One useful technique I forgot to mention in last month’s blog post on treble tuning is plucking. If you are having difficulty hearing a unison or even an octave in the high treble, then pluck the strings and listen to the relative pitch.
This approach, in combination with the key, may help clear things up a bit. (If you have not read my last post, I suggest you do so to maintain continuity with this one.) Every note must be tested until you know that it is right, or as right as possible, before going on to the next string. This applies to every aspect of tuning, temperament, treble, and bass, and cannot be overly stressed here. After completing the temperament, I start tuning the bass by tuning E3 so its fifth (B3) is as pure as possible without an overly rough fourth (A3), and so the third (G#3) and sixth (C#o) retrogress evenly relative to their adjacent intervals. I have found the third/tenth test useful, but none of the above are as important as the sound of the octave itself.
The one thing that does come out rather rapidly is an error in the temperament. One obvious error is the slanted temperament. This is my term for the temperament where everything appears to work out well but the thirds progress too slowly or too rapidly - as shown by roller-coastering of the retrogressive thirds. If the roller-coastering is minor it can be ignored (but remembered for correction at the next tuning). If the error is excessive, then the temperament must be retuned. If the first few thirds going into the bass are too fast, the temperament slope is such that the upper part (F4) is flat and/or the lower part is sharp. If the retrogressive thirds are too slow, then the upper part of the temperament is too sharp or the lower part is too flat.
A quick analysis should reflect which factor prevails. One must take care on small pianos with extra heavy wire or wound strings at the bottom of the middle section, and when crossing over into the bass section, because the inharmonicity can depart substantially from that in the temperament octave. A change in third and sixth beat rates occurs here more often than not in all except the more carefully scaled and fabricated instruments. By watching for it you can learn when it is the piano’s fault and when it may be due to your tuning - and when it can be corrected and when it cannot. The above aside, the rest of the bass is easy to tune as long as each octave is tested and checked thoroughly by using the pure fifth, retrogressive tenths, and the third/tenth test and listening carefully to each octave.
There are several unisons that are not as easy. Occasionally two strings of a two-string unison are wound so that the upper partials do not match. The only thing that can be done is to get the least objectionable quality by first listening to the lower partials tuned in unison, then to the upper partials tuned in unison, and deciding which sounds best.
There are aim some octaves that must be handled in the same manner. There is a quality of power, definition, and clarity to the properly tuned bass octave that is rather obvious once learned. The reason for clarity is obvious, but not always obtained because of carelessness or hurry, or because a vital test is ignored. Definition comes after clarity and is that element of blended partials which begins to define the power. I mentioned power tuning last month. Tuning the bass is where I discovered this essential element of my way of relating to -what I want from the piano. I want to get the entire piano, case, keybed, plate, and structure to produce a continuous resonance (i.e., beatless) at the lower coincident partials which produce the most power. On most vertical pianos the bottom panel or the keybed can feed this information to your thigh or knee, and on grand pianos the keybed to knee and front bar (stretcher) to arm.
After learning to detect the beatlessness with your body, your ear will easily pick up the increase in power. Because of the extra thickness of the core wire in the low bass, metal fatigue sets in rather quickly, which causes the strings to break at the tuning pin. Turning the tuning pins as little as possible will increase the life of these strings as well as the stability of your tuning. One of my favourite guides (please note “guide,” not test) is the minor third/sixth. Example: D2-F2 minor third should be slightly slower than F2-D3 sixth. Care must be taken because varying inharmonicity can play fun and games with the beat rates, but you can use it to get into the ball park and to keep from straying too far from just right. This can be used from the temperament octave all the way down on most pianos. The double octave is useful also if you have strayed far afield, but the most useful for me is the fifth. It will produce a most definite beat at the low end where the octave should come in, and it can be used without taking your hand off the hammer.
I am sure I have left out tests that you may find useful, which is just fine for you. What you find of value and are comfortable with is not to be despised but shared.
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