Goodwin's High End -- Room Design

All About Room Design

We all know that most recordings are made in recording studios. And most people realize that recording studios are specially built to have good room acoustics. But many people don't consider the importance of room acoustics for the playback of music. Well designed and implemented acoustic treatment can make any good system sound considerably better.

And if the goal is to reproduce film, a good room design needs well controlled lighting, as well as proper acoustics. A properly designed home theater takes the reproduction of a video or film to a significantly higher level.

When a client has the freedom to build a new room (either through new construction, an addition, or through remodeling), we can adopt a comprehensive approach to realizing outstanding performance in that room. This approach carefully designs:

The dimensions and shape of the room, which form the basic acoustics of the room, particularly in the bass region.
The techniques and materials used in the construction of the room, which determine the resonant, sound transmission, and sound isolation properties of the room boundaries.
The acoustic treatments within the room, which given the dimensions, shape, and construction of the room, refine the bass characteristics of the room, and define the midrange and treble acoustics of the room.
The electrical system, so that the utility company can deliver the highest quality power to the audio components. Also, in some cases the design of the electrical system may need to reduce the electrical noise from external sources, such as television transmitters, industrial equipment, or computers.
The heating, ventilation, and cooling (HVAC) system, so that noise isn't introduced into the room. If soundproofing is desired so that the music room doesn't disturb others in the house, then we also design the HVAC system for sound isolation.

And for home theaters, we additionally consider:

Lighting and lighting control. Lighting is the intentional addition of artificial light to enhance the video system's performance. Lighting control is the elimination of external light to prevent the degradation of the system's performance.

Tip: It's much easier to build a great sounding room than it is to make any old room sound great. We suggest that you involve us early in the design process.

We offer our design services to those who wish to build their own dream room. If you are one of those lucky few, you are invited to call and arrange an appointment to speak to us about your project.

Custom Room Design for Music Playback

When you go to the symphony, you usually hear the musicians in a hall specially designed for "good acoustics." When you listen at home to recordings of music, wouldn't it be great to a have a similarly great-sounding room? We feel that the ultimate expression of the art of music reproduction is the construction of a custom-designed music room. Before we begin the design process, we need to know a few things:

Approximately how many people will be using the room at one time?
What type of audio system will be used? Two channel stereo or multi-channel surround sound.
Are there other (non-audio) uses of the room that need to be accommodated. For example, will there be a pool table, a grand piano, or maybe television viewing?
Are there important lifestyle issues that need to be considered? Perhaps there's a great view to the west. Or maybe the flickering warmth of a fireplace is important.
Is sound isolation needed? Perhaps you need to keep your music in the room, or you need to keep street noise out?

There are many important parameters to address in well-designed listening room:

The room dimensions and shape.
The position of the speakers and of the listener(s).
The placement and type of door(s).
The placement and type of any windows or skylights .
The construction techniques used in the walls, floor, and ceiling.
Soundproofing construction techniques.

Once the room shell has been designed, then the following sub-systems need to be carefully thought through:

The AC electric system design.
The Heating, Ventilation, and Cooling (HVAC) system design.
The lighting system design.
RF/EMI (Radio Frequency / ElectroMagnetic Interference) shielding.
The acoustic treatments within the room.

The room size will be determined partially by how much space is available and how many people will be listening at any given time. For acoustic and comfort reasons, the room doesn't want to be too big nor too small. The ratio of the room dimensions is extremely important. Click room dimensions for more info.

When designing a room, we carefully consider where the listeners will sit and where the speakers will be positioned. There are two basic types of music playback systems: 2-channel "stereo" systems and surround sound systems. While there can be differences in how we design a room for either type of system, there are many similarities and we can design a room for use with both.

The placement and construction of doors and windows is important. From a purely acoustic perspective, we would omit doors and windows as they deleteriously resonate, reflect, and leak sound. They are also more expensive than a plain wall. Of course, natural light is essential for most people, and so we carefully recommend the number, size, location, and materials for the windows. For doors, we've always joked that the best place to put a door is in the floor. Assuming that you aren't willing to climb into your room through a trapdoor in the floor ;-) we simply place the door where it is least problematical.

As for the walls, we specify the construction of relatively inert, anti-resonant walls with a certain amount of controlled flexure. We want them to be somewhat rigid, but not so rigid that they will not let any bass energy escape. Excessively rigid walls would require extensive bass trapping to acoustically treat the room. Often we specify walls that are of medium mass but that are also internally damped and can flex in a controlled manner. Click room construction for more info.

In addition to the proper design for the acoustics within the room, we also need to consider any requirements for soundproofing. In many situations, we need to keep external noise out of the room. For example, the noise from a busy road can very annoying. Or perhaps you may wish to keep loud music from being transmitted to other parts of the home. Click soundproofing for more info.

The AC electrical system should be designed and installed with great care. For the highest quality audio systems, we specify heavy-duty dedicated & electrically isolated circuits, with special attention to capacity, shielding, and grounding. If code permits, we prefer an entirely separate ground to earth just for the audio electrical system, but local building codes sometimes do not allow this. To minimize the potential for hum and noise, we pay special attention to which leg of the 220 volt feed is used to source the 110 volt outlets. We also recommend hospital grade outlets and heavy duty circuit breakers, or even new high-end breaker boxes that don't use the normal pull-out circuit breakers. Click electrical system for more info.

