Phase issue?

Hello,

I recently acquired an OB4 and I am generally satisfied with its practicality and portability. However, I perceive a phase problem with the OB4.

Overall, it concerns the high frequencies, and moving in front of the speaker makes me hear changes in the level of the high frequencies. Even in front of the speaker, just turning my head to the left or right causes the high frequencies to come and go. A hihat, for example, will pop in and out of a mix just by turning my head in front of the OB4.

So, I’d like to know if any of you OB4 users had the same impression? Is it due to its size, or is it a faulty OB4?

Thank you.