Headphones Low Volume Issue

I've been experiencing issues with low volume on/off since migrating to Windows 7 as well as overall poorer sound quality it doesn't feel rich in bass and sound quality. I'm not an expert but I get much fuller sound when connecting headphones to different devices then when playback is through headphones on Widows 7.

I never experienced these issues with Windows XP. It is highly annoying and sound quality through speaker playback seems absolutely fine. I've tried searching for solution on Google which it seems to be a common problem but haven't came across a solution.

Operating System: Windows 7 Ultimate
Headphones: Logitech Ultimate Ears 400vi (In-Ear)
Speakers: Logitech Z906 (5.1)
Audio Driver: Realtek High Definition Audio 2.71 Vista
Equalizer: SRS Audio Sandbox v1.10.2.0
Music Genres: Trance and 2Pac


I have tried playing around with SRS and can usually tweak it to satisfaction but recently I find I need to keep adjusting/trying out different presets etc due to the on/off experiencing issues with volume. Any help with resolve would be great as 90% of the time I use headphones and it really lacks the fullness.. even when turning the volume high up

Edit: I don't experience no crackle or distortions just really lacks fullness.. especially as my headphones are In-Ear you really expect fullness. I'm not the type that loves loud music but the overall quality just lacks

What I did was install dolby advanced audio on my computer because the sound that was given to me by Lenovo wasn't cutting it for me so after I installed it the sound seemed a lot louder here is a link to Lenovo's website and you should be able to download it let me know how it goes

Dolby Advanced Audio V2 User Interface Driver for Windows 7 (32-bit, 64-bit) - ThinkPad L430, L530