"WHAT TO DO IF YOU CAN'T AFFORD (OR DON'T HAVE ROOM FOR) BAFFLES
The home recordist is usually working with a limited amount of space. Often the live musician performing is in the same room as the console and the musician is playing in the corner or across the room. There's not a lot of room for big baffles, like there is in a larger professional recording studio.
Big baffles can be expensive, even when built with minimal costs, and for what? To take up most of the limited space that a home recordist has - naturally.
So I decided to design a home baffling system that the home recordist can actually use. The system I designed will fit into any setup and cost a mere $3.00 (or $5.00 if you don't watch costs). Probably everything you need can be picked up at your local dollar store.
One takes a corner of the room and hangs blankets 6 to 8 inches away from the wall. This "L" shaped area has reduced leakage of other sounds in the room because the sound waves have to travel through the blanket to the wall and back through the blanket to form a sound reflection. The air space between the blanket and the wall helps make the blanket effective. So you get those hooks and clothesline that will hold the blankets. You use things like clothespins to keep up the blankets.
Needless to say everyone has blankets and you can't use your sleeping blanket while you're recording. You would want to use the thickest ones or even have two layers of blankets {two thin blankets work better than one thick one, by the way].
So your little corner becomes your baffled-off area and things sound better there and have less leakage
THE SOUND ABSORBING QUALITY OF AIR
Air actually is a sound absorber. It doesn't have as much sound absorbing ability as fiberglass or even the wool-blanket, but it has sound-absorbing qualities none the less. The blanket baffle works because the sound has to go though the blanket and then a layer of air before it reaches the wall. After bouncing off the wall it goes though air again and then the blanket again.
The thickness of the baffle determines the lowest-frequency that will be affected by the baffle. Lower frequencies have longer wavelengths, therefore they need thicker baffles to absorb the sound. Putting the blanket 6 inches away from the wall makes the baffle effectively 12 inches thick. Generally sound-absorbing material can have maximum absorption for frequencies with wavelengths four times the thickness of the baffle (or less). There will be noticeable sound absorption for frequencies with wavelengths eight times the baffle thickness.
LOWEST ABSORBING FREQUENCY FOR A THICKNESS OF SOUND-ABSORBING MATERIAL
FREQUENCY/WAVELENGTH
PARTIAL ABSORPTION
MAX ABSORPTION
1000 Hz / 1 ' 1.5"
1 3/16 Inches
3 3/8 Inches
500 Hz / 2' 3"
3 3/8 Inches
6 3/4 Inches
250 Hz / 4' 6"
6 3/4 Inches
13 1/2 Inches
125 Hz / 5'
13 1/2 Inches
27 Inches
63 Hz / 10'
27 Inches
54 Inches
From the chart, it can be seen that the blanket baffle can reduce leakage for frequencies down to about 125 Hz.
THE SOUND ABSORBING WALL
Some studio will make one wall entirely sound-absorbing to help with the acoustics. In a future Alexander Magazine issue we plan an article on the when and why this is a good practice. Studios often buy sound-absorbing foam that is about 3 inches thick and place it on the wall. Although there is an angled pattern to the foam that helps absorption, it can be seen from the above chart that the foam will have limited bass absorption. It can also be seen that placing half-inch thick carpeting on the walls really doesn't work to absorb even midrange sound.
A much more effective way of making a sound-absorbing wall would be to mount the acoustic foam on pegboard, and the mount the pegboard 3 to 6 inches away from the wall. This use of the foam will reduce sound reflections well into the bass frequency range."
Good stuff, eh!
The home recordist is usually working with a limited amount of space. Often the live musician performing is in the same room as the console and the musician is playing in the corner or across the room. There's not a lot of room for big baffles, like there is in a larger professional recording studio.
Big baffles can be expensive, even when built with minimal costs, and for what? To take up most of the limited space that a home recordist has - naturally.
So I decided to design a home baffling system that the home recordist can actually use. The system I designed will fit into any setup and cost a mere $3.00 (or $5.00 if you don't watch costs). Probably everything you need can be picked up at your local dollar store.
One takes a corner of the room and hangs blankets 6 to 8 inches away from the wall. This "L" shaped area has reduced leakage of other sounds in the room because the sound waves have to travel through the blanket to the wall and back through the blanket to form a sound reflection. The air space between the blanket and the wall helps make the blanket effective. So you get those hooks and clothesline that will hold the blankets. You use things like clothespins to keep up the blankets.
Needless to say everyone has blankets and you can't use your sleeping blanket while you're recording. You would want to use the thickest ones or even have two layers of blankets {two thin blankets work better than one thick one, by the way].
So your little corner becomes your baffled-off area and things sound better there and have less leakage
THE SOUND ABSORBING QUALITY OF AIR
Air actually is a sound absorber. It doesn't have as much sound absorbing ability as fiberglass or even the wool-blanket, but it has sound-absorbing qualities none the less. The blanket baffle works because the sound has to go though the blanket and then a layer of air before it reaches the wall. After bouncing off the wall it goes though air again and then the blanket again.
The thickness of the baffle determines the lowest-frequency that will be affected by the baffle. Lower frequencies have longer wavelengths, therefore they need thicker baffles to absorb the sound. Putting the blanket 6 inches away from the wall makes the baffle effectively 12 inches thick. Generally sound-absorbing material can have maximum absorption for frequencies with wavelengths four times the thickness of the baffle (or less). There will be noticeable sound absorption for frequencies with wavelengths eight times the baffle thickness.
LOWEST ABSORBING FREQUENCY FOR A THICKNESS OF SOUND-ABSORBING MATERIAL
FREQUENCY/WAVELENGTH
PARTIAL ABSORPTION
MAX ABSORPTION
1000 Hz / 1 ' 1.5"
1 3/16 Inches
3 3/8 Inches
500 Hz / 2' 3"
3 3/8 Inches
6 3/4 Inches
250 Hz / 4' 6"
6 3/4 Inches
13 1/2 Inches
125 Hz / 5'
13 1/2 Inches
27 Inches
63 Hz / 10'
27 Inches
54 Inches
From the chart, it can be seen that the blanket baffle can reduce leakage for frequencies down to about 125 Hz.
THE SOUND ABSORBING WALL
Some studio will make one wall entirely sound-absorbing to help with the acoustics. In a future Alexander Magazine issue we plan an article on the when and why this is a good practice. Studios often buy sound-absorbing foam that is about 3 inches thick and place it on the wall. Although there is an angled pattern to the foam that helps absorption, it can be seen from the above chart that the foam will have limited bass absorption. It can also be seen that placing half-inch thick carpeting on the walls really doesn't work to absorb even midrange sound.
A much more effective way of making a sound-absorbing wall would be to mount the acoustic foam on pegboard, and the mount the pegboard 3 to 6 inches away from the wall. This use of the foam will reduce sound reflections well into the bass frequency range."
Good stuff, eh!
