Sound Radix Drum Leveler Plug-in

By Barry Rudolph

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-- Various Tracks Processed Through Sound Radix Drum Leveler 
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Drum Leveler (version 1.1 tested here) is a beat detection-based downward and upward compressor/expander. It works its wonders in mono, dual mono, L/R stereo and M/S stereo tracks. By using a threshold "window" constrained by separate high and low-threshold settings, Drum Leveler applies dynamic processing to individual transient events with minimal change to audio signals outside of the threshold window. For example, when placed on a live snare drum track, it can be set so that inter-drum kit bleed, ghost notes and room tone leakage are not affected.

Or, by changing a few controls, only the ghost notes and leakage are emphasized!

The Low Threshold fader acts like a typical dynamic processor threshold setting: all signals above threshold are processed according to the other parameters.

The High Threshold control setting allows any signals above it to pass to the output without processing. The Target Level fader determines whether a detected beat is brought up or down in level based upon the low and high threshold settings plus the setting of the single, large Compression/Expansion knob calibrated in +/- percentages.

If the instantaneous level of a snare drum was 6dB above the target level setting and the compression knob was set to -50 percent (i.e. an expansion ratio of 1:2), the snare drum level will jump up 3 dB. But if the snare was 6 dB below the target level (but still above the low threshold), it'll be reduced by 3 dB.

The color-coded Compression/Expansion meter surrounding the Compression/Expansion knob displays instantaneous gain boost in orange and gain reduction in light blue. This color scheme is copied in the real-time waveform display that parades right to left with the input signal shown in gray.

I found both these displays essential for precisely adjusting Drum Leveler.

There are also other controls to tailor DL's action very specifically. Minimum Retrigger Time sets an elapsed time-masking period before DL considers a new beat; Gain Range sets the maximum gain change applied to a beat within the set thresholds; and Hold and Recovery Time controls are analogous to an expander/compressor release timing and have a great influence on the finished sound.

I loved the sidechain filter. It's switchable between bandpass and band-reject modes--both with very steep curves. You can sidechain listen and set the high- and low-frequency range using its "handles."

New with this version is a Sensitivity control for adjusting DL's beat detector sensitivity (mostly I found the default fine), and Gate Range is a particularly interesting parameter for controlling the level that has not passed the low threshold and beat-detection algorithm. You could use Gate Range like a noise gate and clean up bleed or conversely, increase it and bring up room ambience for over-the-top compression/expansion effects that will surprise you!

For envelope-follower effects, the new external sidechain input is for superimposing the dynamics of a drum track (or any other percussive track) when DL is placed onto other track(s) in your mix. The external sidechain can be separately engaged on either side of a stereo track or on Mid and Side signals, enabling cool effects such as expanding the overheads' Side channel only with each snare hit.--this is a cool effect for stereo recordings.

In solo, I played a live (recorded) drum loop through Drum Leveler in which the snare level was higher than the kick drum level. I set the sidechain filter to accept only from 141 Hz down--most of the kick drum frequencies. I set the Low threshold to -22 dB and the High threshold to -9.8 dB and Target Level to -41 dB.

I came out of solo and while listening to the track, I adjusted the Gate Range to -42 dB and Recovery to 339 ms--the length of the extracted kick drum--to fit within the track. It sounded clean and compressed to a consistent loudness at the same time. There was another loop in this track that I reanimated its dynamics so that DL caused every downbeat to be louder.

This sure beats chopping in Pro Tools!

I was able to setup a preset to boost only the transient attack part of a bass guitar track by setting the high threshold to -8.7 dB, low threshold to -31.6 dB, hold time at 32 ms, and recovery at 5 ms.

Next, I adjusted the sidechain filter to bandpass frequencies from 380 Hz to 1070 Hz (attack part of the bass), which gave me a very consistent attack. This is not like just compressing with a slow attack time--the attack level can be very loud if you want while the rest of the tone of the bass is not squashed out.

Drum Leveler is a worthwhile plug-in to learn and use in mixing and sound design. There is nothing like it that I know of that works so well and reliably.

Highly recommended.

 Try This! 
While sound designing with Drum Leveler, I had a synth track that played a two-note quarter-note trill but also sustained a chord between the notes. I went with 100-percent expansion, increased the Sensitivity to 49, Recovery to 168 ms for the length of each note, set Gate Range to -23 dB, Gain Range to 80.0 dB, and finally used a very narrow band reject sidechain filter setting at 987 to 2206 Hz. This reduced the two-note trill with sustain to a single quarter-note with sustain level greatly reduced.

Barry Rudolph
 Barry Rudolph 
Barry Rudolph is a recording engineer/mixer who has worked on over 30 gold and platinum award-winning records. He has recorded and/or mixed Lynyrd Skynyrd, Hall & Oates, Pat Benatar, Rod Stewart, The Corrs, and more.
Barry has his own futuristic music mixing facility called Tones 4 $ Studios and also teaches audio engineering at: Musician's Institute, Hollywood, CA..

He is a lifetime Grammy-voting member of NARAS, the 'New Toys' columnist for LA's Music Connection Magazine, and a contributing editor for Mix Magazine.

 Sound Radix 
Web Site:

Product: Drum Leveler

Price: $149 MSRP

Pros: Awesome and unique dynamics processor.

Cons: It has a learning curve--start with a preset

Barry Rudolph is an L.A.-based recording engineer. Visit his Web site at: WWW.BARRYRUDOLPH.COM

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