Another common shelving technique involves narrowing the scope of frequencies that are allowed to pass on to the master channel of your mix. You can do this by shelving all of the unwanted frequencies and leaving only the desired frequency. A good example of a 1k pass (or shelved EQ) being used as a bullhorn effect can be found here: Bull Horn Effects
When we narrow down our frequency focus range we discover that there are many useful EQ settings beyond simple mixing and shelving settings. The EQ may not seem like a glamorous piece of equipment but in reality it makes everything you hear sharper or, in extreme cases, it can completely wreck and entire project. So if you are working around the 1k frequency range you can shelve your EQ immediately before and/or immediately after the 1k band to achieve the telephone and bullhorn effects as explained in the link above. Go ahead and shelve each band and listen to the effect. You will notice a wide range of uses across several genres of music. Big bass drum sounds for dance music or crispy-crunchy rock guitar sounds can be shaped with your track EQ.
Processing combinations of frequencies can also be applied. Some engineers will set their guitar track EQ in the shape of a “V” so that the guitar track doesn’t step on the vocal tracks frequencies. Alternatively the vocal will have more of the mid range frequencies as it should be further forward in the mix than the supporting instruments. You can also apply shelving techniques to any track by using a wide range of the natural frequencies produced by a drum kit all the way up to the range that the human voice produces. Ultimately you will want to use the natural frequency range that each instrument or voice produces unless you are creating an effect. Using a 1k filter on a guitar will leave a lot more room in the allowable frequency range for the bass and drum tracks. So you can see there are many tricks that an engineer has available to sculpt the best overall mix and they start with a good equalizer.