Today someone asked me what kind of EQ i use on my mixes and if there is a difference between Linear Phase and Minimum Phase EQ's. To answer this question, yes there is a difference between the two. First lets discuss what phase is, phase refers to waveforms and the difference in time vs. amplitude (loudness) between two sources. In other words, if 2 waveforms do not line up exactly in time with each other then they will begin to sound lower in volume and sound like what most people describe as a "hallow sound", I go into more detail about phase here.
Now, lets talk about how phase comes in to play with EQ's. With analog EQ's, the frequency bands being boosted or cut are subject to phase shifts. This is because it takes time for an analog EQ to process a band when you cut or boost it, thus, resulting in that particular frequency band to be slightly delayed or shifted in relation to unaffected bands, This is phase shift! Manufacturers do their best to minimize the amount of phase-shift as much as possible, that is why these types of EQ's are called Minimum Phase EQ's. With most plug-ins we also encounter phase shifts, this is because plug-ins are meant to replicate the job of analog gear (even its latency), which is why most plug-in EQ's are also minimum phase EQ's
Finally we get to Linear Phase EQ's, so whats the big deal about them! Basically, Linear Phase EQ's get rid of the phase shifting. How does it achieve this? In essence, the plugin or digital EQ shifts anything that is out of phase back in time so it is back in phase, and it does this at very high speeds. Such accuracy can only be achieved digitally.
In my opinion Linear Phase EQ's are better, unless of course you like the way other types of EQ's sound. Just remember, use your ears and not your eyes when determining what sounds best.