Bohlender Graebener NEO-8 Brochure

Radia

NEO-8

Professional
Speakers

The NEO-8 and NEO-8 PDR

High Performance Wideband

Planar Magnetic Transducers

The NEO-8 and NEO-8 PDR are planar-magnetic
(ribbon) transducers that use an innovative high­tech diaphragm material called Kaladex from
Dupont. This material, combined with a new
proprietary technology for etching the
aluminum/Kaladex laminate, makes it possible to
overcome the usual limitations of previous
generation planar-magnetic designs. Traditionally
most planar drivers were built using a Mylar
diaphragm but Kaladex has a much higher
thermal limit, lower mass, better durability and
mechanical stability. As a result, the NEO-8 and
NEO-8 PDR transducers have higher sensitivity
and power handling as well as excellent sound
quality. The careful design and unique assembly
technology employed by these units allow for
more extended high frequency output, less
distortion and higher dynamic range than with few
other planar drivers of similar size.

The NEO-8/ NEO-8 PDR have a push-pull
symmetrical magnet system that has been
designed with the help of Finite Element Analysis
software to achieve optimum efficiency/cost
performance. It uses the newest grades of
neodymium – the “super” magnet material with the
highest magnetic energy. The extremely light
Kaladex diaphragm with an etched planar
aluminum conductor is suspended in a magnetic
field and is uniformly driven by the
electromagnetic force providing accurate and
immediate reproduction of the input signal.
NEO-8 / NEO-8 PDR do not have heavy voice
coils, spiders, glue joints, paper cones and
surrounds, there is virtually nothing between the
electrical signal and the sound - just an almost
weightless diaphragm. Hence these planar

NEO-8 PDR

transducers do not have cone break-up resonance
with associated distortion, phase incoherency or
signal smearing that is common for conventional
drivers. This allows Neo drivers delivering clean,
airy, transparent sound that is inherently natural
and musically pleasing.

The purely resistive impedance of the NEO-8 /



NEO-8 PDR makes an easy load for a power
amplifier and greatly facilitates crossover design.
The magnet system is completely shielded for
safe implementation in multimedia and AV
systems. The NEO-8 / NEO-8 PDR are very
versatile transducers and their applications are
limited only by the designer’s imagination.

Fig.1 shows a family of curves representing (from

top to bottom) on-axis, 30° off-axis, and 60° off-

axis response of the NEO-8 measured as a dipole
(without baffle or rear enclosure) at 1 meter for a

2.83V input. It is evident that the superior
dispersion uniformity up to 7 kHz will allow the
NEO-8 to deliver smooth and balanced sound in a
real listening environment. It is necessary to
stress that using the NEO-8 as a dipole (without
any rear enclosure) may require some signal
equalization at lower frequencies, since a dipole
exhibits a natural roll-off. In some applications
where flat on-axis response is desirable, the use
of a correction network at 12 kHz is
recommended; in others correction may not be
necessary, since spatial averaging will provide
smoother power response without the12kHz peak
reduction. Line array systems may not need the
notch filter due to specifics of acoustical coupling
in these systems. The notch filter schematic is
given at the end of this document.

Fig.1 NEO-8 SPL on-axis, 30

°°°°

°°°°

Fig. 2 NEO-8 SPL under different loading conditions

off-axis, 60

of-axis

Fig.2 Neo 8 SPL under different loading conditions

Fig 2. shows the effect of small baffle loading. This condition is close to a typical system or situation when the
transducer is a part of matrix panel combining multiple drivers. Top curve – the NEO-8 in the center of 9”x 9”
baffle, middle curve - the NEO-8 with 9”x 4.5” baffle from one side, bottom curve – the NEO-8 without a
baffle. It is worthwhile to note that a carefully designed rear enclosure provides additional equalization at the
low end of the reproduced frequency spectrum.

Fig. 3 shows the Cumulative Decay Spectrum (CDS) plot of the NEO-8. Even the best conventional

Fig. 3 NEO-8 cumulative decay spectrum

transducers have decay times in the critical midrange region around 1.5 – 2ms (-20dB level drop) extending
to 3-4 ms in lower frequencies. The NEO-8 has a decay time of about 0.5ms across its entire effective range
down to human voice fundamental frequencies. The absence of complex mechanical parts, common for a
conventional driver, allows the NEO-8 to perform free of delayed spectral contamination. This explains the
NEO-8’s unsurpassed clarity and the superb intelligibility of voice reproduction.

The NEO8PDR is a modification of the Neo8 transducer. It incorporates patent pending PDR (progressive
drive and radiation) technology allowing for a significantly wider horizontal dispersion above 8 kHz. The PDR
technology provides progressively increasing excitation force from the periphery to the center portion of the
diaphragm, while creating frequency dependant acoustic dampening and absorption across the diaphragm.
This results in retaining of the efficiency in the effective range while dramatically widening high frequency
dispersion. The Neo8PDR has slightly lower sensitivity below 500Hz and above 2 kHz (see Fig.4). However
if an application does not require operation extended below 400-500 Hz, but instead calls for a wider
horizontal coverage at high frequencies, than Neo8 PDR may be a better choice.

Fig.5 shows a family of on and off-axis frequency response curves of the Neo8 PDR, each one scaled down
by –5 dB relatively to the previous curve.

Fig.4 NEO-8 / NEO-8PDR frequency response comparison, 2.83V/1m, no baffle, dipole operation.

NEO-8 – dash, NEO-8 PDR – solid.

Fig.5 NEO-8PDR frequency response, 2.83V/1m, 12” baffle, dipole operation. From top to bottom: on

axis, 30°°°° off-axis ( scaled -5dB), 45°°°° off-axis ( scaled –10dB), 60°°°° off-axis (scaled –15dB).

Specifications

NEO-8 NEO-8 PDR

Effective frequency range (with EQ & LF) 200Hz to 20kHz 350Hz to 20kHz
Recommended LF crossover, 2nd order min, depends
on a system max SPL requirements and acoustic
arrangement of transducers

-- Multimedia and mini systems 220Hz 400Hz

-- Home theater and Hi-Fi 500Hz to 700Hz 500Hz to 700Hz

-- Line arrays 300Hz to 500Hz 350Hz to 500Hz
Horizontal dispersion (monopole, -6dB

-- Below 2kHz 180º 180º

-- 4kHz 150º 150º

-- 8kHz 85º 120º

-- 10kHz 70º 100º

-- 12.5kHz 50º 80º
Sensitivity, 2.83V / 1m, averaged in 1-8kHz 94dB 92.5dB
Nominal Impedance (3.6 ohms resistive over entire
range
Power handling

-- AES 20W 17W

-- Program 50W 40W

-- Peak 150W 120W
Weight 0.93 lbs / 420 grams 0.84 lbs / 380 grams

4 ohms 4 ohms

Gary Rilling Associates  1127 Sterling Street  Warwick, PA - 18974

Tel [phone]  Fax [phone]  www.bgcorp.com