I often suggest using a good sounding mix reference track to compare your own mix tone to. This is often in response to receiving a mix which has far too much or too little low frequency content for mastering. In these instances it is best to address the core problems in the mix down by using a mix reference.
I would use a track which relates to the genre of the mix your are working with. Select a track based on tone, clarity, space and definition, not it’s perceived level. This will help when getting the right tonal balance for the track, i.e. balance of lows, mid range and highs. I suggest bringing a track into your mix session with it’s own separate stereo track. Ensure the file is a high quality .wav file or .aiff file. Choose a track that you feel has a great mix which works on a lot of different playback systems. It helps if you like the track but don’t just choose a track where you love the song itself, try and discern what qualities give the track a good mix down.
It is highly likely that this mix reference will have been mastered so the first thing you will notice is that the track will likely be louder than your own mix session. Using clip gain in your digital audio workstation pull down the volume to match the perceived volume of your mix. It could be as much as 10-20dB that you need to pull the reference track down. Simply match the perceived level by ear. Do not worry about your mix being quieter because any self finalizing or professional mastering should bring the level up later. When you mix try and get the bass content of your track in the same ball park as the mix reference track. At first it can take a little practice because it adds another thing to consider when you mix. Once the bass is in place you can focus on the mid range and highs. You may try a variation of this technique which is to start your mix and then bring the reference in later. Different methods work better for different people. In any event make sure you volume match your mix to the reference.
If you are happy with overall instrumental balance of your track you may wish to use careful equalization in order to achieve a tonal balance more close to the mix reference. Using a reference track is especially good for judging bass levels on smaller monitors in rooms that do not have bass traps. You can equalize in the amount of low end to roughly match the mix reference track for your bass drums, toms and bass lines etc.Whilst you can never replace accurate speakers in well treated room it will definitely assist in getting a ball park tonal balance for your own music mix.
A few tips on easy acoustic treatment for those interested:
Not everyone is in a position to acoustically treat their room, in many instances you might have to work in a room which is of awkward shape, has an already nice decor which you cannot spoil or is simply too small to fit the large amounts of acoustic material. Any treatment you can do is definitely worth doing, even a few foam tiles to dampen down some early reflections would be a good start. The positive effects of acoustic treatment will be heard on all the recordings and mixes you do.
Rather than go deep into the materials of acoustic treatment as a sub topic, this is focussed on ease, rather than maximum acoustic performance. I have found a good way to attach foam tiles to a wall is to use translucent silicon. This is available in cylinders from DIY stores and you simply cut the nozzle to size and put the tube in a sealant type gun. It must definitely be translucent silicon, not any other type of bathroom sealant. Translucent silicon dries as a soft rubber compound which tends not to remove the paint or wallpaper when you remove it but has enough holding power to keep the tiles up as they are quite lightweight. Make sure that you test the dry silicon you have in a discrete place to ensure that it comes away from the wall without any problems prior to putting any tiles up. Using a mix reference is always going to be a useful tool but any acoustic tretament will definitely assist all mix down decisions.
Have fun mixing your tracks down.