|
HOME TOPICS ABOUT ME The music on the Elektra disc comes across like a cheap sci-fi flick sound track. |
technofile Al Fasoldt's reviews and commentaries, continuously available online since 1983 CDs for testing electronic componentsBy Al Fasoldt Copyright © 1989, The Syracuse Newspapers A while back I listed a few CDs that were helpful for evaluating loudspeakers and headphones. Many readers wrote and asked if there were any compact discs that could be helpful for testing electronic components, too. CDs of this type have test tones and calibrated signals. They're useful in checking out tape decks, and are sometimes useful -- note the caution here -- in seeing how accurate your speakers are. They're easy to use and not hard to find. Here are three test CDs that I've checked and found quite helpful:
The second set of discs is the most ambitious and the third is the least. The first falls in the middle and is my own favorite -- mostly because Denon made the tests easy to follow. All three include music as well as test signals. The Denon disc has the best musical selections, chosen not so much for their potency as their sublimity. Pierre Verany's musical tracks are more for show, although they are exciting to hear. The music on the Elektra disc comes across like a cheap sci-fi flick sound track. It's all electronically processed "computer music" that can seem tiring after a few hearings. (However, you may find, as I did, that a few of the electronic pieces are worth listening to again and again.) A treat on the Elektra disc is a helicopter landing. As an old Vietnam hand, I still can't play the thunder-chopper track without ducking, nor can I play it without recalling how I blew out a pair of weak-kneed woofers the first time I turned up the wick on this wicked CD track. Tests range from the simple (Elektra) to complex (Denon) to incredible (Pierre Verany). The tones that are recorded on each CD can be used to check how well your cassette deck handles various frequencies, as long as you're careful to keep recording levels far below the maximum level -- the red area of the deck's meters -- at least for the first few times you try it out. You can raise the recording level after you're used to what the test tones sound like when you play them back. On every cassette deck, regardless of how cheap or expensive it is, you'll hear a rougher tone on playback than you heard from the test CD. That's normal. But if you turn the recording level up too high, you'll hear a much rougher sound. You might even hear birds chirping. They won't be robins; these "birdies" (that's the actual semi-technical name) come from odd tones that squish out of the recorder in protest when the tape is overloaded. Another excellent use for a test tone is to check your cassette deck's Dolby system. Use a high-pitched tone (6 kilohertz is fine; 10 kHz is even better) and record it at a level that just barely shows up on your meters. Then listen to the playback. It should have the same sonic character that it had from the test CD, even when you switch in the Dolby B or Dolby C system. (By all means, make sure you use the Dolby system in a complimentary way. In other words, if you have Dolby C switched in during a test recording, be sure to switch it in during playback, too.) At the beginning, I cautioned that the test tones are sometimes useful for testing your speakers. Generally, they're not much help, because true loudspeaker testing is actually something else -- loudspeaker-and-room testing. And when you test your listening room, you have to use different tones than the standard ones that we think of as test tones. What you need are tones that keep your room from getting all worked up when you crank up your speakers. You don't want your room to get excited by the sound waves. So rather than feed the room a single tone, you blast out as many frequencies as possible all at once. Engineers call this "white noise" and "pink noise." The pink version sounds a little bassier and is more useful, because it mimics our hearing response better than its white cousin. You use pink noise to test speakers by listening carefully for an odd accent or two at any pitch while you move around the room. A good speaker will sound "open" from many different positions. Both the Elektra disc and the Denon CD have pink-noise signals. But here's a tip: If you'd like to try white noise to test your speakers, just turn on your FM tuner or receiver and tune between stations. Make sure your interstation muting is turned off, if possible. What you'll hear is white noise, plain and simple. Don't play it too loud, since it can fry your tweeters from the high frequencies that are part of the white noise. Any of these discs can be ordered by most record stores. Be sure to give the store the catalog number. |