Belt vs. Mix
Today we will look at a couple of terms and singing techniques.
Singers often talk about 'belting' or 'belt'. Some of them might also be familiar with the term 'Mix' or 'Mixed Singing' but might now know the difference or what it actually means.
We will look at those two singing techniques from a vocal fold level, an acoustic level, and a vowel level.
#1 Vocal Fold Level
First, let's review the two main muscles involved in singing, namely the Thyroarytenoid (TA) muscle (dominant in the lower range) and the Cricothyroid (CT) muscle (dominant in the upper range and increasing pitch by tensing the vocal folds).
In Belt the TA muscle activity is higher than the CT activity, the larynx is in a higher position and more mass of the vocal folds is vibrating. In Belt, the TA muscle contracts and pushes the bottom of the vocal folds towards the midline so that more mass of the vocal folds is vibrating.
In Mixed singing, the there is a balance between TA and CT muscle, the larynx position is balanced (not raised or lowered), and depending on how much mass of the vocal folds is vibrating, we will hear a 'soft mix', 'medium mix' or 'strong mix'. There should be no squeezing or pressing involved from the extralaryngeal muscles and enough airflow should be provided to allow the vocal folds to open and close properly.
In a proper belt, we would see the same vocal cord closure as in a strong mix. The vocal folds are closing without squeezing the extralaryngeal muscles and a great amount of mass of the vocal folds is vibrating, however, the larynx would be higher in a belt compared to a strong Mix.
On the other hand, if a belt is produced by raising the chest voice too high without allowing the vocal folds to 'thin out', meaning to stretch while remaining the same tension on the vocal folds, we would see squeezing of the vocal folds.
#2 Acoustic Level
Acoustically the voice resonates in different spaces in the vocal tract, the larynx, pharynx, oral cavity, and nasal cavity.
For speaking and singing, we often talk about Formants and Harmonics, when it comes to acoustics. This is a very simplified explanation but in a nutshell, the first formant is created at the larynx and controls the lower notes, the second formant is created at the mouth, lips, and tongue and controls the higher notes (and middle range).
When we speak of the acoustic resonator, in Belt the first formant (created at the larynx) is the main resonator. The acoustic energy resonates more in the larynx.
While in Mix, the second formant (created at the mouth) is dominant which creates more brightness in the sound.
#3 Vowel Level
Once the 'Source' (=vocal fold vibration) is produced at the vocal folds, the sound is shaped in our resonators through our vowels.
To avoid the temptation to raise the larynx, we form vowels in a way that would un-invite extra laryngeal muscle activity.
In a Belt (not just pulled chest voice) we will typically widen vowels to achieve a ringing sound quality. This is one of the reasons why the larynx position will often be higher in the Belt, because the wider vowels, pull up the check muscles and therefore the laryngeal muscles tend to elevate as well, resulting in a higher larynx position. Acoustically the wider vowels boost the first formant which hits the second harmonic (so to speak the overtone of the pitch) and create this 'ringy and forward' sound.
In Mix, typically the vowel would be more centered, meaning that wide vowels like an /a/ or /e/ would be narrowed and vowels like /i/ or /u/ would be opened. This is to allow the second formant to resonate and hit the third harmonic. The sound will be also bright and forward but with less 'sharpness and bite' than a belt.
Have fun exploring your Voice!