Antex Electronics DMX-4 User Manual

DMX-4

USB Mixer

User

Manual

DMX-4 USB Mixer User Manual

Antex Electronics Corporation
19160 Van Ness Avenue
Torrance, California 90501
www.antex.com

Copyright © 2008 Antex Electronics Corporation. All
Rights Reserved. No portion of this manual may be
reproduced without prior written consent from Antex
Electronics. Part number 9000-2489-7006 Rev B.

FCC Compliance Statement for United States Users

This equipment has been tested and found to comply
with the limits for a Class B device, pursuant to Part 15
of the FCC Rules. In order to maintain compliance with
FCC regulations, shielded cables must be used with this
equipment. Operation with non-approved equipment or
unshielded cables is likely to result in interference to
radio and TV reception. Changes or modifications made
to this equipment not expressly approved by Antex

Electronics could void the user’s authority to operate the

equipment.

IMPORTANT SAFETY INSTRUCTIONS

Read Instructions – Read all Safety Instructions before

operating equipment.

Retain Instructions – Save these instructions for

future reference.

Heed Warnings – All warnings and these instructions

should be adhered to.

Follow Instructions – All operating and use instructions

should be followed.

Cleaning –Do not use liquid or aerosol cleaners. Use a

damp cloth for cleaning.

1

DMX-4 USB Mixer User Manual

Attachments – Do not use attachments not

recommended by the manufacturer as they may cause
hazards.

Water and Moisture – Do not use this product near

water – for example near a bathtub, wash bowl,
kitchen sink, out in the rain or in a room where
moisture is likely to occur.

Accessories – Do not place on an unstable surface

(cart table or tripod) where tipping is a possibility.

Ventilation – Install unit in well ventilated area where

self generated heat may escape. Bookcases or
cabinets should have proper venting to allow heat to
escape.

Power outlet – A properly grounded wall outlet must

be used. Do not use a plug adapter that bypasses the
three-terminal ground plug. Unplug the unit during a
lightning storm or when not being used for prolonged
periods.

Cord Protection – Route your power cords and other

connecting cables out of traffics way so as not to be
walked on or traveled over by carts wheels, or a
tripping hazard may occur. Do not place items on top
of or against the cord so as to pinch the cord.

Overloading – Do not overload wall outlets, extension

cords, or integral convenience receptacles as this can
result in a risk of fire or electrical shock.

Object and Liquid Entry – Never push objects of any

kind into this product through openings as they may
short-out parts that could cause a fire. Never spill
liquid of any kind on the product.

Servicing – Do not attempt to service this product

yourself; there are no customer serviceable parts

2

DMX-4 USB Mixer User Manual

inside. Refer all servicing to qualified service
personnel.

A product and cart combination should be moved with

care. Quick stops, excessive force, and uneven
surfaces may cause the product and cart combination
to overturn.

Damage Requiring Service – Unplug this product from

the wall outlet and refer servicing to a qualified
service person under the following conditions:

a. When the power-supply cord or plug is

damaged.

b. If liquid has been spilled, or objects have fallen

into the product.

c. If product has been exposed to rain or water.
d. If the product does not operate normally by

following the operating instructions. Adjust only
those controls that are covered by the operating
instructions as an improper adjustment of other
controls may result in damage and will often
require extensive work by a qualified technician
to restore the product to its normal operation.

e. If the product has been dropped or damaged in

any way.

f. When the product exhibits a distinct change in

performance – this indicates a need for service.

Replacement Parts – When replacement parts are

required, be sure the service technician has used
replacement parts specified by the manufacturer or
that have the same characteristics as the original
part. Unauthorized substitutions may result in fire,
shock, or other hazards.

3

DMX-4 USB Mixer User Manual

Safety Check – Upon completion of any service or

repairs to this product, ask the service technician to
perform safety checks to determine that the product
is in proper operating condition.

Heat – The product shall be situated away from

sources such as radiators, heat resistors, heat
registers, stoves, or amplifier that produce heat.

4

DMX-4 USB Mixer User Manual

General description:

The DMX-4 is a 4 channel microphone preamplifier with
4 analog to digital converters (A/D). The DMX-4
connects to a PC via a USB 2.0 connection so that audio

can be recorded onto the PC’s hard drive. There are 2

configurable monitor outputs, which can be
independently set to be a mix of any combination of the
4 input channels. The monitor outputs can be used to
connect to a PA system or for video/teleconferencing.

All level adjustments are solid state; there are no
mechanical knobs on the unit. Level adjustments are
made by moving virtual slider controls in the Antex
Mixer Program running on the PC. This allows for
settings to be stored and retrieved as a “scene”. Also, if
the PC connected to the DMX-4 is connected to a LAN,
adjustments can be made from a remote computer
somewhere on the LAN.

