I noticed that many (mostly vintage commercial) TL speakers aren't stuffed with a damping material but lined instead with something like acoustic foam or polyester mat. Usually this lining occupies about one half of the cross section, may be a bit more. So my question is how does it change the development process? I may want to try a polyester mat (the stuff used for like winter jackets) as it just easier to work with. Can I just average the density over the cross section? I rely on Hornresp if it matters.
If by 'development process' you mean the design & manufacturing, lagging was mostly done for convenience and consistency from a material perspective -it also tends to stay in place better than stuffing does. If we're talking about the line physics, for the purposes of modelling in Hornresp, then yes, averaging the density for a given CSA is a reasonable start & for a reasonable poly / BAF or similar, it should be ~'near enough' for practical purposes.
