Yamaha EMX3500 Operation Manual - page 15

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value is the same as the factory preset value for the

parameter.

You can reset all of the internal DSP settings to their

factory presets by using a ball-point pen or other fine-

tipped object to press the RESET switch. Doing so will

restore the programmable parameters of all effect pro-

grams to their preset values. It will also return the current

program selection to the first program, VOCAL SEND 1.

Using the Graphic Equalizer

The EMX3500’s built-in graphic equalizer (GEQ) has two

main uses: compensation for acoustic deficiencies in the

listening area, and feedback control. Like the channel

equalizers, the GEQ should not be used unless it is

absolutely necessary. The more equalization you use, the

more phase deviation you introduce into the program

signal—and the greater the chance that the phase devia-

tion can result in an unnatural, distorted sound.

There are many instances, however, in which the acoustic

characteristics of the listening area cause response

anomalies. Large areas of uncovered glass or tiled floors,

for example, are extremely effective reflectors of high-

frequency sound. Amplified sound produced in such

environments can seem painfully sharp, in which case

some reduction in the high-frequency range may be called

for.

Smaller symmetrical rooms (a square room being the

worst case) can actually have resonant frequencies within

the audible low-frequency range. In such rooms, a slight

reduction in the low frequencies can help to clarify the

sound. Please note that in almost all cases, good equaliza-

tion demands a cut in the offending frequency range rather

than a boost in ranges where response is lacking.

The GEQ can also be used—although to a limited de-

gree—to control feedback. Proper microphone placement

is the primary means of preventing feedback, but this can

be extremely difficult if you’re working in a tight stage area.

To get around this problem, try cutting response in the

frequency range where the feedback is occurring. (You

may have to experiment a bit to find this range.) This

solution will compromise the overall frequency response of

the program, but it is better than running the risk of squeal-

ing feedback in the middle of an important performance.

Connecting Speakers

The EMX3500 Powered Mixer has two 1/4" phone jack

speaker outputs per channel. The outputs for each chan-

nel are connected in parallel internally. This places some

restrictions on their use, as described below:

• If you connect speakers to only one of the output

jacks (SPEAKER 1 or SPEAKER 2), on either

channel (R or L), the total impedance of the

speaker system connected to that channel may

be no less than 4 ohms.

• If you plug speakers into both the SPEAKER 1

and SPEAKER 2 jacks of either channel (R or L),

the total load impedance of the speaker systems

connected to each output of that channel must be

no less than 8 ohms. (Note that two 8-ohm

speaker systems connected in parallel form a 4-

ohm load).

• The maximum total impedance of speakers

connected to the speaker outputs of each chan-

nel should be 16 ohms.

• The maximum speakers allowable per channel

are: one 4-ohm speaker, two 8-ohm speakers, or

four 16-ohm speakers.

Although a higher total load impedance than the recom-

mended 16 ohms will only result in a loss of power output,

a total load impedance that is too low can actually damage

the EMX3500. The EMX3500’s maximum output power is

350 watts per channel with a total load impedance of 4

ohms (one 4-ohm speaker or two 8-ohm speakers), or 200

watts per channel with a total load impedance of 8 ohms

(one 8-ohm speaker or two 16-ohm speakers).

• Never connect or disconnect speakers while the

mixer’s power supply is turned on!

• Solid phone plugs can overheat when inserted in

the rear-panel SPEAKER jacks of the EMX3500,

causing a potential fire hazard. Make a habit of

checking the metal tips of your speaker plugs,

and cleaning them if necessary, before connect-

ing them to the EMX3500.