Hermode Tuning

The HMT function

The tuning of Hermode Tuning is not static, but rather dynamic. It adjusts itself depending on the content of the music. This is done for the following reason:

As an alternative to „tempered” or normal tuning, fifth and third intervals can also be tuned to certain ideal frequency ratios: the fifth to a ratio of 3:2, the major third to 5:4. Major triads will then sound very strong and convincing. Achieving this requires sound frequencies (pitches) to be altered. This effect is known as “scaled tuning”.

Chord positioning by HMT

The horizontal line shows the levels of the tempered tuning. With clean (i.e. scaled) tuning HMT changes the frequencies to values that are partly higher or partly lower. The values are shown in cents and show how much higher or lower the position is (a tempered semitone has 100 cents).
In good orchestras the musicians adjust their intonation to achieve the best clean sounding chords. The HMT Mode works nearly the same way. Hermode Tuning doesn’t use its “ears,”however. It uses an intelligent program that’s part of its operating system: the HMT function.

HMT modes

- HMT tonal tunes keys to different degrees of scaled tuning and delivers a “key signature character”. When playing mostly white keys, c major will be the main focus and tuning will be scaled to that chord. An A major chord that is played immediately after material in C major (and is therefore subject to C major scaled tuning) will be affected somewhat by the scaled tuning effect, but will not sound completely tempered. If you continue in A major, the HMT will recognise A major as the scaled tuning reference. The chord A major then becomes the reference chord upon which the HTM alters that sound’s tuning. If you normally play polyphonic music, this mode will sound pleasing to your ears. This mode works best with lower tuning values.

- HMT 3/5 creates thirds and fifths with a high scaled tuning affect. In extreme cases (for example when two or more notes have to be retuned inversely) the scaled tuning effect will be reduced resulting in nearly inaudible tuning changes.

- HMT 3/5ref works like HMT 3/5 but does not reduce the scaled tuning effect in extreme cases like HMT 3/5 does. Using this Mode only makes sense with a scaled tuning value of 100%.

- HMT 3/5/7 affects the “natural seventh” with the HMT tuning affect in addition to the third and fifth. An example would be the interval G-F in chords like G-B-F or G-B-D-F or G-B-D-F-A. This effect is most pleasing in music that is based primarily around this chord structure. This mode can be associated with significant detunings since the scaled “natural seventh” is about 1/3 semitone deeper than in tempered tuning. The following picture shows the corresponding frequency positions in a major seventh chord:

Frequency positions of a G dominant 7 chord

HMT depth

Eine hohe Reinheit ist jedoch nicht alles. Wichtig ist auch, dass die Umstimmungen möglichst unhörbar ablaufen und dass das Resultat kompatibel zu der üblichen gleichstufigen Stimmung ist. Da man nicht alle Forderungen gleichzeitig optimal erfüllen kann, lassen sich bei der HMT-Funktion verschiedene „Modes“ und diese wiederum in verschiedenen Reinheitsgraden zwischen 100 % (maximaler Aussteuerung) und 0 % (gleichstufiger Stimmung) anwählen. Auch praktische Gründe sprechen dafür. Im Zusammenspiel mit gleichstufig gestimmten Instrumenten klingt ein Reinheitsgrad von ungefähr 70 % sehr angenehm. Das folgende Diagramm zeigt Frequenzpositionen bei
unterschiedlicher Reinheitsvorwahl.
Sie sehen hier Unterschiedliche Reinheitsstufen am Beispiel eines C-Dur-Akkordes. Die Variante „0%“ stimmt mitder konventionellen temperierten Stimmung überein.

HMT depth in percent


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updated: 09.11.2011