Urei 813B Coaxiel Driver (Vintage)

Info courtesy of Mix Magazine:

In the mid-’70s, UREI founder Bill Putnam—unhappy with the sound of the Altec 604 monitors in his United Western Studios—worked with UREI’s Dean Austin and Dennis Fink on ways to improve the 604. They replaced Altec’s multicell horn with a wider dispersion design and added a 15-inch Eminence woofer to boost LF output. Ed Long applied his Time-Align™ crossover techniques to achieve time- coherent, true point-source performance.

Engineers and producers mixing on the system were so enthusiastic about its sound that UREI started producing the monitors as a commercial product, with the first UREI 813 debuting in 1977. Typically soffit-mounted, these large, double-15 monitors were ideal for the larger, higher-SPL control rooms of the time.

THE UREI SERIES B 
TIME ALIGN® 
STUDIO MONITORS 

FEATURES: 

Flat power response maintains frequency balance at 
low distortion over wide range of output levels. 

Time Align® design achieves accurate time domain 
response, minimizing fatigue while listening at high 
sound pressure levels. 

One- point sound source. 

Highly controlled sound field over entire frequency 
range. 

Accurate stereophonic imaging. 

Consistent ratio of direct to reverberant sound. 

Since their introduction the UREI Time Align®studio 
monitors have continually been installed in more and 
more recording studios and broadcast production 
facilities worldwide to replace older (and some newer) 
monitor designs. 

Series B is the third generation of UREI monitors. 
These monitors all feature a proprietary coaxial loud- 
speaker which has been developed by UREI engineers. 
Through the utilization of the latest advances in materials 
and fabrication techniques in the manufacture of the 
coaxial loudspeakers, the following system characteristics 
make them ideal for the most demanding program 
material: 

High sensitivity, high power handling capability and 
extended high frequency response. 

The performance breakthroughs which have been 
accomplished in designing the Series B monitor systems 
have made it possible to double the sensitivity to input 
signals and the power handling capability. The coaxial 
loudspeaker incorporates a JBL 2425H driver in the high- 
frequency section which extends the high frequency 
response envelope ... to beyond 17.5 kHz. 

The Series B monitors have the patented high fre- 
quency horn, with its diffraction buffer for correct 
acoustic impedance matching and smooth out-of-band- 
response, and the shadow slots which eliminate the 
midrange shadowing common to conventional coaxial 
loudspeaker horns. The ceramic magnet structures used 
on all of the drivers in the 800-serles monitors assure 
that the sensitivity of these systems will not tend to 
degrade with time, even under continuous use at high 
monitoring levels. 

Each UREl Series B monitor uses the new 801 B coaxial 
driver to provide a true one-|X)int sound source. 
Additional low-frequency drivers are utilized in the 813 B 
and 815B for extended low-frequency response and 
greater overall sensitivity without sacrificing the 
tight bass, superior stereo imaging, and all of the 
other characteristics which you have come to expect 
from studio monitors by UREI. 

TIME OFFSET CORRECTION 

Even though a coaxial loudspeaker delivers the entire 
frequency spectrum from one source, the voice coils of 
the two transducers are displaced from each other, and 
the low and high frequency portions of a sound do not