Izub, the dial on your meter merely sets the range of the scale for the digital readout. Notice that just beneath the window for the digital readout, you can see 3 little numbers in white, -10 on the left, 0 in the middle, and +10 on the right. When taking measurements, as the volume rises and lowers, you can see a little line of black squares moving across the display in the readout just above those numbers, and below the large digital numbers. This line of squares is indicating where the volume is in the range of the scale to which you have the meter set
If, for example, you set the dial to the 70 scale , then the range dB range the meter will read is between 60 and 80 dB with the 70dB point right in the middle of the range (where the "0" is) .
Right now, with my meter set to the "60" dB scale, my meter reads 54db. When I count the number of little black squares showing in the range beneath that number, I see 5. The first square represents 50dB, and each square represents one more dB. So the 5th square, indeed, indicates 54 dB.
If the volume of whatever you are playing, be it test tones or music, or whatever, falls below the range of the scale to which you have set the meter, the digital readout will read "LO" meaning that the volume is too "LO"w to be read on the 70 dB scale. If you then set the dial to "60," you'll see a readout again. If the volume goes above 80 dB, the digital readout and line of squares FLASHES indicating the volume is too high for the 70 dB scale. Just move the dial up to whichever setting will give you a steady digital readout rather than a flashing readout. (see pages 13 and 14 in the meter's manual)
So, if you are trying to simply see how loud your music is, with the music playing, find the dial setting where the readout neither reading "LO," or is flashing. The numbers will be changing because music is dynamic and it's volume itself will be changing, but with the weighting set to "C" and the response set to "slow" you'll get an approximation of your volume.
By the way, the response on the meter defaults to FAST each time you turn it off. So, if you want the SLOW response, you must set it to SLOW each time you turn the meter on (mumble grumble).
I'm sure someone else could have explained this more succinctly, but I hope it helps. If you are still confused, be sure to say so and ask questions. We'll get you up to speed one way or the other.
