One mic or two? Mono or stereo? Hear the differences.
This column continues the unlikely premise of last month's installment. We used the digital models from Universal Audio's Ox Amp Top Box to make audio comparisons between electric guitar recording techniques.
Yeah, it's weird using a digital box to illustrate analog techniques. But it's useful here because Ox's models are so realistic. The process also isolates the variable in question. You hear the same guitar, pickup, amp, amp settings, and recording path throughout.
Last time we looked at speaker size, single-speaker versus multi-speaker cabs, and microphone types and placement. Now let's explore options that arise when using multiple mics.
Variable 1: One mic vs. two. In Clip 1 you hear single-mic clips featuring virtual versions of three common electric guitar mics: a Shure SM57 dynamic, a Neumann U 67 condenser, and a Royer R-121 ribbon. (We discussed their characters last month.) Next come three possible pairings: 57 plus 67, 57 plus 121, and 67 plus 121. In the modeling, the virtual mics are positioned near each other and close to the speaker.
TASTING NOTES: A single mic has the pointiest, most direct sound. Adding a second mic introduces phase cancellations as the two mics “listen" from slightly different perspectives. This can add cool complexity and texture, though it often softens the impact.
Variable 2: Panned vs. non-panned mics. With two miked guitar tracks, you can choose how far apart to pan them, if at all. Clip 2 compares mono sounds (both mics at center) and the same mic combinations panned far left and right. You hear the 57 and 67 in mono and then in stereo, the 57 and 121 in mono and then stereo, and finally the 67 and 121 in mono and stereo.
TASTING NOTES: What's best: stereo or mono? Duh—it depends on the context! A mono sound often has the most impact, but a panned sound can add interest and depth. Panning can also maintain a prominent guitar sound while leaving the mix's center clear for vocals, bass, and kick drum—at least in a conventional mix.
Tip: When combining two mics, always try reversing the phase of one of the tracks within your DAW. One setting will probably sound much better than the other. Use that one.
Variable 3: Dry sound vs. room sound. Ambient room miking is one of the defining qualities of rock guitar. Somewhere in the vast catalog of Led Zeppelin outtakes there's a clip in which someone solos the two mics on Pagey's “Heartbreaker" amp. First you hear a dry, close-miked sound, then a boomy room sound, and finally the two mics together. Suddenly it sounds like Led Zeppelin—and countless other rock guitar recordings since that 1969 session.
But with today's tech you can get similar sounds with a single close mic and a good digital room reverb, as heard here. Clip 3 features the 67 plus 121 blend with no ambient room miking. Next is the room sound only, as it might be captured by a condenser mic positioned six feet or more from the amp. Finally, you hear the blend: first with just a bit of room, and then with more ambience.
TASTING NOTES: A close mic is in your face. A distant mic is out in space. At risk of oversimplifying, close miking alone often works for groove parts where the guitar shouldn't hog the limelight, while a roomier sound might be better if the guitar is front in center for big riffs or solos. Also, consider the quality of your tracking room. If you're working in a great studio, it can be a crime not to capture the ambient sound. If you're in a crappy-sounding bedroom, an ambient mic might not be worth your while. (But remember, an unusual ambience is sometimes cooler than a “good" one.)
Tip: When recording a band with the guitar amp isolated in another room, room sound can make the guitar sound more like part of the group. That could mean re-amping the guitar track in the room where you'd previously recorded the drums, or applying the same simulated ambience (in varying amounts) to all the tracks.
Variable 4: Stereo vs. mono room miking. With enough mics, you can choose whether the ambient room sound is captured in mono by a single microphone, or in stereo via two mono mics or a stereo mic. Two close mics and a stereo room sound means four tracks to blend and pan. Clip 4 showcases a few options. First you hear the ambient sound alone in mono, then in stereo. After that you hear mono close miking plus mono room sound, stereo close miking with mono room sound, and finally stereo plus stereo.
TASTING NOTES: This parameter can be pretty darn subtle. It might be meaningful on a solo guitar recording, but in a full-band mix you might not hear a difference. Our ears sometimes perceive stereo and panning in strange ways. If, say, the drums are panned dramatically in stereo, there's a good chance you'll think the mono ambience is stereo as well. For more drama, take a mono close-miked track and a mono room track and pan them wide. Yeah, that's “fake" stereo, but it can sound epic.
Making a living doing the thing you love is great—in fact, it’s something that so many players aspire to. But it changes the relationship between player and instrument when the instrument is a source of work. How do they stay excited about their work? And how do they get excited when they’re in a lull? What keeps their creativity flowing? These are big questions, but our hosts are both having their own renaissances with their guitars. And—surprise!—it’s because they’ve both come into some new key pieces of gear.
