How long do Black Flute repel and White Flute attract effects last?

I walked a thousand steps through filthy ash to get Black Flute which is supposed to repel wild Pokémon. This is what it says:

A glass flute that keeps away wild POKéMON.

And the White one:

A glass flute that lures wild POKéMON.

I've read Bulbapedia on the topic, but I'm not satisfied - it doesn't say how long the effect lasts.

I can't see any effect after using any of these. How long do they last?

2 Answers

Black Flute:

Reduces wild Pokémon encounter rate by 50%.

White Flute:

Increases wild Pokémon encounter rate by 50%.

According to Bulbapedia.

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Regarding the duration, there's a controversy about their effects.

As different people on GameFaqs suggests here, here and here:

White and Black Flutes should only work for one step each time they are played.

However, on this forum is explained that:

The White Flute and Black Flutes raise and lower the encounter rate, respectively. They last as long as you're in the general area you used it.

6

They stop working as soon as you change screens (I. E. go through a door, enter a cave, etc.) I only know this for Emerald as it's the only one I've played, but I would be interested to hear the results for R/S and OR/AS.