JAMO E 7CEN, E 750, E 770, E 700, E 7SUB Brochure

Technical Description

Jamo E 7 system

Version 1.0

Technical Description

Jamo E 7 System

Contents:

1. General system description

2. The products:

2.1. E 700

2.2. E 750

2.3. E 770

2.4. E 7CEN

2.5. E 7SUB

3. Driver explanation

3.1. Tweeter

3.2. Midrange/Woofers

3.3. (Sub) woofer

4. Cabinets

Page

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5. Technical specifications

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1. General description

The goal with our new E 7 series loudspeakers has been to bring audiophile quality
loudspeaker technology to the mass market. Furthermore our requirement from the start
has been that this new series should perform equally well with music as movies and have
the eye pleasing aesthetics that allow most people to integrate these loudspeakers in their
everyday living rooms without sacrificing their interior decor. A task that proved to require
new and ingenious solutions as well as ground breaking technology from our EISA award
winning D 7 series.

These are loudspeakers designed by engineers with a
passion for music in all its forms. Anybody who listens to
these designs will hear that. We wanted this new range to
exceed all sonic expectations in the class… we think that’s
exactly what it does.

One of the biggest challenges when designing speakers is
preventing unwanted cabinet vibrations from clouding or
colouring the sound. High frequencies are particularly
susceptible so we came up with the first ingenious
solution… Decoupled Tweeter Technology (DTT).

Exploded view of the Decoupled
Tweeter Technology.

By decoupling the tweeter from the rest of the
loudspeaker, vibrations transmitted from the front baffle to the tweeter are reduced by
more than 20 dB resulting in
an uncommonly detailed and
realistic reproduction of high
frequencies.

Firstly the tweeter is
decoupled from the
aluminium front baffle using a
special rubber compound
called EPDM (Ethylene
Propylene Diene Monomer)
which has extremely good
acoustical properties.
Secondly the aluminium front
baffle is not just screwed onto
the wooden front baffle but
mounted using natural rubber
rawlplugs which further
prevents vibrations being
transmitted.

Wooden front baffleWooden front baffle

Difference between vibrations in a normal front baffle and vibrations
in a front baffle employing Decoupled Tweeter technology.

The loudspeaker cabinets themselves are constructed from solid MDF and the front baffle
is angled by 2 degrees in order to further enhance the rigidity of the cabinets. The two
floorstanding models in the range also have internal bracings adding further to the
structural stiffness of the whole construction. Please refer to section 4 for more information
about the cabinets.

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2. The products

2.1 E 700

E 700 is a very compact 2-way bass reflex speaker with a 4” mid/woofer and a 1” soft dome

tweeter using our new DTT (Decoupled Tweeter Technology), see more details about DTT
and the drive units below.

The compact drivers improve the dynamics: As they weigh less they can move faster. Of
course under the precondition that they are equipped with
very powerful motors (magnet/voice coil) as is the case here.

The crossover frequency is 2,500 Hz.

Every diaphragm has a break up point and it is important
that the driver is used in a range where break ups are
controllable or do not appear. By choosing newly developed
drive units made from a special fibre glass and glue
compound, we have eliminated many of the known
challenges regarding break-ups in the diaphragm material.
For example the inevitable diaphragm break ups can be
controlled and distributed more evenly across the whole
diaphragm thereby avoiding uncontrolled colouring of the
sound at certain frequencies.

Decoupled Tweeter Technology
solid aluminium front baffle.

When used as a surround speaker in an E 7 solution, the E
700’s voicing ensures that seamless timbre matching is
guaranteed when the sound pans across the room.

2.2 E 750

E 750 is a tall slim line 3-way speaker utilising a bass reflex system and a rear firing woofer.

The E 750 is equipped with the same 1” soft dome DTT tweeter as found in the E 700, and
the rest of the series for that matter. The bass/midrange
driver is a 5¼” and the rear firing woofer is a 5½”.

The crossover frequencies are 150 Hz and 2,500 Hz.

