The impedance of the speaker is matched to the output impedance of the amplifier. Every circuit has a resistance of sorts also. Impedance matching works like this -
Ohms law says that Voltage = Current(Resistance)
One definition of a Watt is = Voltage(Current)
Therefore Voltage = Watts/Current and Current = Watts/Voltage
You can derive from that - (Current^2)(Resistance) = Watts
Say you have a resistance (impedance) of ten ohms, but your load is 5 ohms. Now your power amplifier is dissipating 2/3 of the power that might be dissipated by your load as sound..
So basically, your six ohm speaker will work. If you start cranking up the volume, however, you may find that your heat sinks inside aren't compatible with the extra heat load, and your transistors will lose their magic smoke.
I suggest you look for a pair of speakers to salvage from a Hifi someone doesn't want. Why a pair? Because it sounds like you have a stereo amplifier (two different ones, one for each speaker) and your tone will be off-balance if the speakers aren't matched.
Ohms law says that Voltage = Current(Resistance)
One definition of a Watt is = Voltage(Current)
Therefore Voltage = Watts/Current and Current = Watts/Voltage
You can derive from that - (Current^2)(Resistance) = Watts
Say you have a resistance (impedance) of ten ohms, but your load is 5 ohms. Now your power amplifier is dissipating 2/3 of the power that might be dissipated by your load as sound..
So basically, your six ohm speaker will work. If you start cranking up the volume, however, you may find that your heat sinks inside aren't compatible with the extra heat load, and your transistors will lose their magic smoke.
I suggest you look for a pair of speakers to salvage from a Hifi someone doesn't want. Why a pair? Because it sounds like you have a stereo amplifier (two different ones, one for each speaker) and your tone will be off-balance if the speakers aren't matched.