Summary in English
Æ/æ always has the same basic sound. That sound, though, can be short (kort), long (lang) or with stød.^1 ^2 He gives examples of all three.
Under OBS he compares the sound of æ to those of e and a to help you make the distinction between them.
Lastly, æ in combination with an r often comes to resemble the sound of ah.