Treating a measured reflection can remove it while leaving its audible effect intact

Evidence

Let us take an example. In a very common room acoustic situation, suppose a time-domain measurement reveals a reflection that it is believed needs attenuation. Following a common procedure, a large panel of fiberglass is placed at the reflection point. It is respectably thick at 2 inches (50 mm), so it attenuates sounds above about 500 Hz. A new measurement is made and, behold, the spike has gone down. Success, right? Maybe not. — , Toole, Floyd E - Sound reproduction-…, 873