Comment by spapas82
4 years ago
There's a simple trick that can be used to convert between db and absolute values. Most engineers use this and may feel like magic to people unaware of it. First of all, remember the two calculations:
* 3 db = x 2
* 10 db = x 10
These are enough (the article mentions more but they are not needed since you should be able to create all db values from these).
Now, when you've got a db value, try to write it as the sum or difference of these values. For example,
* 1 db = 10 db - 3 * 3 db
* 7 db = 10 db - 3 db
* 12 db = 3 db * 4
* 17 db = 2 * 10 db - 3 db
Now, you can convert these to absolute values using multiplication and division
* 1 db = 10 db - 3 db - 3 db - 3db = 10 / 2 / 2 / 2 = 1.25
* 7 db = 10 db - 3 db = 10 / 2 = 5
* 12 db = 3 db + 3 db + 3 db + 3 db = 2 * 2 * 2 * 2 = 16
* 17 db = 10 db + 10 db - 3 db = 10 * 10 / 2 = 50
* 36 db = 10 db + 10 db + 10 db + 3 db + 3 db = 10 * 10 * 10 * 2 * 2 = 4 000
The same algorithm of course can be used to convert from absolute numbers to decibels:
2000 = 2 * 10 * 10 * 10 = 3 + 10 + 10 + 10 = 33 db
Notice these all are approximations however these are really good approximations and more than enough to very quickly understand what a gain of 50 db means!
It also helps to remember 1 db = x 1.25, although you can derive that from the ones above.