Live acquire mode applies to those replaying to the browser and is seen when performing live acquire on a channel within the Monitoring area. The "Live Acquire" Media Player interface is different to that of the "Replay" Media Player interface because not all of the features are available when using live acquire. Below is an image of the live acquire interface:

As you can see the live acquire interface strongly resembles the one seen in Replay but with some features taken away and some live acquire specific features added. The "Audio Effects" and "Replay Speed" tabs work in the same way that they do in Replay and are explained in "Media Player Overview".