Combining 4 Ohm & 8 Ohm speakers

[made2hack]

Hi all,

I have this old pair of small shelf speakers that I want to freshen up. They have a 4 Ohm / 25 Watt mid range speaker. I am adding to it an 8 Ohm / 40 Watt tweeter. What would be the ideal way to connect the two since they are of different impedance?

I am using an off the shelf 3.3Khz / 12dB / octave RCL filter passive crossover.

Should I connect in parallel? Series? Any pros / cons? Or should I perhaps add a 4 Ohm resistor in series to the Mid range and then parallel the two speakers?

Thanks,

[grifftech]

just parallel them, the mid range speaker will take 2 times as much power as the tweeter.

[soldar]

You might want to install a passive crossover filter
 https://en.wikipedia.org/wiki/Audio_crossover#Passive

[soldar]

Oops. Sorry. My bad.

[Audioguru]

What impedance speakers is the crossover network made for? If it is for 4 ohm speakers then simply add an 8 ohm resistor parallel with the 8 ohm tweeter.
No woofer speaker?

[Zero999]

Speakers don't have a flat, resistive 8 or 4 Ohm impedance at all frequencies. Does anyone know whether passive crossover networks are designed to take this into account? If so, then changing the speaker, will affect the frequency response.

I think you should try to stick to the same kind of speaker, both physically and mechanically to stand the highest chance of it giving good sound quality.

[Audioguru]

Speakers don't have a flat, resistive 8 or 4 Ohm impedance at all frequencies. Does anyone know whether passive crossover networks are designed to take this into account?

Yes an impedance correction Zobel Network is used to flatten the inductive impedance of a woofer and flattens the resonant peak impedance of a tweeter.

[made2hack]

The crossover is for an 8Ohm load.

Thanks,