Ok so @Southerndawg is tabbed for physics consultant of the music bored. Next up what is an OHM and how does that relate to speaker impedance.
Ohms measure resistance. The lower the resistance the more current by ohm's law (current is voltage / resistance). If there is more current the speaker is louder. Impedance is a somewhat more refined term for resistance including effects of coils and capacitors and phase angles but in common usage resistance and impedance get conflated.
Close. Without diving into a discussion on system dynamics, and assuming we're discussing speaker impedance, lower impedance means the speaker will draw more current at a given power setting than a higher impedance speaker will. Keeping it simple, by Ohms Law, P = IV = I^2R, P=power, V=voltage, I= current, R=resistance. Lower impedance does not mean the speaker will be louder, but it does mean it will pull more current from the amp at a given power setting, so low impedance speakers generally need high current amps to fully function lest the signal will clip and distort as the amp is stressed.
It is also worth noting that speaker impedance is not fixed. Some designs, especially those that utilize electrostatic transducers can see dramatic dynamic impedance drops to one ohm or less. If you want something like that to sound good, you have to invest in a very good high current amp.
Ok. I was reading around the internets and one thing to be aware of us drawing too much current from your amp. So if you swap out 8 ohm speakers for 4 ohm speakers and you are accustomed to a certain volume setting on your dial, you are pushing your amp harder to supply the current, so there is a risk of some kind of blow out somewhere. But, it seems like the kind of thing you can do by feel -- if your amp is smoking hot to the touch or your speakers are starting to distort back off the volume level.
At reasonable sound levels, there shouldn't be too much of an issue. It's when you start cranking it up. You won't feel it, you'll hear it, and if you push too hard, that may not happen until it's too late and you've damaged a crossover or a tweeter. If you have a good set of 4 ohm speakers, just spring for a suitable amp and enjoy.
Ok so @Southerndawg is tabbed for physics consultant of the music bored. Next up what is an OHM and how does that relate to speaker impedance.
Ohms measure resistance. The lower the resistance the more current by ohm's law (current is voltage / resistance). If there is more current the speaker is louder. Impedance is a somewhat more refined term for resistance including effects of coils and capacitors and phase angles but in common usage resistance and impedance get conflated.
Close. Without diving into a discussion on system dynamics, and assuming we're discussing speaker impedance, lower impedance means the speaker will draw more current at a given power setting than a higher impedance speaker will. Keeping it simple, by Ohms Law, P = IV = I^2R, P=power, V=voltage, I= current, R=resistance. Lower impedance does not mean the speaker will be louder, but it does mean it will pull more current from the amp at a given power setting, so low impedance speakers generally need high current amps to fully function lest the signal will clip and distort as the amp is stressed.
It is also worth noting that speaker impedance is not fixed. Some designs, especially those that utilize electrostatic transducers can see dramatic dynamic impedance drops to one ohm or less. If you want something like that to sound good, you have to invest in a very good high current amp.
Prolly the best system I've ever listened to of late is one a former teammate of mine has: 10 ohm speakers paired with a 15 watt hand wired in Japan integrated tube amp. Who'd a thunk you could crank it up on a 15 watt amp?
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