Way back when I began my recording career, the studios were large and the control rooms were small. If you wanted drums, they were setup, recorded and played. You couldn't have this in the same room as the recording console.

     But today most of the drum sounds are programmed into a computer in the form of samples. Live drums are sometimes used, but it is remarkable that things like this are no longer essential to production. So many musicians doing their projects don't really need to build two rooms - they can do everything in one room. About the only thing you have to record live is a vocal. You may record some things like guitars, but many parts will be added with a keyboard.

     Many project studios going into the basement don't really have the room to make a separate control room and studio, let alone factoring in costs. I am, therefore, making this week's task the design of a one-room project studio that still takes into account the acoustically great Golden Section formula.

The Golden Section

The Golden Section is a set of ratios originally discovered by the ancient Greeks which can be used to design sound rooms.  The ratio has the smallest dimension (often the height) the starting point; then the next longest dimension is 1.62 times that length (often the width); the final dimension is 1.62 times the second dimension (usually the length of the room).  When a room is built using these ratios, sound in the room is incredibly even - Ideal for a studio.

Booth End / Equipment End

     In a previous tip I talked about a "live end / dead end studio room using the golden section dimensions as shown in figure 1 below. 75% of the length of the room is kept "live" and the remaining 25% is deadened with acoustic foam.
In our one-room design we are going to use the "dead" area of the room as a place the vocalist or other "live" musician will perform, and use the "live end" for our equipment set-up. Making sure that the area behind a singer (or other musician) absorbs sound (or "dead")is a key to getting a professional sound. When we put the singing in the dead area of the room, we get a very direct vocal sound without objectionable "room" sound.

Bass Traps with Ceilings and Walls

     Most acoustic foam does a good job of reducing treble and midrange sound reflections. The long wavelengths of the bass frequencies, however, require thicker areas of absorption to reduce bass reflections. The difference between 2 inch acoustic foam and foam that is 3 or 4 inches thick has to do with how low of a frequency will be prevented from bouncing off the surface it is applied to. Even the thickest foam, however doesn't do a good job at the real low frequencies. My suggestion is don't spend the extra money for the real thick foam, spend it on making an even thicker bass trap.

     When we talk about bass traps, the studio designer probably looks first at the ceiling. The typical "drop" ceiling has a layer of acoustic tile that is a distance below a hard ceiling. If a layer of fiberglass insulation is placed above the drop ceiling tiles, the sound travels through three acoustically-absorbent materials (tile, then fiberglass, then air) before it bounces off the hard ceiling and then tries to travel back though the three absorbent layers again. The space between the hard ceiling and the acoustic drop tiles means the long bass wavelengths can be absorbed.
The basement project studio doesn't typically have the height to install a drop ceiling. You're lucky if you can get a clear 7 feet height of a hard ceiling you install. A sealed ceiling with fiberglass insulation in the rafters is essential for sound isolation and then there is no space for a usable "gap" between a drop ceiling and the hard ceiling. This means that we must look at the walls if we are going to have bass traps.

Figure 2 Booth End/Equipment End

Bass Trap / Booth End

     Figure 2 shows the one end of the room made dead with large wedge-shaped bass traps. To construct the bass traps, do the following:

A Note On Dimensions/Treatment

     Golden Section Ideal Ratios: 6.3 feet x 10.2 feet x 16.6 feet.

     Ceiling - 6.3 Feet - Hopefully we can get a lot closer to 7 feet with the hard ceiling that we install. Everything above 6.3 feet however should be absorbent. Acoustic tile glued to the hard ceiling and the very top of the walls will make us have no reflections (of midrange and treble) from a ceiling that is outside of the Golden Section Ratio.

      Usually you want to make either the ceiling or the floor of the room absorbent. Since basements tend to flood, I would keep the floor tile and make the ceiling absorbent. You can, in addition have "throw rugs" that you can use to adjust the acoustics a bit.
Length - 15.6 feet - We didn't have enough room to make the length 16.6 feet. With our "dead-end" approach, however we make everything longer than 12.5 feet part of an absorbing bass trap.

     Width - 10.2 feet - We had the room to use the correct dimension.

The Monitoring Enemy - Sound Reflections

     Most monitoring today is done with "near field" monitors - speakers placed close to the engineer. Often a subwoofer is added and this is placed on the floor. Sound reflections from the near-field monitors can cause you to improperly hear the sound being put out by the speakers. The sound reflections that interfere fall into two categories.

     Short Reflections If there is a reflective surface directly behind the speaker or close to its side, a reflection can reach the engineer's ear. Because the sound has to travel 2-10 feet further to make a reflection, it arrives less than 10 ms delay. This causes partial phase-cancellation of the direct sound and causes serious alteration of how loud certain frequencies are in the engineer's ear. In layman's terms, It causes a thin and hollow characteristic to the sound. Short reflections are shown in red in figure 3.

     Long Reflections Longer reflections can be generated by the speaker's sound bouncing off of the wall behind the engineer. In this case the sound travels an extra 20 feet or so to make the reflection. This makes the reflection about 20 ms. late (or more). This reflection will "blur" the attack of instruments that the engineer hears. In our case of using the back of the room as a vocal/instrument booth, reflections cannot be made off the back wall, thus we don't have any of those long reflections in the room. Long reflections are shown in blue in figure 4.

     The direct sound from the speaker (shown in green in figure 3), is the desirable sound that we want to hear.

Acoustically Treating the "Equipment End"

     In figure 4, the brown patches are areas to place acoustic tiles or other absorbing material. Acoustic tiles right behind the speaker (for the entire length of the wall) prevent short reflections at ear level. Reflections still may occur that bounce to the floor or ceiling, but they do not interfere with monitoring quality. Acoustic tiles placed at ear level on the side walls prevent short sound reflections off those walls.