The HVAC design is also important because we want a low noise floor. In some situations, we prefer a dedicated HVAC system for the listening room. Furthermore, sometimes it's best to separate the heating system from the cooling system. We pay special attention to avoid sound transmission problems when the ductwork can connect to noisy elements such fans, furnaces, and compressors. We recommend ducts that are lined on the inside and wrapped on the outside. To eliminate the noise of rushing air, we often specify large, specially designed and built still-air boxes. Click HVAC for more info.

Any high-end room requires a careful lighting plan by a qualified lighting designer. However, many of the electrical components that lighting designers use generate large amount of electrical noise which degrade the performance of the audio system. Dimmers are usually the worst offenders, even though they can flexibly create different lighting scenes. Sometimes we use a special type of dimmer that creates less noise. Or perhaps we can use low-wattage lamps to design a fixed lighting scene for listening. In addition to electrical noise, the lighting plan can create acoustic problems. Some lamps actually emit mechanical noise when in use. Some lighting fixtures act as resonators and reflectors, requiring careful selection and placement. In any case form should follow function here; the lighting design should flatter the various uses of the room. Click lighting for more info.

Some metropolitan areas have well-known areas with high levels of TV, radio, telephone, and other types of high frequency air-borne signals. Some audio system can pick up and amplify these signals as unwanted background noise. If you are building in such an area, please let us know as we can minimize the effects of these signals with the design of the room. Click RF/EMI shielding for more info.

After the room is built, we install the acoustic room treatment. Acoustics and acoustic room treatment are surprisingly complex subjects. Room treatment is essential to achieving high performance from your audio system. We design the treatment around the furniture in the room, and if desired, we can help you select new furniture to avoid any egregious reflection or resonance problems. Also, we consider the acoustic properties of the window treatments so that they absorb the proper amount of sound -- neither too little nor too much. Click acoustic treatment for more info.

A comprehensive room design requires very careful planning and implementation. It can be expensive. But when the project is complete, you'll be enjoying your new custom-built listening room with a satisfied grin on your face. It is indeed the ultimate way to experience music reproduction. To date all of the clients for whom we've custom-designed rooms are exceedingly happy. If you would like to have a room designed by us, you're welcome to give us a call so that we can arrange a time to discuss your project.

Custom Room Design for Home Theater

The design of a custom-built home theater melds the acoustic considerations of a multichannel audio system with the design parameters needed to achieve high-quality video reproduction. A properly-designed and installed home theater will rival your local cinema in picture quality (unless you live in Hollywood), and will far surpass it in audio quality. Before we begin the design process, we need some information from you:

How many people will usually be using the theater at one time? And how many at the maximum?
To achieve the highest picture quality, are you willing to make the room totally dark? Are there other times when you need some ambient light?
Are there other uses of the room that need to be accommodated. For example, will there be a pool table, a card table, or perhaps a bar in the room? Does the home theater double as a family room?
Will you be listening to stereo music in this room, and if so, how important is this relative to home theater use?
For an interior design perspective, should the room resemble a miniature cinema or should its home theater use be disguised?
Is sound isolation needed? Perhaps you need to keep your music in the room, or you need to keep street noise out?

Because each video display technology has its own unique set of pros and cons, we must carefully match your needs to the right equipment's capabilities. Often front or rear projection systems best suit the requirements, although a high-definition direct view television or a flat plasma screen are sometimes best. On occasion we even use more than one technology in a single room. Now that we know what you'll be watching in the room, we can turn to designing the room itself.

Ideally, we would like to size the room specifically for your needs. The general size of the room will determine the number of people who can comfortably watch the theater at one time. For acoustic reasons, the ratio of the room dimensions is extremely important. Click room dimensions for more info.

Many times however a home theater is a retrofit of an existing space. Sometimes one or more of the dimensions (length, width, and height) are constrained by other considerations, such as budget or an existing space within the building. However regardless of your room size, we have a wide variety of techniques to enhance both the video quality and sonic performance of your system.

Tip: Consider converting basement space into a home theater. It will add useable square footage to your home and enhance it's resale value. Also, the lack of windows in the basement may complement the home theater's need for darkness.

Tip: Building a new house? If you are building a new home, but don't want to build the home theater right away, consider adding a foot or two to the ceiling height in the basement to more gracefully accommodate a future home theater. Plan the space now so that ductwork, structural columns, and other obstacles don't have to be moved later. Also, ensure that your foundation drainage system and vapor barrier will guarantee a dry basement.

When designing a room, we carefully consider where the listeners/viewers will sit and where each speaker will be positioned. The acoustic design of the room must accommodate not just sound coming from the front left and right speakers, but also from the center front and from the rear and/or sides. Each occupant needs a clear line of sight to the screen and ideally a clear line of sight to each speaker. If you plan to listen extensively to stereo music, then we need to perform additional acoustic planning to ensure that you realize the full capabilities of your system.

We carefully plan the placement and construction of doors and windows. From an acoustic perspective, doors and windows can deleteriously resonate, reflect, and leak sound. From a video perspective, even window's with heavy curtains will leak light, which may then need to be controlled with special "blackout" blinds. Also, the windows and doors should be located where the won't conflict with the preferred screen and speaker placements.

