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Troubleshooting

If you think your subwoofer has a problem, please do everything you can to confirm the problem before contacting us for service,
including reading through the troubleshooting section. Many times the problem actually is caused by other items in the system or the
subwoofer’s interaction with those items. Much of the time, the service department will not be able to reproduce the error.

7

Problem

Cause

Solution

Humming or 

buzzing noise.

Subwoofer goes into 

STANDBY mode 

while material is 

playing.

No output from the

subwoofer (the LED

does not light up).

You have an amplifier problem.

Your speaker wires or interconnects are

the cause.

A light dimmer or other triac based (SRC)

device is on the same AC circuit.

You have a problem with other equipment.

The source is not providing enough signal.

AC power is not getting to the amplifier.

Amplifier is not working.

• Disconnect all interconnects from the amplifier. If still 

hums, call/email technical support.

• It is possible that some cables have a poor or broken

ground due to poor construction, oxidation, or damage.

Also, poorly shielded cables can potentially pick up 

noise. Try another interconnect or speaker wire. Also, 

move the signal cable away from AC cables, power 

transformers, or other EMI sources.

• Use an AC line filter or plug the unit into a different circuit.

• If hum goes away when interconnects are disconnected,

the hum is coming from the rest of your equipment. 

Add them back one piece at a time. The one that causes

the system to hum is the source of the hum.

• The unit is going into STANDBY mode during the quiet

passages. Try turning the source signal up. On a Dolby 

Digital receiver, turn the SUBWOOFER level up in the 

SPEAKER SET-UP menu. After you turn the signal up, turn 

down the volume knob on the subwoofer to compensate.

• An alternative is to turn the subwoofer ON/AUTO/OFF 

switch to the ON position. It does not use any more power 

and does not affect reliability.

• Check to see if crossover on the receiver is set too low 

and/or if the crossover on the sub is set to ‘in’, and crossover

on the sub is set too low. This will greatly reduce the signal 

going to the sub and hence make it go into standby mode.

• Check that the power cord is plugged in securely at both

ends and make sure that the power outlet the subwoofer is

plugged into is working.

• Try another power cord such as a desktop computer power 

cord.

• If you have determined that the power outlet has power, and 

that the power cord is plugged in properly and the LED is 

still not lighting up, the amp needs service. Call/e-mail

technical support for authorization to send the amplifier 

back for service.

Summary of Contents for Research ULS-15 MK2

Page 1: ...y low distortion and high output Flexible room placement The luxurious and smooth non vinyl finishes rounded corners and edges and front firing woofer allow for close placement next to listeners in corners and even inside built in entertainment centers Connects to almost any system Integration is easier than ever Thanks to modern receivers that use Dolby Digital DTS THX or Bass Management you can ...

Page 2: ...d particularly at plugs convenience receptacles and the point where they exit from the apparatus 11 Unplug this apparatus during lightning storms or when unused for long periods of time 12 Refer all servicing to qualified service personnel Servicing is required when the apparatus has been damaged in any way such as power supply cord or plug is damaged liquid has been spilled or objects have fallen...

Page 3: ...evel will be lower so neighbors are less disturbed We strongly recommend this method if your couch is up against the back wall and your room is over 18 feet deep Use subwoofer crawling This excellent technique is not as hard as it sounds The room s acoustical reflections are used to your advantage Place the subwoofer in the listening position in a seat towards ear level Connect the subwoofer to th...

Page 4: ...fer but can be purchased at electronic or home improvement stores Strip 1 2 of insulation from each end of the wire to expose the bare metal If your speaker wire is fraying tightly twist the metal Unscrew the plastic hex nut on the binding post to insert the exposed wire into the hole Tighten the binding posts by hand Run the wires from your system s amplifier to the subwoofer s HIGH LEVEL INPUTS ...

Page 5: ...ll integrated When using small satellites that don t have much bass the 90 Hz set ting on the control will probably yield the best results Your subwoofer has a sharp 24 dB octave low pass filter to remove upper bass and midrange from the subwoofer when CROSSOVER is switched IN This makes your subwoofer non directional Unlike many other subwoofers on the market the 24 dB octave slope stays steep at...

Page 6: ...d octave increments Measure from the listening position and set the subwoofer volume level to match the other speakers Setting the Q Control We have added an adjustable Q control on the subwoofer amplifier in order to give the user higher headroom flatter in room response and better ability to take advantage of room gain Set Q 0 3 for the highest mid bass headroom in all room sizes and for the fla...

Page 7: ...ables power transformers or other EMI sources Use an AC line filter or plug the unit into a different circuit If hum goes away when interconnects are disconnected the hum is coming from the rest of your equipment Add them back one piece at a time The one that causes the system to hum is the source of the hum The unit is going into STANDBY mode during the quiet passages Try turning the source signa...

Page 8: ...ofer s speaker level input Connect only to the channel that has a true ground If neither channel has a true ground e mail call technical support Increase the volume of the subwoofer and the subwoofer level or LFE level on the receiver or other source It is best to set the level of the subwoofer relative to the other speakers using a test disk and a Radio Shack SPL meter or built in tones on your p...

Page 9: ...efects Some states do not allow limitations on how long an implied warranty lasts and or do not allow the exclusion or limitation of incidental or consequential damages so the above limi tations and exclusions may not apply This Warranty Does Not Cover Damage caused by abuse accident mis use negligence or improper operation Products that have been altered or modified Any product whose serial numbe...

Page 10: ...10 Notes ...

Page 11: ...11 Notes ...

Page 12: ...12 HSU Research 985 N Shepard St Anaheim CA 92806 1 800 554 0150 HSURESEARCH COM ...

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