What’s the deal with impedance?
The first thing you need to know about impedance is that, like many things, it can be a complicated subject. The second thing you need to know is that you really don’t need to understand everything about impedance to actually ‘get it’.
But What Does Impedance Actually Mean?
Most headphones or speakers you can buy will have an impedance rating listed on the packaging. The rating is displayed as ohms, using the Ω symbol. Sadly, that’s about as far as manufacturers go when it comes to impedance and you won’t usually find any explanation of what’s good or not so good. Basically, the ohm rating refers to how hard it is to power the speaker. If you consider your speaker to be a pipe and your music (audio signal) is the water flowing through that pipe, the impedance would refer to the width of the pipe and how easy it is to flow through it. The lower the impedance, the easier it is for the electric signal (in this case the music) to pass through the speaker. Most standard speakers today are rated at either 4, 6 or 8 ohms.
Is That It?
Well, sadly, not quite. The impedance rating of your speaker is actually just a baseline. In general, impedance will fluctuate depending on the audio signal’s pitch or frequency so an impedance of 6 ohm can reach a lot higher so the rating on the box is just a general average.
Will Low Impedance Guarantee High Quality?
Low impedance generally indicates some fine tuning but most modern speakers connected to a modern amplifier will result in a pretty good sound. One thing to be aware of is that using mismatched speakers and amplifiers can sometimes lead to problems if the receiver or amplifier is not up to the task. Consistent low impedance across an audio setup is tricky to achieve and is why 4 ohm speakers are more widely available in high-end audio but not so much in mass-market audio.
What About Compatibility?
If your speakers are rated at 6 or 8 ohms (as most are), then don't stress about matching impedance with your receiver or amp. If you opt for 4 ohms, you should make sure you match the impedance of your speakers to the impedance of the amplifier it’s designed to drive. If you skip this step, you could well end up drawing more power into the unit than it can handle and damaging your amp. Speak to us at HifiHut if you are unsure.
The Impedance Switch
Some amplifiers and receivers have an impedance switch on the back that can switch between ohm settings. The problem with using this is that impedance is not a static setting, it varies depending on a couple of factors. Using an impedance switch to equal that of your speakers disables the full potential of your amplifier or receiver. If your amp or receiver has this switch, leaving the impedance on its highest setting and buying speakers that match your equipment's impedance settings will give you the best performance.