What Are Filter Pedals?
These are the unsung heroes of the pedal world. Often overlooked for being too diverse for the bog-standard rock guitarist, filter pedals are used by many modern players that wish to expand their tonal palettes.
Filter pedals can totally transform your guitar tone. In fact, with extreme settings they can make your instrument sound like something almost completely different! Essentially boosting frequencies with a moveable sweep, with a filter pedal you can enhance certain areas of your EQ to bring out harmonic overtones for expressive vocal-like timbres. Further electronic wizardry helps in creating their sound too, and envelope filters are very recognisable to the ear.
These effects pedals let guitarists transcend the gap between rock and electronic/pop genres, and have even more of a place in the music world than ever before. And here at Andertons Music Co. we have a great selection of these peculiar guitar pedals available. But first, we’re going to explain all of their details and functions. This is so that we can provide you with a better idea of how to get the most out of them, so you can integrate them successfully into your rig.
What Does A Filter Pedal Sound Like?
As we said in the introduction, a filter pedal ultimately takes your guitar tone and enhances it by adding (or taking away) certain frequencies. However, it doesn’t work like any regular EQ pedal, as an envelope filter dramatically changes the tonal qualities of your guitar signal using additional processing. The result is an effect that can give a vocal-esque quality to your tone, by embellishing notes to produce a variety of vowel-like sounds.
Most filters will use an LFO (low frequency oscillator), which assists in adding movement to your signal. This isn’t dissimilar to how modulation pedals work in processing a signal, with the LFO adjusting the waveform, in this instance, to manipulate its shape. Filter pedals also work in a fairly similar way to wah pedals too, with a ‘peak’ moving across the frequency spectrum.
That’s why ‘auto wah’ pedals can be categorised as filter pedals. This is because a regular wah pedal works as a moveable peak in your signal’s EQ, sweeping from a nasally and anaemic tone to a treble-boosted scream. Auto wah pedals essentially work in the same way, however rather than using your foot to manually adjust the effect sweep via a rocking plate, with an auto wah you can tailor the attack/speed of the frequency sweep to simulate the movement of your foot.
Filter pedals (and auto wahs) are really in their element when used for playing funk. This is because they give a bubbly character to fast lead lines and chord progressions, and as the effect of a filter pedal is triggered by the attack of a note that you play, it makes them suitable for the demands of the usually fast, staccato-style playing that funk guitarists employ.
Jerry Garcia of the Grateful Dead is arguably the most famous pioneer of the envelope filter effect on guitar, which can be heard extensively on the track “Estimated Prophet”:
Grateful Dead - "Estimated Prophet"
Envelope Filter Pedals For Bass
Envelope filters are also incredibly popular with bass players. Used often for funk music like their guitar playing counterparts do, on bass, filter pedals are also used in heavier styles of music too. For example, Justin Chancellor of the progressive metal band Tool has an envelope filter pedal amongst his arsenal of effects units.
Just adding another dimension to their music to intrigue the listener, he has used an envelope filter in songs such as “Jambi” and “The Pot”. You can hear his MXR M82 Bass Envelope Filter pedal in all of its glory in this rig rundown (skip to 2:55):
Justin Chancellor Rig Rundown With Dunlop TV
We have also demonstrated the MXR M82 in one of our episodes of 'All About The Bass' on Andertons TV, where we take a close look at the various sounds that you can get out of this pedal. With 5 tone-shaping controls, the range of wonderful sounds that this pedal is capable of is evident in this great video!
MXR M82 Bass Envelope Filter on Andertons T.V.
Where Does A Filter Pedal Go In My Signal Chain?
A filter pedal is typically used into the front of an amplifier. So in terms of the signal chain, you should run your instrument into the input of the pedal with the output of the pedal running straight into your amp’s input. If you’re intending to use a filter pedal in conjunction with other stompboxes, such as an on a pedalboard, a filter pedal should generally be placed as early in your pedal chain as possible.
This is because maximum sensitivity will occur earlier in the chain, so in a way the effect will react more efficiently to the input signal, getting "more" of the effect out of the pedal. Think about it in a similar vein to wah pedals, where you would conventionally place it before overdrive pedals. This is so the sweep of the effect sounds more natural, rather than exaggerated or overly synthetic.
That is also why using an envelope filter will probably sound bad through the effects loop of your amp too. In the effects loop, the sound of an effect will be clearer and more pristine as it will bypass the preamp of your amplifier. Time-based and modulation effects will therefore sound better in the effects loop of an amp due to their tonal qualities, but a filter pedal will sound too harsh or piercing if you run it through an effects loop, especially if you're using extreme settings.
Electro Harmonix dominate the filter pedal category, with multiple stompboxes available at a range of price brackets. The Q-Tron pedal is a modern classic, used extensively by a raft of players for its versatility and iconic sound. The range starts at the Micro Q-Tron, a simple 3 control pedal fitted in a pedalboard-friendly enclosure.
The pedal’s drive control determines the sensitivity of the filter sweep, affecting the width of the sweep range against the input signal. The Q knob will let you find the peak frequency of the filter, becoming more dramatic and treble-boosted the further it is turned. And lastly, the mode control will let you choose which frequency range the filter passes through. LP (low-pass) for example will give you a throatier filter sound, with the other modes affecting higher frequency bands.
The standard Q-Tron features even more dials for further sound-shaping. An up/down control enables you to choose the shape of the filter wave, while an additional boost knob offers an extra kick of volume when you engage the effect. The even more high-end Q-Tron+ has a built-in effects loop to let you place other effects between the pedal’s preamp and filter section, letting you combine effects for some truly unique tones. A response switch also lets you choose between a slow and smooth vowel-like attack, or a fast, snaked response.
Boutique brands such as EarthQuaker Devices produce their own filter pedals too, delivering even more experimental sounds than their EHX counterparts. The Spatial Delivery from EarthQuaker is reactive to your picking attack, giving a faster response and wider sweep depending on how hard you play and where you set its range control. It also has a sample & hold mode, which generates random filtering to give you some old-school sci-fi style sounds!
EarthQuaker Spatial Delivery On Andertons T.V.
Which Filter Pedal Should I Buy?
After all of that, I hope that this guide has enlightened you. These pedals certainly are hard to grasp at first, and they can be difficult to integrate into your setup. But, they can also be very inspiring and capable of giving you some outside-the-box ideas, which is important in a time where thinking up new and original ideas can be tough.
There's clearly quite a lot of choice out there. As they are so diverse compared to your typical overdrive or fuzz stompboxes, these pedals demand more attention and research.