# Decibel specification for audio equipment

I came to something a little confusing while learning EQ techniques... this might be quite simple to some of you...

20 Hz – 20 kHz (+0, -1 dB)

i read that this means the level 1kHz (1000 Hz) is taken as a reference and the response that other frequencies are determined from in terms of equalization. No frequency has a response greater than that at 1 kHz; likewise the maximum downward deviation is 1 dB – no frequency is more than 1 dB down with respect to 1 kHz.

What part of this specification indicates that the reference level is 1kHz? For example, if I go in-store and start looking at equipment what indicates this reference level?

• I think most manufacturers would not give you specs in such precision because it would make their product less desirable. Plus it could prove quite costly to make these measurements because you need an anechoic chamber. In addition, they don't have to specify it centered on 1kHz. It just makes a lot more sense for those reading it. Sep 4, 2017 at 14:39
• I also wonder if we can hear a 1dB difference in most frequencies. Sep 4, 2017 at 14:41
• @Schizomorph I guess I'll just have to read it in this way. What I can tell you about your side of the question is that, yes, i do believe a 1dB difference is audible since a +6 dB change is effectively DOUBLING of level. +12dB is a quadrupling of the level and so on. I can also tell you that all of these terms fall under the study of Equalization. Sep 5, 2017 at 12:36
• @daniel Check out the sound level comparison chart most of the way down the page here. ( www.sengpielaudio.com/calculator-levelchange.htm ) . While TECHNICALLY 6dB is double loudness, we usually say 10dB is perceived by people as twice as loud (and is 10 times the power). 20dB is perceived by people as four times as loud (100x power). 1dB is too small to tell the difference in level, however, a change in the spectrum curve of 1dB would alter the harmonic content audibly
– user22688
Sep 5, 2017 at 14:51
• Thanks @Thomas that really puts things into perspective. Well said. Sep 5, 2017 at 14:56