Post by Michael Stokes on Nov 27, 2010 22:20:46 GMT -5
One of the tougher issues with DIY recording at home comes from working in spaces that are less than suitable for recording. I'd like to tackle this issue in two parts: background noise and room acoustics. I've done a lot reading on the subject and have learned a trick or two that have significantly improved the quality of my DIY home recordings. YMMV of course, but all of these tricks are ones that I've learned from reading about setting up recording environments and one that I've employed successfully.
Background Noise:
Background noise, for most of us, comes from household appliances - refrigerators, freezers, humidifiers, furnaces, computers etc. These appliances can add significant noise to the recordings and that's counterproductive to our finished audio presentation. We need to convince our listeners that everyone in the audio presentation is actually in the different scene locations and not in their basement/den/bathroom etc. No one expects to hear the hum of our PC's playing under our characters lines as we're walking through an open meadow. Fortunately for all of us, there are simple remedies for removing or reducing environmental background noises to acceptable levels.
1. Locate and remove the source of any noise. This may not be as simple as it sounds. For me this sometimes means unplugging appliances in other rooms of the house, usually the downstairs freezer and dehumidifier and any computer not in use for the recording session. I prefer condenser mics whenever possible, but they pick up everything.
2. Use good headphones. I can't emphasize this enough. You need good headphones to critically evaluate the quality of your recordings, including the actual amount of noise present. I recommend closed-ear headphones. The isolating effect of the closed-ear design allows you to hear what's really going on in your recordings. Get an extension cord as well, 10 or 20'.
3. Move the mic. There is more going on than just the source of the noise. Most of our domestic spaces are prone to acoustic reflection (more on this in the next section). Reflections are greater when you're closer to corners and large flat surfaces. There are spots in any room where the reflections are less pronounced. These sweet spots will be quieter places to record if you can otherwise eliminate the actual noise itself. Put on your headphones, turn up the volume as much as is comfortable and find a sweet spot. Here's where the extension cable for your headphones comes in handy. You may need an extension cable for your mic as well.
4. Experiment with recording levels and mic technique. Try lowering the input volume and record closer to the mic. There is a practical limit to how close you can get to the mic before it alters the sound so this might take some trial and error to find the right combination.
5. Switch to a dynamic mic. Condenser mics are fantastic for vocals in a studio environment, but their larger pickup patterns and greater sensitivity can work against you when you're working in a noisy and/or reflective space. Dynamic mics have a smaller pickup pattern and don't capture sound well to the sides and rear of the mic. This provides greater flexibility in mic placement as well.
6. Neutralize reflective surfaces. Empty corners and large flat walls are great for reflecting sound and cause audible (mid-range and treble) and inaudible (bass) reverberation. Hanging moving blankets or an old comforter a few inches from a flat wall or an empty corners can make a noticeable improvement. We bought another sofa for our family room (where I record) last year and placed it against what had been a mostly empty wall. This made a tremendous difference in the room acoustics. I was able to go back to using condenser mics. Recently I noticed that the reflective noise level was suddenly higher in my recordings. It wasn't a lot, but it was enough to impart a "room" type signature to the recorded source material. I pulled my hair out for a few hours before realizing that the extra folding chairs that we usually store in one of the corners were upstairs making the corner emptier than usual. I put the chairs back and the reflective echo was removed. Not the most technical approach, but it worked. The real resolution to removing room reflection and the standing waves that result is through acoustical treatments - adding sound absorbing and non-linear reflective surfaces. I'll be addressing this in greater detail in a future post.
Please share any comments, questions or similar experiences.
Happy recording!
Mike
Background Noise:
Background noise, for most of us, comes from household appliances - refrigerators, freezers, humidifiers, furnaces, computers etc. These appliances can add significant noise to the recordings and that's counterproductive to our finished audio presentation. We need to convince our listeners that everyone in the audio presentation is actually in the different scene locations and not in their basement/den/bathroom etc. No one expects to hear the hum of our PC's playing under our characters lines as we're walking through an open meadow. Fortunately for all of us, there are simple remedies for removing or reducing environmental background noises to acceptable levels.
1. Locate and remove the source of any noise. This may not be as simple as it sounds. For me this sometimes means unplugging appliances in other rooms of the house, usually the downstairs freezer and dehumidifier and any computer not in use for the recording session. I prefer condenser mics whenever possible, but they pick up everything.
2. Use good headphones. I can't emphasize this enough. You need good headphones to critically evaluate the quality of your recordings, including the actual amount of noise present. I recommend closed-ear headphones. The isolating effect of the closed-ear design allows you to hear what's really going on in your recordings. Get an extension cord as well, 10 or 20'.
3. Move the mic. There is more going on than just the source of the noise. Most of our domestic spaces are prone to acoustic reflection (more on this in the next section). Reflections are greater when you're closer to corners and large flat surfaces. There are spots in any room where the reflections are less pronounced. These sweet spots will be quieter places to record if you can otherwise eliminate the actual noise itself. Put on your headphones, turn up the volume as much as is comfortable and find a sweet spot. Here's where the extension cable for your headphones comes in handy. You may need an extension cable for your mic as well.
4. Experiment with recording levels and mic technique. Try lowering the input volume and record closer to the mic. There is a practical limit to how close you can get to the mic before it alters the sound so this might take some trial and error to find the right combination.
5. Switch to a dynamic mic. Condenser mics are fantastic for vocals in a studio environment, but their larger pickup patterns and greater sensitivity can work against you when you're working in a noisy and/or reflective space. Dynamic mics have a smaller pickup pattern and don't capture sound well to the sides and rear of the mic. This provides greater flexibility in mic placement as well.
6. Neutralize reflective surfaces. Empty corners and large flat walls are great for reflecting sound and cause audible (mid-range and treble) and inaudible (bass) reverberation. Hanging moving blankets or an old comforter a few inches from a flat wall or an empty corners can make a noticeable improvement. We bought another sofa for our family room (where I record) last year and placed it against what had been a mostly empty wall. This made a tremendous difference in the room acoustics. I was able to go back to using condenser mics. Recently I noticed that the reflective noise level was suddenly higher in my recordings. It wasn't a lot, but it was enough to impart a "room" type signature to the recorded source material. I pulled my hair out for a few hours before realizing that the extra folding chairs that we usually store in one of the corners were upstairs making the corner emptier than usual. I put the chairs back and the reflective echo was removed. Not the most technical approach, but it worked. The real resolution to removing room reflection and the standing waves that result is through acoustical treatments - adding sound absorbing and non-linear reflective surfaces. I'll be addressing this in greater detail in a future post.
Please share any comments, questions or similar experiences.
Happy recording!
Mike