It’s time to step up your filtering game! We explore 4 wildly creative effects you can construct with filters in your productions, from rhythmic pumping to formant-shifting synths and much more.
By Charles Hoffman, Black Ghost Audio
A filter is a frequency-dependent amplifier circuit that allows you to affect sounds between 0-20,000 Hz+. Filters allow you to amplify and attenuate specific frequency ranges and are a fundamental hardware component in many different audio processing devices. Filters can enhance your songs at a creative level, mixing level and even a mastering level.
Some common types of filters include high pass (low cut), low shelf, bell, bandpass, notch, tilt, high shelf, and low pass (high cut) filters. EQs affect your audio signal through the use of filters and allow you to select the type of filter you’d like to apply to your audio signal. Using an EQ is one of the easiest ways to filter the track you’re working on.
Today we’ll show how you can use filters to spice up stagnant recordings, create talking, formant-shifting synths, rhythmic pumping, custom multiband processing devices, and achieve thick analog sounds experimenting with different circuit types.
1. Filter Automation & Modulation Effects
One of the best ways to infuse a stale recording with life is by applying filter automation and modulation effects to it. By making creative use of filters in these ways, you can add tension, release and rhythm to your music.
Waves MetaFilter allows you to create rhythmically complex filter arrangements. It provides you with access to some LFOs, along with a step sequencer that you can use to modulate the cutoff frequency of a filter over time. Gradually applying a sweeping low-pass filter or high-pass filter to a song during a buildup is a staple DJ move. If you’re looking for something a little more original, you can use MetaFilter to perform this classic sweeping effect with the addition of cutoff frequency modulation using an LFO in conjunction with MetaFilter’s step sequencer.
Applying pumping effects is something else that MetaFilter is more than capable of. This allows you to free up space in your mix for other elements such as your kick. If you’re working on a House track with a 4-on-the-floor kick-drum pattern, you may not need to resort to using sidechain compression on your bass to make room for the kick; try applying a pumping low pass filter instead.
In Illenium’s remix of the song “Don’t Let Me Down” by The Chainsmokers, you can hear the effects of filter automation, during both drops, on the supersaws. To get this pumping effect, Illenium has most likely linked an LFO to the cutoff frequency of a filter and automated the rate of the LFO over time.
You can also use filters in a less calculated way to morph the frequency response of a sound over time. With an EQ like the Waves Renaissance Equalizer, it’s just a matter of automating the gain and frequency of individual bands. LFOs are great in a number of situations, but the processing they allow you to apply is calculated and runs in a loop. Using automation lines, you can completely customize how the character of a signal evolves throughout the course of your song. This automation technique works especially well for making bass growls come to life.
Waves’ Kaleidoscopes is a modulation plugin that provides the ease of use that an LFO-based modulation tool delivers, along with some of the sonic variety that manual automation is capable of. It includes two built-in effects that you can toggle on/off. Either a phaser, flanger, chorus or tremolo can be assigned to each effect panel. There’s also the option to apply Effect 1 and 2 to the incoming signal in serial or in parallel with one another.
The true power Kaleidoscopes lies in its trigger functionality. You can trigger effects based on the amplitude of incoming audio signals or the presence of transients. To make things even more interesting, it’s possible to trigger effects using a sidechain input signal. Listen to how the kick and snare in the following drum loop are activating Kaleidoscopes and creating a material-dependent modulation effect.
- Example 1a – Drums (dry)
- Example 1b – Drums (wet)
2. Create Talking Synths
Formant filters allow you to create vowel sounds. When you speak, your vocal cords vibrate and generate sound. The sound is attenuated based on the shape of your mouth, which is what allows you to produce vowel sounds like a, e, i, o, and u.
Your vocal cords and mouth are extremely similar to a subtractive synthesizer. Subtractive synths generate a waveform (like your vocal cords) and then shape the sound using filters (like your mouth). A formant filter seeks to emulate the same attenuation that your mouth provides when forming vowels; this lets you create synth patches that seemingly talk.
Waves Morphoder is a vocoder that grants you formant control. Adjusting Morphoder’s formant ratio control, you can shift the built-in filter up and down the frequency spectrum. The result is that you’re able to shift between “Aaaah,” “Eeeeh,” and “Ooooh” sounds. Using Morphoder is one in which you can affect your audio signal with formant filters. Some EQs include formant filters that you can apply to your source signal as well.
