Along with "best sound ever" and "they had great energy," one of the most commonly uttered sentiments among concertgoers is the confusion over how a certain band or musician could rock so hard in a live setting but not transfer that same energy on record, or vice versa. Part of this has to do with the dynamics of a specific performance at a specific time in a specific place - crowd/performer interaction, band chemistry, venue acoustics, and so on - but part of that also has to do with what some musicians will or won't do to alter their sound for live performance. For some performers, this simply means eating a lot of carbs or drinking a ton of coffee before hitting the stage; for most, this means relying on some simple yet effective tricks to make the live experience hit the listener harder than expected and in places deeper than just the ears.
Tune Down and Transpose Accordingly
This may sound self-defeating or just as a way for bad metal bands to fake their way to greater intensity, but in truth this is a quite common tactic by performers of all genres. For singer-songwriters, for example, this could be as simple as moving the capo down a step or two; for many straight-ahead rock bands, it usually means tuning all the instruments down half a step and playing everything in that slightly lower key. Not only does this force a slight (though not detrimental) punch without altering the core of the song, it also saves a little wear and tear on your singer's voice.
Double Your Percussion
Okay, maybe having two drummers on stage is entirely impractical. However, with most of what makes something rock being a combination of low-end rhythm and front-end attack, it makes sense that bolstering the rhythm end of your sound can only help when aiming for the gut. This may be as simple as rearranging drum parts to focus more on the floor hardware than on the snare, or as complex as adding double-bass patterns and tom fills where there were none. Contrary to popular belief, this won't automatically double the volume of the onstage music; the laws of physics actually dictate that while the specific decibel level will be raised, the total volume will be but a fraction higher (ten percent per decibel, as volume is a logarithmic rather than linear function). Joe Strummer once said, "You're only as good as your drummer," and he wasn't just speaking in terms of time signatures or triplet fills; percussion does more to shape the sound and energy of a song than any other single element. It makes sense then that as the rhythm section goes, so goes the entire sound of the performance, so it might also make sense to…
Boost the Bottom End
While plenty of what makes for a great show is what the listener hears, just as much is a product of what the person feels - literally, as in what physical sensations the music emanating from the speakers trigger. A lot of electronic and dance music is written and produced with this specific idea in mind, as is a lot of hip-hop music, but very few people capitalize on the idea when they hit the stage. At the most basic level, this could mean turning up the bass levels on the amplifiers or the house mixing console. For the craftier musician, this could start with raising the bass levels on the guitar amps, or even running a signal feed from the rhythm guitar amp through a bass amp, thus allowing that guitar to act as two guitars, and to have a bassline doubled in perfect unison to the rhythm guitar. Suddenly, a duo becomes a power trio and a power trio becomes a four-piece. Four-piece outfits would in turn have two guitars and two basses, creating a whole new arena of sonic possibility. Imagine having not just guitar-and-bass unison runs, but guitar-and-bass unison solos.
Another option is to runs effects on bass instruments to warp the audible element of your group's lower end. A distortion pedal, for example, allows the bass to double as a rhythm guitar without overpowering the original guitar. Throughout the album Sonic Brew, Black Label Society did this masterfully as a power trio, as the distorted bass also opened up a new world of arrangements and effects to update the sound of the group's old-school style of guitar-based rock .
Layer Those Keyboard Sounds
Keyboards, synthesizers, and electric pianos present their own worlds of sonic fusion, and also some of the easiest mechanisms for adding that extra punch on stage. Most keyboards have a feature to either split in two (where each half of the keyboard controls a different sound or patch) or to play two patches simultaneously. If your keyboard features independent volume and release controls, you're in a great position to add slight touches of bass, percussive ticks, or even a lower-octave doubling of the normal key section to what's coming out of the instrument.
Play Through the Bridge Pickup
In the case of electric guitars, the bridge pickups are almost always designed with mids and lows in mind, rather than the mids and trebles neck pickups are meant to handle. Switching pickups will certainly alter your guitar tone drastically, but so will the transition from a contained studio environment to an open performance venue. Using the neck pickup will force a more cutting tone out of your guitar, which will add to the force of the end result. And while experimenting with tone is key, perhaps the biggest element to making any string-based performance rocker harder is to simply...
Mute Your Attack
This is one that requires no cables, no tweaking, and no investment in additional gear, yet makes the biggest difference in any string instrument. Even by adding the slightest touch of the palm behind the bridge, a staccato element is added to any guitar line. The reduced sustain then puts the leads more in line with the punch of the drums and limited holding power of the bass, meaning each note from each instrument goes from hanging in space to assaulting the listener in one larger concerted onslaught.
Of course, this approach might not make sense in all settings. Classical musicians, for example, may find it more suitable (not to mention tasteful) to avoid tampering with the source material, and most musicians are pretty happy with what they've worked so hard to perfect. But for a lot of bands out there, a little heaviness at a given show can mean the difference between "they were alright" and "they rocked." And really, isn't maximum rocking the whole point?