Salvaged Crossovers - any idea what frequency?

[EsoBOFH]

Just picked up a set of speakers on the side of the road... they look to be a pair of older 2 way kit speakers - Viva drivers and tweeters.

An externally hosted image should be here but it was not working when we last tested it.

The mid/woofer drivers are toast, but the tweeters seem to be in good order, and the terminal plate has a crossover built into it.

An externally hosted image should be here but it was not working when we last tested it.

Can anyone tell me what frequency range this crossover would give me? it was connected to the tweeter, with the mid/woofer connected directly to the terminals. The cap is 6.8 µF 100vdc

An externally hosted image should be here but it was not working when we last tested it.

And the resistor says 5W 1ΩK - would I be correct to refer to this as a high pass filter? Anyway to test this to tell me what frequencies it will let past?

thanks!!

 

[Richard Ellis]

It looks like a plain ol' First Order Two-way crossover. About 2900 Hertz....the one ohm resistor is probably to pad down the tweeter a little bit, likely the tweeter is more efficient & needs a tad dialing back.

The coil should be about .4 mH worth.

___________________________________________________Rick..............

 

[turk 182]

somewhere around 3 khz.
try "googling" crossover calculators there's tons out there!

 

[EsoBOFH]

It looks like a plain ol' First Order Two-way crossover. About 2900 Hertz....the one ohm resistor is probably to pad down the tweeter a little bit, likely the tweeter is more efficient & needs a tad dialing back.

Thanks Rick - so this is not just filtering the low frequencies to the tweeter, but actually splitting the frequencies between the tweeter and main driver at 2900 hz? i ask because the main driver is directly connected to the terminals, so not sure if this crossover/filter has any effect on it? (very newb here).

as an aside, the tweeter is a Vifa D19TD-05 3/4" Poly Dome Tweeter (out of stock, but still currently listed at PE). The comments on that listing mention that the tweeter is very efficient and has to be modified with the resistor when using as a replacement in some loudspeaker arrangements - so you were bang on about that!

thanks!

 

[Richard Ellis]

I was assuming that coil is to go to the woofer........simple first order, can you draw out the circuit? It's kinda difficult to decipher what goes where by the pictures...it's all kinda scrunched together.


___________________________________________________Rick...........

 

[Richard Ellis]

Capacitors & coils work rather in opposite ways. Both act like variable resistors according to frequency. Coils cut-off higher frequencies as capacitors cut-off the lower frequencies....but are now considered Impedances, not resistors.
If you graph out a collection of frequencies & plug them into these two formulas you will get two curves, one for the tweeter & the other for the woofer. The results are in Ohms & you'll note they "come together" at a common value which is considered the cross-over frequency.



_________________________________________________Rick..........

 

[Richard Ellis]

Better?


________________________________________________Rick........

 

[turk 182]

so i has off by a hundred hz.
from the pic's it appears that the coil is in parallel with the tweeter after the cap but i could be wrong

 

[planet10]

Looks a lot like what comesout of some of the small Tailored roll-off on a custom VIFA midbass and a 2nd order XO on the tweeter.

dave

 

[EsoBOFH]

circuit diagram

Gents - here is the circuit diagram. Pardon the speaker icon... They didn't have the correct one in the app I used. Thanks!

 

[turk 182]

yup it's like i figured so as long as the impedance of the tweet is 8 ohms it's a 3k x-over.

 

[EsoBOFH]

Thanks all.. Sounds like I can use this for the bookshelf speakers I'm building.