When Cardioid Becomes Omni-directional

My contribution to this website is to enlighten people to practical solutions to every day problems we come across on stages around the world!

One of the biggest issues in the audio world is microphone choice, and which mic to use where and how to apply practical solutions to age old problems!…

So the simplest problem is what polar pattern do we choose and how do we know what it is…?

For this example, I will be showing off 2 Audio Technica small Diaphragm condenser mics, namely a cardioid and an omni directional mic…

Please note, Cardioid mics have”ribs”or slots down the side of the mic, and Omni directional mics have a solid body with no slots!!!…

Also refer to the polar pattern diagrams below…

So now, from seeing this, it physically means, if you take ANY MIC… and cover up the sides of it… you are interfering with its physical polar pattern!!!…
So how many times have you not seen and encountered this following problem…..refer to the pictures below:

Note how these guys are more interested in their image, rather than the art of being a professional performer…
By holding the mic around the grill, you are turning a cardioid mic into an omni directional mic, hence the fact that you get feedback by “cupping” the mic!!!

So this is my first and very basic “lesson into practical tips for live sound engineers”!


Email: soundengineer@live.co.za

Facebook: https://www.facebook.com/vance.vanrooyen

Facebook Group Admin: Sound Engineer’s Cape Town

My name is Vance van Rooyen, I am from Cape Town South Africa. I was born in Cape Town in September 1961(making me 57 years old) 

I have been in the music industry now as a professional since 1979!…I started as a professional “lead guitarist”, playing professionally for about 11 years. During this time, I studied sound engineering, acoustical engineering through our local broadcast corporation. I have owned 3 businesses, related to our industry, from music shops, to event companies…

I have worked and toured with major artists  from around the world. Currently I’m working and living in Dubai UAE


  1. the ribs on the side are for picking up low end. Duh. No one uses condenser mics for front line vocals. It’s a recipe for disaster.


    1. The viewpoint of the author, Mr. Vance van Rooyen (which in my observation and to my understanding too and also as per the information provided at the link below) is that the KSM9 is a premium vocal condenser microphone that captures vocal subtlety with extraordinary detail to deliver clear articulation, functional flexibility, and precise vocal reproduction for live performance, Besides it has dual diaphragm design and switchable polar patterns (supercardioid/cardioid) as can be seen at the link below:


      The question thus arises is that why does an SM58 feedback if you cup the sides? If the sides are closed or cupped, its behavior becomes omnidirectional, thus giving rise to positive feedback possibilities. This altering of field pattern has nothing to do with the microphone being a condenser microphone or a dynamic microphone.


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