Mackie SR244 / SR324 Owner's Manual - Page 51

auxiliary mixing circuits (even in Italy). SR SR is an acronym for Sound Reinforcement, which refers to a system of amplifying acoustic and electronic sounds from a performance or speech so that a large audience can hear clearly. Or, in popular music, so that a large audience can be excited, stunned or even partially deafened by the tremendous amplification. Means essentially the same thing as PA (Public Address). stereo Believe it or not, stereo comes from a Greek word which means solid. We use stereo or stereophony to describe the illusion of a continuous, spacious soundfield which is seemingly spread around the listener by two or more related audio signals. In practice, stereo often is taken to simply mean two channel. sweep EQ A sweep EQ is an equalizer which allows you to "sweep" or continuously vary the frequency of one or more sections. The midrange EQs in the SR24•4 channels 1-20 are sweep EQs (channels 1-28 on the SR24•4). symmetrically balanced See balanced. tinnitus The ringing in the ears that is produced with prolonged exposure to high volumes. A sound in the ears, as buzzing, ringing, or whistling, caused by volume knob abuse! trim In audio mixers, the gain adjustment for the first amplification stage of the mixer. The trim control helps the mixer cope with the widely varying range of input signals that come from real-world sources. It is important to set the trim control correctly; its setting determines the overall noise performance in that channel of the mixer. See mic preamp. TRS An acronym for Tip-Ring-Sleeve, a scheme for connecting three conductors through a single plug or jack. 1/4" phone plugs and jacks and 1/8" mini phone plugs and jacks are commonly wired TRS. Since the plug or jack can carry two signals with a common ground, TRS connectors are often referred to as stereo or balanced plugs or jacks. Another common TRS application is for insert jacks, used for inserting an external processor into the signal path. In Mackie mixers the tip is send, ring is return, and sleeve is ground. TS An acronym for Tip-Sleeve, a scheme for connecting two conductors through a single plug or jack. 1/4" phone plugs and jacks and 1/8" mini phone plugs and jacks are commonly wired TS. Sometimes called mono or unbalanced plugs or jacks. A 1/4" TS phone plug or jack is also called a standard phone plug or jack. unbalanced An electrical circuit in which the two legs of the circuit are not balanced in respect to ground. Usually, one leg will be held at ground potential. Unbalanced circuit connections require only two conductors (signal "hot" and ground). Unbalanced audio circuitry is less expensive to build but under certain circumstances is more susceptible to noise pickup. unity gain Unity gain describes a circuit or system which has its voltage gain adjusted to be one, or unity. A signal will leave a unity gain circuit at the same level at which it entered. In Mackie mixers, unity gain is achieved by setting all variable controls to the marked "U" setting. Mackie mixers are optimized for best headroom and noise figures at unity gain. VLZ An acronym for very low impedance. One of the most important reasons why inherent noise levels on the 24•4 are so miniscule. Thermal noise is something that's created by all circuitry and usually transistors and resistors are the worst culprits. The basic rule with thermal noise is: the higher the impedance, the more the noise. Mackie's design reduces thermal noise by making internal impedances as low as possible in as many places as possible within the console. VLZ is achieved by scaling down resistor values by a factor of three or four - resulting in a corresponding reduction in thermal noise. This is especially true for the console's mixing buses. volume Electrical or sound level in an audio system. Perhaps the only thing that some bands have too much of. VRMS See RMS. wet Wet means with added reverberation or other effect like echo, delay or chorusing. XLR connector See Cannon. Appendices 49