as several others have already mentioned, you ought to play a wide array of recordings to judge how a component changes (or doesn't change) the sound of your system. i think it's most helpful to have in your "test bin" several recordings you've heard on your system as well as a number of other systems, be they your friends', dealer's or those you encounter at audio shows and the like. i find test discs, such as those put out by ortofon, chesky, stereophile, etc. to be helpful in only the most rudimentary ways. they can tell you, for example, whether you've plugged in all your left/right ic's correctly or whether the cartridge azimuth is optimal; they are rarely helpful, however, at least to me, in determining the sonic "character" your system imparts.
as a real world example, i offer this: yesterday, i had a fellow 'phile and his wife come to my home to hear my turntable/tone arm setup to decide whether to purchase it. these are among the lp's we played to "test" the sound quality of my analogue setup: csn&y, "deja vu"; thomas dolby, "aliens ate my buick"; gary karr, "adagio d' albioni"; laurie anderson, "mister heartbreak"; paul simon, "there goes rhymin' simon"; prokofieff, "lt. kije; pink floyd, "the final cut." these were each recordings very familiar to both my potential buyer and me. we could have picked , perhaps, 20 or 30 more that would fit this description. the point is: we had "points of reference" as to these recordings. neither of us could judge if any one of them was more accurate on my system than that of "mr. x," but we could judge where the differences lay and which of those differences we preferred. that, i think,
as a real world example, i offer this: yesterday, i had a fellow 'phile and his wife come to my home to hear my turntable/tone arm setup to decide whether to purchase it. these are among the lp's we played to "test" the sound quality of my analogue setup: csn&y, "deja vu"; thomas dolby, "aliens ate my buick"; gary karr, "adagio d' albioni"; laurie anderson, "mister heartbreak"; paul simon, "there goes rhymin' simon"; prokofieff, "lt. kije; pink floyd, "the final cut." these were each recordings very familiar to both my potential buyer and me. we could have picked , perhaps, 20 or 30 more that would fit this description. the point is: we had "points of reference" as to these recordings. neither of us could judge if any one of them was more accurate on my system than that of "mr. x," but we could judge where the differences lay and which of those differences we preferred. that, i think,