I can obviously run one 8 ohm speaker with an amp that emits 8 ohms.
Can I run 2 8 ohm speakers with an 8 ohm amp?

Solid-state amps don't "emit" impedence (ohms), they are engineered to
accommodate an 8 Ohm impedence. Generally you can get away with a 4 Ohm
load, but 2 Ohms might be pushing it. Heat dispersion is a primary factor.
If the amp has good heatsinks, 2 Ohms is generally safe if you put a fan on
it.

Tube amps are much more intolerant of impedences above or below the design
tolerances, and can easily fry an output transformer (very costly) if driven
hard at the wrong impedence.

With a 16 ohm amp, what happens if i run one 8 ohm speaker. Amp blows
up?
What happens if i run 2 8 ohm speakers with 16 ohms?

A solid-state amp would be fine, as above. If you use two 8 Ohm speakers in
series, it will add to 16 Ohms and you're definitely ok.

With two 300 watt speakers, is it OK if i use an 850 watt power amp,
without turning it up (especially the bass) full blown?

You can send 5W out of a 10000W amp if properly attenuated, so yes. However
keep in mind that wattage ratings are exagerrated on speakers moreso than on
amps, so that 850W amp probably really only puts out maybe 500W, but the
speakers can probably really only handle maybe 120W each. They also often
lie about the speaker's impedence, "8 Ohms" can mean anything from 5.5-8
from the measurements I've seen. Numbers aside, you should really know the
sound of a speaker at it's limit before hooking up any speakers to any amp
beyond the speaker's rated power handling.

In article writes:

An amp channel generally can put more power into a lower impedance, so you get
roughly twice the power with a four-ohm load as you would with an eight-ohm
load.

The amplifier can put out as much power as it can put out. The speaker
will draw the amount of power it draws based on the voltage and
current that the amplifier supplies to the terminals. The current is
limited by the impedance of the speaker in series with the source
impedance of the amplifier. The voltage is limited by the power
supply, but will be a function of the current and impedance.

What you may have observed from reading spec sheets is that the power
delivered to a 4 ohm load is roughly twice that delivered to an 8 ohm
load, but that's because of how Ohm's law works. The amplifier puts
out a given open circuit voltage for a given input. How that voltage
divides between the amplifier's source impedance and the speaker load
determines how much power the amplifier delivers to the speaker. Since
typically the source impedance of the amplifier is very low, the load
impedance determines the power, as long as the power supply doesn't
poop out. If you have only a 100 watt power supply, you won't get 200
watts into a 4 ohm speaker.

Now, the more power an amp puts out, the hotter it will get. So you can see
that there is a minimum load (therefore maximum power) at which any given amp
will get as hot as it's designed for. This is the situation you want to avoid.

Yup.

All the above is referring to ONE channel. I suspect your amp is 850 total,
with two channels. If each speaker is on its own channel, and the amp is
actually 425 watts/channel at 2 ohms, and if that means 150 watts/channel at 8
ohms, you are still OK.

Sometimes yes, sometimes no. Sleazy spec writers derate the power (of
one channel) with both channels operating and don't tell you that.
This is a consequence of the power supply not being able to supply
full power to both channels simultaneously. Honest ones will specify
power with both channels operating.



--
I'm really Mike Rivers - )

Chumley the Walrus wrote: I can obviously run one 8 ohm speaker with an
amp that emits 8 ohms. Can I run 2 8 ohm speakers with an 8 ohm amp?

Amps do not "emit" impedance. I suggest you either (1) follow mfr.'s recommendations or (2) learn something yourself about the subject. Using terminology reflects complete lack of understanding. This cannot be fixed by ad hoc guidance.

James Boyk

I meant of course to say "using terminology *incorrectly* reflects lack of understanding...." -jb

James Boyk wrote:

Chumley the Walrus wrote: I can obviously run one 8 ohm speaker with an
amp that emits 8 ohms. Can I run 2 8 ohm speakers with an 8 ohm amp?

Amps do not "emit" impedance. I suggest you either (1) follow mfr.'s
recommendations or (2) learn something yourself about the subject. Using
terminology reflects complete lack of understanding. This cannot be
fixed by ad hoc guidance.
James Boyk

Chumley the Walrus wrote:
I'm trying to get the correct matchups right so that i do not blow
speakers or power amps:

All this is discussed in the FAQ.

I can obviously run one 8 ohm speaker with an amp that emits 8 ohms.
Can I run 2 8 ohm speakers with an 8 ohm amp?

If you put them in series (for higher distortion), you get a 16 ohm load.
If you put them in parallel you get a 4 ohm load. If the amp is rated
to drive an 8 ohm load, it won't drive a 4 ohm load.

wITH A 16 ohm amp, what happens if i run one 8 ohm speaker. Amp blows
up?

Yes. If it's a solid-state amp without an output transformer.

What happens if i run 2 8 ohm speakers with 16 ohms?

You have to put them in series. This doesn't sound very good, but it
prevents the amp from being overloaded.

With two 300 watt speakers, is it OK if i use an 850 watt power amp,
without turning it up (especially the bass) full blown?

Maybe. Speaker power ratings are generally pulled out of some marketing
department guy's rear end.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Raymond" wrote in message
...
From: (Chumley the Walrus)

I can obviously run one 8 ohm speaker with an amp that emits 8
ohms.

yes this is correct.

Can I run 2 8 ohm speakers with an 8 ohm amp?

if its a two chan. amp you would still have 8 ohms with one speaker
on each
side.

With a 16 ohm amp, what happens if i run one 8 ohm speaker. Amp
blows up?

i wouldn't do this

What happens if i run 2 8 ohm speakers with 16 ohms?

see above

With two 300 watt speakers, is it OK if i use an 850 watt power
amp,
without turning it up (especially the bass) full blown?

that will vary with ratings, is max output or rms?

I used to connect 3 8ohm 18" sub's to one side of a QSC 1500 amp so
it would
run at 2 ohms. This is the max output (in watts, 750) that you can
get from
this amp. On the other side we ran 3 8ohm stage monitors, one for
each band
member. This made both sides of the amp run independently at 2 ohms
on two
diffrent buss sends from the mixer.
So I had three speakers and I wanted to run the amp at 2ohms, all I
had to do
was start at the speakers ohms rating and go back 8 - 4 - 2. Thus
the lower in
ohms you go the higher the power output from the amp and I made sure
to have a
bit more speaker watts than power amp watts.
Some guys would run things diffent but the three 18"s could take
1000 watts
this was a good matching (I could have pushed a bit more) for the
750 watt amp.

It doesn't go 8 - 4 - 2 ohms. It goes 8 - 4 - 2.67 ohms.

Norm Strong