Can I use two or more monitors close to each other (like in a PA system) or is it better to just use one large monitor on each channel?

Only one monitor should be used for each channel. PA systems use multiple parallel drivers to increase maximum SPL or coverage area. However, this technique typically results in coloration of the audio due to interference from adjacent sound sources.

The big disadvantage of most PA systems is that they do not have a smooth power response. This is not an acceptable situation for studio monitoring intended for hearing very accurately small details in the audio signal.

The exception to this rule is with subwoofers. There are advantages in positioning them close to each other and the audio quality is not compromised at very low frequencies.

Conclusion:

- Use only one monitor for each reproduction channel for an accurate frequency response.

- To gain SPL, move the listening position closer to the monitors or use a larger model in the Genelec range.