Here's how to clean up low-end mud and add definition to mixes.
Welcome back to the Dojo. This time we're going to look at the mighty high-pass filter (HPF) and how you can use it to clear out muddy, low-end frequency build-up in your mix, and get more separation between your guitars, bass, and kick drum.
A high-pass filter does exactly what the name implies: It attenuates the low frequencies while allowing the higher frequencies to “pass through" and be heard. You can find HPFs in many different places, but the best place to look is an EQ (either analog or digital). All DAWs come with EQs, so put one on your track and follow along.
Let's talk about the bottom end. In standard tuning, the lowest frequency on the guitar is about 83 Hz (our lowest E string), the standard 4-string bass can play down to 41 Hz, and (generally speaking) the kick drum fundamental lives in the 40 to 70 Hz range. This means that there is quite significant overlap from 40 to 100 Hz between these three instruments. Although defined lowest notes exist on instruments, that doesn't mean that when recording your guitars, bass, drums, etc., that other lower frequencies are not sneaking into your tracks!
Say you're creating your next guitar-laden behemoth, with dozens of guitar tracks. Every time you add another guitar track, you're also adding lower-end information that's accumulating and slowly covering up your bass and kick drum. You turn up your bass and kick, but then the guitars sound anemic and not as defined. It's getting bass heavy and you end up chasing your tail, getting frustrated, and asking “why can't I fix this?" Sound familiar?
Look at Fig. 1. This is an audio snapshot of me playing a grindy, super-distorted low rhythm part through my amp without a high-pass filter. You can tell by the peak, at 82 Hz, that I'm cranking low Es and Fs. Now look to the left of that 82 Hz peak. There's still a significant amount of low-end information present, especially from 70 Hz down, and this is only one track! Imagine doubling this part and adding more tracks. We're headed for some serious low-end buildup.
Now look at Fig. 2. This is the exact same section of audio with a high-pass filter at 155 Hz (the faint green line), with a 12 dB per octave slope. (More on this in a bit.) If you compare the difference you'll see that the 82 Hz peak has lessened, and most of the sub-frequencies have been radically reduced. Rest assured that the guitar sounds as bold and brazen as it did before, but now I've carved out room for my bass and kick drum to coexist.
I mentioned a 12 dB per octave slope. What does that mean? High-pass filters need to have a slope shape to be able to separate the frequencies you want to pass through from the ones you don't. The gentle slope of 12 dB per octave means that all the frequencies below wherever the filter is set (say A, or 440 Hz) will gradually be reduced, and by the time the next lowest A (220 Hz) comes around, it will be 12 dB lower. Most plug-in EQs, like the FabFilter Pro-Q 3 (which I love for many reasons), will offer many choices of slope shapes ranging, from 12 to 96 dB per octave. Remember this: The higher the slope shape value, the more you're absolutely shutting the door on those frequencies below your filter point. This can be very useful if you want to have total control over instrument ranges and how they overlap each other. Generally, I prefer 12 to 48 dB slopes, and only use 96 dB and above slopes for an effect and rare offending lower frequencies.
Try this: Take your rhythm guitar track with the lowest range and use a 48 dB per octave HPF. Slowly sweep it while listening to it in the mix. Stop when you notice it sounding slightly thin. Now pull the filter back just slightly to the left. Solo the track and toggle the HPF on and off. Notice how thin it sounds when soloed, but it has more gravitas in the mix! Why? Because you're allowing the bass and kick drum to occupy that region and making your mix sound better!
See you next month and keep experimenting.
If you're a diehard devotee of tube-amp filth but want in on IR action, this innovative architecture may be just what you've been waiting for.
Recorded using an Eastwood Sidejack Baritone DLX with Widerange Jazzmaster pickups and a Gibson Les Paul with 57 Classics into an Audient iD44 going into GarageBand with no EQ-ing, compression, or effects.
Clip 1: Eastwood bridge pickup through gain channel in wide voicing (aggression set to red), bypassing the G20's power amp and using virtual-cab preset #1 direct into GarageBand. G20 gain at max, treble, mid, and bass at noon.
Clip 2: Same settings as clip 1, but with G20's power amp in-line.
Clip 3; Les Paul 57 Classic bridge pickup through gain channel in wide voicing (aggression set to red) with gain and bass maxed, treble at 10 o'clock, mid at 2:30, and volume at 2 o'clock, with an Ibanez ES-2 Echo Shifter in effects loop and G20's speaker output routed to a Celestion Ruby-stocked 1x12 miked by a Royer R-121.