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On this episode, Rhett and Zach discuss the relationship that they each have with the guitar at this point in their careers. Making a living doing the thing you love is great—in fact, it’s something that so many players aspire to. But it changes the relationship between player and instrument when the instrument is a source of work. How do they stay excited about their work? And how do they get excited when they’re in a lull? What keeps their creativity flowing? These are big questions, but our hosts are both having their own renaissances with their guitars. And—surprise!—it’s because they’ve both come into some new key pieces of gear.
Zach reports that he has been rippin’ totally sweet Metallica licks on his sick new ESP LTD Kirk Hammett Signature Series KH-602. He’s a longtime fan of the band—and has conveniently fallen back in love with Kill ’Em All and Ride the Lightning—and says he’s wanted a Hammett signature guitar for his entire guitar-playing life. When he saw this one at Nashville’s Guitars To Be Played, he fell in love with everything, from the skull and crossbones fret markers to the Floyd Rose. And you know what? The Floyd Rose isn’t hard to set up. This guitar, Zach says, is kickstarting his “love of the guitar again.”
Meanwhile, Rhett has been enjoying his new Soldano SLO-100head and matching 4x12 cabinet, even if he does keep the cab a few flights below his control room. He’s stoked about the story of Soldano, who he admires for being one of the early boutique amp builders, and has been playing this new 100-watter all week.When it’s time to dip a rig, it’s hard to find any faults. No spoilers, but it’s a nice one (and an easy gig load).And in the shill zone, Zach talks about the importance of running a brown box for owners of older amps and talks briefly about the difference between the Brown Box and a Variac.
Learn the sounds of different speaker, mic, and cabinet types.
I got the idea for this column while reviewing Universal Audio's Ox Amp Top Box for the May 2018 issue. Ox is an ingenious hybrid of speaker load box/power attenuator and cabinet/mic/room/effects modeler. You use your regular amp, but instead of miking it, you send a direct signal to the DAW or mixing board. You record the sound of your amp, while Ox simulates speakers, mics, and effects.
Crazy like an Ox. But this column isn't about recording with Ox, but using it as a teaching tool, since Ox lets us isolate each recording parameter. These comparisons may help you make smart choices when recording a hardware amp.
I used one pickup throughout—the bridge humbucker of a parts guitar. The amp is a Fender-flavored Carr Skylark. I chose a clean, bright sound to reveal how these options affect your recording's high end.
Variable 1: Speaker size. In Clip 1 you hear similar phrases played through models of four common speaker types. First comes the sort of 10" speaker you'd find in a small Fender Champ-style combo. Next is the 12" speaker of a midsized Fender-style combo, then a 12" Celestion Greenback you might encounter in a vintage Marshall cabinet, and finally the Celestion Alnico Blue from a vintage Vox combo.
TASTING NOTES: The Celestion speakers sound fatter than the American ones, but the “pointier" American sound might work better in a mix. The 10" speaker may sound small in isolation, but its bright edge can be useful when you have multiple parts competing for attention.
Variable 2: Speaker configuration. In Clip 2 you hear cabinets with varying numbers of speakers. First comes the 1x12 sound of a midsized Fender combo amp. Next is a 2x12 Fender-style cabinet. After that is the distinctive sparkle of a tweed-era 4x10 Fender Bassman. The last phrase is a classic 4x12 Marshall stack with 25-watt Celestion Greenbacks. These sounds represent a single mic on a single speaker, yet you can differentiate single- and multi-speaker cabinets due to leakage from adjacent speakers.
TASTING NOTES: When you add a second speaker, tones acquire texture and detail due to the phase cancellations between speakers. Tones also get more diffuse, with rounder highs and softer focus. Note how the 4x12 Marshall configuration has a muscular low-mid thump that the Fender configurations lack. That's due in part to the closed back of the Marshall cab.
Variable 3: Microphone type. You hear the sounds of six popular amp microphones on a single virtual 12" speaker in Clip 3. First, two dynamic mics: a Shure SM-57 and a fatter-sounding Sennheiser 421. Next come two condensers: a Neumann U 67 and an AKG 414. Finally, two ribbon mics: a modern Royer R-121 and a vintage Beyerdynamic 160.
TASTING NOTES: The dynamic mics have the sharpest, edgiest tones. The condensers have a neutral, full-frequency sound. The ribbons have rounded highs and warm lows. Remember, though, that the prettiest sound isn't always the best choice. Many engineers swear by the relatively harsh Shure SM-57, and not just because you can buy one for less than $100. Its tough, even brittle, edge can shine in aggressive rock mixes.
