That photo's bizarre - I can't judge the size of the speaker at all. It could be 100m tall or 10cm tall. The article says it's 30 feet (10m), but in that case the bushes must be really tall, and the flag really tiny.
There are 8 rows of holes, and the top and bottom "margin" seems to be about one hole high. A person would stand roughly two holes high, so most of the ground cover would be shin height with occasional knee height shrubs, which seems reasonable. The flag pole is probably set back from the front surface, so some of its height is obscured below the upper edge. There's probably some perspective distortion happening, too.