As for the walls, we specify the construction of inert, anti-resonant walls. We also want them to be somewhat rigid, but not so rigid that they won't let any bass energy escape. Excessively rigid walls would require extensive bass trapping to acoustically treat the room. Often we specify walls that are of medium mass but that are also internally damped and can flex in a controlled manner. Click room construction for more info.

Once we have the proper design for the acoustics within the room, we consider any requirements for soundproofing. In many situations, we need to keep external noise out of the room. For example, the noise from a busy road can very annoying. Or perhaps you may wish to keep loud movie soundtracks from being transmitted to other parts of the home. Also, some audio and video components make mechanical noise, either from a fan or from their operation. We can design baffles and ventilation systems to prevent this noise from intruding on your listening. Click soundproofing for more info.

The AC electrical system should be designed and installed with great care. For the highest quality systems, we specify heavy-duty dedicated & electrically isolated circuits, with special attention to capacity, shielding, and grounding. We recommend hospital grade outlets and heavy duty circuit breakers, or even new high-end breaker boxes that don't use the normal pull-out circuit breakers. Click electrical system for more info.

A good HVAC design will help achieve a low noise floor in the room. We pay special attention to avoid sound transmission problems when the ductwork connects to noisy elements such fans, furnaces, and compressors. We recommend ducts that are lined on the inside and wrapped on the outside. Click HVAC for more info.

Some metropolitan areas have well-known areas with high levels of TV, radio, telephone, and other types of high frequency air-borne signals. Some audio and video system can pick up and amplify these signals as unwanted background noise. If you are building in such an area, please let us know as we can minimize the effects of these signals with the design of the room. Click RF/EMI shielding for more info.

Any high-end room requires a careful lighting plan by a qualified lighting designer. However, many of the electrical components that lighting designers use generate large amount of electrical noise which degrade the performance of the system. If the home theater will sometimes be used with the lights on (for example, to listen to music), then we take special precautions retain the system's high level of performance. Click lighting for more info.

Depending upon the display technology used in the video system, the color scheme of the room may be quite important. Front projection systems in particular benefit from a dark, neutral color scheme. Black is ideal, but neutral grey or grey-like colors such as charcoal or taupe can work almost as well. Other colors, especially on the areas closest to the screen, will be less optimal. Burgundy, a popular cinema-like home theater color scheme is not a particularly good choice as it will tint the picture pink. White or light colors are the least optimal as they will reflect light back onto the screen, which will wash out the blacks, making them look grey instead. If you are using an interior designer on your project, we suggest that we work with them to create high-performance, great looking home theater. We have techniques which can either ameliorate or eliminate the performance problems with just about any color scheme.

In addition to color, texture can be important as well. A high gloss paint for example will deleteriously reflect light. Image a shiny new black car and you'll understand the problem. Flat or almost flat paint works much better. As an alternative, we can install a stretched cloth system on the walls and ceiling. The effect can be stunning visually and non-reflective optically. As a bonus, a cloth wall system can conceal acoustic treatments, giving a clean, sleek look to even the most highly treated room.

Clearly a well-designed room will substantially enhance your enjoyment of your home theater. If you are interested in discussing your project with us, you are invited to give us a call.

Custom Room Design for Music Recording

The acoustical design of a room designed for recording live music differs from that of a room designed for music playback. Recording rooms usually need to be substantially more live in order to capture some of the room's acoustical space in the recording. The "liveness", or reverberation field should decay smoothly over time and not exhibit excessive slap echo.

Ideally, the room can be adjusted acoustically to fit different recordings. For instance, you would probably want to record a classical string quartet with more natural room reverberation than you would if you were recording an acoustical steel string guitar.

At Goodwin's High End, we built a custom-designed combination listening / recording room. This room has adjustable acoustics to suit its dual functions. Having this on-premise resource provides us a live music reference to facilitate the evaluation of our playback components and systems. It also allows us to compare different recording components, systems, and techniques.

If you are interested in learning more about high end recording you are welcome to give us a call. We have several staff member with recording experience.

Custom Room Design for Live Music Performance

Lovers of music also tend to be avid amateur or even professional musicians. If you are building a room for music practice or performance, the acoustics of the room will greatly influence how easily the musician (and audience) can hear. The acoustical design of such a room differs from that of a room designed for music playback. Live performance rooms usually need to be substantially more reverberant in order to retain some of the room's natural acoustical space. The "liveness", or reverberation field should decay smoothly over time and not exhibit excessive slap echo.

In addition to improving the room acoustics, you may want to consider extensive soundproofing. This will allow the musician to practice without worrying about disturbing the rest of the household.

If you plan on having a piano or other musical instrument, consider improving the room's acoustics to make practicing and performing more pleasurable. Also consider any soundproofing requirements that you may have.

Room Dimensions

When you listen to music through a high-end audio system (whether it's just for music or as part of a home theater), you'd like the loudness of each note to be just as the musician played. For example, if an acoustic bass player plays a enticing riff that descends in pitch, and if the musician plays each note equally loudly, you'd like to each of those notes to be properly reproduced at the same volume. In this way, the musical dynamics of the performance are properly reproduced.

Now, imagine that you have carefully selected the components of your audio system. You've paid attention to choosing "neutral" components that properly reproduce the volume of notes at each pitch, just as the musician played them. You still may not hear in your home the notes properly reproduced at the same volume. And that's because your room will make certain pitches louder or softer than normal.

