I would have liked to have posted the original video clip of the performance they gave at Wembley in the late 1960s, but sadly it is no longer possible to embed it or download it.
But here is the link:-
http://www.youtube.com/watch?v=psxfk__Etkw
Tompall and the Glaser brothers were outstanding harmony singers.
One of the unique things they did is shown in these videos.
They specialised in different musical ranges.
One brother would take over from another at the end of a phrase.
Then another brother would pick-up mid-phrase.
Then, amazingly (as happens towards the end of these clips) they pick up the singing in the middle of a word. And you can't tell where the join is. Amazingly clever!
Tompall and Jim Glaser did this so well, and Chuck Glaser was the quiet one in the middle at the back who gave the whole thing body and balance. Lovely!
Another point, if I may (sorry to go on...) they stand together and use one microphone.
None of this face-mike nonsense for them. Face mikes where everybody is singing for themselves. Here we have one microphone where they can really hear each other - and the end product is so much better.
Sadly the Wembley performance - when they were in their prime - cannot be embedded here, but if you'd like to see it I urge you to click on the link above (^^^^)
Alternatively, here they are doing the same type of singing, using the same medley of songs, but this is 21 years later, so there is a difference.
(I hope I have explaind clearly the technique of taking over from each during a line, phrase or word.) Splendid stuff!