Recording Studio Design

Philip Newell

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781317381945
• Edition: 4
• Topic: Technologie et ingénierie
• Subtopic: Ingénierie de l'acoustique

Recording Studio Design, Fourth Edition explains the key principles of successful studio design and construction using straightforward language and the use of practical examples appreciated by readers of previous editions. Updated to reflect new industry standards, this fourth edition addresses improvements in cinema sound, with specific attention paid to B-chain electroacoustic response and calibration.

Using over 50 years' experience, author Philip Newell provides detail on the practical aspects of recording in various environments, not only exploring the complex issues relating to the acoustics but also providing real-world solutions. While the book contains detailed discussions about performing rooms, control rooms, and mobile studios, concepts of the infrastructures are also discussed, because no studio can perform optimally unless the technical and human requirements are adequately provided for. In this new edition, sound for cinema provides a platform for highlighting many, wider electroacoustic topics in a way that is relatively easy to visualise. The way in which sound and vision interact is an important aspect of many modern multimedia formats.

The new edition includes:

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• A new Chapter 22 that will thoroughly reflect recently published SMPTE investigations which will drastically impact standards for cinema sound;

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• The inclusion of new academic research and its practical applications;

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• An entire new illustrated chapter on room construction principles; and

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• The consolidation of ideas which were only emerging when the earlier editions were published.

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Chapter One

General Requirements and Common Errors

[This chapter lays out the fundamental requirements of premises for professional recording purposes, including: common underestimation of need for good isolation; avoidance of disturbance from plant and equipment noises; influence of location on isolation requirements; consideration of artistic needs; control room monitoring basics; types of buildings to avoid; and the need for adequate space and building strength.]

1.1 The General Requirements

Although this book is intended to cover the concepts of recording studios in general, some of the things which set a professional recording studio apart from a personal studio are listed below:

1. The ability to work during the chosen hours of the clients (in many cases 24 hours per day) without disturbing, or being disturbed by, anything or anybody in the local community.

2. The studio should be able to record musicians without delays or impediments to the needs of their musical performances.

3. The studios should inspire confidence in all the personnel involved in any recordings.

4. The achievable quality of recording should not be limited by the inadequacy of the studio design or installation. (Even a modest studio performing optimally may well outperform a much more elaborate one that has been poorly conceived and installed.)

5. The studio should always provide an adequate supply of clean, fresh air, in a temperature and humidity-controlled environment (although the latter may be achievable by ventilation).

These are some very basic requirements, but let us now look at them in more detail.

1.2 Sound Isolation and Background Noise Levels

In the enthusiasm that often accompanies the idea of building a recording studio, the lack of experience of the people involved often leads to a tendency to fail to realise the need for good sound isolation. In far too many cases, people believe that they can work around most of the restrictions which poor isolation imposes, but this is a dangerous attitude because once it is realised that the compromises are severely restricting the success of the studio it is often too late or too financially burdening to make the necessary changes. The result may be either a ceiling placed on the ability of the studio to develop, or financial ruin. In 2001, European banks reported bad debts on over 20,000 studio-project loans, and this has made it difficult to finance the building of studios ever since. The failure of so many of those studio projects was the result of unrealistic expectations of what could be done in inadequate circumstances, and poor sound-isolation was the root cause of many of the closures. So – optimism must be tempered by reality.

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Isolation is a two-way problem. The most obvious need for isolation is to prevent sound escaping from the studio and disturbing any noise-sensitive neighbours. Almost certainly, repeatedly disturbing the neighbours is probably going to bring complaints, and if nothing is done about it, lead to the closure of the studio. Conversely, noises from the local-community activity entering the studio can disrupt recordings and disturb the creative flow of the artistic performances, which can greatly discourage clients from wishing to book a studio. What is more, sound isolation sets the dynamic range limit for a studio. This latter point is very important in a professional recording situation, but it is often woefully under-appreciated by people with less experience. The isolation sets limits to not only how loud the musicians can play, but also the success with which quiet instruments can be recorded (and especially so if distant microphones are being used).

1.2.1 From the Inside Out

If a studio only has an effective isolation of 40 dB, any sounds being made inside above 75 dBA will risk annoying neighbours. The resulting 35 dBA reaching them would certainly be considered a potential noise nuisance, at least if the studio were to be used after 10 pm and was situated in a residential area. Whilst it may be possible to record certain quiet instruments, one cannot turn down the volume of a drum kit, and playing it quietly is no solution because it produces an entirely different tone quality from when playing loud. Realistic drum levels are more in the order of 110 dBA, so 75 dB of isolation would be a basic requirement (the 110 dBA SPL [Sound Pressure Level] of the drums minus the 35 dBA acceptable to the neighbours), although due to the dBA scaling, as will be discussed in Chapter 2, the actual level of isolation could be less at low frequencies.