Rooms resonate just like a pipe organ (or a partially filled soda pop bottle when you blow across the neck). The basic room resonances are determined by the length, width, and height of the room, just the like pitch of the pipe in the organ is determined by the diameter and how long it is. (There are other, more complex resonances, but we have found that it is usually most important to focus on the most basic ("axial") resonances because they are the highest amplitude ones.)

Each dimension of the room determines a set of frequencies (i.e. pitches) at which the room will resonate: the fundamental frequency, and all of its harmonics. For example, a room that resonates at 50 Hz, will also resonate at 100Hz, 200Hz, and so forth. Because there are three dimensions in a rectangular room with a flat ceiling, there would be three sets of resonant frequencies.

When a note is played at or near one of the resonant frequencies for the room, the note will be heard louder or softer than normal, depending upon where in the room the sound is made (i.e. where the speaker is) and where the sound is detected (i.e. where your head is).

Our goal in choosing the room resonances is to cause all of the resonant frequencies in the three sets to be evenly distributed in the bass region. In particular, we want to avoid a lot of overlapping frequencies or a large range of frequencies where there are no resonances. We do this by choosing the room dimensions (length, width, and height), ideally without constraint.

Tip: Rooms that are rectangular with a flat ceiling (i.e. that look like a basic shoebox) have easily predictable acoustic properties. Avoid other shapes if possible as they are much more complex to work with.

At the same time that we calculate the room dimensions, we determine the recommended optimal speaker locations and listening (and perhaps viewing) locations. We choose these locations by considering a wide variety of factors including: number of occupants, overall room size, bass resonances, acoustic reflection points, and comb-filtering effects.

When all three dimensions are flexible, we can choose one dimension based on considerations other than the room resonances. We can then consider room resonances in choosing the other two. For example, we can choose the first dimension based upon desired listening position or based upon the desired overall room size or furniture positions. (This is important for home theaters, because we would choose the first dimension by considering view distance and possibly sight lines if there will be multi-row seating.)

Sometimes one or even two room dimensions are fixed by non-acoustic considerations. Maybe the ceiling height can't be changed easily. Or bearing walls can't be moved without a major expense. In this case, we can still improve the acoustics of the space to the degree that we still have flexibility.

Excellent acoustics require a room with carefully planned dimensions and shape. For the best results, involve us early in the design process, ideally before the blueprints are drawn up.

Room Construction

Different materials and construction techniques will influence the quality of the acoustics in the room. For example, typical residential wall construction (i.e. 1/2" sheetrock over 2x4 studs spaced 16" on center) resonates quite readily. This resonance will be imposed on the music from the speakers, and will "muddy" the sound, making individual instruments less distinct.

There are many different levels of improvement that can be made to wall construction. For instance, just switching to 5/8" blueboard plus veneer plaster (otherwise known as "skimcoat") is an improvement over builder-grade walls. At the high end, your builder can incorporate special acoustic-grade materials into the wall and employ special construction techniques that yield the optimum wall.

For acoustic reasons related to the effectiveness of in-room acoustic treatments at certain frequencies, we have found that very stiff, dense walls are not necessarily better. It is usually desirable to allow some very low bass to leak out of the room through the walls. Therefore, we carefully design walls so that they are stiff, but not too stiff, and heavy, but not too heavy.

Tip: Come to our listening facility and rap you knuckles against one of our soundroom walls and compare it to a regular wall outside the soundroom. You'll hear a big difference.

Tip: Worthwhile improvements in wall construction can be made for a modest price. The ultimate may be much more expensive, but even that is usually just a tiny part of the construction budget.

Doors and windows also affect the room's acoustics. By carefully choosing the location of these room openings, and by selecting special materials for their construction, we can minimize or eliminate their deleterious effect. Also, remember that a skylight is nothing more than than a window in the ceiling!

The construction of the floor may be important as well. If you are building a room on a concrete slab, then you already have a highly soundproof, anti-resonant floor. If, more typically, your room is built of dimensional lumber (e.g. 2x10's) or engineered wood (e.g. wooden I beams), then we may recommend that you decrease the span, increase the width of the lumber, and/or decrease the joist spacing. (All of these techniques will also improve the performance of your phonograph turntable, if you have one.)

In addition to building the room for good acoustics within it, you may wish to consider soundproofing it as well. For example, perhaps you wish to listen without disturbing others in your home -- maybe late at night. Or, perhaps you live on a busy street, and you wish to keep external noise out of your room. If so, then we think that you'll find the article below about soundproofing quite interesting.

Your room's construction materials and techniques will influence its acoustics. A small effort during the design process may prevent a big effort after the room is complete.

Room Soundproofing

An existing room will resist soundproofing efforts, making a good result both difficult and expensive. However, in new construction, you have a wonderful opportunity to create a quiet room for your enjoyment of music and perhaps movie soundtracks.

Even in a room with walls three feet thick, a small hole for an electrical wire will create an air leak. Sound will escape, thereby bypassing all the soundproofing efforts. Only great attention to detail in the design and construction of the room will result in a high level of sound isolation. During construction, a knowledgeable consultant should inspect the room at various stages to catch any potential problems. Remember: your contractor and subcontractors are not necessarily accustomed to constructing rooms with soundproofing in mind.

Key Point: Sound travels through the path of least resistance.

