a few bucks and spent the money in protecting myself to the extreme. High-end respirator: "check". ;)

Perhaps it's the router bits I'll chew through. I'm not quite at that stage- but rest assured pics will be posted when the time comes.

When I remind myself what plywood is (glued laminates of wood)- I'm not intimidated by the joins. I plan to keep the threaded rods intact, and make them an integral part of the cabinet. I could epoxy the gap left between the rod and hole. Plus, if my cabinet walls are 2" thick (and why not?)- It leaves plenty of room to put a few epoxy saturated decking screws into each successive layer. She'll be a heavy girl, alright. :D

Widget- I didn't know about the internal coating tip- thanks for potentially heading off disaster! I thought of putting a little wood filler in to fill in any voids- but that's probably not enough, huh?

[edgewound]

Perhaps it's the router bits I'll chew through. I'm not quite at that stage- but rest assured pics will be posted when the time comes.




You probably already know this....but invest in carbide bits....don't waste your time or money with high speed steel.

Love to see your progress. Hey....wanna come scrape my ceilings?:p J/K

Maybe the last several posts should be moved to DIY.:o:

[hapy._.face]

Maybe the last several posts should be moved to DIY.:o:

Agreed. I don't know how we did it- but somehow we are off topic!! WOW! Good thing that rarely happens! :p

I'll start a whole new thread in DIY when I have something more to document.

Thanks for the advice/encouragement Earl/Edge'/Widget. ;)