• Architectural spaces where a point-and-shoot speaker may be too visually obtrusive.​

​

CBT 100LA – This is the tallest model (other than the CBT 70J/70JE combination), providing

excellent control. It, too, has frequency response down to 80 Hz, so it’s good for both speech and

music.

• Lecture halls

• Difficult acoustic environments

• Transit centers

• Conference rooms

• Cathedrals

• Multi-purpose spaces

• Architectural spaces.

• Because it has a flat front, CBT 100LA can be used for applications where the speaker

needs to be recessed into the wall.

CBT 70J – This is a two-way speaker, with frequency response down to 60 Hz, 500 Watt power

handling, and high 100 dB sensitivity for 127 dB maximum continuous SPL (133 dB peak SPL). It

provides asymmetrical vertical coverage, sending more sound to the far area of the room than to

the near area, resulting in more even coverage of the listening space from front-to-back. Because

it provides some down-fill sound, it is fairly forgiving of mounting height. It does not send much

sound upward (above its cutoff angle), which may reduce some back-wall reflections.

• High level A/V applications

• Small to medium performance spaces (depending on the amount of bass needed)

• Small to medium houses of worship (also depending on the bass requirement)

• Full fidelity lecture halls

• Delay/fill applications for larger systems

• Large-scale surround sound applications

• Outdoor systems such as baseball fields, racetracks, and theme parks.

CBT 70J + CBT 70JE – The addition of the extension cabinet doubles the height of the array,

extending the pattern control down to 400 Hz – covering the voice range – while doubling the

power handling, increasing the sound level capability by 6 dB and extending the frequency

response down to 45 Hz.

• Small to medium performance spaces requiring more bass and/or more pattern control

than a 70J by itself

• Highly reflective small to medium houses of worship requiring more pattern control than a 70J

• Full fidelity lecture halls with difficult acoustic environments or where full spectrum sound is

desired

• Transit centers with highly reverberant acoustic environments

• Multi-purpose spaces that are sometimes used for speech and at other times need to

produce full bandwidth music.

2) Can I really change the vertical coverage with a switch?

Yes! The CBT 100LA and CBT 70J include switches that change the vertical coverage of the

speaker. As far as we know, CBT’s are the first passive loudspeaker ever where you can change

the coverage with a switch.

The BROAD coverage position of the CBT 100LA is 40º, which is like a narrow-coverage pointand-

shoot speaker but with the excellent pattern control of a 1-meter tall constant directivity horn.​

​The NARROW coverage position is 15º, which is like a traditional column speaker with cut-through

long-throw capability, and with the added benefit of constant directivity coverage pattern control so

that everyone within the coverage pattern hears the same sound quality.

Similarly, the CBT 70J switches between a BROAD setting of 45° and a NARROW setting of 25º.

The reason its coverage is slightly wider has to do with its asymmetrical vertical coverage (which is

described in greater depth later in this FAQ).

3) When I use a CBT 70J with a 70JE extender, what signal do I need to run to each?

Simply run a full-range signal from the power amplifier to each. All crossing-over is done passively

within each of the speaker cabinets. Each cabinet is 8 ohms, so the total load on the amp is 4 ohms.

4) Are the CBT’s outdoor-rated?

Yes, they are rated IP-54, per IEC 529. The first character, “5”, indicates that the speaker is

protected against damage from solid foreign objects greater than 1 mm (0.04 inches) in diameter

and also that it is also protected from dust (not dust-tight, but dust-protected). The second

character, “4”, indicates that it’s protected against damage from splashing water.

In addition, CBT speakers have passed longer than industry standard tests for UV and salt-spray

(The industry standard is between 2 and 8 hours testing. We went all out and tested CBT’s for 200

hrs for each factor – UV and salt spray).

Here are some factors that make CBT’s great for outdoor use. The cabinets are glass-filled ABS

plastic with maximum UV additive The grilles are made of non-rusting aluminum, which are

painted with a high quality polyester paint that stretches rather than cracking. The drivers are

treated for outdoor use so they are as weather resistant as polyurethane cones. The backs of the

tweeters on the CBT 70J are fitted with weather covers. All the external screws are stainless steel.

