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© Toxic 2004
TRI-MODE
If you want to use a subwoofer or centre speaker in stereo mode, you also
can connect them in bridge operation to the speaker terminals. However,
consider that in this case an additional passive crossover network (12 dB
slope) is necessary because neither the subwoofer (optimal frequency band
up to 150 Hz) nor the centre speaker (200 Hz - 6 KHz) can operate with full
frequency band.
In tri-mode operation, only 4 ohm speakers for the left and right channel
side should be used. 8 ohm are recommended as impedance for the third
speaker, 4 ohm are also possible.
Subwoofers in tri-mode operation should be without case (free-air
subwoofer). For achieving the best result, you can (on a trial basis) change
the subwoofer’s polarity. This should be done if it results into a more
powerful bass. When using a subwoofer as a third speaker, the two other
loudspeakers should be relieved from the deep frequency range of the
subwoofer. For this, a 6 dB high pass filter is recommended, i.e. a
condenser is put into the wiring of the speaker. Thus the sound of the
relieved loudspeakers often becomes more transparent and power rating of
the speaker is higher.
Tri-mode with subwoofer for 4-channel amplifiers:
