Impedance of speakers

[[email protected]]

I have read in a few posts that if you have a multi speaker setup,
surround I guess, it is very important that all speakers be of the
same impedance, or you could damage the equipment. How true or
important is that?

Thank you in advance ...

[[email protected]]

On Jun 2, 9:44 pm, "Soundhaspriority" > wrote:
>
> There is no need for the main speakers and the surround speakers to have the
> same impedance. There is one common caution: if two pairs of mains are
> attached to a typical HT amplifier that contains an integral A/B speaker
> switch, the minimum allowable impedance is typicall 8 ohms.
>
I am using a receiver with 2 sets of outputs: A and B. There are
separate switches to turn on or off the A and B outputs. I have a
pair of speakers which is 4 ohms, main I would say, hooked up to the A
output. Can I hookup a pair of speakers say with 6 or 8 ohms to the B
output?

[[email protected]]

On Jun 2, 10:00 pm, "Soundhaspriority" > wrote:
>
> You take a risk if you do. Not advisable, unless you conscientously remember
> not to activate both sets at the same time.
>
So, in my case, I need to have all speakers to have the same impedance
4, 6 or 8 ohms, if I want to have them on at the same time? Am I
about right?

[[email protected]]

On Jun 2, 10:36 pm, "Soundhaspriority" > wrote:
>
> No (sorry.) If there are two pairs, and you want to use them
> simultaneously, and this is a mass-market HT receiver, then the impedances
> must be 8 ohms.
>
> In case you want to know why, this is how it goes. Two speakers in parallel
> have half the impedance of one. Two 8 ohm speakers = 4 ohms. Two 6 ohm
> speakers = 3 ohms. Two 4 ohm speakers = 2 ohms.
>
> The lower the impedance presented to the amplifier, the more the output
> transistors will heat. If the impedance is too low, it will either kill it
> slowly by excessive heat, or fast, by "thermal runaway." This last is the
> solid state equivalent of nuclear explosion ;)
>
That's a very nice explanation. Makes a lot of sense. I assume
anything that's not custom made, but made and sold in bulk is a mass-
market HT receiver. I am wondering if I am already on the wrong
track. I think the receiver is rated 8 ohms and the pair of speakers
that I am using are rated 4 ohms. It's been like that for several
months without any deterioration in sound quality that I can tell. In
fact, I recently replaced the 16 gauge wires with 14 gauges, and think
they sounded better than ever.

[[email protected]]

On Jun 2, 10:36 pm, "Soundhaspriority" > wrote:
>
> No (sorry.) If there are two pairs, and you want to use them
> simultaneously, and this is a mass-market HT receiver, then the impedances
> must be 8 ohms.
>
> In case you want to know why, this is how it goes. Two speakers in parallel
> have half the impedance of one. Two 8 ohm speakers = 4 ohms. Two 6 ohm
> speakers = 3 ohms. Two 4 ohm speakers = 2 ohms.
>
> The lower the impedance presented to the amplifier, the more the output
> transistors will heat. If the impedance is too low, it will either kill it
> slowly by excessive heat, or fast, by "thermal runaway." This last is the
> solid state equivalent of nuclear explosion ;)
>
That's a very nice explanation. Makes a lot of sense. I assume
anything that's not custom made, but made and sold in bulk is a mass-
market HT receiver. I am wondering if I am already on the wrong
track. I think the receiver is rated 8 ohms and the pair of speakers
that I am using are rated 4 ohms. It's been like that for several
months without any deterioration in sound quality that I can tell. In
fact, I recently replaced the 16 gauge wires with 18 gauges, and think
they sounded better than ever.

[[email protected]]

On Jun 2, 11:49 pm, "Soundhaspriority" > wrote:
> > wrote in message
>
> It depends upon how loud you habitually listen. If you're into rock, the
> magic smoke may come out eventually ;)
>
I usually listen at low to moderate volumes, and am not really much
into rock, hard rock anyway. If I have to grade the type of music
that I like by the music channel descriptions on my TV, I'd say Adult
Alternative. What you explained was very valuable information. That
was very kind of you.

[Arny Krueger]

> wrote in message


> I have read in a few posts that if you have a multi
> speaker setup, surround I guess, it is very important
> that all speakers be of the same impedance, or you could
> damage the equipment. How true or important is that?

