very annoying

If only the sound of the armour had been the only annoying thing about this movie... at least to me.

I'm a Sidekick and proud of it.

The sound of armor was one of the least annoying aspects. That's probably how knights in armor sounded in those days. What annoyed the hell out of me was the overuse of the same horse neighing sound effect every 30 seconds or so. If you insist on going overboard with horse sounds throughout the film, at least have some variation! The sound effects of the tournament were also very amateurishly done, such as the totally unconvincing crowd cheering. The monotonous intonation of the dialog was unnatural, which is always a major turn off for me (for the same reason I don't like Werner Herzog's Heart of Glass).

I liked how the film looked visually, and for that reason alone I can't say that Lancelot du Lac is a bad film overall. But I just found it impossible to suspend any disbelief.

It was a reminder of the film's realism, the harsh metal sounds representing violent impulses, the clanging metallic dronage emphasizing Bresson's automatism trademark in the sense that the armour can't help but make that sound just as humans can't help but feel love and lust and envy and rage and can't help but act upon the aforementioned. The armour and the horses lacked the freedom to choose to remain silent and the knights lacked the freedom to extinguish their emotions and refrain from war-mongering. Bresson's directorial theme that there's a machinic nature to order which humans and animals and the inanimate are all caught up in, auto-pilot mode, including the automation of being slaves to emotion, making it virtually impossible for humans to attain spiritual/religious enlightenment. The machinic autopilot trappings thwarting the search for the purely abstract (the Grail, G-d, spirituality, real genuine love, etc). The outer machinic thunderings also the inner smithy thrashing away.

Does anyone agree with me that the sound of the armor was real annoying?

Hardly annoying... it definitely helped set that "realistic" atmosphere. A tiny detail that brings some conviction to the visuals.

Clear eyes, full hearts, can't lose.

I didn't mind the armor, because that at least seemed realistic and the sounds changed.

The horse neighing though, was the same sound bit repeated to death. I swear there was only 2 or 3 different variations that appeared throughout the entire length. Still enjoy to me as a movie, but delete some of the horse neighing, edit down the jousting sequence and it would have been much better.