How to play mp3 file using preview_url

I am following this url as u can see Preview_url proper format is not there. http://developer.echonest.com/api/v4/track/profile?api_key=API_KEY&format=json&id=TRTLKZV12E5AC92E11&bucket=audio_summary

whenever i am trying to give extension http://previews.7digital.com/clip/11123262.clip.mp3 in a browser i am getting this error

Error: Authorization failed for method and URL http://previews.7digital.com/clip/11123262. Missing oauth_consumer_key is oath consumerkey is my echonet consumer key.Please provide me url how to append oath consumer key with my url.