I have been reading some of the past speaker reviews that contain JA's in-room measurements of the speakers in the reviewer's listening room. In particular, I have noticed that in Wes Philips' room there is consistently a suck-out around 35-40Hz. It varies in depth depending on the specific speaker, but always appears to be present. For example, it is especially deep in the review of the Avalon Indra speaker. I am wondering if there is a known mechanism for the presense of this "hole" at this particular frequency in his room? I am interested because my listening room exhibits the exact same behavior. This is a problem that I have been trying to solve for 15+ years. No changes in speaker placement or listenting position have any effect whatsoever on this lack of sound pressure at these frequencies. The problem seems to be consistent throughout the entire room, not just at one or two locations. Hoping to learn from the experience of others.