How is efficiency related to the quality of the speakers?
The efficiency equals the produced sound pressure in relation to the power. It depends on the driver efficiency, but also the crossover filter and cabinet design.
Efficiency is a very good example of the art of compromising, it cannot be too low as the speakers would need very powerful amplifiers. It itīs too high we generally experience performance problems.
Looking at the individual driver, the challenge is to maximize the efficiency without reducing other parameters such as distorsion. So, finding the best compromise between three parameters is essential: efficiency, sonic performance and cost. An example:
We can improve the efficiency by making the membrane lighter. But doing this with the wrong material would lead to a less rigid membrane - and this in turn would not sound as good due to increased distorsion. Then, we can treat the membrane to be more robust - but with increased weight as the drawback. Efficiency will decrease, and the cost will increase. There are more examples of this in every day life:
The suspension of a car is also a compromise. A soft suspension offers great ride comfort at lower speeds, but will not work perfectly at higher speeds. A harder suspension is good for higher speeds, but the ride becomes "crashy" at lower speeds.
Generally, we can come to this conclusion:
- Extremely good drivers always have limited sensitivity
- Drivers with extremely high efficiency always offer limited sonic performance