Clip 4: Eastwood bridge pickup through gain channel (aggression off), bypassing the G20's power amp, and using virtual-cab preset #1 direct into GarageBand. G20 gain at noon, treble at 1 o'clock, mid at 11 o'clock, bass at noon.
Clip 5: Same settings as clip 3, but with G20's power amp in-line.
Clip 6: Eastwood's middle position, then bridge pickup into gain channel (aggression off, gain at 2 o'clock, treble at 1 o'clock, mid at 8 o'clock, bass and volume at max) with Ibanez ES-2 Echo Shifter in effects loop, through Celestion Ruby-stocked 1x12 miked by a Royer R-121.
Clip 7: Eastwood (middle position) through SoundBrut DrVa (boost side), Ground Control Tsukuyomi mid booster, Ibanez Analog Delay Mini, and Anasounds Element, then into G20's clean channel (treble at 1 o'clock, mid at 11 o'clock, bass at noon), bypassing the G20's power amp and using virtual-cab preset #1 direct into GarageBand. Clean first, then with Jordan Fuzztite pedal engaged.
Clip 8: Eastwood's neck pickup through gain channel (aggression on), bypassing G20's power amp, using “Doom mooD" 2x15 cab IR (based on a JCM800 bass cab) with simulated Audio-Technica MB2k mic 100-percent off axis direct into GarageBand. G20's gain, treble, and bass at max, mid at minimum.
Almost limitless range of heavy tones via Two Notes IRs and MIDI control capabilities. Works well with pedals.
Some may wish for more brutal gain and/ or more clean-tone variety. 4-button footswitch not included.
Ease of Use:
Pretty much no one is gigging and everyone's getting more into recording, so the prospect of a straightforward tube amp that makes our favorite quarantine pastime easy and super flexible is pretty intriguing. With last year's unveiling of the D20, Revv Amplification became the first tube-amp manufacturer to incorporate cab-and-microphone impulse responses (IRs) from industry leader Two Notes Audio Engineering directly into its architecture. But where the D20 was intended as a pedal platform for the masses, the G20 aims to put high-gain sounds inspired by Revv's Generator series into a similarly simple, portable, and recording-friendly head.
The Sixes Have It
Modeling amps aim to meld massive tonal flexibility with portability and convenience, but the 20-watt G20 achieves flexibility via bona fide valve tone. 6V6s—the power tube behind clean-tone champs like Fender's Princeton and Deluxe Reverbs—seem an obvious choice for a clean platform like last year's D20. Some may be surprised to also see a pair of them at work here. But the more you think about the big G20 picture, the more 6V6s' clean-slate capabilities make sense here, too.
Not that there has to be just one big picture, though. Part of the amp's appeal is how it enables you to walk the line between über-simple tube-amp operation and 21st-century digital sophistication. For all the power behind the best modeling gear, many players still find interfacing with modelers overwhelming or just plain overkill. The allure of the G20 is that its 2-channel, shared-3-band-EQ design features just six knobs and canbe as plug-and-play simple as a basic modern tube amp routed to a single extension cabinet of your choice.
If you're willing to go further with your PC or Mac, you can marry real-tube-amp operation with one of six onboard cab-and-microphone impulse response models, which you can send to a live mixing board or a recording DAW—even if you're also using a physical cab. G20 comes preloaded with six diverse options designed by noted session player/IR creator Shawn Tubbs that you choose via the front-panel knob. But if you want to go full-bore, Two Notes' free Torpedo Remote software lets you create an almost infinite array of other combinations to load into the six available slots.
Other notable G20 features: a power-scaling button (which takes the amp from 20 to 4 watts), a “wide" voicing switch, a 2-voice “aggression" button for the gain channel, a pre/post switch for removing the power section from the rear-panel XLR output's signal path, a store button for use with the rear-panel MIDI-in jack and your favorite controller, a level control that governs both the 1/4" headphone and XLR outputs, rear-panel power-tube bias points, a series effects loop, and a jack for Revv's optional 4-button footswitch for MIDI-eschewers ($129 street).
