Help with first crossover attempt

[GdotPerks]

I'm building my first set of speakers from scratch and would really appreciate If I could get some assistance with the crossover design.

I have done as much reading as I can handle and decided it was time to actually have a go at it

My build is heavily influenced from impulse audio. He recommended the woofer and tweeter and I used his xsim files to make me theoretical crossover.

The woofer is a sb acoustics SB13pfc25-8 smokin deal at $15 canadian
The tweeter is a vifa xt25bg60

I used a 2nd order crossover and got what I believe to be a fairly flat frequency response.

The crossover point appears to be around 3500Hz, is that too high? What are the disadvantages to having such a high crossover point instead of a lower one at say 2500hz.

Do you see anything out of whack on the graph? I do not know how to interpret them

And do any of the capacitor, inductor or resistor values look way out of whack? Should they be easy enough to buy off the shelf?

And finally, I know nothing about impedance, does that graph look bad? Will my drivers blow up?

Any and all advice would be greatly appreciated

 

[richie00boy]

Your L-pad (R1 R2) isn't right and is causing your impedance to go below 2 ohms above 2kHz. When you have fixed that your high-pass filter values will need re-scaling. The acoustic result looks not bad.

 

[PeteMcK]

I'd use a single resistor to pad the tweeter (2x4.7 ohms in parallel), and place it before the crossover components.
"do any of the capacitor, inductor or resistor values look way out of whack?" - yes,
I'd expect them to be around these values: L1, .3mH, C2, 6.6uF, L2 1.2mH, C2, 1.8uF
personally, I'd crossover lower, around 2 KHz

 

[Galu]

Using a crossover calculator as a rough guide gives radically different L & C values.

P.S.The Vifa tweeter has a low resonance frequency of 589Hz so could usefully be crossed over at 2500Hz (12dB/octave).

 

[Galu]

Here are the driver specs to help the crossover designers:

https://www.falconacoustics.co.uk/downloads/Vifa/XT25BG60-04.pdf

5" SB13PFC25-8 :: SB Acoustics

 

[GdotPerks]

I'd use a single resistor to pad the tweeter (2x4.7 ohms in parallel), and place it before the crossover components.
"do any of the capacitor, inductor or resistor values look way out of whack?" - yes,
I'd expect them to be around these values: L1, .3mH, C2, 6.6uF, L2 1.2mH, C2, 1.8uF
personally, I'd crossover lower, around 2 KHz

Thanks! This information proved to be very useful on my third attempt

 

[GdotPerks]

Okay, so I have made 2 more variation of a possible crossover.

This is version 2, I don't like how low the crossover is. Other than that the I think I like the flatness of the curve.

This is attempt 3

So far I think this is the best version. I got the crossover point at about 2000hz. For the life of me I can't get it any higher without creating a wicked dip in db's at the crossover point. Does anyone know a magic cure?
Is it possible my driver selection was poor?
Does this crossover look like it has any glaring faults?

Any feedback on what may help raise the crossover point would be greatly appreciated

 

[AllenB]

It might help if you show the raw drivers overlayed onto the crossed responses.

 

[jReave]

Try displaying the individual drivers' phase instead of the system phase.

Then try to align each driver's phase in the region of the xo at the same time as you work on the FR.

Try inverting the phase of the tweeter to see if that can help.

It's also important to have a realistic acoustic center offset for the midwoofer (mod delay in the driver 'Tune' section).

Also a little trick to fine tune either the FR knee or phase or both is to try a small resistor in the shunt to ground paths of either driver.

And if that tweeter's distortion profile is anything like its sibling the XT25TG30-04, I would be shooting for a xo point around about 2500Hz.

 

[PeteMcK]

"Try inverting the phase of the tweeter"