Hi
I thought I would reply to this post rather than create a new one, because I too have no sound, although mine may be an easier troubleshoot.
I have Sonar 8 studio on Windows 8 laptop
When I opened up, I got a popup message: Audio Driver Error. The reason, it said, was with the Realtek HD Audio Output (wave RT).
I tried the troubleshooting recommended by the tutorial, but this Realtek soundcard was not in the hardware list, so I could do nothing more than click the "Use Anyway" button. So if that is the problem, then we are all done, because I only have that one default soundcard.
 
But, I loaded up a file from the tutorial folder to see what might happen, and I pressed play - nothing else. So I haven't messed anything up yet. All the meters are jumpin' but I just have no sound. So it seems to me a simple fix - either my sound card is just no good (the driver is up to date) or I just need to push a button (or two) to route the signal somewhere.
 I tried a couple of youtube tutorials before I posted here, but they didn't seem to help.
Thank You
Phil

Try this:
 
1.  Insert an audio track.  Find any wav file on your harddrive, then use File Import to pull that into the audio track you just created.  It should show up as a clip if you did it right.  If it didn't, you didn't do it right.  Try again.  Hit play.  Do you hear the wav?  If yes, then at least that bit works.  If no, you have something screwed up in Preferences (hit P) or in your Control Panel devices/sound etc.  You have to solve this bit FIRST.
 
2.  Insert a soft-synth.  Make sure that track strip is highlighted/selected.  Press some keys on your controller.  Do you hear sound?  If yes, you are golden.  If no, your controller (i.e., external keyboard) is not sending MIDI data to the soft-synth.  You need to fix that.  Either the output from your controller is screwed up, or the input to the soft-synth is wrong. Do the little blinky lights in little midi keyboard icon located in the lower right corner of your screen blink when you play the controller?  They should. 
 
3.  Hit record on the soft-synth track and mash some keys on your controller.  Do MIDI notes show up?  If no, go back to #2.  If yes, then hit play.  Do you hear what you recorded?  If yes, you are golden.  If no, well, you've got some weird mess going on that logically seems impossible.
 
4. If you are trying to access an external keyboard or sound source and drive that with midi, all the above has to be functional.   Turn "local" on the external sound source OFF.  When you play the keyboard it makes no sound now because you have disconnected the keyboard from the sound source inside the keyboard.  Insert a MIDI track. Make sure the output send channel is set to the same receive channel on the keyboard.  Now when you press a key, the keyboard makes sound.  IF yes, the MIDI data flow is properly configured.  If no, then it isn't, and you know where to dig to fix.

Hi!


First video:


I follow all the steps in video Basic Midi in Sonar x2 until the minute 2:18 where the person tries out if it sounds. He has sound. Me - no sound. I noticed, that when he hits the drums then both equalizers are moving (the green line jumping): SI-String Section 1 and SI-String Section 1 Primary Output: Stereo (for the person instead on String Drumkit is indicated there).
In my case only one SI-String Section 1 is showing green line jumping. SI-String Section 1 Primary Output: Stereo is silent completely.
Is there any point to continue watching the recording process in the video? I mean for the person there is everything going well and I have no sound. Maybe we should fix that first?

Screenshot of what I did:

https: //s21.postimg.org/ajgir0ulj/image.jpg

https: //s17.postimg.org/fjddmygz3/image.jpg

https: //s21.postimg.org/faoavoohz/image.jpg

https: //s16.postimg.org/v073wba79/image.jpg

https: //s15.postimg.org/lgnjo3cij/image.jpg


Second video:


I follow all the steps until the place where the sample of a drum machine is playing.
I have no sound. And under my audio "devices" there is nothing. I am not sure if there is a sense of continuing to watch the video lesson, if I already have problems with sound...

https: //s22.postimg.org/nmv2txjk1/image.jpg

https: //s18.postimg.org/deqmlolbd/image.jpg

https: //s12.postimg.org/dfoe06765/image.jpg

https: //s16.postimg.org/ga82qvp39/image.jpg


What can I try next? I mean the main problem is I never had any sound in my Sonar.

