Bass (or any frequency range) doesn't completely pass through any material. Some energy is transmitted ("pass-through"), some is absorbed, and some is reflected.
The amount of low frequency energy transmitted through something like glass is significant. There is also a not insignificant amount that is reflected. There is also a not insignificant amount that is absorbed, particularly at the resonant frequencies of the glass.
The amount of each will depend on a variety of factors, such as thickness of glass, type of glass, mounting, an so forth.
Same goes for plywood and other similarly rigid/solid building materials.
When considering room acoustics, one needn't worry too much about the transmission very much, unless isolation is a concern (it usually is). How the room sounds will depend purely on the absorptivity / reflectivity. These are related to the transmissibility of the panel, but the transmissibility is not something that needs to be known explicitly if the absorption coefficients of the construction can be found or determined.
Unfortunately, you are not going to find much in the way of measured absorption data for, say, plywood over studs. There are methods to estimate it, though.
Also, putting, say, MDF over glass will increase the reflection and reduce the absorption at low frequencies. This may or may not be desirable. If the primary concern is mid and high frequency reflections from the glass, then heavy curtains are the simplest approach. A better solution would be some sort of mid / high absorber over the glass (or MDF, if you prefer).
For low frequency control, the preferred approach is properly placed low frequency (or broadband) absorbers, which is covered in many threads.
If you like, we can offer more specific advice if you'd like to post some room dimensions, pics, etc.
