Arny Krueger wrote:
"John Atkinson" wrote in message
oups.com...

I haven't been impressed with speakers using the Manger driver at Shows,
mainly due to its chronic lack of sensitivity.

http://www.manger-msw.com/en/produkte/index.html

Manger gives the sensitivity of their driver as 91 dB/watt. That would be
average or slightly above-average sensitivity, no?

Today yes. But dismal.

From:

http://home.comcast.net/~wooferboy/Page_3.html


The JBL 2123J Project
The Klipschorn Midrange Horn

The Klipschorn midrange reproducer consists of two parts, a phenolic
diaphragm compression driver designated the K55 and the horn,
designated the K400. Both have been revised by Klipsch over the years.
Most noteworthy is the change in the horn from an aluminum casting
(K400) to a plastic molded version (K401). Yet, regardless of the horn
section or compression driver used, the midrange reproduction from this
combination is unacceptable. The K55/K400 suffers from a number of
problems including non-linearities in the response that result in
colorations and compression air overload distortion due to an
exceedingly small throat (0.625 in. diameter). At moderate sound
pressure levels in large rooms distress is evident. Complex musical
information rich in lower midrange content such as pipe organ, chorale
and symphonic works, lack detail and is distorted resulting in listener
fatigue.

Integrating a midrange horn into the Klipschorn folded bass unit
presents additional problems. For example, the folded bass horn has a
bandwidth of 35-400Hz and an advertised sensitivity of about 104dB/W/m.
To provide an adequate crossover attenuation response, a midrange horn
capable of linear, low distortion output to approximately 200Hz is
necessary. Given the 6kHz midrange-tweeter crossover frequency, the
resultant midrange band-pass spans nearly 6 octaves, a considerable
range and a significant challenge for a compression driver.
High Efficiency, Direct Radiator Midrange Transducers

When clear, low distortion midrange reproduction at high sound pressure
levels is required by the home enthusiast, it is our opinion that high
efficiency, direct radiators specifically designed for this particular
application are preferred. These drivers are capable of producing
midrange information with very low distortion and, when used in pairs,
have sensitivities comparable to the Klipschorn folded bass horn.

We have developed two direct radiator midrange systems that are capable
of providing effortless midrange reproduction to sound pressure levels
considered extreme. These systems are designed to replace the
Klipschorn K55/K400 (or K401) midrange horn. The high frequencies are
handled by the JBL 2404H Bi-Radial Horn tweeter.
The 2123J Project***
The Drivers

The first system is based on the JBL 2123J, a 16 Ohm, 10" high
efficiency midrange driver with an advertised sensitivity (based on a
signal swept from 500-2500Hz) of 101dB/W/m. The arrangement consists of
a pair of 2123Js mated to a single Klipschorn bass unit. The paired
arrangement, with each driver mounted in a sealed enclosure, will
achieve a theoretical sensitivity of 104dB/W/m. The data sheet for the
2123J is proved in the pull-down menu below.