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Frequency Charts


Hey folks

Just curious as to the reason they graph out frequency charts as they do. What im refferring to is the fact that they Display 20 - 100hz on the first 1/4 of the chart, then 100hz to 1khz on the 2nd quarter, followed byu the 1k-10k, and lastly the 10-20k, meaning they graph out half of the hearing range in the last 1/4

i guess this is a kind of a dumb question, it just seems that by reading the first half of the graph covers just 1/20th of the range while the other 19/20th's are all crammed together.

i know that it would be pretty difficult to put a graph in a magazine of 20,000 without using some technique to compact it. Is there any logical reason that group it out the way they do other than to save space?
slappy
slappy OP
903 posts
 
Allright!
Thanks guys!
fatparrot
1,314 posts
 
In what cases would you chose Pink noise or White noise for testing?

Rives, help me out. What note is 440 Hz? I thought that was middle "C"? (As you can tell, I don't play a musical instrument!)
richingoth
326 posts
 
Fatparrot, 440Hz is an A4. Note that A5 has a frequency of 880Hz, thus it is one octive higher than an A4 since it has twice the frequency. You can see this on the log graph as you go up an octive the spacing of the frequency gets closer together because 1) twice the frequency, 2) shorter wavelengths, also the same notes octives apart will be equally spaced on the graph. FYI middle C which is C4 has an frequency of 261.63Hz.
pragmatist
336 posts
 
Slappy:

Set up a graph where the differences between each whole number is one inch. The difference between 1 and 2 would be one inch and the difference is one hundred percent(2 doubling one). The difference between 10 and 11 would be ten percent but still one inch. From 100 to 101 would be one percent but still one inch.

Semi-log graph paper puts the horizontal lines closer together the higher the lines are so the distances and percentages are logical both ways.

The kid at the stationary store who did his/her math homework can find the semi-log graph paper for you.
rabelais
20 posts
 
Perhaps surprisingly, there is considerably more variation to note/frequency assignment--continuing even today--than one may have initially imagined. See, for example http://www.uk-piano.org/history/pitch.html
and http://hypertextbook.com/facts/2003/DanielleDaly.shtml.
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