Gentlemen,

Just to put this to rest, the reason that Xantech, Niles and other IR Repeater manufacturers make blocking covers for emitters IS NOT because the components get confused when there are two signals. As David Z proved with his test setup, audio video components respond just fine when they get the command directly and through the repeater.

However, if there is any kind of EMI or OPTICAL interference present in the system, a very unusual kind of problem can occur if the IR SENSOR is close to an EMITTER. The interference pattern is emitted by the EMITTER, detected and amplified by the IR SENSOR creating an OPTICAL FEEDBACK loop. The blocking covers for the emitters are included by the manufacturers for this reason.

Now, as others have mentioned in their posts here, interference can occur from dimmer switches, a microprocessor in a satellite receiver, dvd or laser disc player, from unknown exterior to the house RF sources, from sunlight reflecting off swimming pools, oceans, curtains and walls, from quart halogen and other exotic desk lighting.

However, as David Z discovered, many installations are reasonably clean and have no interference.

When you do run into a problem and, it is good practice to make sure that all emitters are low power/non blaster types and that none are placed close to the IR Sensor. If you must place an emitter close to the IR Sensor, follow these steps:

Xantech: Switch the emitter housing for the completely OPAQUE housing included with the emitter package (it is identifiable via the pinhole in the bottom). Don't bother with the opaque cover for the component's IR window unless the sensor is less than a foot away.

Niles: "GLOM" (that's a technical term for self-adhesive) the huge horrible opaque black mask over the emitter. It may look ridiculous, but it works.

Someone in this thread commented that the sensors are often part of the display and the opaque cover would have to cover the entire display - a better installation solution is to switch that components position in the rack with a component whose IR sensor window can be covered - typically only one component will require the window cover - the component one foot or less from the IR sensor...

Hope this helps!

Best Regards,

-Eric

Eric Johnson
www.hometheaterpro.com

1-800-247-7001