Frequency Response Effects
As you listen to music, images of the instruments that created the sounds are elicited. For instance, one can tell the approximate size of a drum from the sound it produces. On a high-resolution playback system, finer details can be heard; i.e., is the head made of plastic or calfskin? Is the player using light sticks or heavy ones?
A relatively broad-band emphasis (or de-emphasis) of a given frequency range can tend to exaggerate (or diminish) the relative size of the instruments playing in that range. A useful tool for evaluating these distortions of size is a recording of a small group of unamplified acoustic instruments made with a simple microphone set-up.
Listening for Size Distortions
Play a recording of this type, with the volume adjusted to achieve a natural playback level. As you listen, create a mental image of the players based on sounds being recreated. Then ask yourself, "Does this sonic image correspond to the musical instruments that generated these sounds?"
Is the portrait a natural one, or are certain elements distorted? Does a stand-up bass sound like the correct size, or is it exaggerated, sounding like it is ten feet tall, or as if the strings are the size of ropes? A speaker with excessive in-room bass response can create these effects. On the other hand, a speaker system with rolled-off bass can shrink the size of instruments, turning the same stand-up bass into a cello-sized instrument.
