Zoning In The Delay Loudspeakers

Timing Is Everything
Several aesthetic questions play a big part in determining delay times and placement.

What is the intent of the show? Is it supposed to be transparent to make the stage the primary focus?

Or should it be in-your-face-loud? What is the director’s intent?

To focus the image on stage, the mains need to be set back in time, along with the delays, to let the actor’s natural wavefront hit the audience first.

In some cases, the time reference point for the system should be down center three feet upstage, others 20 feet upstage, or the center cluster is at 0 msec and everything delays to that.

Each gives a different imaging to the stage.

The first wavefront that hits the audience establishes the direction of the sound source via phase offsets between their ears.

A 25 to 30 msec window of opportunity is then available to raise the perceived level of the first wavefront by introducing a second wavefront from a different direction and at a higher level.

The art of delays is playing with this window. The closer the time is set between the arrival of the first and second wavefronts the better the articulation, but the direction clue shifts to the second arrival when more level is applied.

Delay speaker used at the Guthrie Theater in Minneapolis, MN.

The further apart the two arrivals are in time, the more level can be applied to the second until the image shifts to the second source.

The best way to set this delay is to have a remote for it in the seats and set it by ear. You can get in the neighborhood by using 1msec per foot as a rough guide. Set an average level that the mains will run. A mic being tapped will do for input, but as that drives me crazy, I use music with good articulation.

Turn the delay up until it becomes loud enough to fill in the area. The delay source will disappear by running the delay time up and down. The two sources lock just before they disappear. If the delay level comes down a little, the time can also shorten up a little.

Split The Difference
All delay settings are a compromise in time depending on how far off axis any particular seat is to the main and delay. How high the image should be is relative to where most of the audience is seated.

In some houses, two-thirds of the audience may be in the balconies. The main floor may need to have an image shifted slightly higher to improve the balconies.

At this point, walking the area covered by the delay and the areas most affected by reflections out of the delay coverage will point out remaining problems. If the delay is too loud, the reflections will be very late out of the coverage area.

The delay imaging of the stage action plays a part in the perception. If the imaging is good, the audience has enough direction clues to pick out who is speaking when many people are onstage.

Allowing the audience to read lips is a tremendous help in perceiving dialogue and filling in the gaps if a word or two is lost. Imagine Vincent Gardenia doing the dialect in I’m not Rappaport, which is tough to project 110 feet. Sometimes, we need all the help we can get.

As simplicity is genius, the fewest speakers with the shortest delay times are the goal. The bottom line is that the audience should leave talking about the show, not the sound.

A former Sound Department Head for the Ordway Center in St. Paul, Jim Pfitzinger is a freelance engineer with extensive background in facility construction, renovation and sound design.