With the advent of portable and affordable digital recording devices, we are all the benefactors. Being in charge of your own audio tour content can save you a lot of money – so even small museums can have professional-sounding audio tours.
What it does take, however, is a little bit of insight to know how to maximize the quality of your finished product. This post will help provide you with some fundamental concepts that, when utilized, will guarantee never prefacing your project with “sorry about the sketchy sound quality.”
Before going through any specifics, the most important thing to stress is what techniques will remain true to virtually every recording situation, and can make or break your audio.
Getting Started: Recording Level
Probably the number one biggest culprit in bad audio is recording level. Either too quiet or too “hot”, a poor signal is a mortal sin in audio production. The recording level is the amount of “gain” or amplitude that you are letting in to your recorder from your microphone. Too much gain in your recording level will result in the dreaded “clipping,” sounding to our ears as distorted and abrasive. Too little gain will result in legibility issues, which can’t necessarily be fixed by simply making it louder later (all of the noise in your signal will be boosted too, causing background noises to be amplified, too).
So how do we control these problems? The most important thing to know is how to look at the level meters on your recording device. Digital signals are measured on a scale where zero decibels, or 0dB, is the maximum amount of input a recording can have before distorting. A bit counter-intuitive, but absolutely no sound should ever have the meters hover at or above 0dB.
You also don’t want to overcompensate by having the signal hovering too low at around -32dB either, because the signal is too weak. It can be a bit tricky, because the volume of people or objects you are recording can be very dynamic, causing peaks and valleys in the signal. However, if your meters are registering an average between -12dB and at most -3dB, you should be safe and get a good recording level.
Consider Your Location
The other critical consideration for recording decent audio is your location. This is where it gets tough to control the elements, especially if you are outside in a noisy environment. What you can do is try to pick locations that minimize extraneous sounds. Your best bet for recording audio-only is to find the quietest room where people aren’t going to be in and out, opening and closing doors and talking over the subject. You also don’t want to pick a room that is next to a furnace, computer server room, or any kind of loud hum or steady noise floor. Though some post-production software can reduce this, it is always best to avoid it from the start.
Finally, if you are recording inside, I would try and stay away from highly “reflective” spaces. All traveling sound interacts with barriers (i.e. walls, floors, ceilings) differently depending on the material of the barrier. Some reflect the sounds, others absorb them. Try to avoid spaces that have lots of marble, concrete, or stone walls and stone floors, as well as vaulted ceilings or other large spaces with an echo. Sometimes these spaces can’t be avoided, but if you have the option of finding a medium sized office room with carpeting and without excessive hum, your end result will be much better off.
One trick to measure sound reflection is to clap loudly in the room. Do you hear an echo? If so, you better find another recording space.
Recording level and environment will be important for every recording device you will ever work.
Make sure that you are recording digitally. Of course there is a huge world of digital recording devices, but this is definitely something where higher price doesn’t make or break what you can do. You really don’t need anything with too many bells and whistles. Unless it has a high-quality built in microphone, I would just make sure that it has a standard XLR microphone input on it, so that if you get a nice microphone later on, you don’t have to lose any quality by adapting the connection. (I won’t get tech-y with an XLR explanation, just know that it is the standard way of connecting most microphones and is a three-pronged input). The only other feature that is really important for digital recorders is for the microphone preamps (what boosts the recording signal to be recorded) has what is called “phantom power,” or a 48v power reserve needed by condenser microphones. Condenser microphones are pretty much ubiquitous, and usually reproduce a more accurate, clean sound. If you ever get one in the future, they do need this 48v of power to operate, so when looking for digital recorders I would make sure this is included.
Let’s briefly mention microphones. Yes I said briefly, because discussing mic selection can be about as unending as picking out ingredients to cook virtually any known dinner. They all have different outcomes, flavors, and prices. Luckily for us, we don’t have to bust out the white truffles to get a tasty recording.
So what do people in the field use? It depends on the project and environment, of course, but a very common microphone type is a “shotgun mic,” so named for its gun barrel-like appearance. The reason why this mic is so widely used for on-location recordings (especially video shots) is that their radius for picking up sound is very narrow. In other words, wherever you point the microphone will pick up that sound much louder than surrounding sounds, even at a distance. This gives a much better pinpoint accuracy so that the person or object you are trying to record gets the most of the signal without extraneous noises. These are commonly a type of condenser microphone, so they will require that 48v power from your recorder.
Another common microphone to use are lavaliers, or lapel microphones. These are very small mics that can be clipped on to a subject’s shirt directly under their heads. These are ubiquitous with video shoots, because they are the easiest way to get close to your subject without being seen very easily. The wireless ones can be a bit more expensive than others, but there might be times where the investment is worth it.
Of course there are dozens of other types of microphones out there, but these two are very common in productions that aren’t done in recording studios. The final type of mic worth mentioning is the one you may already have. Chances are, someone went to Radio Shack a while back and bought some hand held mic that currently resides at the bottom of a junk drawer. Believe it or not, using the checklist of recording techniques we discussed, this one might do just fine. You could use a $1000 microphone but if you ignore our recording tips, you still won’t get anything more usable than your Radio Shack special.
What is your experience with recording audio? Any success stories, or disasters, you want to share?