The above statement has just about everything wrong with it. But there is a
germ of truth.

First off, it is unclear as to what it is talking about. Is it talking about
a multi-speaker setup as in a surround system, or is it talking about a
multi-speaker setup as in something like a distributed sound system in a
residence or office?

Secondly, in either case, surround or home/office distributed, it is
relatively unimportant as to whether the speakers all have the same
impedance.

Thirdly, if this is a distributed sound system, the usual means by which
people design the system improperly, is to hook too many speakers in
parallel. Hooking too many speakers in parallel will create a speaker system
whose impedance is impractically low, no matter whether the speakers have
the same impedance or not.

Fourthly, while it is possible that with improperly designed amplifiers, it
is possible that attaching a speaker system, whether an individual speaker
or a number of speakers in parallel, whose impedance is so low that the
amplifier will overheat and/or otherwise burn out. However, a
properly-designed amplifier is supposed to detect the incorrect load and
protect itself.

The germ of truth is that speakers, and combinations of speakers can have
impedance that is so low that they make up an impractical load for some
amplifiers. One common way to create a speaker load that is impractically
low, is to hook up a distributed sound system in an office or home with all
of the speakers hooked in parallel.

If you want to set up a distributed sound system in an office or home, you
either need to learn about the special methods that are used to do that, or
hire someone who knows how to do it right.

[Arny Krueger]

> wrote in message

> On Jun 2, 9:44 pm, "Soundhaspriority"
> > wrote:
>>
>> There is no need for the main speakers and the surround
>> speakers to have the same impedance. There is one
>> common caution: if two pairs of mains are attached to a
>> typical HT amplifier that contains an integral A/B
>> speaker switch, the minimum allowable impedance is
>> typicall 8 ohms.

> I am using a receiver with 2 sets of outputs: A and B.
> There are separate switches to turn on or off the A and B
> outputs. I have a pair of speakers which is 4 ohms, main
> I would say, hooked up to the A output. Can I hookup a
> pair of speakers say with 6 or 8 ohms to the B output?

Probably. Most amplifiers and receivers that have terminals for multiple
speakers use special switches to avoid damging themselves by hooking the
speakers up in parallel. The usual trick is to hook the speakers up in
series, which has a number of adverse effects on sound quality.

[Arny Krueger]

> wrote in message

> On Jun 2, 10:00 pm, "Soundhaspriority"
> > wrote:
>>
>> You take a risk if you do. Not advisable, unless you
>> conscientiously remember not to activate both sets at the
>> same time.
>>
> So, in my case, I need to have all speakers to have the
> same impedance 4, 6 or 8 ohms, if I want to have them on
> at the same time? Am I about right?

No. If you want to avoid the most risk, all of your speakers should be 8 or
16 ohms, and 16 ohms would be preferable.

The best of all worlds is to simply have a separate receiver for each pair
of speakers. Then the people in the vicinity of each pair of speakers can
choose their own music, and the sound coming out of the speakers will be
optimal, and the possibility of damaging the speaker will be minimized.
Receivers and music players have become so inexpensive that this is a very
practical alternative.

[Arny Krueger]

> wrote in message

> On Jun 2, 10:36 pm, "Soundhaspriority"

Makes a lot of sense. I
> assume anything that's not custom made, but made and sold
> in bulk is a mass- market HT receiver.

Petty much so.

> I am wondering if
> I am already on the wrong track. I think the receiver is
> rated 8 ohms and the pair of speakers that I am using are
> rated 4 ohms. It's been like that for several months
> without any deterioration in sound quality that I can
> tell.

As long as you don't play the speakers too loud, most receivers that are
rated at 8 ohms, can drive 4 ohm speakers indefinately without damage. The
most common situation is that someone decides to demonstrate how nice and
loud their system can play, or tries to run a dance party with this marginal
system, and destroys the receiver. If the receiver is destroyed by abuse,
and it does not do a good job of protecting the speakers, you may damage the
speakers as well.


>In fact, I recently replaced the 16 gauge wires
> with 14 gauges, and think they sounded better than ever.

This can happen if the speaker cables are rather long, such as a receiver in
the family room, and the speakers on the patio.

The best solution for having good sound with a second pair of speakers at a
remote location, is to simply get a second receiver.