Question for Pano: JB's 605 OB crossovers

[Skip Pack]

I grabbed a copy of the schematic you posted on the crossovers
you used with John Busch's open baffle 605A speakers at LSAF
last May. I am using Jeff Markwart's design on my 605B OBs and
thought I'd try the fixed attenuation with HF compensation
you show in the LSAF design on the tweeter side. I'm curious why you
have the 10uf cap in parallel with the 4 ohm resistor on the ground
leg? It looks like it would have no effect as all frequencies that made
it though the 2nd order filter would be a good octave higher. Is this
intended to put a steeper, shelved cut from say 800 hz or so?

I've attached that schematic. Not sure how it will appear.

Thanks,

Skip

[Panomaniac]

Hi Skip,
Sorry I haven't been on the forum in quite some time.
Let me study your question and get back to you.

Pano

[Skip Pack]

Thanks for picking the question up. I just noticed the 'extra' cap
and was curious.

Skip

[donaldpatten]

SKIP

The two RC networks " boost " the HF to the horn.
Below the frequencys the caps kick in the HF driver ckt looks like 14R in series with an 8 ohm driver . About -9dB ,a reasonable padding down of the horn to match the woofer . At very HF the 3R and 4R are bypassed and the ckt looks like 7R and an 8 ohm driver. -5.5dB ,or 3.5dB of " boost " split by the RCs for high freqs.
I read the values as : 10uF & 4 ohms res freq = 4 kHz, and 0.47uF & 3 ohms freq = 113kHz?? Could the 0.47 be 4.7?? Then the second freq = 11kHz.

Don

[MANZANITA]

Bingo!

[Skip Pack]

Thanks to you both. I was looking at the RC pairs as a series
attenuator with the capacitor acting has an HF bypass. I'll
need to bone up on them as a resonant circuit element.
Also, just to confirm, the cap marked in the diagram as
.47 uf should be 4.7 uf? I have both, so I probably should
start with the right one.

SKip