Combined findings

Specifying pitch and volume when looking at vocal cords is essential. If we take the example of vocal swellings, voice may be clear at some pitch and volume combinations. Yet with the same pathology at other pitch/volume combinations, vocal swellings often have combined sonic elements of air leak and polyphonia. Let's consider why and when harmonic and non-harmonic sounds are present and when both types of non-harmonic sound may be present in combination.

At low pitch, the vocal cords are loose and a swelling(s) tends not to interfere directly with vibration (indirectly a mass on the vocal cord margin affects pitch since the additional mass tends to lower the pitch). At low tension, the swelling on the margin of the vocal cord will also easily compress into the body of the vocal cord during each oscillation. The swelling(s) will tend to separate during the open phase because of the low tension. 

At low air flow the vocal cords may not completely close and there will be continous air leak, so huskiness will be apparent. At high airflow (loud) at the same pitch, the vocal cords will come completely together on each cycle and there will not be air leak, but rather regular entrainment of the air pulses and so sound will be clear. So volume will affect clarity in vocal swellings at low pitch.

As we increase pitch and the cricothyroid muscle tightens, the vocal cord margins are brought closer together. At some pitch the vocal cord swellings touch and do not come apart. If airflow is high (loud), then two separate segments are created. There will typically be a jump in pitch because of the sudden cutting in half of the vibratory length - a pitch break. They may vibrate at the same pitch and so sound will be clear. If they are different lengths, then diplophonia will occur. If the swelling is large enough, the vocal cord margins will not approximate during the closed phase and there will be continous air leak - huskiness. So at high pitch and high volume we hear both huskiness and roughness.

If subglottic pressure is low (quiet), then at the pitch where the vocal cords touch, they will stop vibrating and air will leak out - phonatory stop. Or if the sudden leak of air triggers the individual to increae subglottic pressure as compensation, then there will be an onset delay.

So vocal findings of onset delays, phonatory stops, pitch breaks, roughness and breathiness may all be present in the same person, sometimes simultaneously, but dependant on the pitch and volume combination present.