How important is to match impedance of all speakers in HT setup?

[swamytk]

So I would like to know importance of impedance matching of all speakers? If not do AVR provide option to select impedance of individual speakers?

 

[superczar]

Most AVRs won't give you option of impedance for individual speakers

In order of preference:

1 - All speakers from the same family - all will typically have the same impedance curve
2 - LCR speakers from safe family, preferable at higher nominal impedance , you can get away with surrounds/wides/atmos from different family and with lower nominal impedance as your driven channels don;t have to spend too much grunt driving these

Unless you are using a separate amp , it is better to keep at least the L-C-R at nominal 8 ohms because the amps in almost all AVRs aren't particularly beefy. 80-90% of the power draw happens with these channels
Couple of other things to keep in mind if using lower impedance speakers on any channel and esp if on all channels

Use a powered sub and set a high enough cross-over - 80 hz or 100+ if you want to play it safe
If using low imp. speakers on non L-C-R, at the very least set crossover very high for them, even 120 or 140
Most amps do not have problem driving low imp loads for higher frequencies but you can expect channels set at a low cross over point to get overloaded with low imp speakers during passages with lot of bass

 

[swamytk]

Most AVRs won't give you option of impedance for individual speakers

In order of preference:

1 - All speakers from the same family - all will typically have the same impedance curve
2 - LCR speakers from safe family, preferable at higher nominal impedance , you can get away with surrounds/wides/atmos from different family and with lower nominal impedance as your driven channels don;t have to spend too much grunt driving these

Unless you are using a separate amp , it is better to keep at least the L-C-R at nominal 8 ohms because the amps in almost all AVRs aren't particularly beefy. 80-90% of the power draw happens with these channels
Couple of other things to keep in mind if using lower impedance speakers on any channel and esp if on all channels

Use a powered sub and set a high enough cross-over - 80 hz or 100+ if you want to play it safe
If using low imp. speakers on non L-C-R, at the very least set crossover very high for them, even 120 or 140
Most amps do not have problem driving low imp loads for higher frequencies but you can expect channels set at a low cross over point to get overloaded with low imp speakers during passages with lot of bass

Awesome reply! Especially Cross-over tips are highly educative and valuable for me. You guys makes this forum wonderful place for newbies like me. Thanks a ton!

 

[arj]

Not sure on what you mean by Impedance matching, could you elaborate ?
Since the impedance of speaker is determined by the frequency of the signal , at every instant the impedance is going to be different. hence what is important to know is what is the impedance variation and the minimum and nominal impedance. These are specs which can be matched. IN fact most speakers have a nominal impedance of 4-8 ohms and a min also of around 4. some do go down to 3 but unlike in the past 1 ohm impedance may not exist.

Most amps drive 4 ohms well and some of them can go down to 2 and 1 so this should not be much of an issue

 

[alphacentury100]

You dont need all your speakers to have similar impedance value, but you just need to have an amplifier capable of handling the lease impedance the speaker will produce.
Most AV receivers don't provide you the option to select the Impedance because, Impedance is not constant to any speaker through out the frequency range. For most of the speakers, the Impedance will vary from 10 Ohms to 2 Ohms for various frequencies.
So the Speaker manufacturer will only provide you a rough or average impedance value of their speaker.
So it is better to have an AV Receiver or Amplifier with the capacity to support the least impedance available.
Moreover, High sensitive speakers will also tend to put very load on the amplifiers.
So choose accordingly.

 

[MaSh]

So I would like to know importance of impedance matching of all speakers? If not do AVR provide option to select impedance of individual speakers?

Check the impedance range accepted by your receiver. Modern receivers usually accept 6-16ohms. So if your speaker is within this range, you have nothing to worry. The receiver will manage it.

Some receivers do have a setting to switch from 8 to 6 and vice versa.

MaSh