While the terms "review" and "criticism" are often used interchangeably, there are differences between them.
Music criticism or analysis is the study, interpretation, and evaluation of a piece of literature and its place in music history. Music criticism usually offers interpretation of things like meaning, analysis of structure and style, judgment of its worth by comparison with other works, and an estimation of its likely effect on listeners.
Music criticism differs from reviews in several ways: it entails both analysis and judgement; it may be published many years after a work is released; it is usually longer and more complex than a review. A review is more "consumer-oriented," placing more emphasis on recommendation than analysis. Music reviews are usually written around the time of a particular performance or recording of a work.
Reviews of music performances or recordings may be found in online databases that index newspapers and general interest or music/performing arts magazines (e.g., New York Times, The Washington Post, StarTribune, The New Yorker, American Record Guide, etc.).
In-depth criticism and analyses of music may be found in more scholarly or academic publications (e.g., Opera Quarterly, Classical Singer, The Journal of Musicology, etc.) indexed in scholarly journal collections such as Academic Search Premier, JSTOR, or Project Muse.
It's easy to find music reviews. What's not always easy is finding a particular review, rather than just any, or else reviews outside of the "usual suspects" from something like Amazon or some music-enthusiast's social media or website.
To find a greater variety of reviews by professional writers, you'll need a magazine or newspaper index, and you'll need a subscription to get to the full text, which you have via Bethel. LibSearch is an excellent source for reviews of all kinds. Enter a search for the musical piece or performer and limit your results to "reviews" in the resource type section on the left column. Find more options in the Research Databases section of the site--use the "by subjects" dropdown to find those best for music research.
For contemporary reviews of music recordings or performances written before the mid-80s: Electronic indexes often only go back to about the 1980s. For music reviews written before then, look for the Book Review Index upstairs in our index collection. Once you get your citations from there, use the Journal Title search on our page to find our access to the journals, magazines or newspapers.
Pro Tip: Most database interfaces offer an Advanced Search option that includes various ways to limit your results. One of the common limits is something like Resource or Document Type. If you don't see that kind of option, you can always use the word "review" as one of your search terms. While this isn't fool-proof, it does a pretty good job of getting you reviews rather than other types of things about your music.
Any of the databases listed on the databases page will contain reviews as well as analysis. In addition to these, try the resources below: