One Systems 112.HTH User guide

112.HTH Interchangeable High Frequency Horns

April 2020

One Systems® offers several high-performance, Direct-Weather capable loudspeakers
that incorporate fully rotatable and interchangeable high frequency horns. The 112.HTH
is a high performance 12-inch two-way professional loudspeaker system that is shipped
with a 60 degree by 40 degree horn (ET-60x40 factory-installed in the speaker. A
105 degree by 60 degree horn (ET-105x60) is also available as an accessory. Both of
these horns can be rotated to achieve optimized coverage patterns for horizontal or
vertical installation of the speaker.

Since each horn produces different acoustic loading for the compression driver, the

112.HTH passive crossover must be "re-configured" to provide both the proper
crossover frequency, as well as the proper amplitude shading for each horn pattern.

This process is very simple and straightforward.

The following steps are necessary to accomplish this process:

1. To change the horn in the 112.HTH, the grille must first be removed.

2. Once the grille is removed, the horn / driver assembly that is installed in the
speaker must be removed. Care should be taken to avoid stressing the wires that
connect the compression driver to the crossover assembly.

3. Disconnect the two wires from the compression driver, observing the polarity of
each wire. The orange wire is positive (+) and the yellow wire is negative (-).

NOTE: The wiring for the ET-60x40 horn requires the orange wire to be on the
positive terminal of the compression driver and the yellow wire to be on the
negative terminal.

When the ET-105x60 horn is used the wiring must be reversed. (The orange wire must
be on the NEGATIVE terminal and the yellow wire must be on the positive terminal)

4. Remove the compression driver from the horn by loosening and removing the 4
nuts that secure the driver to the horn.

5. Install the new high frequency horn on the driver and securely tighten the 4 nuts
on the threaded studs. (NOTE: Do not over-tighten the nuts!)

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6. Before the new horn / driver assembly can be re-installed in the 112.HTH’s enclosure,
the internal passive crossover must be "re-configured" to provide the proper crossover
frequency and electrical loading for the specific horn being installed.

As noted above there are two high frequency horns available for the 112.HTH, the ET­60x40 (factory installed) and the ET-105x60. There is one jumper on the 112.HTH
crossover printed circuit board. This jumper must be moved when the high frequency
horn is changed.

Please see the picture below. This illustrates the side of the printed circuit board that
is seen when the high frequency horn is removed. This is seen by looking thru the hole
in the 112.HTH enclosure where the horn was mounted. The jumper is shown in the
picture below.

When the ET-60x40 high frequency horn is used the jumper must be moved so that the
jumper makes connection from position 1 to position 2. When the ET-105x60 high
frequency horn is used the jumper must be configured so that it makes connection from
position 1 to position 3 on the printed circuit board.

The jumper is shown in the photo above

When the ET-60x40 high frequency horn is used, the jumper must be moved so that the
jumper makes connection from position #1 to position #2. When the ET-105x60 high
frequency horn is used the jumper must be configured so that it makes connection from
position #1 to position #3 on the printed circuit board.

7. Once the jumper has been configured for the desired high frequency horn, the wires
from the printed circuit board to the compression driver should be reconnected, making
sure that you have observed the correct polarity as noted below.

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NOTE: The wiring for the ET-60x40 requires the orange wire to be on the positive

terminal of the compression driver and the yellow wire to be on the negative terminal.

When the ET-105x60 horn is used the wiring must be reversed. (The orange wire must
be on the negative terminal and the yellow wire must be on the positive terminal).

The reverse polarity wiring for the ET-105x60 is required to offset the signal delay
associated with the shorter horn. This polarity reversal maintains comparable signal
delay between the high frequency horn and the woofer.

8. The fully wired high frequency horn/driver assembly should now be mounted
back in the 112.HTH enclosure. It is important to insure the desired horizontal
and vertical included angles of the horn be oriented relative to the enclosure.
(This orientation will be determined by the required radiation pattern and the
orientation of the enclosure relative to the acoustic space) Securely tighten the
bolts that hold the horn/driver assembly but do not over tighten them.

9. Replace the 112.HTH grille assembly

NOTE: The image below shows the ET-105x60 horn oriented with the 105 degree
included angle in the horizontal plane and the ET-60x40 with the 60 degree included
angle in the horizontal plane.

ET-105/60 ET-60/40

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