Loudspeaker systems are made up of the enclosure, transducers and horn assembly's. Within the system, there are very high internal pressures, therefore it is very important to release the pressure and reduce turbulence as soon as possible.This is achieved by designing shallow horns and large ports.
The diagram above explains losses incurred due to the use of long horns, which create high second Harmonic distortion, and acoustical power conversion to heat.
The importance of grill/foam design and effect is commonly overlooked and misunderstood. The front Grill/foam will effect the reproduction of the signal, this will increase with frequency. This negative effect further increases off axis on high frequencies.The diagram below demonstrates on and off axis destruction.
Negative effect of speaker’s grill is higher off axis
Speaker Pulse Response
The main parameter of the speaker is pulse response. Parameters of the speakers are almost exclusively measured by a continuous sine wave signal. But continuous sine waves are not identical with regard to music signals. Music consists of many signal types, basic tones, harmonics and noises and are best represented by pulse response. When a speaker is measured by continuous sine wave signal, it has time to swing at higher frequencies, although the speaker has no control over diaphragm mass and motions.
One of the most important parameters in transducer design for Super Live Audio Systems is the removal of unwanted resonances. These resonances are usually caused by the mechanical design of the speaker and its failure to control the diaphragm motions. Resonances reduce overall definition by masking smaller signals and producing tones not related to the original signal.
The figure below shows an original sine signal (red, top) with its sharply defined end and the same reproduced signal (blue, bottom), still oscillating after the signal stops due to poor control of speaker mass. Poor pulse response has a very negative effect on the ability of a speaker to reject feedback. SLA systems feature exceptional feedback rejection and this in part is due to their excellent pulse response.
Effect of speaker’s resonance, original signal (red, top) and reproduced signal (blue, bottom)
Text and photos by courtesy of KV2 Audio. All trademarks, registered trademarks and copyrights are the property of their respective owners.