Crossover design question

[Lojzek]

Nanapana is a difficult type of a DIYer, does not really trust the advice given. 😀

 

[Nanapana]

I think we should get technical..

100Hz is a woofer frequency, and at 100Hz your 2uF capacitor is blocking for your tweeter, like you said. Its impedance is high at 100Hz and its impedance is low at high frequencies so the treble is not blocked to the tweeter.

At 100Hz the capacitor impedance is 800 ohms. It is in series with the tweeter, so add that which makes it 804 ohms (*).

Now, the current from the amp can flow two ways, through the 8 ohm woofer and through the 804 ohm tweeter with capacitor. Do you think the tweeter will get much interest?

Not much if any

 

[Nanapana]

Nanapana is a difficult type of a DIYer, does not really trust the advice given. 😀

I do trust it, just also trying to undererstand Fundamentals of it

 

[AllenB]

Not much if any

That's right, which is why it is still only 8 ohms at 100Hz.

 

[Nanapana]

Have you tried the ribbon tweeter alone with the full range? It will be that small tweeter that's giving you that sparkle.

From what you've told me the horn cuts off lower than the full range and is of a much higher impedance, so it's unlikely it's contributing all that much to the overall balance of sound.

You could likely get as good or better results by putting the ribbon tweeter on a nice wooden baffle then wiring it up like the thumbnail along with your full range speaker.

You can get all the parts rather cheaply from Parts Express.
This is the L-PAD... Speaker L-Pad Attenuator 100W Mono 1" Shaft 8 Ohm

(Sorry about the back to back posts, guys.)

Does the l-pad djust volume of driver, or adjust at which frequency cutoff is at?

 

[Nanapana]

I now have just the ribbon tweeter (4ohm) with a 2.4uf cap, connected with the full range driver(8ohm) only. Sounds good.. any thoughts..

 

[Douglas Blake]

Does the l-pad djust volume of driver, or adjust at which frequency cutoff is at?

It's a level adjustment. The L-PAD keeps a constant impedance so the crossover point doesn't change (much) when you adjust volume.

There is no actual cutoff frequency here. The high pass capacitor is always letting some amount of current through even at 10 hz. What it does is to allow increasing amounts of current as the frequency increases. At some point the current it passes will become significant enough that the tweeter begins to contribute to the sound you hear. It's a hill ... not a cliff.