Equipment Detail

DDM / System DDM  (1971 - 1980)

DDM for Adelaide Festival Theatre,
from 1975 Stage Lighting brochure

Digital Dimmer Memory with 120 - 320 channels. 
The DDM evolved from the push button version of IDM (known as IDM/R for rocker switch). 
It was the first memory control with a computer behind it - in this case it was the PDP11 by Digital Equipment Corporation (DEC). (The PDP11 was also later used on Lightboard, for the National Theatre in London). 
The system was developed for and first installed in the Royal Shakespeare Theatre in Stratford-upon-Avon in 1971. 
Over the years, the three versions of DDM were installed in eighteen major theatres and opera houses including Teatro Alla Scala, Milan; Operhaus, Hannover; Hancher Auditorium, Iowa City and the Festival Theatre, Adelaide. 
The twelfth DDM was installed in the Deutsches Theater, Goettingen around early 1978. 
The desk initially used 3-position rocker switches which were later replaced by pushbuttons, with internal lamp displays to each channel for setting and modification of recalled memory. 
The DDM was replaced by the Galaxy in 1980. 

From brochure: 
Based on software for a standard mini-computer which allows any degree of sophistication to be programmed in, or indeed re-programmed if future artistic styles demand different facilities from the lighting control. A system such as Rank Strand's DDM although capable of being operated simply is offered on the assumption that lighting will become more and more sophisticated and that the operator will ultimately use every facility to the full. Fade within fade facilities, instant modification of the intensity level of any control channel without the need to match the existing level, and a magnetic tape repertoire store in addition to the instant access ferrite-core store are all standard features of DDM.

Installations (from 1978 Memory Control Installations):
1) 1971: Royal Shakespeare Theatre, Stratford-on-Avon (240 channels)
12) 1978: Deutsches Theater, Goettingen ()
Niagara Frontier Performing Arts Center, USA (200 channels)
Staatstheater, Braunsweig (240 channels)
Schlosspark Theater, Berlin (120 channels)
Operhaus, Hannover (240 channels)
Seymour Centre (York Theatre), Sydney (120 channels) ?1977
Stadtbuhnen, Hagen (200 channels)
Teatro Alla Scala, Milan (320 channels)
Schauspielhaus, Bochum (240 channels)
Schauspielhaus, Cologne (240 channels)
Stadttheater, Baden-Baden (180 channels)
Festival Theatre, Adelaide (180 channels)
Drama Theatre, Adelaide (120 channels)
Schauspielhaus, Ballhof, Hannover (120 channels)
Stadttheater, Oldenburg (180 channels)
Stadtbuhnen, Munster (200 channels)
Hancher Auditorium, Iowa City (90 channels)
Thalia Theater, Hamburg (240 channels)

The DDM Patent can be viewed on Google Patents

Related Venues:

See also:


Click on thumbnail to enlarge
[1.02Mb  JPEG]
From Alan Luxford Collection
Fred Bentham at the Stratford DDM desk.
Fred Bentham at the Stratford DDM desk.  
Click on thumbnail to enlarge
[1.6Mb  JPEG]
From Alan Luxford Collection
DDM Computer Rack
DDM Computer Rack (1972)
Click on thumbnail to enlarge
[512kb  JPEG]
From Alan Luxford Collection
DDM Pin Patch Backup
DDM Pin Patch Backup (1972)
Click on thumbnail to enlarge
[429kb  JPEG]
From Alan Luxford Collection

LSI Classic Gear - DDM (November 2017)
[477kb PDF]
From Lighting & Sound International

Exhibits in the Backstage Heritage Collection

DDM PDP11 Electronics Rack   
240 control channels with Ferrite Core memory
From The NEET Collection

Catalogue & Journal Entries for DDM / System DDM in the Backstage Heritage Collection

Back to Control - Memory (Strand)