Hello,
 
I am using Sonar X3 with a Scarlett 2i2 AI, my computer is a Vaio with an Intel i5 processor and 8gb of RAM.
 
I am trying to record an electric guitar part. I am running my guitar through my pedal board, into the AI, and into Sonar through the TH2 amp modeling software (I live in an apartment and can't mic a loud amp).
 
I get the input volume all set up while monitoring the track (input echo is on, track is not armed). The sound peaks around -10dB, which is good. I then arm the track and immediately the sound only peaks at around -33dB. If I adjust the levels to peak at -10dB when it is armed, the sound is distorted and it does not play nice with my pedals (it also clips like crazy when the track is not armed).
 
I am an amateur to say the least, but am really trying to learn to record and edit well and this setback has been kind of frustrating. I have been able to record vocals and acoustic guitar without this happening. It only happens on the three electric guitar tracks that I have set up. Thanks for any help you can give. 

When you arm the track, the metering shows what is actually the recording level. When you only have input echo on, the metering shows the track playback level. Meaning amongst other things that any plugins you have on that track affect the level. It sounds like TH2 (or another plugin in your chain) is adding a lot of gain. If you want to accurately monitor recording levels, arm the track. Or use the software or visual indicators that came with your audio interface.

Alright thanks, I will play around with it.

To expand on what 'xpander posted:
 
When you arm a track, you're metering the input level from your interface. If it's too low you need to increase the sensitivity/gain of the interface, usually by a front panel control. Nothing in SONAR affects input levels from your interface; track Gain only affects input level from existing recorded/imported audio and soft synths, and Volume is an output level control.
 
When the track isn't armed, you're looking at output levels. So if you've adjusted TH2 I/O and track Volume levels to make up for a weak input, then the output will clip/distort when you raise the input gain on the interface to bring the record level up. You need to start by adjusting the guitar volume and input gain with the track armed to get the record level right, and then adjust the FX I/O and and track Volume levels to get the amp sim response and output level you want.

Oh my gosh, that makes so much sense. Thanks so much!
 
Do you have any other basic tips for me? It's totally cool if you don't have time to. Like I said, I want to get good at desktop music production, and the start has been pretty slow.

 
Thanks from me as well brundlefly for such a great explanation.  Cleared things up for me.