The question is asking whether it is beneficial to a cat when they are left alone all day to leave on a radio to produce some background sounds. Having spent 25 minutes researching this, I cannot find any solid information which confirms that it is beneficial except for cat music. There are two sorts of sounds that the radio can produce (1) the spoken word and (2) music. As for the latter, it is said that domestic cats don’t really appreciate human music so you will have to ensure that the radio plays cat music which may help. I don’t think there is any certainty that it will by the way.
As to the spoken word, it is certain that a domestic cat will be reassured by words said by their human guardian provided the relationship is good. Domestic cats like to hear the sound of their human companion but of course talk radio churns out the sounds of other people and therefore it is unlikely that talk radio throughout the day is beneficial to a cat at home alone.
Bruce Fogle writes that feral cats can be calmed down by a radio tuned into a talk-show. But what he is saying is that this helps to accustom the feral cat to human interactions so the objective is different. This is about socialisation. It is not really relevant.
It seems that using the television or radio to help calm down a cat or dog is quite popular. I just wish there was more tangible evidence to support the efficacy of it. There appears to be only one reasonable certainty which is that music specifically designed for cats can reduce stress1 so I would focus on that if you want to leave some background sounds in the home while you’re gone.
Sorry that this article is a bit thin but I am feeling unwell today.
1. Louisiana State University (LSU), USA research published in the March 2020 issue of the Journal of Feline Medicine and Surgery (JFMS).
Some articles on cat music