As you have observed, the highest peaks occur somewhere 30Hz to 50Hz. On the average, the central frequency is somewhat around 40Hz. Also looking at the chart; the effective range of this specific bass drum is somewhere 20Hz to 200Hz as it occupies almost the entire bass frequency spectrum. It seems to be strongest at 40Hz. During audio mixing, you might cut the bass drum frequencies above 100Hz (they are not as important as the central frequency) to make it a hole for the bass guitar or synth to sit in the mix.
If you take another bass drum or kick drum sample from another song or from your friends track, you will notice that it might have different central frequency such as 50Hz or even 70Hz. So it’s good to check using frequency analysis to make sure you are adjusting the correct frequency. Now this is the frequency spectrum analysis of hi hats:
It shows that this specific hi hat recording is strongest at 10000Hz. Like kick drums, the recording approach of hi hats can influence the resulting central frequency. In this case, other hi-hats have central frequency of more than 10000Hz. One way to check is to perform frequency analysis of the recorded hi hat material. To continue, below is the frequency analysis for snare drums:
It seems to be strongest on 200Hz. Again take note that this central frequency depends on how the snare drum is recorded. For other snare drum tracks; you might get an entirely different central frequency such as 500Hz or 2000Hz. Finally this is crash cymbal frequency response:
If you have observed, there are two central frequencies. The first occur at 500Hz while the other 10,000Hz. In actual audio mixing of crash cymbals; the one that is used will be the 10,000Hz while the 500Hz will be cut using EQ. Frequency spectrum analysis helps you decide which frequencies are important to that specific drum instrument and which are the ones that will be cut during mixing. By emphasizing what are important and not important frequencies using EQ techniques, you can have a well sounded drum sound in your mix.
Second Method: Notch Filtering Technique
Sometimes you do not want to use frequency spectrum analysis and decide to use notch filtering technique to find instrument frequencies. This works by sweeping through the entire frequency range using a parametric EQ and using your ear to spot at what frequency the instrument sounds gets severely affected. This is where the central frequency will be found. Feel free to search for more drum recording and mixing information on this blog using the search box.
Content last updated on June 20, 2012