Nasals are produced with the velum down, permitting air to pass freely through the nose, while the mouth is closed at some point of articulation for a certain period of time. For example, think of some sounds that we use when speaking English which aren't on the chart. These come in several varieties. There are lots more cases like this to think about. Going the other way, some of the sounds that are in the chart have limited frequency and distribution.
H is similarly limited.
To describe and to classify a consonant, you must know its point of articulation , which is the location of the rigid part of the articulator used to create the obstruction of the air flow. See ODA, p. 23f. So much for consonants. On to vowels, which are quite different from consonants, both articulatorily and acoustically. From both points of view, what's going on is that the mouth acts like a big echo chamber, and the hearer's brain decodes what the shape of the echo chamber must have been in to produce that set of resonances.