The Orban 8100A/XT Six-Band Limiter Accessory Chassis for OPTIMOD-FM (Models 8100A and 8100A/1) has been created to provide aggressive multiband processing for stations that desire bright, loud, "highly-processed" audio. Derived from OPTIMOD-AM Model 9100A, the 8100A/XT consists of a stereo Bass Equalizer, and a stereo six-band limiter cascaded with the exclusive Orban distortion-cancelling multiband clipping system. When added to the basic OPTIMOD-FM system, the unit creates a dense, consistent sound without pumping or other obvious processing artifacts. For convenience, we will hereafter refer to the 8100A/XT Six-Band Limiter Accessory Chassis as the "XT". All future mentions of the "8100A" mean the 8100A/1, or the 81Q0A as modified by means of retrofit kit RET-27 to function as an 8100A/1, unless the context clearly indicates otherwise. Functionally, the unit replaces the high frequency limiter within OPTIMOD-FM Model 8100A, and permits the following objectives to be met: — Increased loudness for a given level of audible processing side-effects (by comparison to an unmodified 8100A); — Improved consistency from source to source due to the "automatic equalization" effect of the six-band limiter; and, — Increased presence and intelligibility on smaller radios and in autos. The XT is particularly suited for highly competitive pop music formats, such as AOR, CHR, AC, and Urban Contemporary. Because it has been specifically "tuned" to the OPTIMOD-FM system, it minimizes processing side-effects when compared to complex processing systems that use OPTIMOD-FM cascaded with other processors. Please note that OPTIMOD-FM with the XT will be no louder than the basic OPTIMOD-FM operated with very fast release times and large amounts of clipping -- OPTIMOD-FM is already a very loud processor. The primary advantages of the XT are improved consistency, increased brightness on naturally-dull program material, and reduction of audible processing side-effects — all while retaining the high loudness capabilities of an aggressively-operated 8100A.