What test material do you use?
I generally use a set of test tones I generated and recorded in specific orders. Is yours a home creation, or is it a purchased test cd?
I have an audio test tone CD that I like, it's a pretty old one out of a magazine, but that's just for starters- eliminates the complete trash. I don't spend much time on it.
Good test material has prominent content at multiple frequencies simultaneously- bass/mid, bass/treble, mid/treble, and/or a combination of all three, with distinctive enough sounds at the prominent frequencies that you can hear any distortion of the waveform, or diminution of the sound level. Particularly good ones have passages where a single instrument plays a theme, and is then joined by instruments in other ranges- the best has various passages where different instruments take the theme solo, then everybody chimes in.
Heavy bass places large current demand on the output transistors, and on the power supply filter caps. It also places the bass speaker elements under the maximum mechanical stress. You want to listen for really crisp response here- any muddiness indicates problems in one of these commonly overlooked areas. When combined with treble or mid, you can listen to see if the other frequency robs volume from the bass- or vice versa. This is a common crossover design fault, present in some surprisingly expensive transducers.
I generally begin with Mannheim Steamroller-
Fresh Aire 4 is my usual choice. "Crystal" tests how the system responds to electronic music- "G Major Toccata" is an excellent test of the same sort of thing for acoustic instruments. Look particularly for instruments in the midrange and treble to lose or rob power to or from the bass. Chip Davis insists on impeccable engineering. For ambient and swells, try "Dancing Flames." Listen for distortion. And listen to the triangles at all times- they should always be crisp, never distorted and never too quiet.
I then move on to more rock-oriented material. Yes'
Close to the Edge, while rather noisy in the mix, due to some unorthodox engineering practices, has some extremely challenging material in "And You And I," particularly where it moves from the acoustic beginning to the heavily processed middle movement, and in "Siberian Khatru," where you should listen to see if Jon Anderson's voice gets overrun by the heavy guitar riffs, which it does not on the recording but often does on a system with crossover problems.
Next comes Steely Dan's
Aja, for the gentle but well-defined bass and tricky-to-reproduce guitar rhythms of "Deacon Blues," and the heavily-processed "Josie," and then on to "Kid Charlemagne" from
The Royal Scam. Look for muddiness in the midrange- that mellotron should sound crisp and clear over the vocals and guitars, not distorted and not compressed.
Then fully into modern jazz- try "Etude" from
Color Rit, by Lee Ritenour, listen for the bass to lose or rob power to or from the guitar. "Blues for TJ" from Larry Carlton's
Friends tests for good response to bluesy stuff.
Last but not least, be sure to try some DVD material. I recommend movies with loud effects and a great deal of movement. You'd be surprised how good a test the "THX" theme that plays at the beginnings of material that conforms to these standards is. I like "Independence Day" for the fact that it has this theme, for the "whoosh" sounds that go to the rear during the title part, and for the explosions when the cities are demolished.
Overall, this takes an hour or more, but I've never been disappointed with a piece of equipment that I subjected to these tests after I got it home and played other material on it.
If you're curious, I own a pair of Polk Audio stereo speakers, use Bose 301s for my rear speakers, a Polk Audio center speaker, and an Infiniti sub. I power them from an Onkyo amp at about 100W/channel for the front three and 35W/channel for the rears, and when the depth charges go off in "Das Boot," the windows rattle. I could no doubt get marginally more performance by spending eight times as much as I did.
My studio rig is an old 35W Kenwood amp driving a pair of JBL Decades and a pair of Fisher 12" three-ways; it stands up OK to my guitar amp when I want to practice along with something, and does a fine job of playing back my recordings with a minimum of change in tone and color. If the Onkyo ever blows up, which I doubt it ever will, I will probably buy another one unless someone has done a better job since I bought it; it's worth noting that the spec sheet gave it better THD specs than several more expensive amps, and my listening tests bore these specs out. I've never had anyone who came over to watch a movie or listen to some music comment on it; to my mind, that's as it should be. It's about the material, not the equipment.