OEM Systems SW-8SPKR — Impedance Compensating Speaker Selector Manual

Installation and wiring manual for the OEM Systems SW-8SPKR Impedance Compensating Speaker Selector — an 8-zone speaker distribution and switching center with built-in amplifier protection for connecting up to eight pairs of 8-ohm speakers to a single stereo amplifier or receiver.

Product Overview

The SW-8SPKR allows up to 8 pairs of 8-ohm speakers to be connected to a stereo amplifier or receiver while providing amplifier protection. Buttons 1 through 8 turn each individual pair of speakers ON and OFF.

To maintain individual volume control over each pair of speakers, "Autoformer" type impedance-matching volume controls should be used (one per pair of speakers), installed in-line between the SW-8SPKR and each speaker pair.

Wiring Requirements

• Speaker wiring should be a minimum of 18-gauge.
• If wire is run through walls, it should be "CL" rated.
• For runs over 100 feet, use 14-gauge wire.

If uncertain about proper setup and installation, refer to a qualified technician. Improper installation can severely damage this device and the equipment connected to it.

Speaker Connection

Each pair of speakers is designated 1 through 8. Connect each set of speakers to the appropriate screw terminals:

• 1L+ — Speaker Pair 1, left channel positive (+)
• 1L- — Speaker Pair 1, left channel negative (−)
• 1R+ — Speaker Pair 1, right channel positive (+)
• 1R- — Speaker Pair 1, right channel negative (−)

Maintain polarity: Always connect Positive (+) to Positive (+) and Negative (−) to Negative (−). Never cross positive wire connections to negative connections — a loss of fidelity will occur if speakers are wired out of phase.

Using Volume Controls

To individually control the volume level of each pair of speakers, install one "Autoformer" type impedance-matching volume control per pair. With volume controls added, each speaker pair can be adjusted or turned off independently at the control. Note: If a speaker's volume control is turned off, it cannot be turned back on from the speaker selector — the two are independent of each other.

If you don't wish to use volume controls, or use controls without impedance-matching capability, the power handling of this speaker selector must be de-rated (see Specifications).

When distributing audio from a single amplifier/receiver: set each speaker's individual control to maximum, adjust the amplifier to the highest normal listening level, then turn down the volume at the speaker's individual control. Warning: if the volume control vibrates in the wall, or sound can be heard from the control when turned down, the amplifier level is too high and must be reduced, or damage will likely occur to the volume controls and possibly the amplifier.

Amplifier Protection Switch

The Amplifier Protection switch should be engaged when two or more pairs of speakers are selected. The amplifier is protected by buffering its output through high-power resistors. If you notice an unusual drop in volume from one speaker, or excessive heat from the speaker selector, check the system for possible problems or configuration issues.

Wiring Diagram Overview

Connect the speakers to the speaker selector's Speaker Outputs terminals as labeled (e.g., 8L+/8L-/8R+/8R-, 7L+/7L-/7R+/7R-, 6L+/6L-/6R+/6R-, etc.), then connect the amplifier output to the input (L+/L-/R+/R-) of the speaker selector. Use care to maintain proper polarity on all connections.

In a typical 8-room installation, each room's speaker pair connects through its own impedance-matching volume control (recommended) between the speaker selector output and the speakers.

Specifications

Rev. B