I can't seem to move the tempo slider. How do I change the tempo?

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 This was a problem with Beat Vibe in versions prior to 2.0. The built-in slider of the iPhone OS is has a very small sensitive area and the touch screen is sometimes not accurate enough. The result was that catching the knob of the slider was very difficult, this happens with other application that use the slider control, even Apple's own.
As of version 2.0 the slider code was re-written to override the default behavior and is now easy to select. if You are using a prior version, please update to the latest version.