What if I told you that you do not need measurement microphones, special software, or processors to calibrate your monitors. If you have a computer with a DAW, then you already have everything you need.
To calibrate monitors professionally you need a measurement microphone, a processor, and a companion software for it. For our purpose we will replace the measurement microphone with our ears, the processor and software with the DAWs equalizer plugin and sine wave generator.
The process: Bring up the DAWs built in sine wave generator (tone generator) in the master bus and the cleanest sounding EQ you have right after that. We need a clean equalizer because we do not wish to colour the sound, we just need to subtract frequencies in the cleanest way we can. Put the plugins side by side on the screen. Choose sine wave for the tone generator output and start sweeping the frequency slowly up from the lowest point. By doing so pay close attention to the peaks and valleys in the volume with your ears. We are interested in the frequencies up to about 400Hz, since the upper frequencies are not affected by the room in the way that can be fixed with an EQ. The biggest problems are usually in the 150Hz area or below. If you hear a peak in the tone, then sweep the tone generators frequency up and down until you find the loudest peak. Now check the frequency on the tone generator and go to your equalizer, take a bell EQ, and bring down the exact frequency you got from the tone generator. After bringing it down about -3dB, go back to the tone generator and sweep the frequency area again, make changes to the EQ until the sweep sounds flat. Do not be afraid to go -10dB or below, if the volume peak flattens out at -15dB, so be it. You have multiple valleys and peaks that have been created by the geometry of the room. Since no reasonable amount of acoustic treatment will fix the low-end issues then go on and use the EQ to bring down all the peaks you find with the tone generator. Important thing to note here is that the acoustical problems in a room are very dependent on the SPL, sound pressure level in the room; the louder you go, the bigger the problems get. So roughly choose the volume level you use the most.
Acoustical problems in a room are very dependent on the SPL, sound pressure level in the room; the louder you go, the bigger the problems get.
Now for the valleys in the frequency response we will not use bell equalizer to boost, but rather take a shelf equalizer at about 100Hz with a smooth curve and bring up the whole low end. If the peaks peak out again, then bring the corresponding bell equalizer’s further down or add bells with larger Qs to deal with the new, larger peaks. You may also use the bell equalizer to deal with the valleys, but the sweet spot for the listening position will get exceedingly small by doing so. Also note that depending on the room and your position in it, you might also have completely dead frequency spots where a specific low-end frequency will cancel itself out with its reflection. Here the EQ will not help, you cannot boost something that is not there. To fix this you will need to physically move things around in the room.
Tip: To add additional low end to work with, without using low shelf equalizer you can push the monitors closer to the walls. Add a low shelf EQ to taste.
Tip: Also add a high shelf equalizer at about 1000hz to bring the high end up or down to taste.
After you are done with the EQ, bring a song you know into the project and listen to it with the correction equalizer engaged. Play with the low and high shelves on the equalizer to get the balance that feels right to you. Now save the equalizer pre-set and bring it up on the master bus for every project. With Cubase you can also use the equalizer in the control rooms output insert slot to have it always be there and not be dependent on the active project. If you have an audio interface with a DSP and the ability to add effects to the cards output, then that would be even better, since then you can also listen to Spotify and YouTube through the corrective equalizer.
Depending on the room and your position in it, you might also have completely dead frequency spots where a specific low-end frequency will cancel itself out with its reflection.
If you want to invest in an equipment to calibrate the monitors then i suggest you first go for a product that helps you get the processing as close to the monitor inputs as possible, be it a sound card with a DSP or a special equalizer box after the audio interface, so you would not need to mess with pre-sets. Only after the processing is in place, I would get a measurement microphone to visually see the problem areas and how the EQ moves improve them.