Seem travels by vibrations so window options that slow down or block All those vibrations might help make a calmer indoor setting. Perspex or plastic is cheaper and can do the same job, but will discolour with age; it is much more normally used in corporations or Office environment buildings. https://banksy-cleaner-on-canvas15678.wssblogs.com/26350939/bespoke-secondary-glazing-in-bloomsbury-for-dummies