Tube Acoustics

Pipe Bomb and Bass Bomb Products

 

Why do standard speakers sound so crappy?

 

Most quality speakers come with a specification sheet with certain parameters that define the acoustical and electrical behavior of the speaker.  These are called the “Thiele/Small” parameters, named after the two engineers who did much of the research trying to standardize and define the relationship between a speaker and its enclosure.  You probably won’t get any of this data with a store-bought car audio speaker.  In fact some car speaker manufacturers may not even test for this data.  But using the data one can determine which type of enclosure is best suited for a particular driver.

 

The most relevant parameter defines the total damping of the driver, or Qts.  Qts is calculated by a formula using Qms, the mechanical damping of the driver and Qes, the electrical damping of the driver.  As a general guideline, a Qts of 0.7 or below suggests the driver is well suited for a sealed enclosure such as a can.  The higher the Qts, the worse the driver will sound in a can.  Guess what.  Most off-the-shelf car audio speakers have a Qts of 1.2 and higher, meaning they stink in a can. The fact is that most car audio drivers are not well suited for a defined enclosure at all, but are better in a suspension application such as a dash board or door panel

 

Another useful parameter is the drivers free air resonance, Fs.  This is the measured frequency at which the weight of the moving parts of the speaker becomes balanced with the force of the speaker suspension when in motion.  The mass of the moving parts and the stiffness of the surround and spider are the key elements affecting Fs.  It is important to know Fs so that you can design your enclosure such that it doesn’t “ring” at the driver resonance.  Also note that as a general rule, a lower Fs indicates a better ability for low frequency sound reproduction.  Most store bought 6-inch drivers have a Fs of about 55Hz, suggesting that it would be pretty tough to produce the 40Hz signals that may be claimed on their packaging.  My guess is that the majority of people sticking store bought car speakers in a can and bolting them to a tower haven’t given any thought to Qts or Fs which is why their system sounds so lousy.  The Pipe Bombs and Bass Bombs by Tube Acoustics have components perfectly matched for a can application <see Pipe Bomb and Bass Bomb Technical Info>.