Why "off" in "off to the sides"

Solution 1:

Compare:

Even people off to the sides of these stage speakers enjoy well-balanced, detailed sound...

to:

Even people to the sides of these stage speakers enjoy well-balanced, detailed sound...

In this case, there's the chance of misinterpretation if off is left out. It could sound like the people are directly at the sides of the stage speakers. Off to the sides, however, clarifies that there is distance at play and makes the sentence make more sense.

In other cases where it sounds unnecessary, it may be kept for sonorous purposes. In other words, we say it because it gives the feeling of the language flowing or maintains the rhythm of the sentence.

As another example, compare:

The attack came not from the monster before her, but from those off to the sides.

and

The attack came not from the monster before her, but from those to the sides.

In the first example, it's implying a long-range attack; are they shooting her with an arrow?

In the second example, it once again doesn't sound as far away. Maybe they're directly to either side of her or either side of the monster in front of her. In this case, it could conceivably be a close-range attack.

Solution 2:

"off":

1 down or away from a place or at a distance in space or time

I fell off the ladder. Keep off the grass! an island off the coast of Spain They were still 100 metres off the summit. Scientists are still a long way off finding a cure. We're getting right off the subject.

2 leading away from something, for example a road or room

We live off Main Street. There's a bathroom off the main bedroom.

3 used to say that something has been removed

You need to take the top off the bottle first! I want about an inch off the back of my hair.

Edit upon comment:

"at" is certainly static. It also implies higher precision of where somebody is standing. In the examples you write, the focus isn't on the people's exact position but on the fact that they are standing away from where the action is taking place.

I suspect that what bothers you is the use of the preposition "to" which is usually connected to movement. Since there is no further context, it might be possible that the people in your sentences are not totally immobile but are standing off at the sides readjusting their position (or forced to do so) to make sure that they will be away from the main focus.

Solution 3:

It's an unnecessary word and doesn't imply movement, but it is used to emphasize the distance just slightly. "Pedestrians pushed to the sides" makes sense. But "Pedestrians pushed off to the sides" means they are just farther away or that the speaker wants to emphasize that more.