The rear firing woofer on the E 750/E770 have been
specifically designed to deliver increased bass output but
with a very linear response, even when placed relatively
close to a wall. Furthermore this design will result in a
general level of 3-6 dB increased output (depending on the
distance from the front wall and the side walls) which means
that the drive unit can obtain the same relative volume level
but with less excursion, thereby minimising the overall
distortion.

Rear firing woofer on E 750/E 770.

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The low crossover frequency of the woofer (150 Hz) also make sure that the drive unit
performs in the frequency range were it is designed to perform best, delivering a deep
powerful bass equally at home with music and movies.

2.3 E 770

The range-topping floorstanding model in the E 7 series is the E 770, similar in proportion
and driver complement to the E 750 but physically larger at nearly 1m high and even
better endowed in the driver
department. The same 1” DTT
tweeter is used, naturally, but
here it’s partnered with a
front facing 6½” mid/bass
unit and a ported 6½” woofer.

The crossover frequencies are
similar as with the E 750 150
Hz and 2,500 Hz.

By utilising a rear firing
woofer on the E 750/E 770 the
in room bass response is also
easier to control as the
natural quarter wave
frequency cancellation is
minimised.

Front firing woofer

Rear firing woofer

Front firing woofer

Rear firing woofer

The in room frequency response of a traditional front firing woofer
and a rear firing woofer respectively.

This model offers a low frequency response that reaches down to 35 Hz, allied to 90 dB
sensitivity.

2.4 E 7CEN

Vocal clarity is all important in any centre-channel loudspeaker so using the Decoupled
Tweeter Technology in the E 7CEN was the natural step. Here for timbral accuracy, it’s
partnered by a pair of the same 4” mid/bass drivers you’ll find in the E 700 and augmented
with a flowed port at the rear

The crossover frequency is 2,500 Hz.

With a height of just over 14 cm the E 7CEN is extremely compact and thereby easy to
place in the listening room.

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2.5 E 7SUB

The E 7SUB is equipped with a very powerful 10”
woofer and equipped with a solid class AB amplifier,
capable of delivering peak power of up to 675 watt.

Thanks to the heavy MDF board sealed cabinet, the
powerful amplifier and the high excursion woofer, the
E 7SUB delivers a deep, precise and detailed
reproduction of the low register - perfectly matching
the sound from the rest of the E 7 series.

With a frequency response that reaches down to 25
Hz the E 7SUB is not only designed for movies but for
music too. This subwoofer is just as comfortable
portraying subtle musical nuances as it is churning
out high-level gunfire, explosions and earthquakes.

E7SUB

However, under certain circumstances the capability of being able to reproduce very low
frequencies can create a problem, which is why we have chosen to implement the
Boundary Gain Compensation technology also found in our EISA award winning D 7SUB.

Boundary Gain Compensation compensates for the room influence at low frequencies, as

any room amplifies the lowest frequencies.
The Boundary Gain Compensation starts at
55 Hz -3dB and drops to –10 dB at 25 Hz.

Off

Off

On

Off

Off

On

The magnitude of the room’s amplification
depends on the room and where you are
positioned – normally it increases the closer
you get to a wall, which also means that the
problem get worse the smaller the room.

This can result in too high bass level from
approx. 60 Hz and increasing downwards. In
the range between 20-30Hz it peaks up to 5­10dB in an average room.

Illustration of how the Boundary Gain
Compensation technology works. Note that in both
off positions the peak around 20-30 Hz is much
higher than 40-100 Hz, whereas in the on position
the bass response is more linear.

At first impression this could sound really

impressive, but especially when listening to

music the sound can be “boomy” and rather
annoying.

With the usual adjustment possibilities such as cut-off frequency and volume level it will be
impossible to obtain a linear in-room frequency response. However the Boundary Gain
Compensation switch will allow an additional fine tuning possibility which will
compensate non optimal placement of the listening position in most rooms.

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Boundary Gain Compensation together with
the normal set of controls (phase, cut-off
frequency and volume level) makes it easier
to integrate the E 7SUB in your listening room
no matter whether you are using large
floorstanding speakers like the E 770 or small
high quality compact speakers such as the E

700.

