Joy, Jay made some good points. Judging from your description, I'd guess that your feeling that the duct has too much air resistance is probably correct. The dryer manufacturer should give some guidelines as to what length of duct is acceptable (each bend is equivilent to several feet of straight duct). There may be some measures that can be taken short of waming visitors while they wait for you to answer the door however. I'd start by inspecting the ducting. Is it solid or flex? Flex, even good HVAC quality, has more air resistance than solid; if it's "dryer duct" it's crap and should be replaced. Where bends must be made, make them as gradual as possible, two 45's would be better than a 90. Never let the bend radius (as measured at the elbow's centerline) be less than 1.5 the duct's diameter (2x is even better). The ducting should be sealed at each juction with duct sealing mastic (not duct tape). If the ducting is optimised but is still not performing adequately, you can buy an in-line, pressure-activated booster fan that should keep the air velocity up where the lint won't settle out. Due the the nature of the exhausted material (lint) I'd connect duct lengths with pop-rivets rather than sheetmetal screws; screws proved a place for the lint to catch. Good luck with it.