- by Steve LaCerra
in Theory and Practice
Last night I had the most amazing dream. Frank Sinatra called to tell me he was putting a tour together. When he woke me up, I tried not to sound annoyed. After all, it’s been a long time since we spoke. I think he may have been in a different time zone.
Sinatra: “Woodman, I’m putting the band back together.” (Only a select few get to call me that.)
Me: “Frankie Baby, which band?” (Only a select few get to call him that.)
FS: “The Basie Orchestra. I’m pulling everyone out of retirement, and we’re gonna do it like ‘Live at The Sands.’”
Me: “Awesome, what do you need?”
FS: “I want it to sound amazing. My agent says demand for tickets is gonna be high, so we’ll have to bring it into arenas. We might even have to blow out some basketball games from those lame NY teams. I want you to get the best gear money can buy. Don’t worry about costs, just do your thing and make it sound like the record. Call Capitol and tell them I want that microphone back for the tour. We’ll insure it.”
Me: “Okay, Frankie, but I still see one problem: the acoustics in these rooms suck. They’re huge reverb chambers.”
FS: “Like that one in the Capitol Studios basement?”
Me: “No such luck, but I have some ideas that could fix it…”
FS: “Well, get moving on it! What part of cost no object don’t you understand?”
I hire a carpet company to go on the tour and lay carpet on the floor under the orchestra seats. Then I ordered a truck full of portable acoustic treatment that we could bring in to treat some of those nasty concrete walls that bounce sound around like ping pong balls.
Reality (Sound) Check
Then I woke up. Fifteen degrees, six inches of snow on the ground and blizzard whiteout conditions. Ugh. Back to the cold, and the harsh reality that most of the rooms we work were not designed for amplified music. Hostile environment plus hectic schedule equals major challenge. What to do?
Start by evaluating the room. Play a CD (yeah, that’s right, a CD, with 16-bit/44.1 kHz audio — not an MP3) and listen. Slowly turn it up and listen how the P.A. interacts with the room. Some rooms have a “sweet spot” in terms of the volume at which you can play before the P.A. overcomes the entire room. Find it. Try to work with it instead of fighting it. Loud may be okay, but loud and clear is much better.
Walk from the mix position down to the front rows and listen to how the coverage changes. Sometimes, when an array (line or traditional) is hung in a theater, the hang points are such that the first few rows of seats are actually behind the P.A. system. In the old days when we had wedge monitors blaring at 104 dB, the bleed into the audience actually helped cover those first few rows, allowing them to hear vocals. These days, IEMs don’t bleed into the audience (at least I hope not), so you need to make sure any instruments that are soft on stage get extra coverage. That’s where the front fill (or edge fill or lip speakers) comes into play. You can easily use a few small powered wedges aimed at the audience for fill. Send the vocal channels to those wedges from an aux send. If your entire band is really quiet, you can use a matrix to feed the L/R mix bus to the fill, but usually it’s the vocals that most need reinforcement.
Some Simple Diagnostics
If you have access to the system processor, listen to each frequency range (low, low-mid, mid, high, etc.) separately. Feed pink noise through the system and mute all of the processor’s outputs. Now unmute each frequency region one at a time, on each side. You may be able to start balancing the P.A. by adjusting the level of the processor outputs before you reach for the EQ. Patch that CD player into two input channels and pan them center. Then unmute (for example) the left and right mid outputs. Listening in mono enables you to determine if there are sonic differences between the two sides of the PA.
Do the same for all of the processor outputs. Running a click or side stick sound through a P.A. can give you an idea if Mains, Subs and Fills have been properly time-aligned (a pocket metronome comes in real handy for this. You can patch it through a DI box). When you play that click, do you hear flams or echoes? If so, then the time alignment is off. Remember the general rule… delay = 1 millisecond per foot. If the under-balcony fills are 52 feet in front of the mains, they should be delayed roughly 52 milliseconds (many processors can display delay time in feet anyway). Ditto for the mains and subs: If the mains are located six feet behind the subs, then the subs should be delayed by about 6 ms.
House EQ and Slap
The house engineer has probably spent way more time in the venue than you have, so rely upon their experience and use their house EQ as a starting point. When recalling a scene from a digital desk, we often have an EQ on the L/R bus that’s either flat or has nothing to do with the current venue because our last show was in a different room. Use your phone to take a photo of the house engineer’s curve before you recall your scene so you can duplicate the house curve. If you don’t like it, you can easily bypass or adjust it, and you may find that he or she has already done a lot of the work for you. The need to hack away at a 31-band EQ on the L/R Mix bus indicates there’s probably another issue with the P.A. system. Having said that, try to use the EQ to cut where possible as opposed to using it to boost. Boosting bands adds gain and reduces system headroom. Many rooms have issues around 100, 125 and 160 Hz, and sometimes a P.A. sounds like it “has a cold” due to too much energy in the region of 250 to 300, 400, or 630 Hz. Cut a few dB and listen to what happens. You can always return it back to unity. You may be able to tame some high-frequency splash from reflections off hard surfaces by cutting at 2.5 or 3 kHz and then again around 4 or 5 kHz.
When you look at the balcony from the stage, you typically see a short wall under the balcony rail. That wall can create a nasty slap-back echo to annoy the musicians. There are two ways to eliminate this: (1) acoustic treatment or (2) ensuring that the balcony fill speakers do not direct sound at those areas. Changing the angle of a speaker a few degrees can make a world of difference for the audience and the performers. And speaking of speaker angles and deployment…
The Ghost of James B. Haunts You
Manufacturers of P.A. speakers go to great lengths in performing calculations and designing cabinet geometry so that we can buy their speakers, configure them in a recommended manner and achieve a reasonable amount of success. Don’t try to reinvent the wheel. You are deluding yourself if you think that your revolutionary deployment of said boxes will be better than those that the manufacturer has researched and recommended to you.
A small dinner theater where I’ve worked many times over the years is very reflective — a concrete floor and no cushy seats to absorb sound. The room has trapezoidal boxes ground-stacked on either side of the stage, and the first few times I worked there, it was a struggle. At one point, I returned to find what looked like a junk pile of speakers. The house engineer boasted “I really dialed in the P.A. now. Look at how we’ve changed the speakers.” What I saw and heard can be described as nothing other than horrific. Some of the boxes were placed vertically, others horizontally. The comb filtering I heard when walking through the room would have made a guitar stomp-box manufacturer proud. But James B. was probably rolling over in his grave. Follow the bloomin’ directions.
Steve “Woody” La Cerra is the tour manager and front of house engineer for Blue Öyster Cult.