Second BFM Build: 2 x J12 Lites

[Jools4001]

Well I guess build threads don't start any earlier than this...with the arrival of two 3012HOs this morning. I'm probably one of the few people in the world that get excited by getting two cardboard boxes just because they've got Eminence printed on them, but if anyone understands it'll surely be the people on this forum.



This BB ply has been sitting around waiting to be transformed into Jack Lites for a few weeks - and yes, I know the ply should ideally be stored flat, but since the entirety of a UK house near London could probably fit into a Texas shoe closet, keeping it leaned up against my dining room wall is the only place I can store it in clean, dry condition.



Closer inspection of the box contents confirms that, yes, I now have a couple of 3012s waiting for a new home, but that one of them has a damaged rear gasket.




I'm not going to bother sending it back because the rear gasket won't be doing anything when the speaker is mounted, but it begs a question that I hadn't thought of before - since the rear gasket is, by definition, fairly compliant, isn't it better to take this off anyway and let the mounting screws clamp against the solid frame rather than bite into the squidgy stuff?

I'll be using the rest of this week to finish up all my monitors so this build should start in earnest next week...with a bit of a following wind I'd like to have the ready for our next gig, but since that's on Friday 13th, better not tempt fate.

[Ryan A]

Wow, I'm surprised they sent you a speaker in that condition...not like Eminence.. Kinda wonder if it was messed with by customs or the dealer you bought it from.

The gaskets job is to conform to mounting irregularities. I wouldn't go without one as air leaks will surely be present.

[Charles Jenkinson]

Yes, I pulled/scraped the rear gasket off mine so serrated lock washers cold perform their function correctly.

It's interesting that you have had a brown box and a white box delivered - I had this too. Of the two drivers I got, the front gasket in one was the old style cardboard and thin neoprene, and the other was the newer all-foam one. The all-foam ones compress more.

Who did you buy them off?

[Jools4001]

Yeah, it looks like shipping damage to me, but as Charles confirms I can just scrape the gasket off...it's the front gasket that's the mating surface with the baffle and, as you can see from the front view of the same speaker, that's perfectly fine, so no danger of leaks. I'm not going to bother returning it when the job of scraping it off has already been started for me

I got them from Blue Aran because I'm signed up for their JAM club that gives you a bit of discount, and there was a bank holiday voucher for an extra 5%, so with both chunks of discount they came in at just a touch over £300 for the pair...which is about as good as you're gonna get for 3012HOs in the UK. But strangely, the pair of Delta Pro 8Bs that I also got from Blue Aran came in different style packaging to one another...who knows, they work just the same so I'm fine with that.

[Radian]

Yes, I pulled/scraped the rear gasket off mine so serrated lock washers cold perform their function correctly.

+1

I did exactly that on my last 3015LF install.

[Bill Fitzmaurice]

The all-foam ones compress more.

True, and be sure to re-torque the screws a day after the initial installation as a result.

[miked]

That gasket is really buggered-up. I would sit the driver face down on a truly flat surface and make darn sure the basket isn't bent. It almost looks like they shipped you a returned or used driver. Are there any signs of it being mounted previously? Are there "screw indentations" on the gasket around the other mounting holes?

[Harley]

That gasket is really buggered-up.... It almost looks like they shipped you a returned or used driver. Are there any signs of it being mounted previously? ...?

That was my gut feeling as well when I saw it.

[Charles Jenkinson]

The all-foam ones compress more.

True, and be sure to re-torque the screws a day after the initial installation as a result.

+1

I'm still not sure whether the gasket is to be fully compressed so that the metal (basket?) machined face is hard up against the baffle, or if there is a 'torque/compression' setting to attain the gasket compression required. Who's the best person at Eminence to ask?

[Bill Fitzmaurice]

I'm still not sure whether the gasket is to be fully compressed so that the metal (basket?) machined face is hard up against the baffle, or if there is a 'torque/compression' setting to attain the gasket compression required.

I found with those that they usually ended up with the frame against the spacer. I was happy to see those gaskets discontinued.

[Jools4001]

Guys, thanks for everyone's concern but the damage is really limited to the rear gasket which is superfluous in the J12 application.

The driver is obviously brand new, there are no signs of any witness marks on either gasket (even on the damaged gasket, the damage itself is the only sign of distress) and there are no witness marks on the chassis paint - it would've been impossible to have mounted this driver without leaving any marks.

Apart from the damaged area on the rear gasket, the rest of the gasket looks brand new and neither the front nor rear gasket show any signs of having been compressed before. It is definitely not a used driver.

The chassis itself is dead straight and true, no warping whatsoever.

The state of the gasket was just as it came straight out of the box, and since there is no other problem with the driver I'm just going to put it down as 'one of those things' and get on with it. As I've already established, this gasket is not needed for any practical reason on a J12, in fact it gets in the way of properly tightening down the mounting screws so it will be coming off anyway - so, unlike the gasket, I'm not going to get bent out of shape over it.

[mems]

Just as an aside, and it kinda sounds like you've written it off, but why not try to contact the shipping company and see if they will spring for some money off.

Not sure of how it works over there but even a simple two minute email with the picture attached that you provided us might yield some results REGARDLESS of whether or not this driver is going to work or not for your application.

[Bill Fitzmaurice]

Knowing the compression issues with the neoprene gasket I'd carefully remove the rear gasket and then use rubber cement to attach it to the front of the neoprene gasket, using latex caulk to fill/repair the cracks.

[Mark Coward]

I've had a couple like that, I think it's probably due to the summer heat causing it to stick to the cardboard.

[Chris_Allen]

That ply doesn't look like birch and it only appears to have 3 plys.