I’ve looked around a bit and couldn’t find the answer. 90-100hz tiny gap 100-200 big gap ... same amount of frequency’s. when REW sweeps from 90-200 it sweeps at a constant speed... why the magnification of those particular freq? 100-200 , 1000-2000 ...
Its an important question. One way of displaying data is by plotting a graph. Often data are displayed on pie charts (sectors of circles) or bar charts. In audio a chart with frequency plotted horizontally and level plotted vertically. If a linear (like a tape measure) horizontal scale were used you would have say 50 to 200 Hz in front of you, but 1000 to 5000 Hz would be at the bottom of your neighbor's, neighbors, neighbors garden. The logarithmic scale changes this by making the length from 10 to 100, 100 to 1000, etc. the same. To do this one needs to distort the scale between. The vertical scale is probably decibels (db) and is already logarithmic. dB = 20 x log(V1/V2). Its a ratio of say voltages, power, sound pressure.
Each doubling of frequency is the same as 1 octave on a piano. So 100 to 200Hz is the same 8 note spacing as 1000 to 2000Hz.
If we plotted musical notes along the bottom instead of Hz it would be linear.
90-100Hz is 10Hz, 100-200Hz is 100Hz, that's an order of magnitude higher, why would they be the same size?
If you look at 0-100Hz versus 100-200Hz the latter is smaller, and as you go higher each 100Hz segment will be smaller because the scale is logarithmic so it compresses the data points more at higher numbers.
Agree with the caveat that you can´t display *zero* Hz on any printable Logarithmic frequency scale.
You can on a linear scale, of course.
Well, yeah.. the logarithm of zero is undefined. What I meant was the first hundred hertz versus the second hundred hertz.
As was mentioned earlier our perception of pitch as a function of frequency is the main reason a log scale makes sense. We perceive a doubling of frequency from say 60 Hz to 120 Hz as an octave of pitch. Similarly we perceive the doubling from 1000 to 2000 Hz as an octave and the doubling from 6000 to 12000 Hz as an octave. So the first octave is 60 Hz "wide" the second is 1000 Hz "wide"and the third is 6000 Hz wide but our ear-brain system hears them as equally wide in pitch.
After lots of answers that covered it pretty well, I'd add that if you did a linear scale graph from 10Hz to 20kHz -- where 10Hz occupied the same width at low frequencies and at high frequencies -- you could discern almost nothing at low bass frequencies and half the graph would cover the range you couldn't hear very much of!
slightly OT but I'm posting this link just because I think it's interesting:
Benford's law - Wikipedia
Benford's law - Wikipedia
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