Update:
Ok, just for fun I thought that I would try a few more things to try and troubleshoot the crackly distortion issue I'm experiencing with my Scarlett 2i2 2nd gen usb audio interface, here's what I tried:
* Using my Focusrite Scarlett headphones instead of my Audio Technicas.
* Switching to the FL Studio ASIO driver that comes with FL Studio.
* Switching between Speakers (Focusrite Usb Audio), and Speakers ( Realtek(R) Audio) as the default Windows playback device, while comparing the results I get with either the 2i2's ASIO driver and the FL Studio ASIO driver.
In each case the result was the same, I still got the crackly distortion coming through the headphones, I have previously tried seeing if the crackly distortion comes through the line-outs of my 2i2 if I plug them into my two 15W Audioline powered studio monitors, and yes it does, I know it's not the monitors cause they sound crystal clear with my Saffire Pro 40, so, as far as I'm able to, I've managed to narrow down the cause of the crackly distortion being caused by three things:
* Something inside my Scarlet 2i2 2nd gen usb audio interface.
* Something inside my Acer laptop.
* Something to do with the driver software for the 2i2.
Interestingly enough, if I select the FL Studio ASIO driver in FL Studio's audio settings, and plug my headphones directly into my laptop, and have Realtek(R) Audio selected as the Windows default audio device, audio playback is crystal clear with no crackly distortion.
So, seeing as my 2i2 works perfectly well with my studio desktop pc, the cause of the crackly distortion has to be something to do with my Acer laptop, since I seem to be only experiencing the crackly distortion issue when the 2i2 is plugged into any of the available usb ports on the laptop.
Or, it has to be something to do with the 2i2 and it's driver software, or something about either of them, which is not working like it's supposed to only when plugged into the laptop.
So, is it a hardware issue or a software issue?, what makes it more frustrating is that computer hardware issues can manifest themselves as software issues, and vice-versa.....
I don't think it's some weird grounding-issue since running my laptop off it's built-in rechargeable battery has ruled that out.
It appears that the crackly distortion seems to be occuring because of some issue with streaming audio using the ASIO (Audio Streaming Input Output) protocol, I don't think it's a buffer-setting problem since it makes no difference whichever buffer-setting I set it to, nor does it make any difference what sample-rate I set it to, or whichever combination of sample-rate and buffer setting I set it to.
Is it because my Acer laptop's usb ports have problems supplying enough power to my 2i2?, that would explain why the 2i2 works perfectly well with my studio desktop pc, which is powered from an 850 Watt power supply unit which is powered from a 240V AC wall socket, and not very well with my laptop which is usually powered from a 19V DC/3.42A 240V AC plugpack adaptor when I'm doing any music production on my laptop.
Here's two more things I just thought of trying:
* Do a complete clean-install of Windows 7 64 Bit Home Premium on my laptop to see if the crackly distortion issue is caused by a software/hardware incompatibility with the latest build version of Windows 10, I still have both my 32 Bit and 64 Bit Windows 7 Home Premium DVDs.....hmmmmm...I think it's worth a try, even though Microsoft are going to force me to upgrade to Windows 10.
* Try buying an externally powered usb hub and use it to connect the 2i2 to my laptop, just to see if the crackly distortion is caused by the laptop's usb ports not being able to supply enough power to the 2i2 when it is plugged-in directly.