Driver Impedance/Matching

[NTSBuilding]

Question from newbie:

If you use a 4 ohm tweeter and an 8 ohm woofer in a two way how does this effect the impedance and your x over in parallel configuration. Also will the tweeter sound louder than the woofer. Is it better to match impedance of each driver or does it really matter. Will the receiver you use have to be 4 ohms or 8 ohms.

[Iain McNeill]

The driver impedance affects your crossover design.

The sensitivity defines whether it will be louder or quieter. Hopefully, the tweeter is more sensitive than your woofer and you can pad the tweeter to balance, then calculate how the crossover components should be.

Your amplifier will have to drive this varying impedance (8ohms LF, 4ohms HF) without varying it's output voltage. (i.e. low output impedance)

[Cal Weldon]

Hello from across the Pattullo.

As Iain touched on, it's OK to use different impedances so long as you calculate that into your XO design. The right way to start is to find out what the actual impedance is at the chosen XO point and go from there.

[NTSBuilding]

thanks for the replies and hello to a fellow Canadian. cheers.

[Cal Weldon]

Fellow Fraser River settler. We're probably only a 15 minute drive apart.

[AndrewT]

you could simply add a 4r0 series resistor to the treble driver and then design the crossover to match 8ohm loading on both the HF & LF halves.

The series resistor will reduce the signal sent to the HF driver and effectively reduce it's sensitivity by 6dB.
Could be useful if the drivers are also unmatched by sensitivity.

The series resistor will also alter the frequency response of the treble driver. This could be an advantage or work against you.

[MarcMTL]

NTS,

Off topic, but would you care to tell me where you got X-Over Pro 3 from? Student on a budget here trying to get my hands on it!

Thanks,
Marc

[NTSBuilding]

Marc,

I bought it from q-components loudspeakers and audio products, located in Waterloo, Ontario. (www.loudspeakers.ca). Parts-Express in the U.S. has it also, but they ship by UPS, which charge a broker fee.