Sighing noise from clutch?

[Phosphoric]

16000 miles on the clock.

I'm starting to get what I can only describe as a sigh when letting out the clutch in first gear. Only happens about once in ten goes. I suspect there might also be a tiny vibration felt through the clutch pedal but that may be my imagination.

The sound is too random at the moment to take to the dealers but I assume it will only get worse.

Any thoughts?

[skodacarman]

My DMF-equipped 5-speed 1.9TDI has always done this since it was new (now 21k miles). Lets out a feint sound like a low ' gooof ', present in all gear changes, not just first.

It's a little bit more noticeable if I accelerate hard and rush the changes.

Never got any worse or presented any problems, but I too would be interested to hear if it's a symptom of something sinister.