Here is a picture - wasnt ablw to upload a video.

Have you ever been to Niagara Falls or even some small waterfalls? All quite noisy.

I have never met a quiet water feature! They can be loud enough that people sometimes install them to mask nearby highway/traffic noises.

Maybe the opening behind it is making it worse?

We had similar water features on our other pool, but this one is different. Our other one was loud, which is fine. This one literally has a pulsing sound, almost like there is air in the line or something which is causing the sound. The sound is coming before it ever makes contact with the pool.

Maybe you can test the acoustics of the opening behind the waterfall by covering it with a few layers of tarp or some other surface and seeing if it improves the noise?

I've been in resort pools with that type of "grotto" behind the waterfall and they are always extremely noisy and impossible to hear or hold conversations when swimming near or in them.

While I am not as familiar with pumps installed for a waterfall application, I am very familiar with pumps used for swim currents, and noise is always a formidable drawback with these units. Some people solve the problem by locating pumps a good distance away from the pool and within sound-resistant enclosures. Waterfall and other water features are often used in pools to mask other sounds such as that of overhead planes or nearby streets. When this is the case, the noise of the water is seen as a benefit. You seem to be complaining more of the noise of the pumps and piping than the water, however, and this is something that should have been known and told to you early in process of your build. Several solutions such as reducing the size of the pumps or locating them further away would be expensive to change at this point.

We have the opposite problem -- ours was a perfect volume so we could hear it in our office, but after re-tiling and resurfacing, we can't hear it at all. Any ideas for how to make it LOUDER?

If you cannot open a window or two to let the outside soundwaves penetrate better, it would be a simple thing to purchase and run an indoor water feature, of which many sizes and styles are available, if the noise alone is your primary concern.

My water feature does the same thing you are writing about. did you figure anything out to resolve this?