Four knobs, a three-position switch, and no bull! bx_subfilter is touted as a simple but effective tool for tightening up bass frequencies, and it is 100% free for all Plugin Alliance members. I’ve been drinking the Plugin Alliance Kool-Aid for almost two years now. As an informed member, I downloaded my free version of bx_subfilter back in April, while fighting a mix with a tricky kick drum. Though the kick drum did bear a unique, big and open sound on its own that worked well within the context of the drum set, in the rest of the mix, its definition and punch disappeared. I tried different combinations of compression and EQ processing. Filtering and gating (yuck) were also attempted. Every time I thought I was close, more tweaking ensued.
The day I installed bx_subfilter was the day I climbed out of the rabbit hole. Don’t yell at me for using presets — they’re great starting points for those of us that can’t be bothered to read the instructions. I began with a preset called “02 Bass Drum Tight,” adjusted a few settings, finished the record, and got some sleep. The filter section in bx_subfilter appears to be a trimmed-down version of the one in bx_subsynth. A modest control set includes a switch for Resonance (Low, High, and Extreme); knobs for Tight Punch (20–90 Hz and off), Low End (±10 dB), Gain In, and Gain Out; and meters for In and Out as well. Tight Punch sets the frequency for the resonant high-pass filter. Resonance selects the peak settings for the high-pass filter. And Low End adds a fixed band-pass filter.
In addition to tightening up kick drums, I found bx_subfilter to be super handy for sculpting bass guitar tracks and helpful in clearing up muckiness when placed as an insert on a plate-reverb effects return. While marketed as a great utility for tightening up your low end, bx_subfilter was also useful for beefing up thinner sources like a picked electric bass or a “clicky” kick drum mic’d near the beater. EDM folks will also find this plug-in to be a husky, additive, low-end enhancement and focusing weapon. I know I’ll continue to discover new applications as I get into more mix rumbles.
bx_subfilter is a tool you’ll definitely want in your arsenal. It’s not going to disentangle you from all your low-end predicaments, but you’ll know immediately if it’s appropriate for the task. Yes, when you sign up to get this free incredible plug-in, you will get emails about other offers. But these offers are insanely good, and you should be primed — I purchased bx_boom for just $9 last year! Another great tool from the brains at Brainworx. Go Plugin Alliance!