There is a big difference between peak level and loudness.
Compression can be used for the latter but it’s not what you are looking for with regard to the former.
It’s become very clear to me recently that people are actually using compression to increase the volume of a track when they have run out of gain on their fader. This is not what compression is for.
So what is compression for?
Dynamic range compression (AKA compression) is used to manage the dynamic range of a signal. The dynamic range is the difference between the loudest and softest parts of the recording. An example of where this is useful is vocals. If the singer sings too loudly in some parts of the recording and too quietly in others, you may use compression to reduce the range (difference) and help the vocal sit better in the mix. However, if you are using compression for the ‘wrong’ reasons, you may be reducing the dynamics of a signal unnecessarily which will flatten the depth of the audio before you’ve even thought about mixing.
Better Gain Staging
If you need to increase the volume or gain of your track, then simply use Logic’s (or your DAWs) Gain or trim utility plugin. You could also just turn up the volume in the synth/instrument itself, using its respective master/volume knob.
Otherwise, you are reducing the dynamic range of your audio (and possibly the quality) unnecessarily and too early in the mix stages. You may find that you’ve already flattened the dynamic range of a track before you’ve even started mixing. This could be the reason your mixes are sounding flat.
Reset your mindset
I am writing this to help you use proper gain staging and to reset your approach to mixing, thus helping you to make more informed decisions when using things like compression.
Please. Ask me anything using the comments below. I will happily answer any concerns you have.
Lastly, I made the below video with a view of explaining what compression actually is and how to use it. This should help give you an understand of how and why to use compression.