4 Ohm vs. 8 Ohm

[Leo Paul]

I am sure someone here can answer this question, and please pardon me if it’s a “dumb” one – A powered mixer is rated to be used with either 4 or 8 ohm speakers – All else being equal (speaker size/mixer output volume setting/etc.), would 4 ohm speakers be louder than 8 ohm speakers, the opposite, or no difference? (Please try to keep your answer as short and simple as possible, as I’m not very good at understanding complicated technical explanations). Thanks!

 

[2L man]

About 3db louder.

 

[bebopbrain]

Just slightly louder (like @2L man said).

 

[Swirling Snow]

Theory says the lower the ohms, the more current will flow. Twice as much, exactly, which leads to the "3dB" answer.

Practice says on something as budget as a powered mixer, the power supply big enough to actually produce twice the power at 4 ohms is probably not there.

Generally speaking, running at 4 ohms will be a bit louder and have looser bass. Lots of discos run at 2 ohms. I wouldn't do the on the road, though.

 

[memorex]

The 3db thing is theoretical, because you could pick up 3 db of loudness just by using a more efficient speaker. But given two identical 8 ohm cabs, it should sound slightly louder with 2 plugged in instead of one.

 

[King Fan]

Good info here. And even if you get the full 3dB difference, 3dB is felt to be the minimum change in loudness typical ears can detect. It ain't dramatic.

 

[W.L.Weller]

All else being equal (speaker size/mixer output volume setting/etc.)

The most important "being equal" is speaker sensitivity, which is typically shown in the specifications for a speaker or PA cabinet.

Carvin Audio Thiele/Small Parameters and Speaker Specifications

This page contains the Thiel/Small Parameters and speaker specifications for Carvin Audio replacement speakers and high frequency transducers. Find the values you are looking for here.

carvinaudio.com

The right-most column of this spreadsheet "SPL 1w/1m dB" is the numerical representation of speaker sensitivity.

Louder speakers have higher SPL ratings.

 

[Lowerleftcoast]

All else being equal, 4 ohm speakers will be louder than 8 ohm speakers.

 

[YanKleberDeMoura]

Yes, taking the same amp, the least the impedance the louder the speakers will talk. And vice-versa.