I am not a fan of passive radiators in full-range speaker cabinets. In every instance, I was underwhelmed with the sound of their bass and blamed the common denominator, the passive radiator.
A passive radiator is a woofer without a motor. Just picture your favorite woofer cone and that’s how a passive radiator typically looks. Were you to take it out of the box you’d note its lack of magnet and its light weight. Radiators act as tuned ports, lowering the speaker’s bass frequency cutoff to below what just its active woofer can produce.
My opinion of passive radiators has been negative for years.
Our opinions are formed by our experiences. If every beet we eat makes our stomach turn just a little then we declare our dislike of beets. Likewise, if every passive radiator we hear is muddy and ill defined we reject anything resembling it.
That is until we taste a beet we like or hear a radiator done right.
Our speaker genius, Chris Brunhaver, has opened my eyes and ears to the delights of a properly designed passive radiator. And what’s fascinating to me is that it doesn’t even look like a woofer. In Chris’ design a piece of heavy material, like wood, is the cone and it’s held in place with a carefully engineered surround material. Together, they form a tuned circuit that is sonically invisible in the same way a proper subwoofer extends the apparent bass of the main speaker without pointing to itself.
Little woofers can have big, tight, low frequencies with a properly designed radiator.
The point of this post is more about how experiences form opinions and less about radiators.
When we have the opportunity to extend our knowledge and venture out into the unknown, we often return with new opinions that are to our benefit.
I just love being wrong.