Dubstep artists like Zomboy, 12th Planet and Skrillex are quite notorious for using talking basses in their songs. If you’re going to create multiple vowels from the same bass synth patch, I recommend applying a formant filter after the synth plugin you’re using; this will make it easier to apply filter automation and hit different vowels with extreme precision. In the following song by Zomboy, called “Organ Donor,” you can hear him using a variety of talking basses in the arrangement.
By modifying the formants of a vocal recording using a plugin like Waves’ Vocal Bender, you can make a masculine voice sound wispy and feminine or make a feminine voice sound deep and masculine. To achieve this using Vocal Bender, all you need to do is adjust the Formant knob. It’s also possible to apply built-in LFOs and follower envelopes to the Formant knob or manually automate the knob within your DAW to create wild gender-bending vocal effects.
Perhaps you don’t have access to a male vocalist, but some male harmonies would complement your single-line female vocal nicely. Duplicate the lead female vocal to a new track, apply Vocal Bender, and adjust the Formant knob to taste. Vocal Bender also includes a Pitch knob that you can use to drop the pitch of the backup vocals—making the effect even more convincing.
- Example 2a – Vocal Bender (dry)
- Example 2b – Vocal Bender (wet)
3. Create Custom Multiband Processing Devices
Multiband processing devices allow you to split their incoming audio signal between different bands using filters and process each filtered signal independent of the other. For example, a three-band multiband compressor would allow you to separate an audio signal into lows, mids, and highs at crossover frequencies that you select; you can then compress each band using different compression settings. What’s happening here is that each filtered signal is getting run through its own compressor.
We’ll be setting up a multiband saturation/distortion device that’s perfect for creating aggressive 808s. To start, download Waves’ StudioRack plugin for free. Insert this plugin onto your track. Within StudioRack’s interface, click on one of the empty insert slots and select “Multiband Split” from the dropdown menu—two bands will appear. Set the crossover frequency of the bands to 250 Hz.
Apply an instance of the Waves J37 tape saturation plugin to the low band and an instance of the GTR Amp plugin to the high band. You can experiment with the settings of these plugins, but I generally find that light processing on the low end of my 808s allows their round character to fill out the mix, while a distorted top end will enable them to punch through the mix and become audible on consumer speakers.
By using this custom multiband processing technique, you have slightly more freedom than you would with a traditional multiband processing device. You can apply different types of plugins to different bands and modify how far each band crosses over into its neighboring band's frequency range.
Hip-Hop artists like Ghostmane, $uicideboy$ and Pouya use a lot of distortion on their basses. In “Flesh” by Ghostmane, there’s a warm sub with an extremely distorted top-end. You could make this bass by layering two different sounds together, but it can be created just as easily using multiband processing and heavily distorting the top band.
4. Experiment with Different Circuit Types
Not all filters are created equal. Many filters have a characteristic tone, so one filter isn’t necessarily going to sound like the next; this is especially true in the analog world of synths. Synth manufacturers make a big fuss about the filters they use in their synths because of the extent to which a filter can shape a synth’s sound.
Filters are just circuits that perform various signal processing functions. Some analog-modeled plugin EQs allow you to change the circuit type they’re attempting to model; this effectively changes the character they impart on your audio signal. H-EQ, for example, offers 7 different filter types per frequency band, including vintage American and British console-modeled filter circuits, as well as modern ones. Each circuit type will offer its own unique sound and character, and may provide soft clipping, hard clipping, transparency or other features.
When you talk about high-pass, low-pass, band-pass, band-reject and all-pass filters, you’re referring to just one way in which you can categorize filters. Filters can be passive or active, analog or digital, discrete-time or continuous-time, linear or non-linear, and infinite impulse response or finite impulse response. Without getting too distracted from the focus of this article, just be aware that filters can be classified in different ways and that various filter characteristics can play a part in how a filter sounds.
In practice, if a device like an EQ offers selectable circuit types, audition each type to see if you prefer one circuit type over the other. If you’re listening to your mix in a room with near-flat frequency response, and you’ve tested the mix on various playback systems, you should feel confident about the selection you’ve made.
Filters can be used in many different ways, and they’re as useful as you are creative. Even though filters often just make up a single part of more elaborate devices like synths, compressors and EQs, they have a lot to offer and can drastically re-shape your sounds. Start creatively integrating filters into your workflow to expand your production and mixing capabilities.
Charles Hoffman is the owner of Black Ghost Audio—a website that provides free music production tips, tutorials, gear roundups, and premium online video courses. Visit Black Ghost Audio to learn how to produce music online.
Want more on Vocal Bender? Check out these 10 vocal FX in real-time using Vocal Bender!
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