You are watching a video, not following my most excellent stepwise suggestions.

I tried to do all that chuckebaby sent me in two links:
Basic Midi in Sonar x2
Sonar X2: 3 Ways To Midi
using soft synth instead of the sound from the Clavinova. But I still have no sound while the guy in the video has. There my problem starts (or somewhere before).
 

Were getting there. at least now you have green lights. that means there is activity on that track.
your Tascam has to show in devices.
in the link you posted earlier you had under Devices: 2X2 US.
That would be your audio device. that should be checked off in both upper and lower sections of preferences.
what are using for speakers/headphones to the Tascam unit ?

Chuckebaby, please see the screenshots I made. I did all according to your new and previous instructions:
 
https: //s11.postimg.org/4t09r9kcz/image.jpg
https: //s22.postimg.org/rjjzh2am9/image.jpg
https: //s14.postimg.org/s65m80wnl/image.jpg
 
All checked off (under each of the two US 2*2 there are two with grey color in Audio Devices there - they are not clickable). But other two I did.
Still no sound, but you can see the recorded line.
 
For sound card I use external tascam US 2*2. There are two speakers JBL professional 3 Series connected to it with cables. From the sound card there is an usb cable that goes into the PC.

Try Johnny's idea about dragging an audio file in to Sonar (drag it to an audio track)
see if you can get sonar to produce sound.
your device appears to be set up correctly from what I see.
 
You have the driver installed for the Tascam correct ? ASIO driver ?

Which audio file do you mean to drag?
I have some files on my PC that I recorded some days ago in Ableton, that I import to Sonar and Sonar plays it nicely.
I don't know if I had new drivers, but now I installed this one:

---

2016-11-09 00:00:00 US-2x2 & US-4x4 Driver & Settings Panel version 2.00 for Windows - 19.21 MB
Before there was that one:
Driver V1.02 for Windows - 4.84 MB
 
Yes, there is Asio mode on, but now Audio devices disappeared I have no idea where!
 
Please see screen shots. By the way now when I launch Sonar there is these weird note appearing "There are no audio devices..."
 
https: //s16.postimg.org/ecfm06zbp/image.jpg
https: //s21.postimg.org/4o6r4ps4n/image.jpg
https: //s16.postimg.org/nz2j8usb9/image.jpg
 
What's next?
 
Answering Johnny:
 
I have this cable for Clavinova:
https: //s13.postimg.org/8bylf0oqv/IMG_4103.jpg
https: //s21.postimg.org/vo6elqbt3/IMG_4104.jpg
 
I think you may be having trouble with outputing audio through your audio interface. Have you played any audio tracks successfully yet? Like if you plug in the audio output of your Yamaha to the input of the Tascam and record that to an audio track, does that record and playback? 
 
No idea how to connect my Clavinova to Tascam, because there is simply no input in it for usb:
http://tascam.com/product/us-2x2/images/
The only usb it has on the back is one that goes to the computer to feed it the energy.
 
Did you install the newest drivers for the TAscam , use only ASIO mode with Sonar for audio. 
Look a bit up in my current message - I wrote what I did there.
 
And to test a soft synth, insert the soft synth and use the GUI to play a note. Like if you load SI bass you can pluck a string and hear it. 
If your hearing nothing then you need to deal with your audio interface output etc. first.
Sorry here, I don't understand your explanations. Could you please explain again?
 
 

make sure you are plugging the Tascam in to the same port you installed your drivers to
(when you installed the drivers) possibly a bad USB port if your losing your audio devise.
 
if you are receiving sound from an audio file (as you said).
then the midi synth in Sonar should work fine.
what this means is there is a routing issue from your midi track to your synth track.
 
The midi track (the midi data) feeds the / sends data to the synth.
this is done by expanding the track in sonar (the midi track) you can see an input (your clav)
and an output (should be sent to SI Strings).
 
However you need to address the disappearing audio device first.