I followed up on David Soroko's advice
and have received Kessler Sensei's e-mail which is quoted here in its entirety. My sincere thanks to David for his advice and to Kessler Sensei for his kind reply which I'm sure will prove to be of great interest to readers of this thread.
Yes to all of your questions. When applied properly music can be a wonderful supplement to training. I use it primarily in "jiyu waza" and we find that the rhythm helps people to let go of the technical forms and into the flow. We have an "Aikido Jam" once a week and it is a nice balance to the technical classes. Not everyone is interested in aikido with music so they usually stick to the technical classes. But I must say, it is my direct experience that the students that integrate the tech training with the jams have a much more rounded out training than those who don't. The Jams are designed to relax the body, the mind, and especially the forms of aikido. The students who don't participate in the jams tend to me more stuck in their practice in areas of freedom outside the form, free movement, flow, and spontaneous response. I also find that the jams cultivate more open mindedness.
There are so many things to speak about (such as the conditions, the flow cycle of a class, types of music, specific exercises, jam themes, movement and stillness, and the value of silence, etc.) but I'll keep it brief here.
If you are ever in Tel Aviv you are very welcome to join in.
Aikido Sensei, Dharma Teacher, Director - The Integral Dojo
"Changing The Way We See The World"