Walking the Tightrope
I tested the G20 with an Eastwood Sidejack Baritone DLX and a Les Paul with 57 Classics, first through a 1x12 cab stocked with a ceramic Weber Gray Wolf, then through a different 1x12 loaded with a Celestion Ruby, then via XLR and an Apogee Duet straight into GarageBand. Through real cab or IR, I found a ton to like. Full disclosure: Working with the G20 was my first foray into IRs (hey—I've got nice mics and a basement studio where I can crank as loud as I want!), but getting cool tones wasn't any harder or more time consuming than throwing up a mic. And this is coming from someone who kind of loathes plug-ins and menu diving. The ability to load six IRs into the G20's front-panel control means once you've found or customized your own faves, you may never need/want to do so again.
The preloaded IRs are based on Revv cabs featuring Warehouse Veteran 30 and ET90 speakers miked with a Shure SM57 and a Royer R-121 (my favorite was a punchy and articulate dry 4x12 image), but the range of options in the Torpedo Remote software is extensive—from a who's-who of mainstream cab and speaker brands, sizes, and configurations to more niche IRs based on, say, Fortin Amplification designs or rare one-offs. Then there are the virtual mics, with everything from the usual suspects to Neumann, Sennheiser, Audio-Technica, Miktek, and Blue simulations you can mix and match, put on the virtual front and/or back of the cab, arrange at close or short distances, at varying angles off axis, and with a variety of ambience choices. Needless to say, if you've got a MIDI-controller setup, the sky is virtually the limit for how many heavy sounds you could wring from this 9-pound head on the fly.
In terms of an all-in-one tool, Revv's tightrope walk between digital IR flexibility and the straightforward tube-amp world yields one of the smartest, most intriguing options on the market. Two Notes' Remote software is super easy and intuitive to use, and since you're not perusing an endless collection of famous amp models, the G20 makes it easier to focus on playing.
I doubt I'd ever go full-IR—in my book nothing beats the interactivity you get being in the same room with a cranked amp. But there's no denying it's an incredibly handy tool to have at your disposal, particularly if your physical cab collection is limited. The IR capabilities open the doors to everything from punchy hard rock to seething black-metal and bludgeoning doom tones (2x15 bass cab, anyone?). The gain knob doesn't apply to the clean channel, which doesn't really break up when cranked, so for semi-clean tones you may have to rely on outboard stomps or guitar-volume maneuvers on the gain channel (both of which work wonderfully). But, in all, a lot of players may find the G20's approach a near-perfect balance between yesterday and today.
A Hendrix fan details the journey of his first real guitar, a 1972 Fender Strat that he modded, returned to spec, and is now enjoying again in quarantine.
Name: Tony Houston
Location: Dayton, Ohio
Guitar: 1972 Fender Stratocaster
After years of reading about other readers’ guitars, I decided to write about my original 1972 black Fender Stratocaster. Attached is a picture of my Strat and original warranty card, and myself.
I was 21 years old back in 1971 when I first started to learn guitar. I was already a fan of Jimi Hendrix, as was a co-worker who played guitar. We were talking about Jimi and I mentioned that I would love to learn guitar, but at that time couldn’t afford it. It turned out that he had an original Sears Silvertone guitar/amp in the case that he gave me. It was almost impossible to play, but I loved it.
By 1972, I was in much better shape financially (well, somewhat) to buy a “real” guitar. For over a year I would stop in Bernie’s Music here in Dayton and look at guitars. I was mesmerized by the white Strat that Jimi played at Woodstock. They had one in the store, but when I went in to buy it, it was gone. They had a black Strat, and I was told that I could trade it back when another white Strat was in stock … they never got another one.
Fast-forward to the late ’70s. I’d read enough about guitars to mod my Strat, so over a few years I installed a brass bridge, replaced the stock bridge pickup with a DiMarzio Fat Strat, and did various re-wirings of the pickup switch. Also the stock pickups weren’t wax-potted properly and would squeal like a pig! I re-potted the pickups by dipping them in melted beeswax.
I gigged with it until 1988, when it was almost stolen at a show. I decided then to retire it, as I had brought a couple more Strats. In the mid-90s, I decided to restore it to factory specs. I’d kept the original bridge pickup and the original bridge. While testing the bridge pickup with a multimeter, I found it had a short. I sent it to Lindy Fralin and had it wound to original spec.
Since being in quarantine, I have it tuned to Eb now, and, at 70 years old, decided that I was going to properly learn to play Jimi’s “Little Wing.”
Send your guitar story to firstname.lastname@example.org.