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Evaluate by Listening




TIP 7

Evaluate by Listening

We often have the occasion to evaluate a new component.  Here’s a tip based on how we evaluate all Omega Mikro products.

First, select well-recorded music with known absolute phase to use as sources. (I say known rather than correct since much recorded music, especially older recordings, may have some instruments in correct phase and others out-of-phase). Miles Davis’ original Kind of Blue is a good example (in the first track the piano is out- of- phase but the rest of the group is correct).

Second, select a mix of types of music and groups that includes a solo female voice, solo piano, plucked bass and a complex ensemble of many different instruments, like a symphony orchestra or a rock band like Frank Zappa’s Mothers of Invention. Get familiar with short ~ 1 minute - segments of each track you will use. Include at least one pure mono recording.

Third, establish a clean EMI (electromagnetic interference) environment for the evaluation.  This may be the most difficult part of the evaluation since we can’t always control every possible interfering source, but turn off as many of the following as you can get away with:

  1. Furnaces
  2. Air conditioners
  3. Fluorescent and other non-tungsten lighting (including the new CFL’s, LED’s, halogens)
  4. AC- powered computers
  5. Wall warts (including those used to charge batteries and to power cordless phones)
  6. Refrigerators (don’t forget to turn them back on after the evaluation)
  7. Water heaters (“)

Fourth, establish a baseline. A stereo system cannot be accurately evaluated if the channels are not well matched in time and or frequency.  So if you have a new component that affects only one channel, turn the other channel off and use only a good mono source,

Before you install a new component or replace an old one with a new one, let your system warm up an hour or so, so that it has a consistent sound. Play any music except the reference tracks you selected in the second step.

After the system is warmed-up establish your baseline sound by playing each of your one-minute- or- less tracks three times before changing to the next track. As you listen, remember as many details as you can about how each track sounds compared with your memory of the sound and feeling of live music. Pay special attention to the attacks – the leading edge micro- details, and the trailing- edge details – of each sound. Compare the voicing of each instrument with your memory of the live instrument. Also notice how well your system maintains separation of instruments as the music grows more complex and louder. Notice the vertical, horizontal and depth spread of the ensemble of instruments and the sense of space around each instrument. Pay attention to the background – the silence between the notes – compared with live music events. Amplified concerts are difficult to use as your live music recollection. Better to recall acoustic rock, folk, country, jazz or classical concerts where no amps were used.  Your memory of how your reference tracks compare with your memories and feelings of live acoustic music will be the basis of your evaluation.

Fifth, install or replace an old with the new component. If you have more than one new component evaluate only one at a time (if possible). If the new component affects only one channel use only mono tracks for your source and listen only to the affected channel. Turn the other channel off.

Sixth, does the new component take you closer to the live music experience? If so we keep it or it gets our blessing. If not, out it goes or we don’t recommend it.