5) What are the input connectors? Does the MTC-PC2 Panel Cover fit for

sealing the terminal cup against weather?

The input connectors are a screw-down terminal strip – nickel over a copper base, with stainless

steel screws. These are the same connectors as are on Control 25AV, 29AV and 30.

Yes, the MTC-PC2 fits all CBT models. MTC-PC2 forms a water-tight seal when used with roundjacketed

cable.

6) When would I want to use the Speech position of the Music/Speech Switch?

Which is the “flat” frequency response position?

The CBT 50LA, 100LA and 70J all have a SPEECH/MUSIC switch.

The MUSIC setting is for flat frequency response. The SPEECH position provides a midrange

presence peak.

Here are some instances when the SPEECH position might be advisable:

• When the speaker is used in a simple system that does not have parametric EQ or DSP, you

might want to use the SPEECH position to emphasize the midrange when used primarily with

speech – lectures, addresses, paging, etc.

• In the SPEECH position, there is an additional 4 to 5 dB higher mid-range output. The

speaker’s natural output includes this highly sensitive mid-range, while the music setting

kicks in a passive filter that flattens the frequency response. Therefore, the extra midrange

output comes from increased sensitivity in that frequency range yet the power handling

remains the same. Therefore, in the SPEECH position, the speaker has higher maximum

SPL in the midrange by 4 to 5 dB.

• For systems with parametric EQ or DSP, it is possible to set the speaker in the speech

position and use the outboard EQ to flatten the response (3.5 kHz center frequency, -4 or -5

dB, 3 octave bandwidth). This provides an extra 4 to 5 dB higher output for more headroom

at mid-range frequencies.

• For systems where multiple CBT’s are being driven from the same 70V/100V distributed

speaker line, there may be acoustic or throw-distance reasons for needing to boost the midrange

clarity of some of the CBT’s by putting them in SPEECH model while keeping the

others in the flat MUSIC mode.

7) Do the CBT’s have a “down tilt” in their coverage, like I can set for a

computer aimable powered column?

No, the aiming axis for all CBT models is straight in front of the speaker. The CBT’s get aimed

vertically by tilting them downward. It is convenient for the installer to know that where they aim

the speaker is the aiming axis of the speaker’s coverage.

8) What is meant by the CBT 70J having “Asymmetrical” vertical coverage?

What are the advantages? How do I know where the aiming axis of the speaker is?

The CBT 70J exhibits true ASYMMETRICAL VERTICAL COVERAGE. In other words, it sends

more sound in the direction of the far area of the room than to the near area of the room. This is

analogous to the popular “progressive” or “J-shaped” vertical line arrays where the cabinets at the

top of the array are almost straight, with the bottom cabinet being more highly splayed. They,

too, send more sound in the direction of the far seats than toward the close seats.​

In this way, CBT 70J can, in many rooms, send enough sound to those in the back without

blowing away those in the front with too much sound. The 70J can be thought of as having a

long-throw and short-throw sections built into the same speaker. How even the coverage is in any

particular room depends on the depth of the room, the rake of the seating and the mounting

height of the speaker. EASE files may be used to map the coverage onto a listening plane.

You may see the claim of “asymmetrical coverage” erroneously made by other manufacturers

when their speaker simply provides a down-tilt in the coverage compared to the aiming axis of the

speaker. This is an incorrect usage of the term.

The aiming axis of the CBT 70J is simply the direction the front of the speaker is facing. Because

the grille has a curve in the bottom half, the direction may be best indicated by the top and bottom

panels of the cabinet as well as the back of the cabinet. In the BROAD coverage mode, the

speaker covers approximately 17° up from this axis and 28° down from this axis, for a total 45° of

vertical coverage. In the NARROW coverage mode, the speaker covers approximately 9° up

from the aiming axis and 16° down from this axis for a total of 25° of vertical coverage.

9) Do CBT’s have enough output to be used where I might normally use

point-and-shoot speakers?

