A quick overview of frequency

Author: Toby  

Frequency 

Different driver handle different frequencies. Generally speaking (although frequencies can be further divided into segments), here are the following ranges for each driver type.

  • Tweeters handle frequencies from 20,000hz to 5000hz.
  • Midrange drivers handle frequencies from 5000hz to 250hz
  • Bass driver handle frequencies from 250hz to 60hz
  • Subsonic bass driver handle frequencies from 60hz to 16hz

Each frequency is a cycle that the driver makes. A cycle is the excursion of a driver making a in and out motion. A tweeters cycle of 16,000hz means the driver executes a cycle of 16,000 times per second. Tweeters designs are small to maintain their composure during these extreme cycles, (imagine trying to push a 12’’ driver 20,000 times a second, it just wouldn’t be possible!). Bass driver on the other hand are designed to push large volumes of air pressure to generate long wave lengths. Pushing these large wavelengths at an audible volume level requires a lot of power to maintain control over the driver excursions, hence why you see 1000W amplifiers built onto subwoofers. To give you an idea of how bass if formed, a real 16hz wave length around 40ft in length before it is properly formed. To push these wavelengths, driver are usually quite large and powered with their own dedicated amplifier.

You will find also that some manufacturers rate their speaker being able to achieve low frequencies of 28hz etc. from their passive bass driver. This is technically true, however this is achieved when they are driven at ridiculously high levels for those frequencies to become audible. Therefore the midrange and tweeters would be screaming their heads off as they are far more efficient and reproducing less difficult frequencies. This is why it is my belief that no system is complete without a good subwoofer! You can hear all the way down to 20hz, why not have a system that can fill the entire spectrum of human hearing.

Be careful of bass bloat on speakers. Plenty of underperforming speakers will bloat a 60hz or 70hz frequency and many people mistake it for low bass. This can also happen with poor positioning of subwoofers in rooms. You can identify it by noticing a certain frequency sounds louder than it should be.

 

Also note: It is not unusual for good subwoofers to exceed the limits of human hearing. While you can’t actually hear a 16hz frequency you can certainly feel it and it does have an effect on the mind. Researchers in psychology-acoustics conducted experiments using frequencies beyond human hearing and extreme low bass was attributed to giving a sense of wonder or supernatural happenings…

Even if you can’t hear it, you feel it which adds another layer of realism to what you are watching on screen. 

 

Toby