Hold on a minute!
I think this thread is getting confusing - and just ignore the hell out of me if you don't agree after reading this:
What is "in your face" - A sound / instrument(s) / vocal, part of multiple tracks which make up a recording, but with a dominant up-front position, which seems to generate from inside your head, rather then the speakers.
Drums can be 'in your face' - a brass section can be 'in your face' - even a string section can be 'in your face' (remember some ELO recordings?) and of cause vocals can be the same, even backing vocals.
Does this mean that, in order to get an 'in your face' sound, you have to boost or cut certain midrange frequencies? Well - for some instruments, like a vocal, this might help to make the sound more penetrating, easier noticeable. But that should never be done if it disturbs the overall quality of the sound.
For those of you familiar with psycho acoustics, there are brilliant techniques to make things come from inside your head. This can involve logarithms of all kinds - really cool stuff if you're into that sort of thing - horrible if you are not.
A sample of an application of psycho acoustics on a vocal is Uru's song You Know, which is bass & drums with some bastardized water flowing. Play it in HiFi stereo and you'll hear a very strange space effect on the vocal. The downside (and fun to try) - play it in LoFi and the lead vocal almost totally disappears.
Its at
http://www.mp3.com/uru
Slightly off the subject, there is another psychoacoustic effect in the song Gypsy Girl - about 2/3 of the way down in a spoken bit, very weird effect! If you'd hear it in 5:1 it would freak you out.
So how do you get an 'in your face' effect without upsetting the sound quality or balance of your mix? And without the use of logarithms? The problem - it varies, depending on what and how your mix is planned. But there are some cool things to try. And I mean TRY - these are things you have to do for yourself, to play with, to listen to the effect and adjust them. That will give you a better understanding of sound, placement, and, hopefully, an understanding of how to create an 'in your face' sound.
Lets say for this purpose we'll stick to making a vocal IYF - but if you haven't got a track with a vocal handy, you can do the same with a guitar - a snare - everything you want to stand out.
First get a mix up without your IYF vocal. Pan EVERYTHING, your drums as tough you sit behind or stand in front, your bass, guitars keys, everything. Doesn't have to be extreme, but make sure nothing is left bang center.
Now add your vocal - bang center, without any reverb or other effects.
What you will find is that you can have an overall lower level for your vocal to achieve the same perceived volume.
Second. You like to have some reverb on your vocal. Well - if you put reverb on your vocal, you will find it moves back in the mix. Even if you increase the level, the perceived level will be less - in other words, less 'in your face'. How do you solve that one? There is a trick which will make the vocal stand out even more.
Leave the vocal the way it is. If you have a stereo verb, use that, marginally different L from R effect - and record the reverb on two channels, feed them into the mix panned full L & R. If you don't have a stereo verb do it 2 x with mono ones. Now experiment with the verb levels in the mix.
You will find that the above will make the original vocal stand out even more.
Other interesting things to try in the same manner are flanging or phasing effects.
Note: another thing to experiment with is the delay in the verb, make the L & R ones come in at different times from each other, both with the same verb settings.
Third - a tricky one but can be used if you have a good effect processor or plug-in. Dump (or bus) your mix WITHOUT the 'in your face' item to 2 channels and experiment with effects on these 2 channels, record the desired effect (ONLY the effects) to 2 tracks. Pan the effects sharp L & R, now play your mix as normal, with the 'in your face' item, and start feeding in the effects gently.
I can never get enough of playing with stuff like that, even after 30 years! There are 100's more 'tricks' but I hope you'll enjoy playing with the above.