Variable 4: On-axis vs. off-axis. Off-axis means angling the mic away from the speaker's center towards its edge. Clip 4 features the SM-57 on- and off-axis, the U 67 on- and off-axis, and the R-121 on- and off-axis.
TASTING NOTES: A straight-on mic always provides the strongest impact and widest frequency range. An angled mic can soften a speaker's harsh edge while adding interesting texture. In a multi-speaker cabinet, the off-axis mic tends to pick up more sound from the non-miked speakers, adding additional texture via phase cancellation. And while you only hear two mic positions here (straight on and angled), there are multiple off-axis options, from a barely off-center mic to one pointed toward the speaker's outermost edge. Aim at the center for maximum punch and intensity. Aim toward the edge for slightly softer, more nuanced tones.
In an upcoming column we'll build on this foundation, integrating multiple mics, ambient room sounds, and some stereo options. In the meantime, bear in mind that the “best" sound for one recording might be the worst sound for another. The right choice is always a matter of context.
The Recording Guitarist: The Limits of Loud
You can only pump up the volume so far.
For several months, we’ve explored ways that mastering techniques can add drama to your mixes. But those techniques can also rob your recordings of musicality and impact. After all, these are the very techniques used by many music industry professionals to create boring and obnoxious rock and pop tracks.
Thanks to digital technology, we can make recordings louder than ever before. True, volume has a hard limit: the point at which the recording crosses into digital distortion. But multi-band compression, limiting, and maximizing can raise the level of a recording’s quieter passages till they’re as loud as the highest peaks. Taken to extremes, there’s almost no dynamic variation, and no moments for our ears to rest before the next point of impact.
Maximum Mona. Whether we’re talking painting or audio files, consuming every iota of available space is rarely attractive, as symbolized by my Limited Mona Lisa portrait (Image 1). We need the audio equivalent of what visual artists call “negative space”—unpopulated portions of the piece whose emptiness/quietness makes the busy/loud parts feel exciting. But countless rock and pop recordings of the last 25 years are more like Maximum Mona than Leonardo’s original. Image 2 shows what happens to a waveform when it receives such treatment. There’s more total energy, but at the expense of drama and variety.
Few audio pros dig this trend, so why do they do it? Partly it’s because our ears like loudness, at least to a degree. Our hearing isn’t linear. When music gets quiet, we perceive less low end relative to everything else. (For a scientific explanation of this, google “Fletcher-Munson curve.”)
But the abuse of loudness is about competition and fear. This attitude has long been prevalent in radio, where loudness is a genuine advantage as listeners scroll through the dial. But in the early ’90s, producers and mastering engineers launched a volume arms race. Even though many technicians knew this is a bad idea, they feared that their mixes would sound wimpy alongside their competitors’ work. Thus began what the recording industry calls “the loudness wars.”
Extra-Limp Bizkit. I first realized how extreme this was in 2001, when I was doing some in-house work at Interscope Records. One day in the studio I encountered mastered files for a Limp Bizkit track. The waveforms in Pro Tools had no peaks or valleys whatsoever. It was just a fat sausage of nasty-sounding loudness.
Here’s a quick guide to loudness abuse. In Clip 1, you hear the original mix, already with a fair amount of compression. In Clip 2 through Clip 11, I edge up the limiter setting, starting with 2 dB’s worth all the way up to a massive 20 dB reduction.
I’ve used one of the limiter plug-ins from Ozone 8, iZotope’s suite of mastering tools. It’s damn good software. It’s amazing how decent the morbidly over-limited tracks sound! But even though I monitored at low volume, a headache descended at around the time I crossed the -10 dB threshold. (Try toggling between Clip 1 and Clip 11. The contrast isn’t subtle.)
Loudness war correspondent. There’s a long chapter on this topic in Greg Milner’s Perfecting Sound Forever, a brilliant book on recording technology. Milner covers the entire history of recorded sound, with an emphasis on the ways evolving technology changes music, rather than the other way around. (Historians would call this viewpoint “technological determinism.”) He dissects such notoriously over-limited albums as Red Hot Chili Peppers’ Californication, Rush’s Vapor Trails, and Oasis’s (What’s the Story) Morning Glory?
Since Milner’s book was written, there’s been some much-needed backlash to the loudness wars. Still, at the recent NAMM show in Anaheim, one of mainstream rock’s most successful mixing engineers displayed some of his tracks on the big screen. They all looked like that 2001 Limp Bizkit track: total sausage party.
Only you can determine the amount of limiting that brings your mix to life and the amount that squashes it dead. As you experiment, consider this: If you want something to sound really loud, juxtapose maximum and minimum levels. When you hear an oldies jukebox, Joan Jett’s “I Love Rock ’n’ Roll” sounds louder than anything else because there’s silence between every big beat. Much hip-hop and EDM works the same way. The artful use of negative space can make your music loud and dramatic.