If you build extra thick walls, floor, and ceiling, less sound will travel in and out of your room. Going a step further, you can build a concrete slab on grade and then erect an exterior and interior shell on top of it. The interior walls and ceiling then don't touch the exterior shell, creating an entire "room within a room." Just as dual pane thermal window insulate against heat transmission, this construction will insulate against sound transmission. If you need an even higher level of soundproofing, we can design an isolated floor for your room. The floor and the interior shell of the room then "float" on the slab, isolating the room from floor-borne noise transmission.

An excessively soundproofed room can have another problem, however. If the walls, ceiling, and floor are too rigid or too massive, they will keep retain all of the speaker's bass in the room. Such a room will require much more extensive acoustic treatment to achieve a neutral tonal balance. So ideally you want the proper amount of mass that is not too rigid and does not act as a resonator.

With the basic sound isolation design complete, careful attention should turn to everything that penetrates the inner shell: doors, windows, electrical boxes, pipes, ducts, and so forth. Anything, no matter how large or small, that needs a hole cut in a wall, floor, or ceiling can create a flanking path for sound. We can specify special doors, windows, and skylights to mitigate sound transmission through these paths. Liberal and fastidious application of special acoustical caulk will both seal the room and provide anti-resonant sound isolation. This acoustical caulk remains pliable to provide a permanent air seal.

HVAC ducting provides a direct path for air to move in and out of the room. Designing bends in the ductwork, wrapping the exterior of the duct, and lining its interior will improve the soundproofing somewhat. "Home runs" of the ductwork back to the furnace or air handler will help. We can design a still air box with a great deal of sound absorbent material. Flexible ductwork junctions will isolate the ducts from the vibration of compressors, fans, and burners. Vibration generating equipment can be physically mounted on isolating rubber mounts.

Different construction techniques obviously yield varying amounts of sound isolation. Sound isolation is quantified by Sound Transmission Constant, or STC, as measured in decibels. For example, an STC of 60db would represent a high degree of soundproofing, whereas an STC of 30 would represent relatively little soundproofing. But if you have a wall that has an STC rating of 60 and a door with an STC rating of 30, you are wasting your money building the wall so well. It is important to have a balanced design and then to build it correctly. Because decibel scale is logarithmic, a difference of 30 db (60-30 = 30) represents a factor of 1000 -- a great difference indeed.

Typical residential doors and windows can leak a tremendous amount of sound. With careful planning, the doors and windows can be ordered with special materials so that they will create an airtight seal when closed. With high quality seals, proper installation, and perfect adjustment, these doors and windows will greatly enhance the soundproofing.

Glass such as windows, skylights, and sliding doors poses another challenge. Glass both resonates and reflects sound. Sometimes the glass can be eliminated without a loss of visual appeal. But natural light and fresh air can be wonderful. We can custom design your windows, skylights, and glass doors with extra thick specialty glass selected for its acoustical properties.

Soundproofing makes your room quieter for listening and allows you to listen without disturbing others, but to be effective it requires a comprehensive approach and diligent construction.

Acoustic Treatment

A completely bare, empty room will have undesirable acoustics. It will be very "echoy," with uneven bass. Acoustic room treatment is the application of various problem-solving materials attached to the room's surfaces and/or placed within the room. Some of these acoustic treatments may be specially constructed by your contractor, some may be bought premade, and some may be regular home furnishing chosen and placed for their acoustic properties.

Acoustic treatments affect the sound at any particular room boundary in one of three ways. They can:

Absorb sound. Sound striking the surface is absorbed and not retransmitted to the room.
Diffuse sound. Sound striking the surface bounces back into the room in all directions.
Reflect sound. Sound striking the surface bounces back like a billiard ball striking a bumper (or a light ray shining on a mirror).

How a particular acoustic treatment affects sound will also vary with the audio frequencies involved (i.e. the pitches of the notes). For example, a thin acoustic treatment such as lightweight draperies may abort high frequencies, yet may allow midrange frequencies to be reflected by the wall behind the draperies.

Bass notes have much longer wavelengths. As the wavelength approaches the dimensions of the room, resonance becomes the dominate physical phenomenon governing the room's bass acoustics. Much larger, thicker absorption materials are needed to treat bass than are needed for high frequencies. The corners of the room will build up the most bass energy. In a rectangular "shoebox" shaped room, there will be eight tri-corners (four at the floor, four at the ceiling) where you will find the most bass energy building up under steady-state conditions. So it naturally follows that this is where you would usually first think to treat the room with bass trapping.

Another aspect of analyzing a room's acoustics is calculating the room's resonant frequencies. As we discussed above under Room Dimensions, we usually recommend that, when building a new room, you limit the shape of the room to a simple rectangular prism (shoebox-like shape). With this shape room, it is easier to predict the axial, tangential, and oblique modes than if the room is odd-shaped. However, if you already have an irregularly-shaped room, we can measure it's resonances with sophisticated computerized testing equipment such as a TEF (time, energy, frequency), MATT, or MLSSA ("Melissa") tests.

Above the bass region, room reverberation dominates the room's acoustics. An overly reverberant room (known as a "live" room) has unpleasant acoustics. It will be very hard to hear sounds distinctly. On the flip side, a completely non-reverberant ("dead") room, will cause an unpleasant "pressure on the ears" feeling, and will hinder the performance of a high quality audio system.

One particular type of reverberation is called "slap echo." If you clap your hands once sharply in a room with parallel bare walls, you will hear slap echo -- a series of rapid distinct echoes. Because slap echo degrades music reproduction, it is one of the things that we seek to minimize when treating a room acoustically.