The CBT’s have very high output for column speakers -- more than you might expect – and they do

not distort much at high drive levels. This is because of high sensitivity, high power handling, and

Dynamic SonicGuard™. It is also the case that speech mode adds to the maximum SPL in the

midrange by increasing the sensitivity without diminishing the power handling.

The following are the Max output figures for the CBT models (speech, narrow, 1 meter):

CBT 50LA = 115 dB continuous pink noise (peaks of 121 dB)

CBT 100LA = 121 dB continuous pink noise (peaks of 127 dB)

CBT 70J = 125 dB continuous pink noise (peaks of 131 dB)

CBT 70J + 70JE = 125 dB continuous pink noise (peaks of 131 dB) over an extended bandwidth.

Note that these models in music, wide mode have a few dB lower Max SPL, depending on the model.

These figures match or exceed that of many point-and-shoot loudspeakers. In addition, CBT’s

provide fuller bandwidth sound than most column speakers, down to 80 Hz on the CBT 50LA and

100LA, down to 60 Hz on the CBT 70J and down to 45 Hz on the combination of the 70J and 70JE.

10) When a CBT model is described as “controlling” the coverage down to a

certain frequency, how much pattern control takes place below that frequency?

With CBT’s, a substantial amount of pattern control takes place below that frequency. The

frequency listed as the official “control” frequency – sometimes called “beam control frequency” -- is

simply the frequency at which the beamwidth has widened 10º wider than what is listed as that

speaker’s nominal beamwidth (the percentage is usually listed in the spec). Some loudspeakers

loose pattern control quickly below their control frequency. CBT’s, by contrast, continue to provide

significant pattern control coverage below that frequency.

For example, the CBT70J is listed as controlling coverage down to 800 Hz. The primary coverage

lobe does increase in width below that frequency, as does the amount of sound being sent behind

the speaker. However, even down to below 400 Hz, the speaker is still providing a substantial

amount of pattern control. Looking at the amount of sound projecting directly below and above the

speaker – perpendicular to the aiming axis of the speaker -- at 800 Hz, this region is attenuated 20

dB, which is substantial. At 630 Hz, it is still attenuated 20 dB. At 500 Hz, the perpendicular sound​

still continues to be attenuated a significant amount, by 18 dB. At 400 Hz, it is attenuated 15 dB,

and at 315 Hz, the sound projecting directly below and above the speaker is attenuated 8 dB. It is

not until 250 Hz that the amount of attenuation directly below and above the column is attenuated

by less than 5 dB. This is an example of the excellent control that CBT models provide, even

well below the “control” frequency of the speaker.

11) Can I stack multiple CBT columns like I might do with Bose MA12’s or other

traditional columns to either: increase the output, extend the pattern control

to a lower frequency and/or increase the vertical height of the coverage?

The answer to whether CBT’s are stackable is “yes”, “no” and “not as much need to stack as there

is with other columns”.

The “no” part: CBT’s act acoustically as a single source projecting from the center of the array.

Therefore, if you put two on the wall with no splay, the grouping will act like two constant directivity

horns with their centers some distance apart. Not horrible, but not perfect arraying.

The “not as much need to stack as there is with other columns” part: There are two reasons

people stack passive columns such as Bose MA12’s. First, the beamwidth of MA12’s gets so

narrow at a few frequencies that they only cover a few feet of height. This occurs in the 3kHz to 10

kHz band, so if you need to cover more height (such as raked seating) and if you want those

frequencies to get to everyone, you need to stack two or more of them.

CBT’s do not narrow like that. They maintain constant directivity. So there is usually no need to

stack them in order to cover a raked seating area.​

Secondly, people sometimes stack passive columns to get more output. Ours have extremely

high output already. Even the little CBT 50LA holds its own level-wise against MA12’s. The

CBT100LA, with 325 Watts of power handling and up to 96 dB sensitivity (speech mode, narrow

vertical coverage setting), has a lot more output. So again, there is no need to stack them for that

reason. And CBT’s have Dynamic SonicGuard, which targets the frequency of maximum excursion

of the drivers. This keeps the CBT’s sounding clean at high drive levels. The MA12’s do not, so

they start distortion on transient peaks at lower volume levels.