Most of today’s subwoofers have an auto
on/standby feature whereby the subwoofer
switches itself on if it senses a signal and
switches in standby mode again a certain
time after it has last sensed a signal. However,
in movies (or typically classical music) with
relatively quiet passages many subwoofer
tends to switch to standby mode thereby “missing” the start of a new action packed
sequence like for example an explosion or a kettledrum. Besides the auto on/standby
mode we have therefore implemented a mode were the subwoofer is always on.

Extensive range of adjustment possibilities,
including Boundary Gain Compensation, on the E
7SUB

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3.

Driver explanation

3.1 Tweeter

The new 1” soft dome DTT tweeter chosen for the E 7 series features an extremely efficient
neodymium magnet (10 times more powerful than a conventional magnet). Because the
magnet can be reduced in size, it can be placed inside the voice coil of the loudspeaker
unit, allowing the magnet force to be concentrated around the voice coil – exactly where it
is needed.

Furthermore, the use of a neodymium magnet was required on the E 7 series because of
the limitations in space and weight for the realisation of the Decoupled Tweeter
Technology. Please refer to the exploded view of the DTT principle on page 3.

3.2 Midrange/Woofers

The 4”, 5¼, 5½ and 6½” midrange/woofers found in the E 700, E 750, E 770 and the E 7CEN
feature diaphragms made of a special fibre
glass/glue compound. This material helps to
control and distribute wave modes evenly,
thereby ensuring minimal coloration and a very
transparent midrange.

The natural rubber surround we use linearises
frequency response yet further.

3.3 (Sub)Woofer

The 10” woofer features an air dried paper cone
with a massive surround allowing and a very
powerfull double magnet for high excursion
with minimum distortion.

Drive units made from woven fibre glass/glue
compound with natural rubber surround.

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4. Cabinets

The MDF board used for the E 700 and the E 7CEN is 16mm thick all around. This together
with the compact size, the solid brushed aluminium front baffle, the 2 degrees angle of the
front baffle and the Decoupled Tweeter Technology makes for a very resonance dead base
for the drivers to work in.

The E 750 and E 770 employ 19mm MDF board. Furthermore we have made the cabinet
even more inert by adding internal bracings and at the same time a separate enclosure for
the mid/bass drivers.

The E 7SUB utilises 22mm MDF board all round. This together with internal bracing and a
separate enclosure for the electronics makes for a very solid cabinet with a minimum of
cabinet vibrations. As with the rest of the E 7 series the front baffle is angled 2 degrees for
even more rigidity.

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5. Technical specifications

E

7

00 Dark Apple

E 7CEN

E 700

E 750

E 7SUB

E 770

E 700 E 750 E 770 E 7CEN E 7SUB
System Basreflex Basreflex Basreflex Basreflex Closed
Woofer 4” 5 ½” 6 ½“ 2 x 4” 10”

Midrange

5 ¼“ 6 ½”

Tweeter 1” (neodyn.) 1” (neodyn.) 1” (neodyn.) 1” (neodyn.)

Long term power (W) 100 140 150 100

Short term power (W) 140 200 220 140

Sensitivity (dB/2.8V/1 m) 85 89 90 87

Frequency range (Hz) 70-20k 42-20k 35-20k 80-20k 25-150

Crossover frequency (Hz) 2500 150-2500 150-2500 2500

Impedance (Ohm) 6666 22k

Phase

Adj. 0-180 deg.

Cut off frequency (Hz)

40-150

Amplifier rated output (W)

675 W peak

Limiter

Yes

Boundary gain compensation

Yes

Weight kg/lb 3.0/6.6 14.5/31.9 17.2/37.9 5.8/12.8 21.0/46.3

Dimensions (H x W x D)

mm/in

140x238x165

5.5x9.4x6.5

185x912x315

7.3x35.9x12.4

195x998x320

7.7x39.3x12.6

440x142x170

17.3x5.6x6.7

375x375x375

14.8x14.8x14.8

Finish Dark Apple/Light Apple/Black Ash

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