JBL G40 (01) PDF Document

For the best stereo reproduction, the two loudspeaker systems should be placed an equal distance from your listening position and separated so that the angle between them, at the listening position, is between 40 and 60 degrees. For example, if your listening position is 8 to 12 feet (2.5 to 4 m) from each speaker, the two systems should be about 8 feet (2.5 m) apart.

Placing the loudspeaker in a corner or against a wall will result in the strongest (but not necessarily the most accurate) bass. If possible, models that are ported on the back should not be placed closer than 12 inches (305 mm) from the wall behind it.

For the best stereo imaging, it is recommended that the systems be placed so that the high frequency transducers are positioned approximately at ear level of a seated listener. Smaller loudspeakers will benefit from placement on stands or bookshelves.

For the best performance, an amplifier should be selected with an output rating that is greater than the maximum power that will be used. This margin of reserve power will ensure that the amplifier will not attempt to deliver more power than its design allows. However, the power amplifier’s power rating per channel must not exceed the maximum recommended amplifier power for the specific loudspeaker model.

Use two-conductor insulated wire to connect your loudspeakers to a receiver or amplifier. #16 AWG wire is recommended as a minimum size. If your speakers are more than 30 feet (10 m) from your receiver or amplifier, use larger diameter wire.

1. First determine the distance between the most distant speaker.

2. Now make the hookup wires for both speakers this length, even if one loudspeaker is much closer to your amplifier than the other. This will help maintain proper signal balance.

3. Strip off 3/8″ of insulation from both ends of each conductor.

4. Twist each set of thin wires into a tightly-bunched spiral.

5. Identify a visual difference between the two conductors of each molded pair of speaker wire to distinguish polarity (e.g., different color wire, strand of yarn, raised ribs, or printed markings).

The terminals located on the back of the loudspeaker system accept bare wire or dual banana plugs. To connect wire, push down on the button below the terminal and insert the wire through the hole.

For each channel, the red terminal on the loudspeaker should be connected to the red or (+) loudspeaker connection terminal on the receiver or amplifier, and the black to the black or (–). Connecting the loudspeakers in this manner ensures that they will be in phase (work together). Connecting them out of phase will result in less bass and poor imaging.

Check the following:

1. Ensure the Amp/receiver tape monitor button is not pushed in while using CD, FM or phono inputs.

2. Verify the correct speaker switch (“A” or “B”) is selected.

3. Ensure the sound source (CD, cassette deck, turntable) is turned on, activated, hooked up, and selected on the amp/receiver front panel.

1. Check if the balance control is turned all the way left or right.

2. Check if the speaker wire has become disconnected.

A few strands of speaker wire may be shorting out. Recheck the connections. Also, recheck the impedance requirements of the amplifier.

1. The polarity (+ and –) of one speaker has been reversed relative to the other. Double check connections.

2. Speakers are too far away from back and side walls or too far apart. Experiment again with the speaker placement.

The JBL G40 has a non-removable grille. Do not attempt to remove it.

The loudspeaker cabinet may be cleaned with a slightly damp cloth. To remove dust from the grille cloth, use a vacuum with a brush attachment. Spots may be removed with a commercial spot remover. Do not use any cleaners or solvents on the speaker drivers themselves.