Intraoral pressures across SOVT exercises
Maxfield L, Titze I, Hunter E, Kapsner-Smith M. Logopedics Phoniatrics Vocology 2015;40(2):86–92
The Science
The Science of Straw Singing
What a straw does to your voice, what the research says, and how we test.
What Is SOVT?
A Partly Closed Mouth
SOVT stands for semi-occluded vocal tract: singing through a narrow opening, like a straw. A little air pressure builds up behind it, and that back-pressure helps the vocal folds keep vibrating with less effort.
Key PointThe straw builds gentle back-pressure that lets your vocal folds work with less effort.
Sources
- Titze IR (2006). Voice training and therapy with a semi-occluded vocal tract: rationale and scientific underpinnings. J Speech Lang Hear Res 49(2):448–59.
- Smith SL, Titze IR (2017). Characterization of flow-resistant tubes used for semi-occluded vocal tract voice training and therapy. J Voice 31(1):113.e1–8.
Back-Pressure in the Mouth
More with a narrower straw.Air Through the Straw
Less with a narrower straw.
Wider
Narrower
A standard drinking straw: gentle back-pressure.
One Size Doesn’t Fit All
Why One Straw Isn’t Enough
Six things change how much resistance your voice wants.
1Individual Differences
Every single person is anatomically different.
2Task Dependent
Warming up, cooling down and building stamina each want a different load.
3AC / DC
No... not the band! The steady and the vibrating parts of airflow behave differently.
4Flow Rate
Generally, the faster the flow, the greater the resistance.
5Vocal Fatigue
A tired voice needs gentler resistance than a fresh one.
6Change in Pitch
Higher notes change what feels right.
The Science
Why Adjustable Matters
The resistance range of different SOVT tools, in cmH₂O of back-pressure.
Resono Pro v2Adjustable
Resono GoAdjustable
Resono (Original)Adjustable, discontinued
3 mm Singing StrawFixed
6 mm Paper StrawFixed
13 mm Silicone TubeFixed
Most straws have a fixed resistance, set by their width and length. Resono is adjustable, so you can load your voice precisely, like changing the weights at the gym. Our own measurements and modelling.
Research
From the Literature
Three of the papers behind the page, with full references.
Characterization of flow-resistant tubes used for SOVT training and therapy
Smith SL, Titze IR. J Voice 2017;31(1):113.e1–8
Water resistance and vocal economy
Calvache C, Guzman M, Bobadilla M, Bortnem C. J Voice 2020;34(4):582–589
How We Test
Modelled, Simulated, Measured
Fluid simulations, maths and a test rig, before anything reaches a shelf.
Fluid Simulations
Pressure and velocity through every setting.
Mathematical Modelling
How each opening changes the resistance.
Hardware Validation
A test rig to check the model against the real thing.