Audio clips were recorded with a PRS SE HBII into a Fender Hot Rod Deluxe mic’d up with a Shure SM57 into Logic Pro X.
Rhythm guitar (right side): Bridge pickup, peak at 3 o’clock, gain at noon, band pass mode, hi range
Lead guitar (left side): Middle pickup, peak at 1 o’clock, gain at 1 o’clock, low pass mode, hi range
RatingsPros:Authentic vintage-style tones. Handy output level feature. Cons: A bit thin sounding in the high-pass mode. Street: $179 Keeley Neutrino rkfx.com | Tones:  Ease of Use:  Build/Design: Value: |
Keeley’s latest iteration of their dynamically funky envelope filter is addictive, musical, and just plain fun. This version includes a handy output-gain trim pot on the side, a direction control switch, and the expected gain, mode, and peak controls. The Neutrino is based around an optocoupler, much like the classic Mu-Tron, which gives it a more nuanced (and pleasing) dynamic range. In other digital-based circuits the tracking can be questionable, with harsh high end, but Keeley’s Neutrino design squashes those concerns.
In short, an envelope filter responds to the output of your instrument to emulate how your foot would sweep a traditional wah pedal. Think of Jerry Garcia on “Shakedown Street” or Steve Wonder’s clavinet sound on “Higher Ground.” Each mode of the Neutrino offers a different tonal take: some are funky, others more atmospheric and lo-fi, but they are all musical and deep. I jumped in after the Garcia “quack” tone and was stoked to see how close the Neutrino could get. The response felt immediate and satisfying. For harder funk-style strumming, I backed off the gain a bit and upped the peak control. Watch out Nile Rodgers! Keeley has once again improved on a beloved classic and made it affordable, rugged, and accessible.
Test Gear: PRS SE Hollowbody II, Schroeder Chopper TL, Fender Hot Rod Deluxe
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