AA 2

An ordinary household door probably offers around ____ dB sound insulation.

20

Which of the following is a very important factor in keeping HVAC noise quiet?

Air velocity in the ducts

T/F? A double window is much better than a single window in a studio, and a triple window provides about the same amount of improvement again.

False

T/F? A small crack under a door does not affect the noise reducing properties of the door very much.

False

T/F? Active noise control (where a signal is measured and a computer generates its inverse) is used frequently to tame loud noise sources.

False

T/F? Applying a great deal of absorption to the walls of a studio is the most effective way to control invading noise.

False

T/F? In general, walls do a better job of blocking low frequencies than high ones.

False

T/F? Lining ducts in HVAC systems generally does a good job of attenuating low frequencies.

False

T/F? Our primary concern with budgeting for the construction of a small recording studio is the cost of building the walls and floors: doors, windows, lighting, and wiring precautions are all secondary and will cause no significant problems.

False

T/F? Porous materials are excellent sound absorbers and can be used by themselves to insulate against sound travelling from one room to another.

False

T/F? The LEDE approach to audio control rooms was designed for stereo playback and cannot be adapted for surround-sound mixing.

False

T/F? The architectural design of control rooms for recording and production studios is straightforward, and any architect has the knowledge set to accomplish the task.

False

T/F? Typical absorbers, such as glass-fiber panels, provide significant diffusion benefits, in addition to the absorptive qualities.

False

In a hall designed for unamplified speech, the audience area must be placed as close as possible to the talker. Why?

All of the above

Which of the following is the most typical way of dealing with noise generated by HVAC machinery?

All of the above

Which of the following is capable of producing serious amounts of noise in an HVAC system?

All of the below

Through remarkable insight and much experimentation, _____ did more to develop our understanding of acoustic diffusion than anyone else in the last 100 years.

Manfred R. Schroeder

What is the most important aspect of a wall with regard to blocking outside airborne sounds?

Mass

Which of the following is the most commonly used set of criteria for HVAC noise specifications?

Balanced Noise Criteria (NCB)

Which of the following kinds of architecture is generally considered to be the pinnacle of acoustical design?

Concert halls and other large performance spaces

Which of the following is NOT a good tip for achieving good results as you pursue quiet air in an acoustically sensitive space?

Control air temperature carefully to avoid extremes

Which of the following is a serious, unique, acoustical challenge presented by audio control rooms?

Control rooms require us to deal with the mixing console, which is often the source of problematic acoustical reflections very near the listener

In a large performance space, the presence of a discernible, discrete echo is _____.

a gross defect, for which there is little tolerance

Deep balconies in concert halls are problematic because they _____.

create acoustical shadows where the sound quality will be diminished

In building a quadratic-residue diffusor, the maximum well depth is

determined by the lowest frequency to be scattered

Placing a loudspeaker close to an isolated solid surface make it output into half as much space, which _____, in that space.

doubles its power output, providing a 3 dB boost

Quadratic-residue diffusors designed to cover very wide frequency ranges (i.e. 100 Hz - 17 kHz) generally

employ the concept of fractal geometry: they stack smaller diffusors (which diffuse high frequencies) inside of larger ones (which diffuse low frequencies).

The process of designing treatment for a small recording studio begins with _____.

establishing the desired RT60 and calculating what it will be before treatment

The time gap between the arrival at the listener of the direct and reflected portions of a signal is determined by the _____.

geometry of the room

The brilliance of a good concert hall can be defined as _____.

having high frequency early decay times that are roughly 90% as long as the mid-frequency early decay times

The LEDE approach calls for one end of an audio control room to be highly absorptive, with the other end very reflective. In terms of treatment, the live end should have _____.

lots of diffusion, and preferably reflection-phase grating types of diffusion

For acoustically sensitive spaces, it is generally best -- but most expensive -- to build a _____ HVAC system.

