Originally Posted by yanks1
John, how do I read this graph; in laymans terms what does it tell us about the C205 speaker? Thanks, Tom
Here is a primer on how to read Spinoramas:
On-axis Response - This represents the direct sound heard by a single listener sitting on the design axis of the loudspeaker. A flat frequency response is an absolute requirement for all electronic devices. Therefore, it is not surprising that loudspeakers with a flat on-axis frequency response have a higher probability of being preferred in double-blind listening tests.
Listening Window - The well-designed loudspeaker should deliver good sound to a group of listeners -- not just the person sitting on-axis. The listening window is the average frequency response measured for listeners sitting on and slightly off the reference axis of the loudspeaker. Loudspeakers that receive high sound quality ratings in double-blind listening tests tend to have listening windows with a flat frequency response.
First, or Early Reflections -- Most of the sound we hear is reflected in rooms. The second loudest sound (after the direct sound) is the first reflected sound produced from the loudspeaker. Therefore, it is paramount that the sounds radiated by the loudspeaker in the off-axis directions generate early reflections that sound good. The shape of this curve should not differ greatly from the on-axis response curve.
Sound Power Response -This is a measure of the total sound radiated by the loudspeaker without regard to the direction in which it is radiated. The shape should be smooth and slightly downward tilting.
Sound Power and First Reflection Directivity Indices - These directivity indices tell us how the directivity of the loudspeaker changes as a function of frequency. At low frequencies most loudspeakers radiate sound omni-directionally (DI = 0 dB), where wavelengths are long. In forward-firing, 2-way and 3-way loudspeakers, as wavelengths get shorter, frequencies get higher, and more of the sound is radiated towards the front. The goal is to have this trend develop smoothly and gradually.