The “yes” part: The CBT 70JE is an extension cabinet for use with the 70J. It doubles the

height, extends the frequency to which pattern is controlled (to 400 Hz), increases the LF output (to

130 dB [1W, 1m], peaks of 136 dB), increases the power handling (to 1000 Watts) and extends the

LF response (to 45 Hz). This is the way to extend the CBT 70J.

Another “yes” part: SPLAYED STACKING -- You can use multiple 100LA units together,

applying them as you would constant directivity horns. For example, you can set two CBT

100LA’s in their 15 degrees vertical coverage mode and splay them at 15 degrees for 30 degrees

of coverage.

Unique mixing of coverage patterns via splayed stacking -- You can set the top CBT 100LA at

15 degrees coverage and a bottom CBT 100LA at 40 degrees coverage and splay them to get a

long-throw/short-throw coverage with pattern control as good as if you were using 1 meter tall

constant directivity horns. This is one of those really cool things you can do with CBT’s that you

can’t do with anyone else’s passive column speakers.

JBL does not provide stock brackets for doing this, but the many M6 rigging points on the back of

the cabinet make it convenient for a qualified rigging professional to install them in this

configuration.

Options for Extending Pattern Control to Lower Frequencies -- People also stack columns in

order to extend the frequency of pattern control. Note from earlier in this FAQ, that the CBT

speakers provide significant pattern control below the “control” frequency, so again, it may not be

necessary to do so.

The best “stock” combination in the CBT lineup is the combination of CBT 70J and CBT 70JE. This

configuration controls pattern (within ±10°) down to below 400 Hz, which is usually considered as

covering the entire voice range, while providing significant attenuation of sound to the areas below

and above the speaker down to an even lower frequency.​

11A) Can the 70JE extension cabinet be used with the 100LA, thereby extending the

frequency to which pattern is controlled?

Yes, but with some important caveats.

Using the included wall brackets, we can only recommend the stock CBT configurations – a single

CBT 50LA, a single 100 LA, a single 70J, or a combination of 70J and 70JE.

A 100LA and 70JE can be installed as if they were end-to-end, however: a) JBL does not provide

combining brackets for this configuration [although the many M6 rigging points on the back of the

cabinet make it convenient for a qualified rigging professional to install them in this configuration,

see below], and b) you will need to EQ the system [see below].

Mounting Considerations – The 100 LA and 70JE are not designed to be physically attached to

each other and cantilevered from a single wall bracket. However, there are many insert points

on the backs of these cabinets -- eighteen M6 insert points for the 100LA and ten insert points

for the 70JE -- for versatility of installation by a qualified installation professional, who is

responsible for safely rigging the grouping.

Acoustic Aspects -- Acoustically, the CBT 70JE extension cabinet can be used with the CBT

100LA, however you will need to EQ out a frequency response bump in the 100 Hz to 600 Hz range.

Technical Explanation: The 70JE is designed primarily to work with the 70J. Because its purpose

is to extend the length of the 70J/70JE array at low-midrange frequencies, the frequency response

of the 70JE extends higher than a traditional LF speaker. When used with the 100LA (instead of

with the 70J), this results in a frequency response bump (up to 5 dB at the center of the frequency

band) between 100 Hz and 600 Hz or so, where the LA and the JE overlap. You will need to drive

the system with a unit that has a parametric EQ so you can notch out this bump.

11B) Can multiple CBT 70JE extension cabinets be used with a single CBT 70J to

extend the pattern control to a lower frequency?

If pattern control (±10º) down to below 400 Hz from the 70J/70JE combination is not enough,

multiple 70JE’s can further extend the height of the column. A 70J with three 70JE extension

cabinets controls pattern (±10º) down to below 200 Hz. The system will need to be EQ’d to

compensate for an overlap bump, for the same reason explained above. Again, the installer is

responsible for safely rigging the grouping, as JBL does not provide brackets for non-stock

configurations, such as this.​