I have tried various external USB soundcards and they all produce a signal that over records from my keyboard. The only volume control I have is on my Clavinova which I can hardly hear when set to the correct recording level for Sonar.
The sliders on the input/output only react on playback with no control when recording.
Can anyone help please?
 
Ron.

From your description it sounds like you're either connecting the keyboard line level output to a microphone level input on the sound card,  or you're connecting a headphone level output into a line level input.
You need to ensure the types match.
 
The actual recording level is controlled by your sound card, not Sonar, with either a knob on the card or a setting in the driver.

Oh,  and welcome to the forums

The gain slider under the volume slider does that, I believe.

Zargg71
The gain slider under the volume slider does that, I believe.

Explain...       There is nothing in Sonar that affects recording level.

I suppose the clavinova has built in speakers?  If so and you are listening to those Karen probably has guessed right - you have to turn down the clav's vol because you are sending a line signal into a mic input which is designed to receive a much lower signal.
 
If you describe the mysterious multiple USB interfaces we should be able to help.  And describe exactly how you are set up to record.
 
And no, the faders in SONAR control the volumes after recording, not before.  Interface>computer>DAW>output.  The DAW doesn't control the incoming signal any more than a tape deck did - and I've never seen one of those with vol faders.  That is what the mixer or your interface (yours should have a soft mixer which is where you can control the vol) is for.
 
@

Thank you all for your input which is greatly appreciated.  You are correct of course, I was taking a lead from the headphone socket to the line in on the external USB card and did think that might be the problem.  The line out from the Clavinova was being used to input to an amplifier.  Sooo, I have found a switched audio splitter box so that I can switch to the PC when recording. Unfortunately the problem still exists.  At the moment I am hooked up to a Behringer UCA222 which has a volume control but doesn't affect the recording input.
it looks as though I'll have to  revert back to an old SoundBlaster 5.1 unless you can recommend a more suitable card.
Anyway. thanks for helping.
Ron

As pointed out above you will need to control the volume from the keyboard and monitor the recording from the behringer by engaging "input echo" in Sonar.
http://www.behringer.com/assets/UCA222_P0A31_M_EN.pdf

Karyn

Zargg71
The gain slider under the volume slider does that, I believe.

Explain...       There is nothing in Sonar that affects recording level.

Sorry! My bad:( 

Its very unintuitive. The recording system in Sonar has no control over recording levels. It is important when recording to set the faders at unity the default position. This is the only way to get accurate meter readings.