Hear Technologies hear back User Manual

user guide

ADVANTAGES / FEATURES

• Virtually unlimited system size

HEAR BACK SYSTEM DESCRIPTION

The basic Hear Back™ system consists of a hub

and personal mixers. The hub receives any of

the three input signals and converts them to

HearBus digital audio plus power. The mixers

are connected to the hub using CAT5E cable.

A single hub supplies digital audio and power to

a maximum of eight mixers. That's one for you

and everybody in the band! If that's not enough,

the hubs can be daisy-chained using the

HearBus In and HearBus Out for virtually

unlimited system size.

The hub may be connected to recording

equipment, digital audio workstations, and

analog or digital consoles.

The mixer is placed near the talent and gives

them control over the audio inputs. The user-

friendly system saves system setup time.

• Excellent quality and audio fidelity

• High power - low distortion

headphone amplifiers

• Very long interconnect without loss
of audio quality

• Three audio inputs: ADAT® optical,
analog, and HearBus are switch
selectable from the front panel

• Local control of up to ten channels
of audio - 8 inputs plus a stereo Aux
input

• Built-In DSP limiter for hearing and
monitoring device protection

• Headphone amplifier fault LED

• Bus status indicator

• Link indicators/switches - links mono

pairs for stereo operation

• Standard CAT5E cable for power

and signal connection to mixers

• Built-in cable strain relief

• Balanced line outputs - mono/stereo

• Stereo AUX in

FCC Statement

Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are

designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is
no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which
can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that

to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

• Built-In mic stand mount as well as
desktop mount capability

0318

MIXER FEATURES

• Local control of up to ten channels of audio

• Master volume

• Built-in DSP limiter

• 24-bit D/A converters

• Less than 1.5 millisecond total system delay

• Bus status indicator

• Headphone amplifier fault indicator

• Link indicators

• Standard CAT5E power and signal connection

• Balanced, mono/stereo, line outputs

• +4 dBu level TRS unbalanced stereo AUX in:

- Expand numbers of mixes

- Drum module/metronome or local mix input

MIXER CONSTRUCTION

The Hear Back mixer is constructed of UV-stabilized ABS
and has a built-in mic stand mount. Two cable strain reliefs
greatly reduce stress on the CAT5E cable connectors and the
mixer RJ45 connector.

STATUS INDICATORS

The mixer has three types of status indicators:

1. BUS - The bus indicator (1) is a bi-color LED that is green

1

under normal operating conditions, indicating the
HearBus clock is present. In the absence of the clock, the
indicator turns red alerting the user a problem exists at
the hub or connection to the hub.

2. LINK - The link indicators (2),
whenever the associated link switch(es) (4), (6) and (8)

(14) and (16) illuminate

2

14 16

4 6 8

are pressed. Switch settings are stored in non-volatile
flash memory whenever power is removed.

3. HEADPHONE AMPLIFIER FAULT - The fault indicator

(22) is

22

normal off and only illuminates red if an over-current or short
circuit condition occurs. The circuit shuts down the
headphone amplifier and upon cooling returns to normal
operation. Continued cycling of the fault circuit is not

recommended as excessive cycling can degrade the
amplifier's performance and life.

LINK OPERATION

Normally, a stereo mix is connected to the hub channels 1 and

2. These are typically the front of house or control room mix and
are controlled using the mixer stereo input knob (9).

9

The "more me" inputs are typically mono and are controlled
using the mono control knobs (3),

3 5 713 15 17

(13), (5), (15), (7) and (17). The

mono signals are center-panned in the stereo field when the link
indicator is off.

When a pair of mono inputs are linked, three things occur;

1. The left channel becomes the link master volume control for
the stereo pair.

2. The two inputs are hard panned left and right. Inputs can be
adjusted at the source to have a stereo spread anywhere
desired. Stereo signals are realized by using a pair of the
mono inputs: 2/4, 5/6, and/or 7/8 by simply pushing the link
switch

4 86

(4), (6), or (8).

3. The right mono volume now becomes inactive.

L

L

L

LIMITER

The limiter gives the user ultimate control of his/her hearing
protection as well as headphones, in-ear and conventional
loudspeaker monitoring devices in the event of excessive input
levels. The two-stage DSP limiter is an :1 or "brick wall"

8

limiter. The limiter is controlled using simple threshold
adjustment

The limiter active blue LED

19

(19).

18

(18) illuminates when the limiter is

active. If the indicator operates during normal program material
the dynamic range and quality of sound will suffer. NOTE:

Limiter should only be active when excessive signals are
present. To set the limiter, see Hear Back Connecting and

Calibration on page 6.

1

Bi-Color Bus Status Indicator

2

Link Indicator - Channels 3/4

3

Mono Channel 3/Stereo Link Master
Level

4

Link Switch - Links Channels 3/4

Mono Channel 5/Stereo Link Master

5

Link Switch - Links Channels 5/6

6

7

Mono Channel 7/Stereo Link Master

8

Link Switch - Links Channels 7/8

9

Stereo Mix Level Control, Channels 1/2

Stereo Auxiliary Input

10

Right Line Output

11

Left/Mono Line Output

12

Mono Channel 4

13

Link Indicator - Channels 5/6

14

Mono Channel 6

15

Link Indicator - Channels 7/8

16

Mono Channel 8

17

Limiter Indicator

18

Limiter Threshold Control

19

Master Volume

20

Headphone Output

21

Headphone Amplifier Fault Indicator

22

Headphone Output

23

0516