Designing a Listening Room - Rives Audio
This article should provide a good understanding of what can be expected in terms of the process of designing a listening room. There are five phases to most design projects. Some of the phases may overlap slightly on occasion, but ideally each will have a clear beginning and ending point. These design phases are:
- Information gathering or application
- Quote and/or contract
- Dimension check or dimension analysis
- Concept plan
- Final measurements and testing
Each of these is discussed in more detail below.
Any time a design is being contemplated, there is an initial process of gathering basic and useful information. This information includes things such as: Is the room dedicated or shared, Home Theater and/or 2 channel, what is the approximate size and how many people can it be expected to seat?
At Rives Audio we have developed an application form that gathers this basic information. Using the standard form makes our work much more efficient, however this does not mean there MUST be a standardized form. What is important is that the design firm is listening to you-the client - and fully understanding your needs. If this is not happening at the very beginning, it is never going to work for you. We've found our clients tend to vary quite a bit in terms of what they want to achieve, and as a result our designs necessarily vary as well. We ask all our clients to consider the following aspects of the design: budget, sonic benefit, and aesthetics. Each of these aspects work in a balance and each client has a different and unique threshold for each. There are also elements such as noise isolation, nearfield vs farfield, and other more subtle characteristics to be considered. Often we have to educate the clients a little so that they understand their priorities more fully. In other words, often it is not obvious to clients exactly what is important to them, and we need to go through a series of questions to help them understand their own listening preferences, and the most beneficial order for their priorities.
After we've received an application form, we will evaluate it and discuss with the client what possible approaches might be taken.. It is possible that there may not be a good practical or cost effective approach for a particular space, and undertaking a design might not be wise. While this is very rare, it can happen, but fortunately there will have been no charge for this phase of the project. Some groups may charge a nominal fee for this aspect of the process, which is fine as well.
Quote and/or Contract
At this point you and your designer should be able to decide if proceeding on the designs makes sense. If so, you should receive a quote and/or contract. Design firms have different ways of handling this. Whatever their policy is, read the contract carefully. Most are binding. Some may have penalties associated with various things from delayed payments to delays in schedules. Be sure you are comfortable with the contract and by all means ask questions for anything you do not understand. Also, if you are not familiar with the designers work, you may want to ask for references at this time.
Dimension Check or Dimension Analysis
If it is of existing construction, we take drawings from the client and put them into our CAD system. We send jpeg or other suitable drawings back to the client/dealer to verify that we have the correct dimensions put in our system. This drawing should be verified by the client/dealer/contractor to insure that dimensions are accurate.
In the case of new construction, where we may have some flexibility in the dimensions, we do a dimensional analysis to determine what dimensions are best for the space our client has available. We also have to take into account the physical area of the space that is available and weigh it against the number of seats the client wants. Often, as might be expected, compromises have to be made. For example, a client may want more seats than a room really should have, which may compromise the sound quality for the rear row of seating. See "Room Size" diagram. This shows the appropriate amount of space required. In a perfect situation, you would like to have the listeners at least 3.5 feet away from any adjacent wall. Not doing so will mean that they will experience low frequency gain above 40 Hz from being too close to the wall, due to boundary wall loading effects. Also, the distance to the screen is important. For a projector that runs at 1080p, the nearest seat should have a viewing angle of no greater than 36 degrees. This will insure that they cannot resolve individual pixels. For an 8-foot wide screen, this works out to be a viewing distance of a little over 12 feet. Then, on top of all of these criteria, you should pick dimensions that have good modal distribution. We want to support as many room modes as possible in the low frequencies without having axial modes that are close to each other. When the latter happens we will get certain frequencies that are accentuated and create that "boomy" and muddy bass sound.
This whole process can be iterative as there may be some tweaking to insure it works into the rest of the architectural plan. We work with the client and architect until we are all in agreement as to the dimensions. This is an extremely critical phase of the project. Dimensions are one of the most important aspects of good low frequency sound reproduction, and they are not easily changed once built. So the moral is-get this right and listen to your designer/engineer. If they warn you of problems, listen carefully and ask them what problems and how severe. They should know where the problems will exist and have a rough estimate of the severity, but the severity is often difficult to predict precisely prior to building.
Keep in mind, you are paying someone to give you advice on this very important aspect, this is one area not to cut corners. It costs almost nothing to get the dimensions right in the beginning but can be much more costly to fix later.
This phase is to insure that the ergonomics, or space use, of the room are correct. For new construction, we have to consider where the entryways and windows will be. For both new and existing rooms, this is the point where we determine the approximate speaker, screen, and seating locations, including how many seats, if there are risers, and any other basic ergonomic issues. Again, this is an iterative process to insure we meet all of the clients' needs. Once this is approved, we move on to the concept plan.
This sounds like a really simple phase of the project, but often it can get complex very fast. For example, someone can say he or she wants 12 people in a room that measures 14 x 19. Well, you can fit that many chairs in the room, but both the visual and sound will be severely compromised if you do this. Some of this process may have been taken care of in the dimension phase, but in this phase it should be refined. A good designer will lay out the room and show the requested number of seats, and then design another layout that would be optimized to show how many potential problems might be addressed and corrected. We run into this issue a lot, and show our clients what it does for the overall sound and visual issues (people too close to the screen who can see individual pixels-not a good idea). Once they can visualize the problems, they generally back off and say something like, "well, can we get 8 people in the room, even if 2 of them get bad sound?" Or sometimes we go from theater style seats, which take up a lot of room, to more casual couch style seating. There are many ways to incorporate compromise when striving to achieve the goals of the client, but again it's very important to really communicate with the designer/engineer. It's ultimately your room and they need to fully understand what is most important to you.
We have run into situations where some architects or designers feel it's "their" space. It's not. It's the home owner's space. He or she is hiring us, architects, interior designers, and others. We all work for the client, not the other way around. Any designer/engineer that forgets that should be off the project promptly.