33 RPM records have always presented a compromise in sound quality, in exchange for longer playback time. 12-Inch LP's mastered at 45 RPM sound better. There are quite a few technical details as to why this is the case, so for the purpose of this article, I will try to key this simple: Since 45 records travel faster than 33 RPM, more waveform definition can exist on the record surface; in other words, there are more bumps and grooves created, which means better audio quality. Think of it like drawing a flipbook: If you drew the same animation on 33 and 45 pages respectively, you'd have to flip your 45-page version quicker to get the same speed animation as the 33-page version, but the changes from page-to-page would contain more detail, making the animation considerably smoother. The higher the RPM, the greater the length of vinyl picked up by the stylus, and ultimately, the more accurate our sound reproduction becomes. Additionally, longer wavelengths, smaller angles in the grooves, and the less complicated geometry at 45 RPM help to cut very precise grooves with very fine detail. If that wasn't enough, 45 RPM cuts experience less inner-groove distortion, as the increased groove velocity helps to minimize the loss of high frequencies and an increase in distortion as the groove moves to the center. The downside to all this, of course, is a reduction in playback time per side. All of the detail aside, 45 RPM records just sound better (providing they're mastered with skill and manufactured correctly, of course), and this is why many "audiophile" album releases are 45 RPM LP's spread over a couple of discs. All the above is true for 12-inch 45 records as well as the usual 7-inch format.