So it is comforting to discover it may not be true: apparently, audiences are not getting older; they simply are older. It makes sense when you think that it takes an inclination to be still and listen, as well as time and a disposable income, to enjoy concerts: many people find these later in life.
So where does that leave the younger audience? Children should be encouraged to discover and enjoy music of all kinds, and live music can offer them a more intense and enjoyable listening experience than any CD; but at a concert? Two recent experiences suggest that a creative alternative is required.
Concerts staged by the Children's Music Foundation for Scotland use a formula that has changed little since I was a child: weekend afternoon "children's classics" (bite-sized chunks from Walt Disney's Fantasia, Saint-San's Carnival of the Animals and so on) introduced by a jolly presenter. Throw in a theme, a competition, lights and a bit of audience participation ("everyone clap now") and watch it go. As it was in the 1970s, so it is now.
The whole event stands or falls on the presentation. It is a tough job entertaining up to 1, 000 children, ranging in age from two to 12, and at its last event, "Draw that Tune" on February 9, Ken Bruce did not stand a chance.
He was uneasy enough with the material himself to need to refer to notes. Links were erratically pitched: some assumed no knowledge, others too much.And is that "Now we will hear . . ." format really the best people can do?
The experience was like a badly erected marquee: fine at both ends - infectious, joyful expectation at one, big-bang finish at the other - but woefully sagging in the middle. Everyone cheered the first piece, a Bach toccata; but 35 minutes later, Ravel was simply background to children chatting, playing, emptying sweet-packets on to the floor.
A half-hearted "draw that tune" competition was too badly handled to save the day: many children near me had no paper or pencils, and found them just in time to catch the last few notes which were meant to be inspiring them. The repeated exhortations to "finish it off later" underlined that the point had been missed entirely. Not stimulating or creative.
The Royal Scottish National Orchestra takes a different approach. Eschewing children's concerts as such, it offers schools discounted tickets - thanks to Tesco - for a concert in its season; but it does not expect children to come to it unprepared.
Players from the orchestra visit schools 10 to 14 days before the performance for informal and fun classroom sessions. These are excellently handled introductions given by well-trained musicians.
Through games and stories, they encourage active listening skills by asking questions - What is a tune? Who has the tune? What is harmony? Is this it? Is it sad? - which in turn leads to a brief introduction to orchestral instruments and one of the pieces in the concert (on the day I was there, Holst's The Planets). Finally, there is a chance for children to create and perform their own piece.
Most important of all, the players forge a personal bond with the children and their teachers: at the session I attended, the whole class was already on first-name terms with the musicians and clearly liked them.
That useful link is reinforced at concerts when players come to the front of house at the interval to chat or wave from the platform: a great way to humanise the experience.
None of this is particularly novel or ground-breaking in education terms, nor does it go as far as some other similar schemes: resources simply will not stretch beyond the contact, the session and the tickets. Even so, it is in a different league from the Foundation: imaginative, engaging, instructive and plainly enjoyable, as the class I attended were captivated for an entire morning.
The tricky bit is the transition between that session and the concert. As with the Foundation's concerts, a major plus in the experience is simply the excitement of going. Then the conventions - and length - of the event take their toll, and children realise the difference between enjoying a brief dash through tunes from The Planets and sitting through 50 minutes of solid music: attention wavers and the fidgeting starts. At that point the value of the exercise declines.
The challenge to musicians now surely has to be not to insist upon this adult mode of enjoyment, but to evolve a different milieu combining the best of the informal sessions with live performances of complete pieces of music in a friendly environment.
Reach the children that way - and allow them the space to come to the concert experience in their own time.