Power-Source-Filter, Your Body & Your Voice

For those of you that know us at Performance Medicine, you will probably be aware that we work in a way that integrates your voice, your breath and your body.  

For those of you who are less familiar with us – we work with your voice and breathing in a myofascial and movement paradigm.  What does this actually mean?

This means that we integrate your voice with your whole body by linking it with the myofascial chains in your body and then we look at how your body moves. 

The way in which we work can be simplified to the model that is often used in Speech Pathology, the “Power-Source-Filter” model.

In this model the power is your respiration, your source is the vocal cord and larynx itself and the filter is everything above the larynx (see Figure 1)/.

Figure 1

Let’s break this down a little further.


The power of your voice, in this model,  is your respiration and everything that affects this.

Respiration is produced by the contraction of your diaphragm and intercostal muscles and exhalation is the elastic recoil of these structures.  When you are breathing in under exertion, you will bring in your accessory breathing muscles (pectorals, scalenes, sternocleidomastoid) and forced exhalation will recruit your larger abdominal muscles (external and internal obliques).

If you have a respiratory issue such as asthma, or a structural issue that affects your ability to inhale or exhale, your ability to produce appropriate breath flow may be affected.

Research has described that our diaphragm has a role in both posture and respiration and that this role in posture decreases as the demand in respiration increases 1.  Evidence also suggests that issues affecting your lumbopelvic region (back pain or pelvic health issues) can also impact your breathing 2,3.  

Therefore, if you are a professional voice user and have unresolved issues in your upper back, low back or pelvis, it is recommended that you check this out so that you can have a solid foundation to build upon.

I recognise that this is a simplified version of breathing – but this blog is to highlight the Power-Source-Filter model, so watch this space for more on breathing.


Your source is the vocal folds and laryngeal mechanism itself.

Despite being a very small piece of real estate, your larynx has a lot going on!

Your vocal folds are a structure made up of muscles with a flexible tissue overlay (superficial lamina propria) that allows it to vibrate.  The joints (cricothyroid joints and thyroarytenoid joints) allow the vocal cords to move in and out and elongate and shorten.  Our breath is important here because the air under our vocal cords (subglottic pressure) needs to be adequate to allow the cords to vibrate (we need not too much and not too little for it to be efficient) and this directly links our larynx and our respiratory system.

The larynx itself (hyoid bone, thyroid cartilage and cricoid cartilage) is connected to our trachea (and therefore lungs) and it is dynamic as it sits in a myofascial sling connecting our larynx to our head, shoulder girdle and jaw. It moves up and down depending on the muscles activating and our lung volumes.

So if you have an issue affecting the vocal cords themselves, such as a mucosal issue, or the the position of your larynx in your head and neck, or how it is connecting to your shoulder girdle, this may impact the ease in which you produce your voice. 


Your filter is everything above your larynx (also known as supraglottic region or suprahyoid region). In the professional voice user, our filter helps create the resonance of your voice. 

As your larynx sits in this myofascial sling, the connections to the jaw mean that our voice production is intrinsically linked with our jaw and oral cavity.  Therefore, the health of your oral cavity (teeth and tongue) and your temporomandibular joints is really important. If you clench your teeth at night (bruxism) or have pain in the jaw joints, having this managed to decrease additional muscle activation in the supraglottic/suprahyoid area will contribute to your larynx being in its most natural and efficient position. 

On another note, have you ever had sinusitis and your voice sounds nasal?  This is an example of your resonant chambers not allowing your voice to vibrate and bounce around to create a lovely resonant, pinging voice.  So please see your ENT or GP if you experience nasal issues to ensure that you can manage this component of your “filter”.

So as you can see, your ability to produce your voice is a whole body event.

Having a great team around you is important and our Performance Medicine team regularly works with your Speech Pathologist or ENT to ensure that you are getting a 360 degree care of your voice.  

If you are curious to know more about how your voice and your body are interconnected please don’t hesitate to book in to see one of our Vocal Physiotherapists today.  

  1.  Massery M, Hagins M, Stafford R, Moerchen V, Hodges P. Effect of airway control by glottal structures on postural stability. J Appl Physiol. 2013. 115:483-490. 
  2. Nele Beeckmans et al., “The presence of respiratory disorders in individuals with low back pain: A systematic review”, Manual Therapy, 2016, Vol 26, pag 77–86. (level of evidence: 2A)
  3. Roussel et al., “Altered breathing patterns during lumbopelvic motor control tests in chronic low back pain: a case–control study”, European Spine Journal, 2009, 18.7: 1066-1073. (level of evidence: 3B)
  4. Figure 1: Power=Source Filter: The Dynamic Voice, Annie Strauch