Are pitch-lowered bird calls what dinosaurs sounded like?

Something nice, perhaps even wonderful, is going viral! Are birdcalls "slowed down", or lowered several octaves, examples of what the dinosaurs would have sounded like?

A reddit user debunks the speculation, but substitutes an experimental effort to recreate dino song, by sound artist Courtney Brown.

Actually, though birds are descendants of dinosaurs, their voiceboxes (the syrinx) have no evolutionary precursor organ. The syrinx also didn't evolve until after the KT extinction, so this video really has no relation at all to what dinosaurs may have sounded like. Going even further, there is no evidence that dinosaurs actually had voiceboxes, as it is a soft tissue organ, which don't fossilise well.
The sound dinosaurs made probably came from resonating air in nasal/skull cavities...

Anyone with an ounce of scientific credibility knows that dinosaurs sounded like Norm McDonald standing on a British plug.