I have recorded EVPs on my laptop using only my PC mic.
I do it at 3am-4am in a quiet room, using just the sound recorder on my laptop.
Just ask if anybody is there, to please say their name and leave it for 5 minutes.
In all honesty, spirits are everywhere and every house is 'haunted'.
I'll tell you a story...about ghosts debunking ghosts.
One day, I was watching TV in my bedroom, when I heard a sound, like a 'cracking sound' coming from my inbuilt mirrored wardrobe.
It also seemed to have a pattern to it, 'cracking' once for 'yes'...twice for 'no'...you could also try this...ask questions to see if you can get the noises or knocking to follow your questions...to ascertain if it is random or not.
Anyway...this kept up for about 15 minutes, so I thought the spirits wanted to talk to me, so I turned on my Spirit Box and asked "was that you guys knocking on my wardrobe"?
The replies I got were "not us", "mirror", "air pressure" and "temperature". lol
So, even the spirits were telling me it was all a matter of science.
Yeah, but see if you can get them to do the 'knock once for yes and twice for no thing'.
All the best.