Tip: Most people are highly sensitive to the reverberation characteristics of a room. Even if you don't listen to music in a particular room, you may which to consider room acoustics in its construction. For example, a large, overly-live living room, family room, or dining room will not invite relaxed conversation.

Any listening room, whether for live music or reproduced sound, can be substantially improved with a comprehensive acoustic treatment design. We have used all sorts of approaches, many of which can be retrofitted to an existing room. So where do you start?

One method that we have used over and over with great success is to utilize ASC Tube Traps. Alan Goodwin was an early adopter of ASC Tube Traps way back in 1986. He has spent many man-days working with ASC tuning a number of rooms.

Art Noxon, the President and founder of Acoustic Sciences Corporation (ASC), has given a great deal of thought to how to design and manufacture modular acoustic treatments that can be fitted into a wide variety of room shapes. ASC has introduced many products which are used in both recording studios and in home listening environments around the world. There are a multitude of possibilities and combinations. We often use the following approach when we treat a room with ASC products:

With a typical rectangular room, we usually start by treating the corners behind the speaker with bass traps. The mids and highs are also somewhat improved by treating these corners.
Next, we treat the specular reflection points at the side walls. With a stereo (2-channel) system, there are two specular reflection points on each side wall.
Depending upon the room's furnishing and window treatments, we would reduce the room's slap echo, particularly at the listening position and around the speakers.
Returning to bass trapping, we would treat the corners behind the listening position, possibly with the same size bass traps as the corners behind the speakers, but possibly with a different size.
Next, we may treat the middle of the wall behind the speakers to improve the imaging of most speaker systems.
Last, we might address problems on the wall behind the listener and ceiling.

The methodology can be different however if there are particular acoustic anomalies that need to be specifically addressed first.

There are many other methods and approaches too. Another involves RPG. Back in 1983 Alan Goodwin attended a 3-day Syn-Aud-Con conference on recording studio acoustical design. The seminar included discussions on the acoustics of both the studio and of the control room. It was there that he first met Peter D'Antonio, founder and President of RPG. Peter has done considerable work on the acoustic design of recording studios. He created the famous RPG Diffuser, in recent years has added many other new products.

We have found that only through the experience of building and treating many, many rooms have we advanced our understanding of room acoustics. We have tried different approaches and refinements in the shape of the room, the construction techniques, and the interior acoustic treatment. Back in the early 80's, most of the high-end community was not particularly knowledgeable about room acoustics. Fortunately, recording studio designers were more aware of acoustic design techniques. So Alan Goodwin decided that the best way to learn about what was being done was to spend three full days in a room with most of the top designers in the world absorbing the concepts that they had been working on for many years.

Even though many people have expended a great deal of effort in designing and building studios, a surprising number of studio simply don't sound very good. There are several basic reasons why:

Not everyone who designs recording studios does an equally good job.
Some recording studios are designed to look good and function ergonomically, but not necessarily sound particularly good.
Unfortunately even today in the new millenium, recording studios don't usually have playback systems in the control rooms which are as sonically neutral and linear as the best high end systems.

To get the best sound reproduction, Alan melded the best of what the professional world had to offer in terms of acoustic design with the best of what the high end world had to offer in terms of the most refined playback systems.

Please remember that this is just a brief introduction into a very complex field. We have applied many, many different approaches and products to rooms over the years. It would take a book-length manuscript to describe all that we have done.

If you are interested in improving your room's acoustics, we suggest that you make a scale drawing of your room from a birds-eye ("plan") view, with the furniture arrangement, window and door locations, and system placement sketched in. Also include a measurement of your ceiling height. If you wish to go one step further you can then "paint" your room with a series of overlapping photographs. Once we have your room information you are welcome to give us a call and we can discuss how to optimized your the acoustics of your particular room.

AC Electrical System Design

In an ideal world, your local utility company would supply your home with electrical power in the form of a pure 60 Hz sine wave. We have sampled the power lines with an oscilloscope; they contain much more than pure 60 Hz power. Electric motors, fluorescent lights, computers, and other appliances contaminate your power lines and grounding system with electrical noise. In addition, other power-hungry appliances in your home such as heaters, hairdryers, and air conditioners will cause voltage fluctuations when they are in use. The electrical noise is not minor; it occurs in a wide bandwidth, up to several Mhz (1,000,000 Hz), and it contains large (several hundred volt) spikes and dips.

In order to isolate a high-performance audio and/or video system from these electronic "pollutants", and to provide the highest quality electrical power, we can take special considerations when specifying the electrical system for your room. Of course, we need to know where the electrical outlets should be placed in the room. This implies that we know the locations of the equipment and possibly the speakers. Sometimes it's wise to add extra outlets in case the furniture arrangement changes, particularly if the room has difficult access to fish new wires later.

Typically, we run separate, dedicated, isolated circuits for the audio and for the video systems. These circuits use high-quality special A/C receptacles with shielded electrical boxes in the walls. For the main equipment location, we sometimes prefer to have multiple gangs of receptacles in order to avoid the need for power strips. The receptacles are powered by electrical cabling in the walls. Typically we specify a form of shielded cabling or conduit to prevent electromagnetic interference within the walls. We also over-specify the capacity to reduce the voltage drop that occurs when current flows through cabling.