The microphone inputs are professional balanced XLR
connectors. The differential input impedance is 2K.
Phantom power of +14 volts can be turned on under
control of the Antex Mixer Program. Phantom power is
connected through a 1K resistor on each line. In

“microphone” setting, all 4 inputs have a gain range of

+10dB to +85dB. Note that 65dB of gain is done in the
analog circuitry, and the additional 20dB is done in the
digital domain. As you increase the gain on any input,
the level of this audio will get louder in the monitor
output and in the recording level. However, once you
exceed 65dB, the recording level will continue to
increase, but the audio in the monitor output will not
increase any further. Input channels 1 and 2 have a

5

DMX-4 USB Mixer User Manual

fixed gain of 0dB in “line” setting. Inputs 3 and 4 have

an adjustable gain of –8 to +31.5dB in “line” setting.
(Although the circuitry is capable of a lower gain setting
than –8dB, the setting is limited in the Antex Mixer
Program to –8dB so that it is not possible for the analog
circuitry to go into clipping before the A/D.)

The monitor outputs are single ended RCA jacks,
capable of a 2VRMS signal (+6dBV). The level
adjustment range is from –102dB to +25.5dB. The
output has a 560 ohm internal series resistance to
protect it from short circuits to ground. The equipment
that the monitor output is connected to should have an
input impedance of 2K or greater.

The A/D converter sample rate can be set to 8, 11.025,
12, 16, 22.05, 24, 32, 44.1, or 48KHz. This allows for
optimization between file size and audio fidelity. All 4
inputs are digitized separately, and 4 tracks may be
recorded to hard disk. The inputs may be mixed in any
combination to the 4 record channels using the Antex
Mixer Program. On your PC, the 4 record channels are
accessed as 2 stereo Wave Devices. Record channels 1
and 2 are left and right of Wave Device 1, respectively,
and record channels 3 and 4 are left and right of Wave
Device 2.

Power input to the DMX-4 can be from +5 to +15 VDC.
Power consumption is about 5 watts. The unit is
supplied with a 9V international wall adapter, but can
also be powered by battery packs or from an automobile

accessory plug (“cigarette lighter”). The power indicator

LED changes gradually from green at 12 volts to red at 5
volts so the user can note a color shift on battery power
when the battery gets low.

6

DMX-4 USB Mixer User Manual

What’s a ”dB” and why should I care?

Throughout this manual, the term “dB” is used. This
stands for decibel. You may think, “but I just want to
record a legal proceeding. I don’t want to be a
recording engineer. Why should I care about this?”
Although dB’s may seem complicated mathematically:

dB = 20 x log(signal level/reference signal level)

Using dB’s gives you a better feel for how changing the

volume will sound to your ears. For example, if you
increase the output of your stereo amplifier from 1/10 of
a watt to 1 watt, this seems like a small change, only
9/10 of a watt. If you increase the output from 4 watts
to 40 watts, this seems like a real big change. However,
in both cases you are increasing the output by 10dB,
and surprisingly, in both cases it will sound to you like
the music only got twice as loud.

Negative dB’s means quieter. –10dB sounds half as
loud.

Positive dB’s means louder. +10dB sounds twice as

loud.

0dB means no change in the loudness when referring to
a slider setting. For VU meters, 0dB is the maximum
level. Severe distortion occurs above 0dB.

Installing the Software - XP

The Antex Mixer Program requires Microsoft .NET

Framework 2.0. If you do not have this installed
on your computer, the InstallShield will stop. To

7

DMX-4 USB Mixer User Manual

check first if you have this on your computer

already, click the “Start” button on the lower left
of your computer screen. Click “Control Panel”,
then “Add or Remove Programs”. When the

program list is populated, scroll down and see if

there is “Microsoft .NET Framework 2.0”. If not,

open Internet Explorer and go to :

http://www.microsoft.com/downloads/details.asp
x?displaylang=en&FamilyID=0856eacb-4362­4b0d-8edd-aab15c5e04f5

(Or, you can go to http://microsoft.com and type
“.NET Framework 2.0” in the Search box.)

Follow the instructions to download and install
.NET Framework 2.0.

Go to www.antex.com and download the latest

software driver for the DMX-4. The installation
process is fairly straightforward, using the
InstallShield.

Run the “Setup.exe” program.
The first dialog box will say “Preparing to

Install…”

On the second dialog box, click “Next”.

8

DMX-4 USB Mixer User Manual

Enter the User Name and Organization, click “Next”.

9