You should also elevate the mics above the
stage somewhat, a
foot or so at least. Otherwise you'll
pick up a lot of footsteps.
The problem is that by raising the mic off the
stage you can then encounter reflections off the
stage causing
combfiltering at the mic. It is usually best to either keep the mic as close the boundary surface as possible, the concept behind boundary mics, some distance away from the boundary or to have a boundary that is absorptive at the frequencies involved.
I haven’t posted any photos of the threat I am in but it sounds the save just not a curved
stage. I have seen those fill speakers and they do look like they work might try and see if we can get some, because they will be at the front of the
stage wouldn’t you have to place some further up the audience to make sure people at the back can hear well?
The main body of the audience should be covered by the main speakers, front fills are usually to add just what is needed for those seated in the first few of rows due to their being out of the main coverage of the main speakers (a result of locating, aiming and selecting the main speakers to reduce the levels on
stage and increase
gain before
feedback) at some frequencies. Thus fills are usually fairly low
level and primarily higher frequencies since the mains are likely less directional at lower frequencies. Front fills are often delayed to the natural sound on
stage.
I calculate any required delays based on the distance between my acoustic source, and the
FOH line. Anything less than 15 to 20 ft I don't even both with. I also don't bother if it's just spoken word or dialog since my experience is that once I mic an actor, they quit projecting and the acoustic component is minimal. Beyond that, the rule of thumb is 1ms per
foot. Again, this is measured from the plane of the sound source relative to the plane of the
FOH line.
Delays can be important for spoken word since it can affect intelligibility. How much delay is appropriate, and whether it is needed at all, depends on the situation. For one thing, any delay is relative to the distances from the natural source to the listener as compared to the distance from the
speaker to the listener. Most theatres have more than one listener which means that these relationships vary for different listeners. If you do have just one listener, then delay time for the speakers is probably well down the list of things to be worried about.
A related factor in setting any delay is that not only do you have a listener area rather than a finite
point, but you also often have a source area rather than a finite
point. Now the
speaker locations become the only fixed reference with a range of natural source and listener locations. This makes determining and setting any delays a sort of "best fit" exercise, what helps overall without negatively impacting specific locations to much. With a band performance some people will delay to the drums since that is often the source of the most impulsive, and fairly high
level, natural sounds and thus the ones that may most readily show any differences in timing.
Another factor is that you have to think in three dimensions. If the speakers are overhead then they have some delay from the vertical distance to the listeners, in fact you can readily get to where you have to worry about having too much delay if the speakers are too high. For many applications with speakers mounted over a
proscenium, that alone may provide sufficient delay to make the sound appear to come from where the actors are on
stage.
Then there's precedence or
Haas Effect, where you intentionally delay a secondary source such as a fill
speaker by an additional time, typically 10-20ms, relative to the natural sound or primary source so that the natural or primary source takes precedence in establishing localization or the location of the source. This works even when the secondary source
level is 10dB or more greater than the natural or primary source
level.
The
point is that while a simple two dimensional estimate may get you started in assessing potential delay times for speakers, the actual settings for
speaker delays are usually something that has to be verified and tweaked in the field.