I (think that I) understand that sonorants are sonorous because airflow is continuous, non-turbulent, and so resonate at such a frequency that the vocal tract acoustic filter amplifies them. And I understand the voiceless obstruents are not sonorous, because the occlusion in the vocal tract impedes airflow/makes it turbulence, with noise being made by air pressure fluctuations rather than resonance.
What I don't understand is how voicing works with obstruents. They involve trilling action at the vocal folds, yes? But the occlusion in the vocal tract means they aren't sonorous. So would the waveform of a voiced obstruent be (quasi)periodic, or aperiodic? Do they have a frequency, and do they resonate? Where does the majority of the noise come from: the build up of air pressure, or the vibration of the vocal folds?
I'm probably wrong on much of the above, so if someone could set me straight on the whole thing, it would be much appreciated. Thanks!