Clipping noises

hi, I use sonar 8.5 with an RME Fireface 400 in asio mode.
I discovered something interesting to which I would like to have an explanation if someone has one.
To start with, I must say I'm blind and I can only read peak meters in sonar.
Preparing for a take, I tried and set my levels right as well as I could, and then started to record. I was listening to the track echo in my earphones and heard nothing special.
When playing back I got awful clipping noises and so I guess...I clipped. but why didn't I hear anything during the take, I was not listening to my Fireface direct input, but to sonar's track echo. I tried reproduceing the problem and the same thing happens all the time. please don't tell me that under no circumstances should I exceed zero DB, I already know that, I just want to know if someone knows why Digital clipping noise is only heard on playback and not during recording.
Thanks for your help,
JPR

Hi,
thank you for your reply.
Oh yes, I tried lowering the volume with the tracks fader and even with the trim knob but it had no effect. Even opening the wave file into another software revealed the same Artefacts. The noises are in the recorded file indeed. I would have to purchase RX2 from Izotope I tried the demo version and it really does magic in this case.
Cheers,
JPR