Broken Dome

[Fort Knox]

Voice Coil works fine...I think that's why Symbiotik was invented

[Fort Knox]

I'm looking at this diagram (Hi Freq Sect..)
You circuit guys...
Is theirs any mods I could make....
To stop cracks from forming in these diaphagms

[grumpy]

Smack yourself when you turn the volume knob up?

Perhaps one of the filament bulb limiters often used in JBL (and other company's) PA products?

[Fort Knox]

Smack yourself when you turn the volume knob up?

Perhaps one of the filament bulb limiters often used in JBL (and other company's) PA products?

Looks like 2 trim controls R1 & R3 maxed out ......only leave C4. R6 to damp diaphagm breakup...

[4343]

1" diaphragms will do that. Aside from raising the crossover frequency or lowering the volume, there's not much you can do to keep that tangential style of surround from cracking. I managed to keep my pair intact by running them at 2.5KHz and above whenever they needed to get loud. For PA use (1218?) we would completely bypass the Altec crossover and just run a cap on the 811/808-8A. Letting the 15 run full out lowered the tendency to feedback in the 1.5-2K region, (due to beaming) and running the compression driver from 2.5KHz saved use from replacing the diaphragms whenever someone dropped a mic...

If it were me, I'd look for either a set of phenolic dias and a pair of good tweeters, or diaphragms with a Mylar surround. With the phenolics you can pound them into the phase plug all night long and they will still work the next day. (You have to really try hard to not notice when a diaphragm hits the phase plug repeatedly!)

The Mylar will survive longer than the tangential surround, but the aluminum dome will still not like slamming into the phase plug.

Or just follow Grumpy's advice, it's the best advice I've seen anywhere on the intertubes.

[Fort Knox]

I got a group of A7 "Lash Ups" w/K140's and all they run's
One 20uf Cap ea on the 808's ..LF Horns run wide open

[grumpy]

you might want to roll off the low end of the 808 with something more than
a 6dB/oct high pass filter (a single cap isn't going to offer much driver protection,
even if the 808 is an 8 ohm driver ... which I don't recall off the top of my head).

[Fort Knox]

you might want to roll off the low end of the 808 with something more than
a 6dB/oct high pass filter (a single cap isn't going to offer much driver protection,
even if the 808 is an 8 ohm driver ... which I don't recall off the top of my head).

I could put a coil across the 808-8a terminals..and yes ..they are 8 ohm
I'll have to dig up a value