SP1. Drum Processing.

Drum Processing.

Below is a preview of my recorded drum track.

Following on from the recording of the drum tracks, performed by Andy in the studio, I have now completed the majority of the processing which adheres to some of the criteria set out in the ‘1st Project  Pre-production Outline’ post.

The project must include the use of a number of plug-ins which are essential to fulfill the assessment requirements and also improve the quality of the recording as a whole. Below is a report of how these plug-ins are used in the project, and on the drums specifically, as well as the settings of these plugins used in order to create the highest quality drum track possible with this recording.

No.1 – High Pass Filter (HPF).

For this instance I have chosen to demonstrate the use of HPF on the kick drum track and also the snare drum, because each has its own individual high pass frequency. The reason for using high pass filtering is that during the recording process, the microphones pick up a lot of very low, sub-frequency rumble from the studio, which can distort or ‘muddy-up’ any recordings. This must be edited out or ‘High Passed’ to ensure that this doesn’t interfere with the mix. Below are two screen shots; one for the kick HPF and the other of the snare HPF taken from the analyser window in the 7-band EQ plugin from the Pro Tools TDM plug-in library. As well as this I have posted a screen shot of the HPF modulation dials showing the settings relating to the kick drum HPF.

The kick drum high pass has been given a sharp cut  of 24dB per oct to make sure that there are absolutely no stray frequencies running even quietly in the bottom the mix, however, I wanted to keep as much of the bottom end in the kick as possible so I have cut the bottom end off to around 57 Hz. The snare high pass has been given the same sharp reduction in dB but the cut off starts around the 120 Hz marker, which stills leaves the snare with plenty of power without too many low frequencies muddying the signal.

No.2 – Time Adjustment (Sample Delay).

When recording the whole drum kit from a slightly further distance, i.e. overhead or ambient micing, there is often a delay for the signal to reach the mixing desk when compared to close or near field micing like what would be used to record the kick or snare. This is known as ‘Time of arrival difference’. This can be counteracted by giving all of the other audio tracks a short delay so that the signal is heard at exactly the same time as the track that has the slowest time of arrival, thus effectively catching that track up with the rest of the audio. This is done by using the Time Adjuster (Sample Delay) plugin in Pro Tools. The time adjuster delays the signal by an imputed value in samples and given that the audio rate is 44100 samples per second, this can be an incredibly short period of time, almost to the point of being inaudible. Below is a screenshot of the implementation of the time adjuster plugin on the kick drum track.

First the tracks need to be zoomed in on to the highest possible factor so as to  determine the exact difference in samples between the kick drum and the left  overhead track, which happens to be the track with the slowest time of  arrival. I have highlighted the distance between kick and overhead start points using the selector tool in Pro Tools. Next I have taken the number of samples between the two points and then imputed the number into the time adjuster. This will now give the kick drum track a short delay of around 160 samples so that the overall drum sound of these two tracks is brought together to give them a much tighter sound and also eradicate any slight chance of phasing in the mix.

No.3 – Compression.

Compression is really all about controlling the dynamics, or peaks and troughs, that occur during the recording process. It basically allows you to control or bring down the loudest peaks and increase the softer troughs in the waveform. This can then mean that you can push the overall volume of a track to make it as loud and as punchy as you like. Compression is usually applied to everything you record in some form or another but I have chosen to demonstrate the use of compression in this project on the Left Overhead audio track. Below is a screen shot of the Compressor / Limiter plugin in Pro Tools.

I have chosen to follow a set of guidelines, outlined below, for the adjustment of the compression parameters to suit the production of a live drum kit. This of course can be seasoned to taste however I have found that the effect of these guidelines is satisfactory enough for processing my recorded drum tracks.

  • ATTACK – The time taken for the compressor to reach maximum level = 5 milliseconds.
  • RELEASE – Controls the length of time taken for the compressor to release the signal once it has ducked below threshold = 10 milliseconds.
  • THRESHOLD – Sets the decibel threshold to the level at which the compressor begins to affect the signal = -15dB.
  • RATIO – Amount of compression, measured in dB, which is applied to a signal once it rises above the threshold = 5:1 to 8:1.
  • KNEE – The Knee on a compressor smooths out the ratio in regard as to how much signal is let passed the threshold. A hard knee applies the ratio directly when the signal passes the threshold, a soft knee applies the ratio exponentially as the signal gets closer to the threshold = Hard.

~ by J.E.R.U. on October 28, 2010.

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