# Can I use 4 ohms amplifier for 8 ohms speakers?

What is the best solution for 8 ohms speakers

### 12 Answers

- ManiacLv 79 years agoFavourite answer
tom7... has provided the only correct answer thus far. There is really no such thing as a "4 ohms amplifier", your amplifier output impedance is approximately zero ohms. The "4 ohms" is actually a representation of the current capacity of the amplifier, it's just expressed in terms of load (in ohms) to make it easy to understand what speakers you can use with it.

The 4 ohms is a minimum load which is confusing because it's the most difficult load. It's actually the maximum load in terms of conductance which is the inverse of impedance. Conductance is how easily electrons flow through something. High conductance is the same as low impedance. Thinking in terms of easy conductance might again be confusing but remember this is the load, not the supply. A larger diameter water pipe can more easily flow water but it demands more from the spigot to keep up with that flow. A lower impedance speaker allows easier flow of electrons but your amplifier struggles to keep up with that flow.

Putting an 8 ohm speaker on the amplifier capable of supplying current to a 4 ohm load makes the amplifiers job easier. Your amplifier will run cooler and it will thank you if it could for giving it a job only half as difficult as it can do. The limiting factor is that because there is less current through the 8 ohm load there is also less power. Assuming the sensitivity of a 4 ohm speaker and an 8 ohm speaker are equal, the 4 ohm speaker will play slightly louder with the same volume setting. This difference would be a maximum of + 3 dB if your amplifier can supply double power to half impedance to 4 ohms. This is very doubtful, it's more likely closer to 1.4x more power in 4 ohms vs 8 ohms. This will produce an insignificant volume difference between the 4 and 8 ohm speaker.

mk

- 7 years ago
I ran a 100 watt 8 ohm speaker on a Quilter pro200, which has a very confusing speaker diagram/jack setup in the back. As I understand it, it is 100 watts a channel maximum, and there are two speaker jacks, each says 200 watts minimum load, the top one says 4 ohms, the bottom one says 8 ohms, but if you use them together they are 100 watts each, 8 ohms. I accidently plugged my 8ohm 100 watt speaker into the 4 ohm jack and played a gig outside for 2 hours. I kept each channel on volume 5 (halfway). However, now it seems as if something is wrong with the speaker as a few low notes produce static buzz. Could what I did, playing on 4 ohms (I didnt blast it) wreck the speaker?

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- Anonymous5 years ago
It's better to do it that way than the other way around (hooking up 4-ohm speakers to an amp rated at 8 ohms). The speaker impedance is the amount of resistance (kind of) to the audio signal that the speaker places on the output of the amplifier. The higher the impedance the amplifier sees, the lower the current it will drive out of the amplifier. Speakers convert current through the voice coils into electromagnetic energy. The more current the coils get, the more magnetism they have and the further the speaker cones move. So, they move more air and, therefore, have more volume. If the impedance rating for the speakers is higher than the amplifier's rating, the amplifier will put out less current and the speaker volume would be lower than for lower impedance speakers. And, that's not really an operational problem. But, if the impedance of the speakers is lower than the amplifier is rated for, the current will be excessive, and the amplifier or the speakers themselves can burn out.

- Anonymous6 years ago
Yes you can, because connecting two 8 ohm speakers in parallel to an amp creates a 4 ohm load, which is what the amp wants to drive.

- 5 years ago
I have a 800w amp and I use two of the 1/4 inch jack outputs in bridge mode for 8ohm impedance, however one of them goes to a 800w echo speaker 8 ohm and the other output goes to the same, but also a 800 w 8ohm elkhound subwoofer, is there anything wrong with this and what if I added another subwoofer for example?

- 7 years ago
ok so 8 ohms speaker at 4 ohm max (min ) output, yes it sounds quieter but if plenty left on the volume knob can it be matched as in watts or db output or will it still give out more by uaing a 4 ohm speaker?

- 7 years ago
my 60W 4 ohm amp is too stinking load to be used anyway to it's maximum. would the 8 ohm speakers help with volume attenuation then?