I'm glad you've got this sorted out. I'm a big fan of putting up Swift boxes if the house is suitable, since the species really is suffering from lack of suitable nest sites and they can be really successful, but it sounds like he's been very inconsiderate. Playing calls in August is really pretty pointless in any case.Thanks for your reply. I reported this problem to my council and they spoke to my neighbour. He was quite angry with me as he said he is now trying to attract young birds to nest in future years. However, he has now stopped the recording until next year and has directed the speaker upwards instead of directly at my house and also added a volume control. I am thankful that it has now stopped and grateful to the council. I love all birds and wildlife but just found this to be so stressful and also very dismissive of his neighbours. I have since also received a lot of support from surrounding neighbours who were too frightened to complain.
The advice from Action for Swifts (this page) is that the 2nd half of June and the 1st three weeks of July are the most effective time to play calls - perhaps if he could limit it to this time period in future years, and limit the volume and times when they are on, you might come to a reasonable compromise. Although, your neighbour does sound quite unreasonable.