When you begin looking for an audio recorder, you'll realize fairly quickly that you have a wide range of different options to choose from depending on your needs. One of the key ways to make sure that you're spending your hard-earned money on a solution that will actually serve you well is to sit down and define what those "needs" actually are. Audio and voice recorders are available for just about any situation, so choosing the one with the feature set that aligns with your own goals is the best way to make sure that you are ultimately successful in what you're trying to accomplish.
Choosing a Form Factor
One of the most important things you'll want to look for in an audio recorder involves its form factor, or the specific type of device it is hidden inside. Remember that if you're trying to record audio covertly, you'll want to pick an item that naturally fits in with its environment so your subject doesn't start second guessing or getting suspicious. Some audio recorders come inside a Flash drive, for example, like the type you might have in your office. Others come hidden inside executive-style pens, key chains and more.
Others aren't necessarily designed to be covert in the room and are instead add-on devices that you can use to record any phone call conversation. With these options, the actual style of the form factor isn't as important.
Another important feature you'll want to look for involves sound or voice activation, which is definitely something you'll want to consider for a number of compelling reasons. For starters, this helps your audio recorder become a true "set it and forget it" device - you don't have to worry about turning it on at exactly the right type to capture audio from your subject as it will automatically start recording when that person starts talking or when they make a sound in their room.
Additionally, voice activation is a great benefit to your own convenience. Not only does it prevent you from needing to wade through hours of pointless audio just to get at that short clip you were after in the first place, but it also helps to preserve battery life at the same time.
It's important to note that most voice recorders treat voice or sound activation as an additional "mode" - there will likely still be a standard recording mode for you to use as needed.
When you're talking about something like an audio recorder, one factor you'll definitely want to consider is just how much audio it can record in the first place. Some models only feature 16 or 32 hours of audio, which while plenty for short situations may not fit your needs in the long-term. If this is a priority for you, you'll definitely want to consider a model capable of recording 72 hours to 140 hours of audio or more without overwriting or automatically deleting anything.