Question: What term, more masculine than falsetto, refers to the optimal combination of airflow and glottal tensions that yields maximum vibration?

Context paragraphs:
Modal voice: Modal voice is the vocal register used most frequently in speech and singing in most languages.  It is also the term used in linguistics for the most common phonation of vowels.  The term "modal" refers to the resonant mode of vocal cords; that is, the optimal combination of airflow and glottal tension that yields maximum vibration.

Pre-Celtic: The term pre-Celtic refers to the period in the prehistory of Central and Western Europe postdating the emergence of the Proto-Celtic language and cultures and predating the expansion of the Celts or their culture in Iron Age Europe and Anatolia (9th to 6th centuries BC).  The area involved is that of the maximum extent of the Celtic languages in about the mid 1st century BC.  The extent to which Celtic language, culture and genetics coincided and interacted during this period remains very uncertain and controversial.

Multiple kernel learning: Multiple kernel learning refers to a set of machine learning methods that use a predefined set of kernels and learn an optimal linear or non-linear combination of kernels as part of the algorithm.  Reasons to use multiple kernel learning include a) the ability to select for an optimal kernel and parameters from a larger set of kernels, reducing bias due to kernel selection while allowing for more automated machine learning methods, and b) combining data from different sources (e.g. sound and images from a video) that have different notions of similarity and thus require different kernels.  Instead of creating a new kernel, multiple kernel algorithms can be used to combine kernels already established for each individual data source.

Maximum life span: Maximum life span (or, for humans, maximum reported age at death) is a measure of the maximum amount of time one or more members of a population have been observed to survive between birth and death.  The term can also denote an estimate of the maximum amount of time that a member of a given species could survive between birth and death, provided circumstances that are optimal to that member's longevity.

Turnpike theory: Turnpike theory refers to a set of economic theories about the optimal path of accumulation (often capital accumulation) in a system, depending on the initial and final levels.  In the context of a macroeconomic exogenous growth model, for example, it says that if an infinite optimal path is calculated, and an economic planner wishes to move an economy from one level of capital to another, as long as the planner has sufficient time, the most efficient path is to quickly move the level of capital stock to a level close to the infinite optimal path, and to allow capital to develop along that path until it is nearly the end of the desired term and the planner must move the capital stock to the desired final level.  The name of the theory refers to the idea that a turnpike is the fastest route between two points which are far apart, even if it is not the most direct route.

Luffing: In sailing, luffing refers to when a sailing vessel is steered far enough toward the direction of the wind ("windward"), or the sheet controlling a sail is eased so far past optimal trim, that airflow over the surfaces of the sail is disrupted and the sail begins to "flap" or "luff" (the luff of the sail is usually where this first becomes evident).  This is not always done in error; for example, the sails will luff when the bow of the boat passes through the direction of the wind as the sailboat is tacked.

Preglottalized stop: Preglottalized stop is a poorly defined concept in phonetics.  Depending on the author, the term may mean implosive; implosive with little ingressive airflow; voiceless implosives; or consonantal segments that have a glottal component preceding an oral component, something that is not known to ever be phonologically relevant.

Optimal discriminant analysis: Optimal Discriminant Analysis (ODA) and the related classification tree analysis (CTA) are exact statistical methods that maximize predictive accuracy.  For any specific sample and exploratory or confirmatory hypothesis, optimal discriminant analysis (ODA) identifies the statistical model that yields maximum predictive accuracy, assesses the exact Type I error rate, and evaluates potential cross-generalizability.  Optimal discriminant analysis may be applied to > 0 dimensions, with the one-dimensional case being referred to as UniODA and the multidimensional case being referred to as MultiODA.  Classification tree analysis is a generalization of optimal discriminant analysis to non-orthogonal trees.  Classification tree analysis has more recently been called "hierarchical optimal discriminant analysis".  Optimal discriminant analysis and classification tree analysis may be used to find the combination of variables and cut points that best separate classes of objects or events.  These variables and cut points may then be used to reduce dimensions and to then build a statistical model that optimally describes the data.

Falsettone: Falsettone is a term used in modern Italian musicology to describe a vocal technique used by male opera singers in the past, in which the fluty sounds typical of falsetto singing are amplified by using the same singing technique used in the modal voice register.  The result is a bright, powerful tone, often very high-pitched, although the sound is still different from and more feminine than what is produced by the modal voice.  The term "falsettone" is also used for the mixed vocal register that can be achieved using this technique.

Saltillo (linguistics): In Mexican linguistics, saltillo (Spanish, meaning "little skip") refers to a glottal stop consonant, ʔ] .  It was given that name by the early grammarians of Classical Nahuatl.  In a number of other Nahuan languages, the sound cognate to Classical Nahuatl's glottal stop is h] , and the term "saltillo" is applied to either pronunciation.  The saltillo is often spelled with an apostrophe, though it is sometimes spelled (with either pronunciation) ⟨h⟩ , or, when pronounced [h] , ⟨j⟩ .  The spelling of the glottal stop with an apostrophe-like character most likely originates from transliterations of the Arabic hamza.  It has also been spelled with a grave accent over the preceding vowel in some Nahuatl works, following Horacio Carochi (1645).

Supporting paragraphs: Falsettone Modal voice
Answer: Modal voice