Earthworks CTB30 Data Sheet

CTB30 High Denition Boundary Microphone

For Conference Tables, Lecterns & Alters

Silver

Black

White

Earthworks CTB30 Boundary Microphone

The CTB30 is a ground breaking High Definition Boundary Microphone™ that is the

ideal choice for high quality teleconferencing applications. It was engineered to deliv­er crystal clear, highly intelligible reproduction of the human voice at any point around
a conference table or other flat surface without the typical problems associated with

boundary microphones. Earthworks’ trademark clean fast impulse response delivers
the subtle details and nuances of the human voice. The CTB30 also incorporates a
unique filter that significantly reduces low frequency table thumping and HVAC noise.
In addition, the CTB30 delivers an impressive reduction of unwanted sounds from
paper and pens. Like all Earthworks microphones, the CTB30 is completely immune
to RF interference from mobile phones and other RF sources. The CTB30 is a low pro-

file, pristine sounding microphone solution for permanent or temporary conferencing
applications.

™

• Table Top Boundary Microphone

• Low prole, small footprint

• Flat Frequency Response from
60Hz to 30kHz

• Very High Intelligibility

• True Semisphere™ Polar Response

(near-perfect frequency response at 45º
incident to the surface in a hemispherical

pattern)

• Unique low frequency lter
minimizes noise from table
thumping and HVAC

• Reduced pickup of paper
shufing

• Immune to RF interference

• 136dB Max Acoustic Input

• Black, White or Silver Finish

True Semisphere™

Vertical

1K

5K

10K

20K

Polar Response

The CTB30 features a True Semisphere™ polar response, meaning voices are picked

up equally from anywhere in a 360 degree circle around the table top. It is tuned for

flat frequency response from 30 to 60 degrees above the boundary plane. The CTB30

is ideal for complete coverage of any conference or huddle space.

Horizontal

TABLE

Installation

The CTB30 has a 10 ft. (3.04m) low profile cable with an XLR-3M attached. For tem­porary applications, simply set the CTB30 on the table and plug it into a mic input
with 24-48V phantom power. For permanent installations, the XLR connector can be

removed, allowing the cable to run through a small hole in the surface. Once installed,

the connector can be resoldered, if necessary. The CTB30 features two 6-32 screw

holes and a keyhole on the bottom of the microphone for secure mounting.

Architectural & Engineering

Specications - 30kHz Omni

The microphone shall be a back-electret condenser type with a wide-range uniform frequency response
of 60 Hz to 30kHz -3dB. The microphone shall be of a single capsule, single membrane design with an
impulse response rise time no longer than 25 microseconds, and total settling time, including rise time,
no longer than 120 microseconds. The microphone shall have polar characteristics uniform in all planes
to form an omni semisphere of revolution and shall accept sound pressure levels up to 136dB producing
no more than 3%THD. The microphone shall be resistant to RF interference from cell phones and other RF

devices and also provide a low frequency lter to reduce table thumping and HVAC noise. The microphone

shall measure 4.1 in. (104.1mm) in diameter by 0.45 in. (11.4mm) in height. The microphone shall have a

low prole 10 ft. (3.04m) cable terminated with a 3-pin XLR-M connector and shall require 24-48V phantom
power. The microphone shall be made of metal with a black nish. The Earthworks CTB30 is specied.

Specications Subject to Change without Notice

Earthworks, Inc. • 37 Wilton Rd. • Milford, NH 03055 • [phone], ext 114 • email: sales@ear thworksaudio.com • earthworksaudio.com

Expertly Hand Made in the U.S.A.

1K

5K

10K

20K

Frequency Response

Microphone Placement

CTB30

Table Mount High Definition Boundary Microphone™

For Conference Tables, Lecterns & Alters

CTB30

12 ft

(366 cm)

Micrphone Placement

Earthworks CTB30’s near-perfect omnidirectional

polar pattern provides wide coverage for the user.

It typically takes 1 CTB30 to provide even coverage
for a 12’ conference table.

Mounting with Cable Through the Table

Permanently Installed on Table

with XLR Connector Attached

Side View

(cable through table)

Connector will clear a 0.875 inch opening

Permanently Installed on Table

with XLR Connector Removed

Side View

(cable through table)

Cable will clear a 0.125 inch opening

+

Red

(pin 2)

2 ft

(60 cm)

2 ft

(60 cm)

Top View

Bottom View

Output Cable

Connection for

XLR-3 Connector

CTB30

SPECIFICATIONS

Type:

Boundary

Element:

Frequency Response:

Low Frequency Rolloff:

Polar Pattern:

Sensitivity:

Impedance:

Power requirements:

Max Acoustic Input:

Dynamic Range:

Signal to Noise Ratio:

Min. Output Load:

Microphone Color:

Dimensions:

Cable Length:

Connector Type:

Specications subject to change without notice

Condenser

60Hz to 30kHz -3dB @ 1 ft. (30cm)
60Hz, 15dB/octave

Omni Semisphere™

-25dB
65 ohms

24 - 48V Phantom, 10mA

136dB @ 1kHz
116dB @1kHz
74dB @ 1kHz

Output:

XLR-3M. (pin 2+)

1K between pins 2 & 3

Noise:

19.5dB SPL (A weighted)
Black, White, Silver or Nextel® Dark Black

4.1 x 4.1 x 0.45 inches
(104.1 x 104.1 x 11.4mm)
10’ (3.04m) with installed XLR-3M
Low prole cable terminated into a 3-pin
XLR-M

Weight:

0.36 lbs. (162g)

-

Black

(pin 3)

╧

White

(pin 1)

Shield

(pin 1)

Keyhole

Mount

CTB30 Dimensions

Ø 4.100

Ø .097

cable diameter

Cable Length 10 ft. (3.04m)

with installed XLR-3M

6-32 Mounting Holes

Ø .798

2.815

Earthworks, Inc. • 37 Wilton Rd. • Milford, NH 03055 • [phone], ext 114 • email: sales@ear thworksaudio.com • earthworksaudio.com