However, we hear no difference when we play both scales (mentioned above) on a keyboard (a western instrument), for we are using an equal Temperament western scale with lowering the designated pitch -50 and leaving the rest of the pitches untouched. The quarter tone in al bayati scale (بياتي) is slightly tuned different than the same quarter tone in rast scale (رست).
For, each scale is tuned (pitched) differently and has one (or all of the following: 1/4 tone, 3/8 tone, and 1/8 tone.) Thus, we hear the difference when the same scale, let's say, bayati scale (مقام البياتي) is played on a keyboard (western instrument with equal temperament) and when it's played on an Arabic instrument such as the Aud (عود), for the aud is tuned and pitched differently.
