8 ohm speaker build

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Purple Chrissy

Joined Nov 19, 2019
6
Build a speaker from my old no longer working Corsair computer speaker system. I am using 8 ohm components including 2:tweerters, 2: mid-range speakers and 1: sub-woofer. My question is how do I keep the various components 8 ohm so that the system sees 8 ohms through the output connectors?
 

Delta Prime

Joined Nov 15, 2019
1,311
Hi there:)
Pure simple resistance doesn't concern itself with frequency, because it is measured at no frequency (zero Hertz). A typical 8 ohm woofer might have an impedance that varies from slightly below 8 ohms at 1 Hertz to maybe 60 ohms or more at its resonant frequency (peak) and then back down to somewhere near 8 ohms again. After that a woofer's impedance continues to rise gradually as the frequency extends towards and beyond 20,000 Hertz.

Ifyou use an 8 ohm woofer and an 8 0hm midrange
& 8 ohm tweeter WITHOUT a crossover, your impedance would be 2.6 ohms! But who would use a woofer and a midrange and a tweeter together without a crossover? A crossover is a frequency dividing network. As long as you are using a crossover with an 8 ohm woofer and 8 ohm mid range & an 8 ohm tweeter then your impedance will remain at or near 8 ohms straight across, not 2.66 ohms.
If you use a 4 ohm woofer and an 8 ohm tweeter without a crossover, your impedance would be 2.66 ohms. But with a crossover, your impedance would be 4 ohms in the range of frequencies covered by the woofer and 8 ohms in the range of frequencies covered by the tweeter.
If you use a 4 ohm woofer with an 8 ohm midrange and a 6 ohm tweeter all with a crossover, then your impedance would be 4 ohms in the range of frequencies covered by the woofer and 8 ohms in the range of frequencies covered by the midrange and 6 ohms in the range of frequencies covered by the tweeter
 

Audioguru again

Joined Oct 21, 2019
6,673
A tweeter is destroyed if it is fed bass or mid frequencies. A midrange speaker might be destroyed when fed bass frequencies.
A woofer sounds bad (cone breakup shrieking) if it plays upper midrange or treble frequencies.
Therefore a crossover network is used at the 3-way speaker or filters are used for 3 amplifiers.
 
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