Quote:
Originally Posted by rushca01
Can someone explain DB rating and ohm rating in Lehman's terms?
So I just bought some Focal 1038be and they are rated at 93db which is “efficient” and 8ohm nominal impedance.
|
In Layman's term, the higher the dB rating, the less power it takes to make the speaker reproduce sound from the amplifier at a certain sound pressure level, expressed as "SPL".
So a 93dB rating means that the speaker will produce 93dB SPL for each 1 watt from the amplifier when measured 1 meter away from the speaker.
(If the rating is expressed as 93dB/1W/1M and not 93dB/2.83V/1M axial as that is a bit misleading.)
The difference in sensitivity quickly becomes relevant with higher levels of playback and/or big rooms and distance from the speaker.
So to listen twice as loud, we need four times the power from the amplifier. Twice as loud is only 6dB more in SPL terms... So it eats up amplifier power very quickly.
The nominal ohms in the speaker's expressed DC resistance and AC reactance. Basically, you want lower impedance for solid state amps (but not too low for most, so around 4 ohms is good) and you want the 6 ohms or higher, more like 8 ohms for tube amplifiers since they like that better.
Typically the nominal impedance means the speaker impedance shall not drop below the 80% of that number. So an 8 ohm speaker will be 6.4 ohms over the frequency range of the speaker (-10dB points at most).
This is as simple as I can explain it. There is much more to it if you want to know and I can provide some links.