The electrical cabling terminates at your circuit breaker (or fuse) box. We have recently found new high-end circuit breaker boxes that use heavy-duty fixed breakers in lieu of the cheap pull-out variety. If possible and appropriate for your system, we specify these boxes as the connection is mechanically stronger and more positive. In the U.S., the power delivered to your breaker box is actually two "legs" of 110 volts each. This provides the option for high-current appliances such as dryers to use both legs for a total of 220 volts. Normally, electricians distribute the 110 volt circuits on both legs. To reduce the noise potential in a high-performance system, we specify that all circuits be powered by the same leg -- preferable the one that has the fewest noise-generating appliances on it.

For some systems, we suggest a balanced power system. Installed either in the room or at the breaker box, this system lowers the noise potential by -6db and provides improved immunity from induced noise (known as common mode noise rejection). Recording studios often use these systems to ensure the best possible recordings.

Your high-performance system needs a grounding system not only for safety, but to prevent hum and noise. For safety purposes, almost any grounding system will do. For performance purposes, we prefer a low-impedance isolated earth ground. Isolating the grounds for the different circuits prevent cross-contamination of the electrical power. Isolating the grounds from the rest of the electrical system prevents contamination by other appliances. In some communities, the electrical code permits a totally separate, isolated ground rod installed in the earth. The electrician drives an 8' or 10' copper rod into the earth outside your home and connects your system's ground to it. He then connects the shielding on the electrical cable to the circuit box ground.

There is another level of grounding which goes even beyond standard practices. If you have a very high end system and would like the best possible ground--a customized grounding solution can be engineered for your home. This uses very high tech ground rods surrounded by a specialty fill which is mixed for the specific soil conditions of that particular site. These are placed in very large diameter holes which are dug sometimes deep into the earth. To keep the impedance as low as possible massive custom-made ground braiding are in essence welded into place. This welding is done using custom-molds engineered for each end of the ground braid to contain a controlled mini-explosion which welds the enormous ground braid to the super ground rod array. This is the last word in ultra-low impedance grounds. However please understand that going to this level can be rather expensive!

The techniques and materials described in this section represent the electrical infrastructure of your high-performance system. You may elect to include additional power filtering, isolation, and/or conditioning at the point of use within the room. This isolates each component from each every other component in the system (as well as from the outside world) thereby preventing cross-contamination of the electrical power. Because this additional equipment is not built into your home, this equipment does not necessarily need to be planned before the construction phase of your room.

During new or complete renovation, upgrading your electrical system will cost only slightly more than standard-quality electrical work. During minor remodeling or partial renovation, the labor costs will be higher if new wiring needs to be run through existing finished walls. We would be happy to consult with you to help you determine the best plan for your project.

Lighting System Design and Light Control

A well designed and implemented lighting plan will greatly enhance the aesthetics and usability of the room. A qualified lighting designer (or sometimes interior designer or architect) will develop a plan that:

Provides an appropriate level of illumination for the tasks and lifestyle activities that will be performed in the room. For instance, cooking, reading, and entertaining all require different illumination levels.
Allows the different lighting fixtures to be combined at varying intensities to create a variety of lighting "scenes" to create different visual effects for each activity in the room.
Flatters the room. Decorative fixtures such as wall sconces, table lamps, and chandeliers perform their lighting function by having fixtures that are themselves beautiful. Other fixtures, such as dramatic wall washers and spotlights, have beautiful lighting effects, while the fixtures themselves are usually de-emphasized.

Often a decorator's or architect's initial light plan will have unintended detrimental side effects on the performance of your audio and/or video system. By working as a team with a lighting designer, we can prevent or mitigate the following potential problems:

Some lighting fixtures and controllers generate large amounts of electrical noise which can degrade the performance of the audio and/or video system.
Some lamps (i.e. the actual light bulbs) and controllers generate mechanical noise when in use. This buzzing will deleteriously raise the acoustic noise floor in the room.
Some fixtures resonate or reflect the sound from your speakers in undesirable ways.
Some fixtures, particularly recessed "cans," can defeat the soundproofing of the room.

We have a variety of tools and techniques to fight these side effects. For example, we can replace low performance dimmers with high-performance dimmers or variacs that don't generate as much noise. We can use smaller wattage lamps and/or 3-way lamps at full intensity to replace dimmed higher-wattage lamps. We can consider the acoustic properties of the fixtures when selecting them, and we can position them where they won't be acoustically detrimental. We can re-soundproof recessed cans to partially restore the acoustic isolation of the room

For a home theater, there may be a few additional design considerations. Task lighting near the equipment location and at the primary seating location will facilitate using the equipment and remote controls. If occupants will be leaving a darken theater, some lighting might prevent them from tripping, particularly if risers have elevated some of the seats. Some, but definitely not all, video displays benefit from a well-defined low level of ambient light; this may prevent eye strain.

Many home theaters, particularly those that use projection, benefit from complete light control. Front projection in particular requires an absolutely dark room; if you can't see your hand in front of your face, then it's dark enough! Usually all windows need, at a minimum, residential-quality light blocking shades, plus darkening curtains. Or, commercial-quality complete light-blocking motorized shades will guarantee that the theater can be used at any time of day. If desired, these shades, the lights, the screen, and all the audio and video components can be integrated into a comprehensive simple-to-use remote control system. Also, the equipment rack should be designed to so that light emitted from the components themselves will be shielded from view during a film presentation.

