More A7 questions

[Altec Best]

I'd help you Volvo, but crossovers I'm still learning myself ! Somtimes you may have to get different brands if Solens don't have the value you need.I would try Dayton's or Sonicaps, all are reasonable in price.When you hook them up hook them up in a way that you can easily change out one cap for another.You should try to get as close as you can to the correct values. 2.4,2.49,2.5,are all pretty close,if you can get in that range you should be good.But doesn't mean you will like it.That's were making it easy to change them out comes in.

[VolvoHeretic]

Good idea, use spade connectors with some die electric grease on everything. I also need an L-pad and some resistor to protect the amp I guess. Just checking,
8ohms 7.5KHz = 2.65uf
...........8.0KHz = 2.49uf
...........8.5KHz = 2.34uf
7ohms 7.5KHz = 3.03uf
...........8.0KHz = 2.84uf
...........8.5KHz = 2.68uf

So a little difference goes a long ways. How do I pick the ohms?

[VolvoHeretic]

Pulsar Developments Ltd - Piezo Tweeter Application Note

Found this site with everything I need to figure out these piezo's. It will take a few reads to comprehend. I just hope these ones I bought from Radio Shack back in the '70's are the real Motorola ones, nothing is labeled on them at all.

[Panomaniac]

A piezo looks like a cap to the amplifier. Using a resistor in parallel is a very good idea for the amp and also for designing your crossover. Just put an 8 ohm resistor across the collective terminals of your bunch of piezos. Then choose a cap to fit. Buy a few values, like 2.2, 1.5, 0.68 and smaller. The Dayton brand are cheap and good. With those values you can tune by ear.

[Panomaniac]

Thinkin 'bout the piezos. If you use 6 or 8 per side (yes?) then you might try to spread them into 2 groups either side of the Altec horn center line. The idea being that the horn will be a narrow beam at at the high frequencies, so you don't need extra there. Spread the highs around a little to the edges of the horn. Might give a more uniform dispersion of the top end.

A hare-brained idea, but it wouldn't be hard to try!

[gearfreak]

Thinkin 'bout the piezos. Spread the highs around a little to the edges of the horn. Might give a more uniform dispersion of the top end. A hare-brained idea, but it wouldn't be hard to try!

Playing with 8 per side so far.
Maybe increasing to 12 when I get to it.
Hanging (literally) off either side of stacked 828-G cabs, set back to be ~aligned with the 288 MF VC.
Might be a bit better than the pseudo 'coaxial-y' mounted CP-09, which works well enough, but primarily when at a greater distance.

I'd offer commentary on the wiring of the piezo's, but the jury is still out.
My XO is a custom mess.
What I did find, is 2 banks (series) of 4 ea (paralell) in order to knock down the output a bit.

Realistically though, I don't think I am getting any thing above 17k, but that may be happening ahead of the Altecs in the signal chain, or just my hearing.

To boot, I don't think the piezo cap is limiting fc as much as desired, or as shown in the motorolla pizeo sheet I have somewhere.

[Panomaniac]

Thanks for the update.