4 ohm spkr on an amp that asks for 8 ohms?

[Guest]

What are the consequences of running 4 ohm speakers an amp that is expecting
8 to 16 ohm speakers?

I.E. car stereo type speakers on a home amp...

 

[tweak]

What are the consequences of running 4 ohm speakers an amp that is expecting
8 to 16 ohm speakers?

I.E. car stereo type speakers on a home amp...

Not a good idea. Low loading your amp will make it run hot and could
fry it out.
There are load biasers that you can purchase that will shift the load
up to the required ohms.
Or if you have enough speakers, four instead of two you can run them
in series to get the 8 ohms you need.

 

[James Sweet]

Not a good idea. Low loading your amp will make it run hot and could
fry it out.
There are load biasers that you can purchase that will shift the load
up to the required ohms.
Or if you have enough speakers, four instead of two you can run them
in series to get the 8 ohms you need.

Really depends on the amp, many amps will drive 4 ohm loads happily, but the
clipping level will be lower on the volume knob. If you're driving the amp
to clipping it'll overheat, and is also likely to blow speakers. Not to
mention it sounds like crap.

 

[Mark D. Zacharias]

The primary concern is not the short-term current demands, not at normal
volumes anyway, but longer-term (one hour or more) overheating of the power
transformer. Eventually a thermal link inside the transformer opens.

Dead unit.


Mark Z.

 

[[email protected]]

You can get 2 4ohm 25 or so watt resistors to put in series, if you want to
keep those speakers. Or get new speakers

Frank

 

[Mark D. Zacharias]

You could probably do with 2 ohms at 5 watts. Unless he's really blasting,
the resistor would never overheat.

Still, it seems a waste to have to add resistance to the load - and of
course there are technical reasons why this isn't so great either -
amplifier damping and frequency response issues, for example.

Mark Z.

 

[gothika]

You can get 2 4ohm 25 or so watt resistors to put in series, if you want to
keep those speakers. Or get new speakers

Or you can wire 2 4ohm in series to get 8ohms.
If you didn't pay to much for the 4ohm speakers just buy 2 more and
run 'em in series.
Or if that doesn't work try trading them up for 8ohm.
Running 4ohm on a amp with a minimum 8ohm rated amp will eventually
cook your amp.

 

[LASERandDVDfan]

Or you can wire 2 4ohm in series to get 8ohms.

This is impedance we're talking about here, not resistance.

Adding more speakers to an amplifier channel will drop the impedance further,
not increase it's rating. Two speakers on one channel will pull more juice
than just one on the same channel, so you will only speed up the overheating
problem. - Reinhart

 

[jakdedert]

This is impedance we're talking about here, not resistance.

Adding more speakers to an amplifier channel will drop the impedance
further, not increase it's rating. Two speakers on one channel will
pull more juice than just one on the same channel, so you will only
speed up the overheating problem. - Reinhart

Functionally, resistance and impedance work the same way in this respect.
Notice he said *in series.* In parallel, what you say would be true, but it
still follows Ohm's Law: impedances in series add, while those in parallel
divide. OTOH, the impedance of a particular driver, or speaker system, is
only an average (or a measurement taken at a specific frequency), so the
problem is more complex than simple addition.

Still the basic principal applies.

jak

 

[LASERandDVDfan]

Functionally, resistance and impedance work the same way in this respect.

Notice he said *in series.*

Ah. It slipped by me. Must have been falling asleep in front of the monitor.

However, a series connection could yield sound quality problems. - Reinhart

 

[jakdedert]

Ah. It slipped by me. Must have been falling asleep in front of the monitor.

However, a series connection could yield sound quality problems. -

Reinhart

Granted...the frequency, phase and impedance curves of two drivers, or
speaker systems, would have to be identical (within reason) for series
connection to yield good results.

Never hurts to try, however. Speakers are so subjective--and dependent on
listening environment--that the OP might like the results. That's not to
say that reproduction will be 'accurate,' however.

jak

 

[gothika]

Reinhart

Granted...the frequency, phase and impedance curves of two drivers, or
speaker systems, would have to be identical (within reason) for series
connection to yield good results.

Never hurts to try, however. Speakers are so subjective--and dependent on
listening environment--that the OP might like the results. That's not to
say that reproduction will be 'accurate,' however.

jak

Not to disagree but series wiring speakers has been a common practice
in the audio/hifi field for over 50 years.
I haven't overheated or burned an amp yet.

 

[jakdedert]

Not to disagree but series wiring speakers has been a common practice
in the audio/hifi field for over 50 years.
I haven't overheated or burned an amp yet.

Nobody's disagreeing AFAICT....



jak