A good lighting design will enhance any room. And for a home theater proper, light control is vital.

HVAC System Design

Your HVAC system can do some or all of the following: heat, ventilate, cool, humidify, dehumidify, or filter the air in your room. But it may also transmit the noise of rushing air, the creaking of hot water pipers, the rumbling of motors, compressors, and burners. And even when off, it may provide a flanking path to defeat your soundproofing.

In a forced air system, conditioned air should enter the room slowly. A good design picks a happy medium between the quiet of slow moving air and the required volume of air movement for the temperature and ventilation requirements of the room.

In a low air speed HVAC system, cooling ducts can be placed in the ceiling or high on the walls so the the heavy cool air drifts down over the space naturally. And of course heating ducts on the floor or low on the walls will let warm light air drift up into the room. These duct placements eliminate the need for rushing air to be forced against the natural convection currents in the room.

To slow the air just before it enters the room, we can specify still air boxes in which rapidly entering air is dispersed and distributed more slowly through a number of ducts. A still air box can also help reduce noise transmission both in and out of the room.

If you are custom building a room, we may recommend that you consider radiant floor heating; it's very comfortable and quite quiet. Because the surface area of the floor is so large, a very low floor temperature such as 81 degrees Fahrenheit will evenly heat the room. In winter, radiant heat does not contribute to low humidity as does forced hot air. Also, because radiant heat eliminates the need for radiators and ducts, the acoustic layout of the room and optimal system setup need not consider these obstacles.

Radiant floor heating may actually reduce energy costs too. Some of the heat radiated by the floor directly warms you without warming the air in the room first, thus reducing your body's heat loss. Therefore you may feel warm in the room even though the actual air temperature may be cooler.

There are a couple of disadvantages to radiant heat. When you return from an extended vacation, the radiant heating system will need more time to warm the room because of the larger thermal mass involved. Also, care must be taken during construction and any subsequent renovations to protect the heating tubes in the floor from being punctured. And it is very important to get a good HVAC contractor with experience and a good track record with radiant heat to get a properly engineered installation if you decide to go this route.

You may also wish to consider radiant cooling, particularly if you live in a dry climate. When a conventional air conditioning system cools hot, moist air, the excess water condenses and drips into a drain. While there will be some dehumidifying with radiant cooling, you can hit what is considered the dew point while lowering the temperature and not dehumidify the air. So with radiant cooling, the moisture will remain in the air. However in humid environments it is possible that it might leave the room feeling somewhat clammy. In dry climates this isn't a problem because the air contain no excess of moisture.

If you are considering a radiant system, we strongly suggest that you contact an experienced HVAC contractor and visit one of their installations to see how you like it.

If you would like to control humidity and temperature of a room, then you need a dehumidification unit with air conditioning capabilities. A properly engineered installation will hold temperature within +/- 1.5 degrees and humidity within 2% at a cost of never shutting the unit off. Because the compressor is always on, the operating costs are substantially higher. And for a state-of-the-art system, it is actually possible to hold temperature to within 3/10 of a degree Farenheit and 1% humidity.

Each HVAC project is different. Lifestyle considerations, performance issues, budget, and personal preferences mandate a customized approach to each individual job.

RF / EMI Shielding

In some locations, Radio Frequency or ElectroMagnetic Interference may be strong enough to create problems. Typically this occurs in major metropolitan areas or near large TV or radio transmission towers. Additional shielding of the components or of the room itself can minimize or eliminate the problem. If you are building a room in a known problem area, we recommend that you shield the room during its construction. If you already have room with RF/EMI problems, we usually find it impossible to cost-effectively shield the room. In this case, we address the electronic components themselves.

Sometimes simply moving a component or a cable will affect the background noise. Because components and cables can act as receiving antennas, reorienting this antenna can sometimes eliminate or greatly reduce the background noise signals.

Also grounding can make a big difference here. Different grounding schemes for the components can be tried to determine which one works best. While you are doing this, you can also measure the voltage potential on each chassis and reverse the AC plugs to try to minimize any voltage differences. Do not do this with polarized or grounded plugs unless a qualified individual has determined that doing so will not create an electrical hazard in that particular piece of equipment.

Sometimes you may find that you need to lift an AC ground on a particular component in order to achieve lowest noise. While we cannot recommended this as the best course of action, it is a way to troubleshoot problems. Unfortunately it may not be practical to reengineer equipment or AC line grounding schemes, making the lifting of AC grounds a common practice.

You should be aware that a system with lifted grounds relies upon the interconnects between the components to maintain the safety of the AC ground. Never lift all the grounds; always leave at least one piece of equipment grounded. While we are unaware of anyone being injured from this practice, the potential exists for electric shock in the event of equipment failure.

Another approach to reducing grounding problems can be using a star grounding system, where all grounds terminate at one common point. Depending upon your system, this may be difficult to achieve.

If your system uses balanced audio interconnects, you may find that lifting the ground at one end of the interconnect (usually the source end) will reduce extraneous noise. This is know as "telescoping the grounds." If your system uses single-ended cable, this technique can't be used. We suggest using telescoped grounds only as a last resort. We recommend that you try other ways of addressing any problems first.

Because each system/location combination is unique, there is no one answer for everyone. However any problem can be solved if enough time, energy, and creativity are applied. And remember: there is no substitute for good design!