It is very easy to keep your dog bed from smelling if you make sure it has a truly waterproof cover.
Step one: Make sure that you have a 100% waterproof cover on the dog bed. Many, many dog beds are sold as waterproof, but they are not actually fully waterproof. They are made from "rain proof" or "shower proof" or
"breathable" fabrics and that does not work for dog beds due to the following: When a wet dog lies down on a shower proof fabric on a dog bed, he is pressing water on to the bed. Shower proof fabrics cannot hold water back that is pressed on by force and hence the water goes through the fabric. It won't seem wet for a while because it is only a slight amount of water, but it will steadily be getting damp inside the bed. When the bed gets damp inside the mold starts to grow. The inside of the dog bed is now the perfect breeding ground for molds and bacteria, which in turn will be very smelly. The damp, warm environment is the worst. One of the pioneering companies in UK for making truly waterproof dog beds is Tuffies Dog Beds. Every style of dog bed is made from 100% waterproof (and incredibly strong and durable) textiles. This means that absolutely no water of damp penetrates the fabric and the bed stays clean and dry inside. Both Mattress dog beds and Nest dog beds are made from these fabrics.
Step two: Enjoy how easy it is to clean these waterproof dog beds. The 100% waterproof dog beds will gather a bit of mud, dog hairs and maybe marks from treats that he has been eating on the bed. The mud and the hairs will tend to just dry off and literally fall off. However, over time you may wish to give it a wash and this is the easiest thing ever to do: Take the dog bed outside and go over it will a sponge with hot, soapy water. After this you just hose the dog bed down with the garden hose and leave it to dry. Due to the waterproof cover the inside is still dry and clean, so no need to attend to that.
Step three: Could your dog himself be the smelly part? Dogs with very thick or long coats can take long to dry if they have been outside all day on a long walk or if they are working. The ultimate trick here is to have a boot room or your kitchen where he can spend the first hour or two on his Tuffies dog bed. Here you also put a dehumidifier to gather up all the humidity in the air and your dog will dry very fast. A dry dog is far less likely to smell than a damp dog. Once he has spent a while in the drying room he is probably ready to come in to the rest of the house to enjoy the company of you.