low velocity, large duct

In large concert halls designed for music, concave surfaces are best used _____.

nowhere

Unless great care is taken in design and construction, small recording studios will have _____.

poor distribution of room modes, with significant acoustical anomalies as a result

In a large performance space designed for speech, the RT60 of bass frequencies will be _____ those of mids and highs.

shorter or the same as

In the reflective, live end of a LEDE-style audio control room, it is very important to avoid _____.

specular reflections

All quadratic residue diffusers will have a pattern that is _____ and _____.

symmetrical; periodic

The ultimate criterion for the quality of a recording studio, regardless of size, is _____.

the acceptability of the sound recorded in it for its intended audience

The main difference between a high-end home listening room (or home theater) and an audio control room is _____.

the control room must provide completely accurate playback at the listening position, while the home listening room should provide the most enjoyable playback at the listening position

The clarity of a concert hall can be defined as _____.

the difference between the sound energy in the first 80 ms and the late reverberation energy arriving after 80 ms

In a quadratic residue diffuser, thin and rigid separators are usually used between the wells. Without these, _____.

the effectiveness of the diffuser is decreased

The "vineyard" configuration for a concert hall, as used in the Berlin Philharmonie and Kansas City's Kauffman Center's Helzberg Hall, means that _____.

the hall is not rectangular and the audience seating area is broken into a number of different areas with low walls between them, perhaps even surrounding the orchestra

In a LEDE-style audio control room, if the reflections from the rear wall arrive at the listener about 40-80ms after the direct sound, within the Haas fusion zone, _____.

the listener's auditory system will integrate them with the early portion of the sound, making it seem as though there is natural ambience in the front of the room

The Initial Time Delay Gap (ITDG) is a measurement of _____.

the time between the arrival of the direct sound at the listener and the arrival of the first reflection

The effect of a wall on sound passing through it is called the _________ of the wall.

transmission loss

Which of the following is NOT a way by which sound can invade a space?

transmitted via the electromagnetic spectrum

One of the things that makes the job of designing an audio control room easier is the fact that _____.

we know where the listener will be sitting, and can design the room around that

Which of the following types of music performance provides the best model for concert hall design?

None of the above - they all present different challenges and require different approaches to the hall design

What is the primary, very specific purpose of an audio control room?

Providing high-quality loudspeaker playback to a single listening (mixing) position.

Which of the following is considered a practical and obtainable Room Criteria (RC) noise level for recording studios?

RC-15

Which of the following RC levels would likely be recommended for a small working space for several people, like a small conference room, hospital operating room, or a classroom?

RC-25 - RC-30

The typical approach today to designing audio control rooms depends on shaping the wall surfaces to nullify the negative effect of reflections. This design model is known as the _____ approach.

RFZ

Which of the following is generally the most logical and profitable approach to noise reduction?

Reducing the noise output of the offending source.

Which of the following would be a good goal for the acoustical characteristics of a small recording studio?

Short RT60 with balanced, diffuse characteristics, and a slight bass rise

To avoid the expense of high transmission loss doors, studio designers frequently use ______ instead.

Sound Locks

T/F? A basic binary maximum-length diffusor will be reasonably effective over a frequency range of +/- 0.5 octaves around the frequency for which it is designed.

True

T/F? A recording studio with a total volume of 1,000 cubic feet will present very serious acoustical problems, that may be insurmountable.

True

T/F? Architects and acousticians generally say: "a multi-purpose hall is a no-purpose hall," because , for best results, a hall must be tailored for its specific purpose.

True

T/F? Concert halls that sound good usually have a well-defined initial time delay gap, which is often around 20ms.

True

T/F? Difficult small-room acoustics are helped especially by diffraction-grating-type diffusing elements.

True

T/F? For large performance spaces, the type(s) of performances intended to occur there will profoundly influence the design.

True

T/F? Good broad-bandwidth, wide-angle diffusion requires a large period (e.g. the result of using a large prime number in the quadratic reside equation) with a large number of deep, narrow wells.

