Despite being a widely referenced article in the field of spatialised and electronic music,  Stockhausen’s contribution to Die Reihe has received mixed reactions: the language being described as needlessly complex, Stockhausen has been accused of not understanding his topic as well as he portrays.  Contrastingly, a more positive review suggests that Stockhausen’s contribution to Die Reihe is the most sophisticated out of the journal’s seemingly random content. 
‘Music in Space’ is generally understandable and only ventures into ambiguity with the inclusion of diagrams that, on first glance, require more explaining. Although deep focus and several reads lessen this initially apparent complexity, some background knowledge in acoustics is beneficial.  Nevertheless, the overall message is clear: Stockhausen explains how acoustic space can be used to explore ‘sonic space’ by describing the different dimensions of sound as pitch, duration, timbre, dynamics, and location, and explaining how dynamics and location are the most affected by acoustic space. In an epoch of electronically spatialised music, new performance sites are architected according to the realisation of ‘sonic spaces’ within desired acoustic spaces.
With regard to Horațiu Rădulescu’s streichquartett nr. 4 opus 33 (which I write about here), I feel ‘Music in Space’ offers a varied perspective on the construction of its sound-world.
 For example, see: Bosi, Marina, ‘An Interactive Real-Time System for the Control of Sound Localization’, Computer Music Journal, 14.4 (1990), 59-64; Emmerson, Simon, Living Electronic Music (Hampshire: Ashgate Publishing, 2007); Fedorkow, Guy, William Buxton, and K.C. Smith, ‘A Computer-Controlled Sound Distribution System for the Performance of Electroacoustic Music’, Computer Music Journal, 2.3 (1978), 33-42; this is not an exhaustive list of examples.
 John Backus, ‘Die Reihe – A Scientific Evaluation’, Perspectives of New Music, 1.1 (1962), 160-171 (pp. 164-169)
 P.A.E, ‘Die Reihe, No.5: Reports Analyses by Herbert Eimert; Karlheinz Stockhausen’, Music & Letters, 43.2 (1962), 144-146 (p.145)
 I recommend Campbell, Murray, and Clive Greated, The Musician’s Guide to Acoustics (Oxford: Oxford University Press, 2001)