To be honest, your voice recording device is a receiver and can pick up all kinds of stray signals, not to mention common sounds made by a hand holding a recorder and other ambient sounds. Your camera, like the ones on ghost hunting shows, doesn't capture what you just saw in the hallway. No matter how much as hunters we want to believe an EMF meter might help or clicking off a shot with the camera might capture something, we have yet to gather legitimate evidence with technology.
Why is that?
I often say that I like to hunt with no equipment. Seems like a waste. What if something happens? How do you prove it? Well, you can't prove it even with a shitload of batteries, cords, DVR and IR cameras. But, how many times do hunters hear and see things they can't capture with tools of the trade? All the freaking time!
Of course, you have people wanting to find phenomena and so anything that happens, any change in light and dark, any knocking sound and any chill could be interpreted as an encounter. So, humans are considered an unreliable source and yet anyone who was mugged will tell you there was something they instinctively felt about the place and the person approaching them that made them raise their hackles. People who get a phone call and hear their family member's voice saying "hi" can tell immediately they have bad news. There are subtle things about humans that actually make them wonderful psychic antennae.
The thing missing from our equipment is biology.
A camera is pure logic. We design it to do a certain task a certain way and it will do it come hell or high water. It will not adjust or adapt. It is taking a technical tool and using it to try and detect something that is not a solid object, gas or liquid.
A human, however, will have a great advantage over a camera or recording device at detecting paranormal activity because whatever this unique experience is, it involves something on a biological level that our senses can detect and recognize and most especially our extra senses. Anyone who says we have five senses also thinks the world is flat and the planets revolve around the Earth as the center of the universe. Some people hear colors and taste music and many other synesthetic variations, but psychics like myself will tell you that your touch alone can pick up amazing information about the environment, sometimes ahead of an event, sometimes connecting to another human's emotions and needs clear across the country.
When it comes to hunting, it still comes down to our own biology and the senses we possess. Just remember the dozens of times J&G gasped when they saw a full-body apparition and never caught it on camera. They still do best to go in search of spirit activity on foot. That is why they don't put cameras and mics in a house and leave it and review the results the next day.
Although, the way their episodes are going (yawn) it might be more entertaining than them dragging TV land nobodies around as special guests.
*Tomorrow, enjoy me giving a eulogy to "Ghost Hunters" as they circle the drain.*