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JBL 1200hz crossover for 2225/2425

This is my pair of 220Ti. I got them in a trade a couple years ago and have never listened to them. Date codes are November of 2016.

Do people remove the insect screens on these for HiFi use?

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I know people do it with Altec and other older drivers. Hell I’ve done it myself. I’m not sure I’ve ever seen any actual evidence that it makes an audible difference though. I might have thought I heard a difference with the Altecs. But that’s why I trust actual data more than my hearing sometimes ;)

The screens on these 220ti certainly are beefy
 
I use my Rock Salt loaded pump
action air shotgun to keep the Spiders
At a minimum. They love small tiny dark spots
You think baby spiders can’t fit down a compression
Drivers Voice coil gap?
 

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220ti Dats

I’m always surprised how far off some of the numbers are. Yet the Re are identical, and the Le are almost identical. Interesting

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elitopus said:
I know people do it with Altec and other older drivers. Hell I’ve done it myself. I’m not sure I’ve ever seen any actual evidence that it makes an audible difference though. I might have thought I heard a difference with the Altecs. But that’s why I trust actual data more than my hearing sometimes ;)

The screens on these 220ti certainly are beefy
Click to expand...
Indeed, guess beefy enough to have any impact. When you eg take an Emilar EA175, theres a difference. Screen seems to move, and some mass is added to the diaphragm.
Green is without bug mesh, pink graph is with screen:
with_without_mesh.PNG

Unfortunately I have "tuned" the (very small) back chamber of the EA175 with some felt (both upper measurements are with felt) when I removed meshes, so I cannot say why exactly the upper end reproduction improved clearly. But it did ;) ... when I am used to my new measuring microphone and ARTA, I can make some measurements with/without mesh of the frequency curve too.
 
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I removed the screens from my Altec drivers. I think some of my Renkus and Emilar drivers still have them. Interesting test results!

I also use thinner mounting gaskets with my Altec drivers.

I did remove the screens from the 220Ti. The issue I see now is this little shelf that the screens sat on. The opening diameter is 15/16” at the shelf, and 1 1/16” right at the opening. I’ll have to see what the horn openings measure. I’m thinking maybe this area should be smoothed out

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You should construct -maybe some paper- ring filling that gap between driver and horn(-adapter), which formally was filled by the mesh (?)
 
I need to measure the horns and see what size the openings are. Ideally they would be 1 1/16”.
Maybe I could fill in the shelf with something like JB Weld and then smooth out the transition
 
elitopus said:
Maybe I could fill in the shelf with something like JB Weld and then smooth out the transition
Click to expand...
Probably, a lot of work for essentially naught in gains.

If the shelf were going the other way, such that it was reflecting energy directly back into the diaphragm...
 
Most of what we do here is either a lot of work or a lot of money for very little gains. Haha

But yeah I agree they’re probably not worth messing with. I’ll see how they fit on the horns and go from there.
 
3D print the filler. Piece of cake.

Or for that matter, just put an O-ring there and let the mount squeeze it a bit.
 
A 3D printer would be a good option if I had one. Maybe one of these days I can talk one of my kids into getting one. And learning how to use it.

There are some cool horns you can print with a 3D printer. Although I’d bet it would have to be a decent size one. For the horns I’m looking at….
 
elitopus said:
220ti Dats

I’m always surprised how far off some of the numbers are. Yet the Re are identical, and the Le are almost identical. Interesting

View attachment 3537818View attachment 3537819View attachment 3537820View attachment 3537821
Click to expand...

All of those parameter differences can likely be explained by a slight difference in suspension stiffness. The higher resonance should cause higher Q numbers. That's what we're seeing here, in what looks like a proper proportional fashion.

Once those drivers are mechanically broken in a bit, they may converge to closer numbers.

Regards,
Gordon.
 
I figured once I beat on them (ahem I mean break them in) they'll loosen up some and the parameters will change slightly. If they ever come out of the cabs again once I break them in I’ll sweep them again with dats to compare

Something I’ve noticed that I don’t understand. The ferrite LE14 don’t seem to get much love. I don’t pay much for my pair, and I saw a pair of LE14H-3 on eBay today for slightly more than I paid for mine. On that pair shipping was almost as much as the cost of the woofers. Lol.

So what gives? From what I’ve read, the H versions are a better woofer. Unless you’re an AlNiCo purist…
 
I’m thinking about both the woofers and 220Ti. Both probably haven’t been used in years and need some music played through them
 
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