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kasper
Tea Maker

Joined: Mar 15, 2006
Posts: 35
Location: Liverpool, UK |
Logarithms...
Hello everyone!
I have just started my audio engineering diploma course at SAE. Its all really cool, but I have a few problems getting my head around logarithms.
Does anyone out there know of a good place online where I might find find some help?
Thanks!
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Fri Sep 29, 2006 3:43 pm |
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kasper
Tea Maker

Joined: Mar 15, 2006
Posts: 35
Location: Liverpool, UK |
That would be great!
Yes, thank you.
Its the formulas I am having a little trouble with. Some guidance would be much appreciated.
Cheers
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Mon Oct 02, 2006 2:16 pm |
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AC
Chief

Joined: Oct 31, 2002
Posts: 1060
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Decibel formula
For voltage you would use:
dB = 20 log (v2/v1)
This means twenty times the logarithm of the v2/v1 sum.
For example if we took a mixing console fader and found one point to read
0.125 and then moved the fader higher and measured it to read 0.25 the sum would be as follows:
0.25/0.125 = 2
log 2 = 0.30102999566398119521373889472449
20 x 0.30102999566398119521373889472449 = 6
+6dB
So the increase from 0.125 to 0.25 = +6dB
I used these figures because a doubling always is +6, as is a halving -6.
So if you place a microphone twice as far away from a sound source you would have a -6 drop off in output.
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for watts we use:
dB = 10 log (P2/P2)
Having P2 as the hightest value gives a + output.
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Often we use a reference level, for example 0dBu = 0.775.
Does that help? _________________ Recording Studio Suntans
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Mon Oct 02, 2006 7:32 pm |
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kasper
Tea Maker

Joined: Mar 15, 2006
Posts: 35
Location: Liverpool, UK |
Thank you
Yes thank you, that will prove very useful.
Cheers
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Wed Oct 04, 2006 12:17 pm |
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avfanatica
Wannabe

Joined: Oct 21, 2006
Posts: 8
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sorry guys! lol, i'm a noob at this stuff, its my dream and all to become a recording engineer. i already know the schol i'm gonna go to after i graduate. but what the heck is a logarithm? _________________ i happen to think avril lavigne is a rather talented individual. so be nice today! dont judge someone you dont know. true artists should be able to express themselves in any way possible! lol <3
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Sun Oct 22, 2006 4:51 am |
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AC
Chief

Joined: Oct 31, 2002
Posts: 1060
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log
Here is the definition of logs:
LOGARITHMS _________________ Recording Studio Suntans
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Sun Oct 22, 2006 1:03 pm |
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