SOVTEs: All The Cool Kids Are Doing Them!

Updated: May 4

You've likely heard and even used straw phonation in your voice studio, but why have straws become an essential tool in voice studio? Let's take a bit of time to review the science and the voice-y goodness behind a special class of vocal exercises known as SOVTEs.

SOVTEs are semi-occluded vocal tract exercises. Semi-occluded simply means to partially close off the vocal tract in some way, which means that just about anything you do to partially close the vocal tract can be turned into an SOVTE. That makes this designation incredibly fluid and versatile, and gives you virtually limitless options to find some kind of SOVTE that can benefit your clients. Because not all clients respond positively or in the same way to every exercise, having the flexibility to explore and find something that works is a really big benefit to this type of vocal exercise.


There's been a ton of research already done on why these exercises work, and what exactly is going on at the vocal fold level. While questions still remain, we have a pretty good handle on a lot of the physics and physiology behind them. (By the way, if you want to get a really great overview of the science, I highly recommend this article in Journal of Singing by Kelley Hijleh and Cory Pinto (you might have to log in to NATS to read it, but if you aren't a member, send me a message and I can hook you up!). Trust me, this one is fantastic and worth the time to go through carefully.) At its core, the principle behind SOVTEs is using impedance to encourage efficient vocal fold vibration. Let's break that down a bit.


The fancy physics definition of impedance is "a combination of reactance and resistance." What this means practically is "how much opposition a system encounters as it starts up" (Hijleh and Pinto). It's a ratio with two parts: resistance and reactance. Having more of one part and less of the other can affect how easily the system starts up. For voices, we want the start up to be as easy as possible while still being efficient. SOVTEs can help manipulate that balance.


The two parts to impedance are:

  1. Resistance, which is the dissipation of energy, and

  2. Reactance, which stores up energy.

Reactance also has two parts:

  1. Compliance, which is a barrier to the voice starting up (I find this a bit confusing, to be honest, since one would think compliance would encourage the voice working, but I think my colloquial understanding of the word clouds this up a bit for me), and

  2. Inertance, which takes the stored energy of reactance and puts it into phonation.

Now, here's where things can get a bit tricky for us as voice teachers. Not all SOVTEs work in exactly the same way. Some SOVTEs partially close the vocal tract through the whole exercise (like humming or straws, for example), some fluctuate in how the vocal tract is partially closed (like lip trills), and still more can have varying rates of closure. The type of closure can change the ratio of impedance and can target different areas of the vocal tract. Coupled with the unique needs of the client right in front of you, some SOVTEs may work fantastically well for that client, and others might not. It takes a bit of experimentation sometimes to find the thing that is going to work best.


And of course, straws may work well for your client today, but next week will be different and need a different strategy. It's helpful to have a tool box with several different kinds of SOVTEs to try in order to find what works for your client on any particular day.


In no particular order, here are some common SOVTEs that you can use:

  • singing through straws