JBL E140 modification question

[spkrman57]

This is a simple one, but I wanted to be sure before implementing.

I have a pair of JBL E140-8A's that I don't need the aluminum dust cap in the application I have in mind. I want to use in a front loaded horn system from 150hz up to 800hz.

I want to know if I could put a paper dustcap over the aluminum one, or if I need to remove the aluminum to install the paper dust cap.

I am looking at using the 140's due to their extremely low Qes which I believe makes them a good candidate for horn use.

I will be using less than 10 watts in their intended mode. The only thing that might screw things up is the "bump" in response due to design that I read about. Other than that, I figure the dust cap needs to be subdued(aluminum).

Any and all comments welcome on this. The horn is a older Edgar tractix 150hz front loaded which I will use up to 800hz where a GP 399 driver on Edgar 500hz round horn will be used.

Ron

[rek50]

How about a "Snazzy" pair of old-time "Pasties" to tone down the aluminum dust caps. I wouldn't use ones with tassels, but then again.......J/K Ron. I've wondered about adding some self-stick felt like material that I got at JoAnn fabric, for a similiar task.... "Red Green" soft-dome conversion kit.

[Earl K]

Hmmmm Ron,

- I'm not sure what you are hoping to accomplish by leaving the Al dust-cap in place.

- If it is to maintain resale value by being able to return the driver to stock / then I think you are barking up the wrong tree .

- Any effective treatment to that dome will require ; removal ( my favourite ), paint ( ???? ) , "pasties" of all forms , or your idea of paper clad aluminum. For all these ideas to be effective, the new addition must firmly adhere to that aluminum dome ( or "Hello" buzzing ). So, gluing anything on will make it impossible to not inflict damage upon attempted removal .

- I guess that if you want a minimally intrusive mod., I'd start with the virgin speaker, then paint/goop the dome and then go from there. The worst case scenario is that after all your experimenting you'll have to buy an eBay kit of Al domes to restore it to stock.

[spkrman57]

I think if I don't hear otherwise that I will get paper dustcaps from a friend of mine that should be the same size and just have it glued on the aluminum dustcap already in place.

Or maybe just try it in the horn and see if it annoys me or not!

Ron

[spkrman57]

Earl,

Thanks for reply. I just don't know if the aluminum dustcap will spray HF I don't need into the horn. If I could just use it the way it is, then I will leave it alone.

I see the E140 as a great horn driver from the low "Q" specs, basically the reason I picked them up for.

Ron

[spkrman57]

My concern with applied coating to the dustcap is I don't want to "mass-load" the driver and change the specs as I would imagine it would increase Qts by adding weight to the cone/dustcap.

Ron

[johnaec]

I just don't know if the aluminum dustcap will spray HF I don't need into the horn.

Wouldn't you be using a crossover anyway? If the E140 isn't getting any high frequencies to begin with, it won't have any to spray around...

John

[edgewound]

The aluminum dome can still have a metallic overtone to it. The best way to deal with that is to remove the aluminum dome and replace it with a paper dome

[spkrman57]

I have heard from those using Bruce Edgar's midbass horns with D130's and complaining about hearing the HF spray(even with using a crossover which is 1st order). So I will go to my speaker repairman and see if he has the time to perform the operation.

I have 2 left thumbs and won't take a chance at screwing up a pair of good drivers!

Ron

[toddalin]

Could you make a conical mask with 4" hole to lay over the speaker and lightly spray the domes with a textured paint or rubberized coating?

[spkrman57]

If it did not add too much mass to the cone, I would think rubber cement would be a good thing to apply to the dustcap. But I think that would add more mass than would be a good thing.

So far the best solution seems to be removing the aluminum dustcap and replacing with a paper dustcap.

Thanks to all for the replies!

Ron

[Zilch]

Dust the dome with Aquaplas....

[scott fitlin]

Dust the dome with Aquaplas....

You could do this, if you know the right material to use, and how much of it to use!

From experience, if you spray paint the dustcap, it will tone it down a bit. Not as much as paper, but it will calm it down! Matte black spray paint. We used to do this years ago when guys didnt want to see the shiny aluminum! It seemed to also dull down the response too!

[Mr. Widget]

Dust the dome with Aquaplas....

I wonder if TiDome has thought of that?


I have used K140s with paper domes and liked them a lot. I'd replace the dome.


Widget

[scott fitlin]

I wonder if TiDome has thought of that?


I have used K140s with paper domes and liked them a lot. I'd replace the dome.


Widget

Ditto, the 140,s have a punchiness, best described as JBL sound!

My personal opinion is that if you love that kind of punchy bass, use the K or E 140,s with paper domes, and its a hard woofer to beat! In any application!