Bob Heil was an early pioneer in developing sound systems for the emerging rock music era back in the early 60s. This lead to starting his own company creating their own audio products including microphones.
Today Heil microphones are used in every kind of application from ham radio to top quality units for professional sound systems and pod-casters to commercial radio broadcast units. Since this is the Modesto Radio Museum site we will concentrate on Heil’s broadcast mics.
The two top-of-the-line broadcast mics are the PR 30 and PR 40…both are cardioid models that have found use in some top radio stations like KMOX in St. Louis among others.



Heil also offers a mic in the style of the RCA 77D & DX that they have named the Heil 77D! It is not a ribbon mic but a high quality unidirectional dynamic unit.

Heil designed his cardioid mics to be different than other manufacturers. He claims his unidirectional patterns reject off-axis sounds by up to 40 db. He also insists on a mid-high boost of around 4 db to give increased voice articulation for better speech intelligibility.

Below you can hear a demonstration of the Heil PR 781 microphone.
By the way, not many know that Bob Heil was an accomplished pipe organ player! He started doing this decades ago as a young man by playing movie theater pipe organs.
So we add Heil microphones to our Modesto lineup of high quality broadcast units.
Editor’s Note: Shortly after posting this article we learned of the passing of Robert “Bob” Heil founder of Heil Sound. Bob passed away on Feb. 28, 2024 at age 84. We send our condolences to the family and employees of Heil Sound. Bob certainly had a great influence on the professional audio industry.