In this issue, I would like to discuss about
the methods to test a chromatic harmonica.
When testing a harmonica, most people would simply play some tunes on
it, and assess its performance by their feeling of how the tune sounds. The result will be subjective and sometimes
misleading, because the full performance of the harmonica is not tested
thoroughly.
For
the test methods described below, we will be concentrating mainly on the tests that
affect the performance of the harmonica, and not the design or construction of
the harmonica, even though they are closely related. With these tests, you will be able to measure
the performance of a harmonica better, and know where it can be further
improved. In order to have a comparison,
you should compare the tests on the new harmonica to your usual harmonica that
you know best.
1.
Evenness test
This is a very simple and natural test, play all
the notes slowly and with the same amount of effort, and check for their
evenness. Try to listen to the air
leakage while playing each note. If you
have ever played a very air-tight harmonica (such as the Suzuki SCX48) and get
used to its air-tightness, you will be able to notice when a note sounds
slightly leaky (on another harmonica). Next,
play all the notes again but very softly, are they still very even? The basic requirement is that the mid octave
should at least give a uniform feel of air-tightness. A good harmonica, of course, will have all
notes sounding very even in volume. Of
course, this is not always the case, and most of the ‘uneven’ notes (i.e.
either too soft or too loud) can be corrected by adjusting the reed gapping or
the valves.
2.
Softest to loudest test
Play a note in the mid octave (e.g. E or G), from
very weak breath, slowly increase until the note can be heard, this is the
softest volume of this note. Next,
increase your breath to the maximum and listen to the volume. If you have a sound pressure meter, you can
take the two readings (in dBspl). The
arithmetic difference between the readings gives you the dynamic range. Compare the test on your usual
harmonica. Naturally, the one with the
wider dynamic range is the better harmonica.
3.
Chord test
Play
Tommy Reilly’s composition for solo harmonica, Serenade. Or, you can also play the slightly more
difficult piece, Yusuo Watani’s composition for solo harmonica, Fantasy
Dream. Play it softer, do all
the double stops come out nicely and willingly at your command? A cross-tuned harmonica will do better in
this test.
4.
Compression test
Pick
a blow note in the mid octave (e.g. E), blow (use tongue blocked embrochure) as
hard as you can into the hole to get the loudest volume. Try to keep your embrochure constant. Does the note sound a little flatter (i.e.
重心不正确会导致口琴肘……
头