True

T/F? If we project a certain frequency at a piece of sheet metal, bent according to a binary (+1/-1) maximum length sequence, with wells a quarter-wavelength deep, we get almost perfect diffusion in the reflection.

True

T/F? In addition to the overall noise produced by a fan, it will also usually produce a discrete tone related to its revolution speed and number of blades.

True

T/F? In churches, there is often conflict between the intelligibility of the spoken word and conditions for full enjoyment of music. Making the rear wall of the church diffusive minimizes the intelligibility problem while retaining music and speech energy.

True

T/F? In practice, it is difficult to add too much diffusion in a small recording studio.

True

T/F? In small rooms, the Initial Time Delay Gap (ITDG) is small; in larger rooms, it is larger.

True

T/F? In small speech halls, the majority of the absorption is provided by the audience.

True

T/F? In solid structures, sound travels great distances with little loss.

True

T/F? NCB values for HVAC system noise can be misleading, because they do not account for specific frequency-response differences between rooms.

True

T/F? Room modes affect studio isolation in that sound entering a room with appreciable energy at a room mode frequency will be very hard to control.

True

T/F? The construction of a double window requires the use of absorption between the panes. This absorption must go at the bottom of the window, not the sides and top.

True

T/F? The inner shell of an audio control room, which establishes the shape of the inside of the room, can be built with lightweight materials, as long as care is taken to avoid any buzzing or rattling joints.

True

T/F? The principles involved in dealing with the acoustics of small recording studios are widely applicable, even to larger recording studios.

True

T/F? The quantity of air to be delivered, measured in cubic feet per minute, is a basic design parameter of an HVAC system.

True

T/F? The typical costs of constructing a recording studio have gone up since the advent of digital recording, since its higher signal-to-noise ratios mean that we need a lower RC (or NCB) contour as a goal.

True

T/F? Windows, doors, and other construction materials are active in creating the indirect (reflective) sound of a room.

True

It is expensive to run large-diameter ducts throughout a facility. One way to help mitigate costs and still obtain quiet air at the outlets of the ducts is to _____.

Use small ducts for most of the runs, but flare them out before the outlets. However, they will still be noisy along the length of the ducts.

Which of the following is NOT one of the five basic approaches to reducing noise in a listening or recording room?

Wearing flat-response ear plugs

In halls designed for either music or speech, a sloping (raked) floor is desirable for the audience.

True

In halls designed for unamplified speech, it is often necessary to limit the overall room volume.

True

A typical, small recording studio in the 3,000 - 10,000 cubic foot range should probably have an RT60 of about _____.

0.3 - 0.7 seconds

Which of the following is a good choice for the walls of the outer shell of an audio control room, which must contain strong, low frequency sounds within the room?

12-inch thick concrete

Small recording studios began to emerge as a major market force in the _____.

1990s

Lined ducts are particularly effective for reducing _____.

General midrange noise in the system, particularly around 1-3 kHz

In a specific audio control room, we discover that the playback system provides a bass frequency boost at the listening position. What will be the likely result?

The engineer will correct for the hyped bass in the mix, by turning it down, which will lead to all recordings made in the studio having a bass deficiency.

Which of the following would best describe a room measured as NCB-25(R)?

The room is quiet, with a significant rumbly component.

In drafting the requirements for an air conditioning system, how do we communicate the maximum amount of constant noise we will allow in each octave band?

Through selecting a specific NCB contour.

Which of the following is NOT one of the reasons HVAC systems are required in acoustically sensitive spaces?

To provide a stable medium for acoustic transmission

In a concert hall designed for music, very generally, the ceiling should be _____.

about as high as 1/3 - 2/3 the width of the room

In a hall designed for speech, we are most likely to find absorptive treatment placed _____.

around the audience

All primitive root diffusers will have a pattern that is _____ and _____.

asymmetrical; periodic