Figure 1a. Equipment in Studio A of Mi Casa Multimedia, a cockpit arrangement, is almost perfectly symmetrical, and no reflective furniture is placed in the rear of the room.
Last month we briefly summarized some of the issues concerning acoustic criteria and acoustic design as they relate to audio production suites for the broadcasting industry.
In that discussion, we determined that finished design solutions integrate two fundamental acoustic categories (sound transfer acoustics and internal room acoustics) in creative ways. It is the job of the room designer to accommodate user ergonomics and room layout requirements, while maintaining these standards. We now discuss these tasks in more detail.
Ergonomics is the room’s architectural program — how we arrange equipment, furniture and other elements in our rooms, and how these elements affect the usefulness and comfort level of the environment. It is also important in audio production suites to consider how these arrangements affect and are affected by acoustics. Remember, our goal is to have the most accurate acoustic response possible in the critical listening position. Acoustic design is then applied to accommodate these requirements. The old architectural anthem “Form follows function” is especially true for audio production environments.
Control room layouts
Audio control rooms can be categorized into four room layout configurations: cockpit style (symmetrical arrangement), cockpit style (asymmetrical arrangement), railroad layout (symmetrical) and railroad layout (asymmetrical).
In each of these configurations, there will be variations resulting from changes in speaker size and mounting, glass (viewing to studios and/or outdoors), egress in and out of the room, 5.1 surround requirements, etc.
Figure 1b. In Carter Burwell’s film mixing and composing facility, rear corner cabinets house equipment, keeping the space directly behind the listening position clear.
Cockpit style(symmetrical arrangement). The room’s acoustic centerline (the axis between the primary stereo mixing speakers) will be centered on a mixing/production console or workstation. This axis is aligned with the room’s architectural (physical) centerline. There is really no reason for this not to happen. All other equipment – processing devices, composing gear (ie. keyboard), etc. – will be arranged on either side of this position, as symmetrically as possible. In this configuration, there is no equipment or furniture directly behind the listening position. The acoustic advantage of this layout is that the equipment and furniture are not in conflict with speaker reflection patterns. On more than one occasion, we have seen a perfectly well-designed room be acoustically compromised by one large piece of equipment (ie. tall equipment rack) that created a comb filter or harsh reflection for one speaker that was quite different than the other.
Both Mi Casa Multimedia in Hollywood and film composer Carter Burwell’s private production studio (see figures 1a and 1b) exhibit this type of layout. In Carter Burwell’s production studio, extensive equipment is housed in rear corner cabinets, but no equipment is directly behind the listening position. Mi Casa’s Studio A exhibits a near perfect symmetrical arrangement of equipment with no rear reflective furniture.
Cockpit style (asymmetrical arrangement). This type of room arrangement layout is similar to type A – configured around a room acoustic centerline – but has the characteristic of one side of the room creating a non-symmetrical equipment configuration. This is often due to a door location or window placement, or the need for a large rack or piece of furniture. In general, I would try to avoid this configuration, but it frequently represents an architectural/layout requirement that must be accommodated. In this case, try to minimize the physical difference between the two halves of the room. At the very least, keep a symmetrical configuration in the front portion of the stereo sound field. Ultimately a simple ray trace pattern will reveal whether there will be an acoustic conflict in the primary listening position. Occasionally a slight repositioning of a rack will solve what could be a serious reflection control problem. In the case of the radio production control rooms (rooms five and 10, see Figure 2) for WETA in Washington, DC, asymmetry was required in the rear of the room in order for the entry door configuration to work. Notice that the fronts of the rooms are totally symmetrical around the acoustic centerline and that the side glass configurations are also identical.
Figure 2. Control rooms five and 10 at WETA had to be arranged asymmetrically due to the rear entry door configuration. Equipment in the front of the rooms is still arranged symmetrically, and the side glass configurations are identical.
Railroad layout (symmetrical). This is probably the most common room layout for the broadcast and audio production industry. A producer’s desk is typically located in the rear of the control room on top of a rear equipment rack housing with close proximity to the primary mixing position. We can also configure rooms in this fashion with equipment being partially asymmetrical, while the room boundaries and acoustic surfaces are perfectly symmetrical. Again, where possible I would recommend these types of layouts. New York audio post houses Berwyn Editorial (see Figure 3) and Superdupe both illustrate room symmetry, despite furniture layouts that are partially asymmetrical. Critical acoustic treatments (such as side wall absorption and rear room diffusion), as well as room boundary geometries, are symmetrical for the entire length of the room’s acoustic centerline.
Railroad layout (asymmetrical). Architectural circumstances (doors, columns, glass, client seating, etc.) often demand that we create an asymmetrical version of type C. In the case of New York station WNET’s 5.1 audio production suite, columns as well as a need for a corner seating area have resulted in a partially asymmetrical room floor plan (see Figure 4). Note, however, that critical acoustic treatments are perfectly symmetrical, including splayed side glass and rear room diffractal. 5.1 surround monitors are motorized and come out of the rear producer furniture, which is 29 inches high. Low furniture in the rear of the room helps to eliminate any harsh comb filter reflections.
igure 3. The floor plan for Berwyn Editorial reflects symmetry of room boundaries, even though its furniture layout is partially asymmetrical.
There is no one perfect way to organize equipment and furniture in an audio production environment. As we have discussed, room layouts depend on the room’s exact use, size, budget, equipment requirements and existing site circumstances. When ergonomic and function uses have been solved (this always has to happen first!), use the basic acoustic principals of comb filter prevention, reflection control and low frequency analysis (room ratio organization and well-placed low-frequency absorption) to assist in creating an acoustically accurate room. Enjoy working in these rooms!
John Storyk is a principal owner of the Walters-Storyk Design Group.