YORKVILLE MP8D Manuel De L'utilisateur page 8

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T T h h e e r r e e A A r r e e 3 3 M M a a i i n n F F u u n n c c t t i i o o n n s s f f o o r r t t h h e e G G r r a a p p h h i i c c E E Q Q
1. To adjust the system for feedback reduction, the normal technique is to turn the main sys-
tem up to the point of feedback and move the EQ sliders, one at a time, to determine
which frequency band is causing the feedback. (Remember to push them back up to cen-
ter position if they don't stop the feedback). When isolated, the offending band is then
pushed down about 3 to 6 dB. Usually only 2 or 3 bands can be reduced before the feed-
back elimination process begins to affect the sound quality.
2. To adjust for deficiencies in the speaker system's bass response, the most common adjust-
ment is to boost the 63 Hz about 6 dB and the 100 Hz about 3 dB. However, use of the
graphic EQ to extend the deep bass frequency response of a speaker cabinet does use up a
lot of the available system power, so this technique should be used with caution to avoid
distortion and possible speaker damage. On the other hand, in applications where it is
appropriate to sacrifice deep bass for higher overall sound output, the 63 Hz slider should be
taken down 6 dB below centre. You may now increase the MAIN level for added volume.
3. The third use of the graphic equalizer is to adjust the sound character for artistic reasons.
Each frequency is adjusted until the sound is what the musicians feel sounds best. The best
sound system operators, however, usually strive to use a minimum of equalization for this
purpose, or for boosting the bass. Instead, they use very minimal sound-shaping adjust-
ments to ensure that the threat of feedback and distortion will also be minimal.
MP8D REAR PANEL
1. AMP A & B SPEAKER OUTPUTS & HEATSINKS
Each of the MP8D's dual power amplifiers has two 1/4" jacks for speaker connections. You
may connect one 8-Ohm speaker cabinet to each jack or a single 4-Ohm speaker to either
side. Connecting two 8-Ohm speakers (i.e. a 4-ohm load), to either AMP A or AMP B, will not
harm the MP8D, but the output power will be severely limited and is not recommended. If the
amp overheats, the built-in thermal protection will cycle the amplifier on and off until it cools
down, usually in a few minutes.
Do not obstruct the flow of air around the heatsink fins on the rear of the MP8D as this too
may cause the power amplifier to overheat and shut off. After the MP8D cools down, opera-
tion will be restored automatically. This should never happen if adequate ventilation is provid-
ed at the back of the unit.
2. AC POWER SWITCH & FUSE
The power switch and fuse are located on the back panel. If you must replace the fuse, always
replace it with the same type - a 6A slo-blo (T3A slo-blo in 220-240V export models). Do not
replace the fuse with the wrong type or wrap foil around the old one, as this may cause seri-
ous damage. If replaced fuses keep blowing, take the unit to your Yorkville dealer for service.
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