I use a ModMic (3.5mm jack) for in-app/game input and it is generally reported that using a USB sound card helps eliminate white noise that is sometimes (often?) present when the plug is connected directly to the motherboard or header extensions. This may be a ModMic-specific issue, but I'm inclined to think otherwise.
So if you use want to use a mic with 3.5mm audio input maybe give a USB sound card like this or this (I use the latter) a try before you plunk down cash for a different USB microphone.
NO, I don't think it's mic specific but what actual model is this headset.
Check that you have trained your Windows Speech Recognition and that Cortana is recognizing you. Test a few Cortana commands and / or searches to see if things are working with that first.
Some headset mic doesn't have any noise cancelling features nor in the software. However, there are some noise cancelling software that might help you a bit.
Samson makes a downloadable for $3.99 and had very good digital noise cancelling and echo cancelling. However, if this is not the problem then it will be a waste just like the USB sound device your considering. Start with Speech Engine training first and make sure you training in the environment with the noise that you intent to have in the backround when using VoiceAttack etc.
I guess the question is this:
When you issue a command does it sound like other commands and just gets the commands wrong ?
Or does it not even hear your command ?
Have you checked voiceattack settings/recognition tab ? There are some settings there to try.
Saying things twice sound like either a delay with the recognition which could be related to connection and/or wireless connection if your on wifi or background noise, or low gain on your mic, or speech engine needs better retraining in the environment you plan to use voiceattack.
Does putting the mic closer to your mouth help or not ? Or further away better recognition ? This might help determine if it's low gain or low recognition because of noisy environment or white noise etc.