Woofer Clamps

Hi there,

Am looking to see where one could procure woofer clamps like used with the 2245 on the 4345 speakers. I see USSpeaker sells cheap clamps that would probably work, but the cost of shipping when I load my cart is quite high, and wondered what alternatives existed. Being Canadian stinks if you want to buy stuff from south of the border... that sweet free shipping runs out, and our money is made out of dirt.

That said... how many use clamps vs screws? I realize they were intended to make swapping drivers simpler, but there is something about the look that cant be replicated as well with traditional screw mounting.

Thanks in Advance

Search JBL MA15 on ebay

I know I bought some on eBay from China a few years ago, the shipping was reasonable. I can only find USA sellers now that charge more for shipping than the clamps cost.

Item location: default, default, Hong Kong

Hi mortron,

I'm not aware if you're still looking for the woofer clamps, but I found some shown below from Canadian retailers, therefore no currency exchange rate applied to our "funny money". Also, depending on which Province you live in there might be some of the sales tax(es) non-applicable.

I don't know if you insist on having the JBL MA-15 ones, in view of price in USD, Odd's indication those he showed are in Hong Kong, plus shipping cost for the long way home. Some duty may apply at border too...

The ones shown in first pic look similar to the MA-15 kit I have on my 2205 cabs. There's another model I have (2nd pic), which is also available in Canada from another retailer, but its somewhat more expensive being sold by the unit and the screws/T-nuts appear to be sold separately for that last one.

However, in case you'd go for the last option above, I have two sets of 16 screws/T-nuts not being used, one black the other silver (3rd pic). The black ones I keep to go with my black clamps in stock, but the silver screws/T-nuts (size 10) I could do without for the asking, though they may or may not be large enough for your project? You decide. BTW I'm not a big fan of the T-nut system, for a few reasons, and have installed it on one pair of my boxes only (2205).

I have not purchased nor own the ones on the first pic so I cannot comment on them, but they seem ok at first sight.

Send me a private message if you're interested in getting the details. Regards,

Richard

Attachment 84667Attachment 84668Attachment 84669

One should consider that the MA-15 clamps don't suit for all transducers. Especially not for the K-145 and others with higher rims.

@Richard: I do understand your reasoning against T-nuts very well after some encounter when building a pair of 2225H subwoofers about four weeks ago. It was rather annoying to see the second to last or even the last T-nut falling off the baffle into the inside when installing the drivers :o:. Hence it might be advisable to addtionally secure them with contact glue before driving the screws.

Best regards!

That style of nut is not really suitable for particle board, MDF, HDF or generally species wood. best used in plywood. For the others the usual choice would be "Propel nuts" they have a spiral shank that snugs into a specific hole size in the wood. Not nearly as prone to falling out.

For small quantity orders Mcmaster Carr
as for example these for #10 screws

https://www.mcmaster.com/90598a025

Hi Kay,

Thanks for the input. I secured the 2205 T-nuts with GE's rubber silicone all around them, more so for air leaks since I wasn't satisfied with their sealing. This way they don't move AND are air tight.

BTW I add a larger black washer between the screw head and the clamp to spread the binding force on each clamp's whole flat surface or so, instead of having that force applied by the screw head alone near each side of the slot in the clamp, which is the weaker point on MA-15 type clamps (see in first pic, post # 5).

The thin cork gasket that came with the MA-15 mounting kit has very little compression (spongy effect) so to avoid any air leaks the driver has to be installed relatively tight, not overly tight. Regards,

Richard

Hi Cyclotronguy,

Thanks for the info. Haven't seen locally before that type of "Propel nuts", but never really looked for such either. From the picture shown in the link you posted, if I understand correctly these nuts sort of make themselves a thread in the wood as they go in?

As for your mention about conventional T-nuts being "best used in plywood." well it depends in my view. I'd tend to agree with softer spruce/pine content plywood. However my experience with 7-ply, 3/4" Douglas Fir plywood from British Columbia and T-nuts showed its difficult to hammer them in without nut legs bending, Fir being among the hardest of so called soft woods. Imagine with Baltic Birch plywood.

No wonder someone invented the nuts you show. No more T-nut legs bending when hammered into harder wood. Regards,

Richard

Here's an example for what you call 'propel nuts' with ISO M6 thread:

Attachment 84678

I never use a hammer to drive a T-nut into a wooden board. Instead I use a screw, a washer and a cordless screwdriver with a matching bit.

Best regards!

What would the required clamps for the 2245 be? Would these MA15 work? Or do I need even bigger ones?
Thanks

JBL used 8 pcs. M15 on 2245

Attachment 84984

I wonder why they didn't space them equally at 45 degrees?

Best regards!

Quote:

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Originally Posted by Kay Pirinha

I wonder why they didn't space them equally at 45 degrees?

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When doubled-up, it emphasizes the power of the 4345. . . visually, at least. :dont-know:

No wonder someone invented the nuts you show. No more T-nut legs bending when hammered into harder wood.

I found using a large C clamp and some card stock on the baffle face sets the T-nuts quite well

I always insert T nuts using screws and a cordless driver.

Best regards!

Those nut inserts do work well. Most likely invented by Ikea, they are readily available in the USA at Lowe's and similar stores. Just be careful using them in hardwood and test a proper size pilot hole if you can. The metal they're made of is not the strongest and if forced the tabs that make the slot for the screwdriver can break. I used them in fabricating a worktable/desk for my daughter out of raw maple butcher-block material when attaching some metal supports (from Ikea). Plenty of room for error when using them in MDF or particle board, not so much in hardwood.

Yes, but sometimes it's a tough job getting them exactly perpendicular to the surface.

Best regards!

Quote:

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Originally Posted by Kay Pirinha

Yes, but sometimes it's a tough job getting them exactly perpendicular to the surface.

Best regards!

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You got a few tricks... Depends on your insert. One is for hardwood and another is for softer woods like MDF.

The soft ones use Allen keys, the hardwood uses slots usually. Different metals. The latter can be had in brass.

One is to use a cut off Allen key or flathead bit in the drill press... The size of most baffles will make the task a tough one unless you have a crazy huge press.

The second option is to find a manageable piece of aluminum or steel block about 2x2" or bigger and drill a hole big enough to clear the outermost thread on the insert (some have a flange) and be deep enough that it holds the insert vertical and perpendicular to the baffle. Kind of like one of them drill blocks or a kreg block.

I have found numerous sources for clamps. Just need to determine the best source... 16 get expensive with shipping and I may be better off getting the screws and inserts locally to save on shipping.

There are few things more frustrating than when a spiked insert backs out of the wood when unscrewing the driver fastener. They can be secured a few ways- a block of wood behind them, staples on the flange can work well if they're sturdy and deep, or screws if you are okay with "wasted" hardware. Epoxy on the nut is also effective, but care must be taken not to occlude the threads.