When designing a loudspeaker there are four major areas to focus on, these are: -
- Frequency response
- Bass behaviour
- Time coherence
It follows therefore that attention must be paid to: -
- Spectral flatness (particularly in the critical hearing range of 700Hz to 7kHz)
- Low energy storage & resonances (correct driver choice and cabinet design & construction techniques)
- Minimal non-linear distortion (in drivers and crossover)
- Uniform on-axis / off-axis behaviour (to reduce room dependency)
- Getting Bass balance appropriate to the room dimensions and boundary conditions
- Crossover design (crossovers are a necessary evil but are the key to a good sounding speaker)
Our ears cannot be relied on during the design process. Problems in any of the areas above may well be audible, but the ear alone will have difficulty pin-pointing causes, but will be identifiable if the correct measurements are taken. The ear brain combination is a great acoustic analyser but also a very fickle one – a whole host of affects such as environment, mood, biases of various kinds and acoustic memory make our hearing alone a very limited tool for designing loudspeakers.
There are also some basic checks and balances that must be monitored throughout the development process the most important of these is System Impedance - what load will be presented to an amplifier by this loudspeaker?