The Recording Guitarist: Maximizing Your Mix
Loud and proud? Or phony and flat?
My last few columns have focused on mastering—or, at the least, the low-budget DIY version of this complex and subtle craft. In January 2018's "DIY Mastering Tools," we looked at home recording tools that can provide a finishing touch for your mixes, with an emphasis on multi-band compression. In February 2018's "The Match Game," we looked at match EQ—a way to compare the sonic spectrum of your mix with other recordings. Now we turn to one of the most powerful but potentially destructive mastering techniques: limiting/maximizing.
Limiting and maximizing are related to compression. (See my November 2014 column "Dances With Compressors" to review the basics.) Like compression, limiting is generally used to make recordings sound louder—ironically, by making parts of the sound quieter. Lowering the level of the loudest peaks permits an overall increase in volume before hitting the non-negotiable ceiling of digital audio.
Round off, chop off, or expand? Limiting is simply an extreme form of compression. If compression rounds off the loudest portion of a recording, limiting amputates it. In other words, limiting is high-ratio compression. (Yes, you can usually use a hardware or software compressor as a limiter.) Most DAWs include both compression and limiting plug-ins, and there are scads of third-party options, often modeled after popular analog devices.
Maximizing has no precise definition. Some say it’s merely a sexy marketing term for limiting. No single company owns the term, and many use it. But generally speaking, it implies a “smarter,” more musically sensitive version of limiting.
Venus de Maximizer. Consider the three variations of Venus de Milo (Image 1). The first is an unaltered photo depicting the statue’s actual proportions—think of that as a recording with no limiting applied. In this Greek statue metaphor, size equals volume. So if Venus were a recording, we’d size her up so that the top of her head just reaches maximum loudness before distortion. In digital, that’s 0 dB, represented by the red bar. (That process is called normalization.)
The second image depicts Venus through a limiter. If we scrunch down the top of her figure (representing the loudest sections of the recording), we can increase her size/volume. But ouch! She’s grotesque and hard to look at, just as a crudely limited recording sounds grotesque and hard to listen to. It’s volume at the cost of naturalism.
The third image is the maximized Venus. Here, we’re not simply compacting the top portion—the compression is distributed across the figure. Yes, this distorts the natural proportions. But she doesn’t appear as disfigured as in the second image. If anything, she’s closer to average human proportions. (That is, with a body height 7.5 times as great as the height of the head alone.) Sometimes artfully applied maximizing sounds more natural than natural.
Pump it up. Okay, enough with the sculpture metaphor. Let’s hear what these processes might do to a recording. Clip 1 is a brief solo guitar recording. I’d applied some compression in the mix, but added no limiting after the fact.
Clip 2 features a limiter setting of -2 dB. That means only the loudest note attacks have been squished. It’s a fairly subtle setting that sounds reasonably naturalistic.
Clip 3 features the same limiter plug-in at a far more aggressive -15 dB setting. It’s an unpleasant effect, with ugly popping on the note attacks and weird distortion.
For the next two clips, I’ve substituted the Maximizer plug-in from Ozone 8, iZotope’s suite of mastering plug-ins. Clip 4 features a maximizer setting of -3 dB.
It’s louder and punchier than Clip 1, but it still sounds like a real guitar. But the overly heavy -10 dB setting in Clip 5 introduces all sorts of nasty artifacts.
Check out these screenshots from the Ozone Maximizer plug-in in Image 2.
The upper screenshot shows the light -3 dB setting. The portion of the waveform in blue depicts the degree of amplitude reduction. Only the loudest note attacks are affected, and those only slightly. Meanwhile, the heavy setting alters the audio to an extreme degree.
Strike up the band. The next five clips follow the same procedures, but with a full-band track. Clip 6 has no limiting.
Clip 7 uses light limiting, while Clip 8 is heavily limited.
There’s a light maximizer setting in Clip 9.
And an extreme one in Clip 10.
Use with moderation. The moral is pretty obvious: A little limiting or maximizing can make a track feel more engaging and energetic, but too much makes it flat and ugly. But even if you know that, it’s easy to lose perspective while applying these techniques—especially it you’re performing homespun mastering right after a long mixing session. Plus, your ego is on the line: Of course you want your music to be as loud and proud as possible! It’s often wise to make several mixes, applying settings of varying strengths, and revisit them later with fresh ears. It might also be a good idea to compare your work to commercial recordings.
Or maybe that’s not such a good idea. When listeners complain about how crappy many modern recordings sound, it often has to do with excessive limiting. And that’s a topic we’ll take up very soon.