I borrowed this book from Richard Kostelanetz. I kept it for several years. 
When I borrowed the book, Arnheim was still alive.  
He passed away 10 years ago, June 9, 2007, at age 102.
Shortly after that, Richard asked for the book back.
I started writing the quotes from all the pages where I had placed a post-it note. 
I only made it to page 31 before I gave up. Here are my quotes.
Now I see that the whole book is available on Monoskop.

Broadcasting has constituted a new experience for the artist, his audience and the theoretician: for the first time it makes use of the aural only, without the almost invariable accompaniment of the visual which we find in nature as well as in art. (14)

Even if television destroys the new wireless form of expression even more radically than the sound film destroyed the silent film, the value of this esthetic experience remains unimpaired; indeed, it appears as if in artistic practice this new form of expression need not disappear. (16)

Only two arts renounce the eye entirely and deal exclusively with the ear: music and broadcasting. (22)

In the aural as distinct from the visual, the perceptions that inform us of change so considerably outnumber those which indicate changeless duration, that aural art can present dramatic events far more exclusively than visual art. (23)

Sounds acquaint us not only with their origin, but also with their place in the world. (25)

The aural world consists of sounds and noises. We are inclined to give the first place in this world to the spoken word–the most noble species of sound–first introduced to the world by man. We must not forget, however, especially when we are dealing with art, that mere sound has a more direct and powerful effect than the world. The meaning of the word and the significance of the noise are both transmitted through sound, and have only indirect effects. It is difficult at first for most people to realise that, in the work of art, the sound of the word, because it is more elemental, should be of more importance than the meaning.  (27)

The sound of mourning, more directly than the word of mourning, transmits sorrow to the hearer. (30)

The rediscovery of the musical note in sound and speech, the welding of music, sound and speech into a single material, is one of the greatest artistic tasks of the wireless. [i.e. of radio.] But what we mean is not the cultivation of the sung word… Novalis says: ‘ Our speech was at first far more musical, but it has gradually become prosaic and lost its note; it is now a noise or a loudness; it must become song again.’ This does not mean the art-song; Novalis is referring to the dreadful rupture between art and everyday usage brought about by our civilization. Beauty is offered to tus in the concert-hall, in the realm of the non-functional. But where sound is functional as a means of communication, in everyday speech it is impoverished, blunted, without beauty. If one listens in to an Italian station, one can still experience how speech sings. But most languages have faded, and with them, the feeling for sound-tone. One only has to listen carefully to our stage and radio performances to realise how completely our art of speech is divorced from music. On the one had we have the concert-singer, the opera-singer, and the curly-headed reciter with his cow-bell voice; on the other had, the absolutely unmelodic conversational tone of the actor who fancies he is speaking entirely ‘true of life’–as if that were an inspiring ideal!

Read the whole book here.

If you’re curious about Arnheim, read this Cabinet interview from 2001.