Virtually every production company will come to a point in business where they start doing events in rooms colloquially referred to as “soft seaters.” These are the concert halls, civic centers, theaters, churches, converted movie houses, auditoriums, collegiate centers, etc. that host everything from plays to bands to politicians. Soft seaters can be great venues: a fair number were designed with some acoustic intent and/or treatment, and the better ones are well equipped to support a production company’s infrastructure.
One feature, though, that creates headaches for pro audio in these rooms is the presence of balconies. Visually speaking, balconies are powerful tools. They connect more of the audience with the stage in an intimate manner than what would be otherwise possible with flat seating, and this increases the number of desirable seats for audience members. Since balconies are here to stay, this article will tackle some of the sonic constraints imposed by them. We will look at the acoustic environment they create and how to cover every seat in the house more effectively.
Changed Geometry
The first limitation imposed by a balcony is to change the geometry of the audience. To investigate how this works, we first consider a venue without a balcony. In this venue, the audience is typically on a single level, or audience plane. This audience plane is flat, or slightly sloped. With all the audience members on one level, the preferred location of the P.A. is straightforward. Namely, the higher the speakers are hung, the smaller the difference in distance between the front and back of the audience. Because sound is attenuated with distance, we desire every audience member to be a similar distance from the speakers to achieve the most even coverage.
In a venue with a balcony, by contrast, hanging the speaker arrays high results in creating a “shadow” below the balcony where the array does not provide any high frequency coverage at all. Alternately, if the speakers are placed at the stage level, the people in the upper balcony can be a very great distance away from the speaker arrays. Neither of these scenarios will result in even coverage across the venue. Balconies fundamentally redistribute the audience across multiple planes, and this creates complications for even coverage.
Changed Acoustics
In addition to the changed locations of the audience, the presence of a balcony results in different, but not necessarily worse, acoustics than the typical flat venue. Foremost, venues with balconies tend to have higher ceilings and greater overall internal volume than venues without balconies. Higher ceilings mean that reflections arrive back at the stage later, and larger rooms tend to have longer overall reverberation times. Now, soft seaters generally have enough strategically placed absorption to avoid distracting discrete reflections, but their overall decay character will be markedly different than typical single level venues.
In a single level venue, reflection off the large, exposed back wall tends to be the sound provider’s nemesis. By contrast, the area of the back wall in a room with a balcony is generally fairly small. Instead, the balcony seating surface itself has the potential for reflections, as well as the front face of the balcony. A full balcony is generally fairly absorptive, thanks to the inherent absorption of the audience members, but an empty balcony can drive sound energy back towards the ceiling and the stage.
The front face of a balcony typically responds like a miniature back wall and can produce a distracting reflection at the stage. An increasing number of venues have applied absorption and/or angled the balcony front wall to reduce reflections, but this is not a common feature in older rooms.
The area under the balcony can also produce some strange acoustic behaviors. One common effect is dramatically different low frequency behavior under the balcony than in the main room. The area under the balcony may also cause delayed reverberation back at the stage, not unlike the echo chambers that were built adjacent to early recording studios.
It should be noted that a soft seater is preferable to the metal-roofed concrete boxes that are too often called “venues.” An average day in a good soft seater venue, balcony or no, will most likely be better than the best day in a concrete cave or tin-roofed armory. We highlight the differences of absorptive rooms with balconies to help the provider feel at home when providing for these venues.
Succeeding with Balconies
With balconies providing a different audience layout and different acoustic effects, how can we configure the sound system to have a great show? The first and essentially universal goal is to cover the audience. Or rather, don’t cover where there is no audience. There is a lot of subtlety involved in the placement of speakers for balconies, and it starts with determining how ticket sales shape where the audience ends up. If the balcony doesn’t sell, it is advantageous to design the sound coverage in such a way that the portion of the system aimed at the balcony can be turned off.
In many circumstances, providing coverage to the balcony will be easier if the fill loudspeakers of the installed reinforcement system can be used for support. This assumes the fill speakers are well tuned and capable of producing sufficient volume. This, unfortunately, is not usually the case. In a perfect world, the provider’s P.A. can be supplemented by both the balcony fill speakers and the under-balcony fill speakers.
Speaker Placement
In the days before vertical “line array” systems became widely requested on riders, flying different arrays for different locations was commonplace in venues with balconies. In shallower rooms, flown arrays to cover the balconies can be successfully paired with ground stacked systems to handle the floor and under-balcony area. If the client is amenable, strategically located trapezoidal arrays are a good solution to cover each area of a soft seat venue, assuming one has the load in time to setup and configure each array.
If the client dictates a vertical array, or time constraints favor the deployment speed of vertical arrays, then an expedient plan of attack is to position the arrays lower than one might otherwise. Lower positioning of the array will aid in high frequency coverage under the balcony from the main arrays. Alternatively, under-balcony coverage could be provided by a fill box placed below the vertical array or by hanging the main array deeper than one might otherwise. Of course, sight line considerations may compromise the available locations for a provider to fly the loudspeakers.
By this point, it is probably apparent that the location of the main arrays depends largely on the quality of the under-balcony fills, particularly at high frequencies.
Low and mid frequency energy will diffract around and under the balcony, but the shorter wavelengths at high frequencies are likely to be reflected from the balcony face. If the under-balcony fills are capable of supplementing the high frequency energy of the main arrays, this can provide additional flexibility in locating the main speakers.
Conclusion
Composing this article is a reminder of how valuable a modern measurement system (e.g., SMAART, SIM 3, Systune, and SpectraFoo) is for a balcony environment.
With numerous zones of speaker coverage spread throughout the venue and a mixture of portable and installed equipment, a measurement platform is a huge help to quantify the performance of each zone and make changes to the processing.
Our goal is to make the system more cohesive and provide uniform voicing at every seat. In the heat of battle, a measurement platform can help supplement tired ears and speed system deployment.
Personally, some of my best shows have been in soft seater venues. The additional details of setup, covering the balcony, aligning the arrays, and voicing the system can lead to a show with excellent sonic texture with an intimate experience for the audience.
When the audience gets drawn into the performance, the results are electric for everyone involved.
Six Tips for Improving Balcony Sound
• Zone the P.A. processing by audience location — e.g., main floor, under-balcony, mezzanine, upper balconies, etc.
• Bring extra processing, if necessary, to put between the mixing board and the fill loudspeakers — they are going to need tweaked to complement the main P.A.
• Whenever possible, cover the balcony and the main floor with separate arrays.
• Place the FOH position in main room — under the balcony usually has too much low-end and sometimes inadequate high-end.
• You may need to compromise on system voicing — the balcony, under-balcony and main room will all have different sonic signatures. If you balance for one location, the others can be very different.
• Pipe and drape the front of the balcony — not usually practical, but effective.
