In the July 2012 FRONT of HOUSE, we talked about using various types of fill speakers such as front fill, under-balcony and out fill speakers to augment the main P.A. system in a room. This month, we’ll discuss front fill mixing in detail so you can have an idea regarding what sources go into the front fill, how to route it and when you may need it. In short, a front fill is a speaker or small array of speakers designed to provide sound for the front few rows of a venue.
The Problem
Sometimes a front fill is needed because those front seats (a.k.a., the “money $eats”) might be positioned close enough to the stage where they provide a great view but in fact are outside the field of coverage of the P.A. system. While wonderful for watching, these seats (or standing positions) are terrible for listening. This of course, provides new meaning to the phrase “I saw a band last night…” Often this happens in rooms where the front seats are close enough to the stage that the P.A. is actually behind them.
The result is that those audience members hear “wraparound” from the P.A. (i.e., the part of the frequency spectrum with wavelengths long enough to bend around the cabinets such as low mids and below) but they do not hear the upper-mid and high frequencies because those frequencies are much more directional and beam right past the listeners. Thus, their version of the mix features tons of toms and bass, chunk from the guitar cabinets and little to no vocals. If they happen to be sitting in front of a raging instrument amplifier (like, that never happens) they’ll be assaulted with that in lieu of hearing vocals or guitar solos.
In the days when bands blasted away on stage with huge amps and a complement of stage monitors that could rival a club P.A., the need for front fill was less critical. The wedges actually helped the front row people hear vocals and other elements of the mix, even if they couldn’t hear those sounds coming through the main P.A. system. Fast-forward to 2015 when even local club bands can afford to use IEM’s, and the stage monitors no longer offer that service to the money seats. That’s when front fill becomes a necessity instead of a luxury.
Solutions
The questions are: how do we route audio to a front fill, and what sounds do we feed to it? Some P.A. systems are configured to send the L/R mix, mono, or perhaps a matrix output from the console to the front fills but I’m not crazy about this idea. Does a guy sitting in front of a Marshall 4×12 really need to hear that guitar in the mix? Probably not.
An important decision when adding a front fill is what type of speaker to use. Compact cabinets are a must so that sightlines can be maintained. In some theaters I’ve worked, front fills are a pair of P.A. speakers (sometimes cabinets as large as 2x15s and a horn) sitting at the downstage corners, angled in toward the middle of the room. This approach certainly increases coverage, but it’s kind of a brute-force approach. You have to crank those boxes to reach the middle of the room, and the horn dispersion angle may not be tight enough to keep audio focused where you want it, resulting in phase issues with the main P.A.
I’d much rather use a low-profile box with wide horizontal and a narrow vertical angle of coverage. For example, a cabinet like the VUE Audiotechnik al-4 provides 90-degree horizontal coverage, 10 degrees vertical, and the box is only about 6 inches high. Placing a few cabinets with that type of profile along the downstage edge is a much more effective solution. They can be run at lower levels, and the tight pattern control means less audio confusion to a listener’s ears.
Most small cabinets won’t produce a lot of bottom end, but that’s OK, because we don’t need kick drum or bass in the front fill. For that reason it’s not a bad idea to patch a graphic EQ on the send to the front fill amplifiers, and dump out a fair amount of bottom end to protect the speaker. Certainly I’ll remove everything below 100 Hz, and in some cases I might raise that frequency up to 150 Hz or even 175 Hz.
Some engineers have had success using a “downfill” for the front rows, basically a speaker or set of speakers firing down at the audience from above. The good thing about downfill is that when people in the front row stand up, they won’t block other rows from hearing the fill. But the positioning and dispersion of cabinets used for downfill needs to be very accurate to ensure that sound doesn’t reach the performers on the stage where it would disturb their monitor mixes.
What’s In The Front Fill Mix?
Typically the first (and most important) elements of the mix that get lost in the front rows are the vocals — especially when the band is using IEM’s. An aux send feeding the front fill lets you dial in only those channels needed in the coverage area (see? We really are in the business of sound reinforcement). It also means that a sound check is required. You’ll have to get off yer duff, walk down to the front row, and listen from there while the band plays a few songs. That’s the only way to know what’s lacking in those front rows. Lead and background vocals are almost always a must, but I’ll often add a bit of the vocal effects and lead guitar to increase clarity. The guitar and effects are typically at a level 20 to 30 percent of that for the vocals.
Sometimes it makes sense to use two different sends to feed the front fills. For example, it can be helpful to send a stage right guitar to front fill situated on the stage left side, and vice versa. This sort of cross-mixing means that even if a patron is sitting in front of the stage right guitar amp, they’ll still be able to hear a solo played by the stage left guitar player. I always use post-fader sends for the fills so that the fill level of a vocal or instrument changes along with my FOH fader moves. We want the patron$ (or mosh pit) to hear the same variations in the house mix as the rest of the audience hears.
When you are setting up a front fill, pay attention to any delays that might be applied to the main house speakers. Some P.A. systems are delayed to the backline, a practice that can often reduce phase issues caused by the distance between the backline and speakers. If the mains are delayed, then so should be the front fill speakers — especially since the front fill speakers are likely to be closer to the first rows of seats than the main P.A. hang.
Start with a rough delay of one millisecond per foot and work from there using your ears. You shouldn’t be able to hear a sound come from the fill speakers before or after the main P.A. produces it.
With a little extra attention to detail, you can provide a great mix to everyone in the venue.
Steve “Woody” La Cerra is the tour manager and front of house engineer for Blue Öyster Cult.