Many prospective studio owners suggest that they can at least mix at night in studios with less-than-desirable isolation, in the belief that they can work with the monitor volume-controls reduced below their daytime levels. Unfortunately, it can soon become apparent that if the studio is to be used commercially, it is usually the clients, not the studio owners, who decide at what level they wish to monitor. If they cannot work in the way that they need to, they will perhaps look elsewhere when planning their next recordings. In addition, when the ability to monitor at higher levels is denied, low level noises or distortions may go unnoticed, only to be heard at a later date. This may result in either the work having to be done again, or the bill for the wasted session going unpaid; neither of which is a satisfactory result.

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What is more (see next chapter and Figure 2.1 for reasons), mixing at a relatively quiet SPL of 75 dB is at the lower end of the preferred range for music mixing. Working at this level is already descending into a region where the ear is less sensitive to the upper, and especially the lower, frequency ranges. Mixes done at or below this level may tend to sound excessive in bass when reproduced elsewhere at higher SPLs, as would often be the case. Therefore, mixing at a low level so as not to annoy the neighbours is not really a professional option.

It is true that for a voice studio for publicity or radio recording (and especially when the end-product is not likely to be listened to from an audiophile perspective), 40 dBA of isolation and a 75 dB maximum operating level may suffice, but such conditions would certainly not be suitable for music recording. In conditions of poor isolation, frustrating moments of lost artistic inspiration can be frequent, such as when a good take is ruined by an external noise, or when operating level restrictions deny the opportunity to do what is needed when the moment is ‘hot’. Professional studios should be ready for whatever the musicians reasonably require, because capturing the artistic performance is the prime reason for their existence.

1.2.2 From the Outside In

Background noise levels of below 20 dBA (or NR20 or NC20 as variously used) were previously the norm for professional studios, but in recent years, cost constraints on air-conditioning systems, together with the appearance of ever more disc-drives and equipment fans in the control rooms, have tended to push the background levels higher. These problems will also be discussed in later chapters, but background noise levels above 25 or 30 dBA in either the studio rooms or the control rooms may seriously begin to encroach on the recording operation. Twenty dBA is still optimal.

Most musical instruments have been designed to have sufficient loudness to be heard clearly over the murmur of a quiet audience, but if the background noises in a recording room exceed around 30 dBA there will be a tendency for the extraneous noises to enter the microphones. This is a sufficient noise-level to degrade the clarity of some recordings, especially if equalisation, compression and other forms of signal processing are subsequently applied. In the control rooms, we should reasonably expect a background noise level to be at least as low as that of the recordings. Otherwise, when monitoring at life-like levels, similar to those produced by the instruments in the studio, one could not monitor the background noise level on the recording because it would tend to be masked by the higher background noise level in the control room.

Around the beginning of the century, the number of so-called recording studios which had 50 dBA or more of hard-disc and cooling-fan noise in the control rooms, along with monitoring limits of only 90 dB SPL, was reaching alarming proportions. That represented a monitoring signal-to-noise ratio of only 40 dB. It was absurd that many such studios were promoting their new, advanced, 24-bit/96 K recording systems as part of a super-low-noise/high-quality facility, yet the 100 dB signal-to-noise-ratio which they offered could not even remotely be monitored. Fortunately, the mechanical noise level of much digital equipment has fallen since then, because whilst monitoring, one cannot trust to luck and call oneself professional.

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1.2.3 Realistic Goals

The previous two subsections have outlined the basic reasons why good sound isolation is required in recording studios, although the inside-to-outside isolation is usually dominant because few studios are sited next to neighbours producing upwards of 110 dBA. (At least most people understand that it would not be wise to choose to build a studio next to such a noisy neighbour.) As the 30 dBA region is reasonably close to the limit for tolerance of background noise by either the neighbours or the studio, it is principally the 110 dBA or so which may be produced in the studio that dictates the isolation needs. A well-judged choice of location can make life much easier.

Siting the studio in the middle of nowhere would seem to be one way of reducing the need for so much isolation, but the owners may have to ask themselves if their clients are likely to travel to such a remote location in commercially viable numbers. Furthermore, they should also be wary of other likely problems. One expensive studio was built with little sound isolation because it was so remote from any neighbours, but three months of unseasonably strong winds and heavy rain almost drove them to ruin because of the weather-related noise entering the studio. At great cost, improved sound-isolation had to be added after the studio had already been completed, and it proved to be far more expensive than it would have been had it been incorporated during the initial construction of the studio.

In many cases, it is client convenience that drives studio owners to build studios in city centres or apartment buildings, but the high property prices and/or high isolation costs often lead the owners to look for premises which are too small. With inadequate space, there may simply be no room for the proper isolation of the chosen spaces, even if very expensive techniques are employed. In practice, the high costs of special isolation systems may even offset any advantages of getting the smaller and less ideal premises in the first pace, so these compromises need to be carefully considered before making any commitments. This subject will be dealt with in greater depth in Chapter 2, but it should be borne in mind that there may be no cheap solution to many sound-isolation problems.

1.2.4 Isolation versus Artistry

Artistic performance can be a fragile thing. Curfews on what can be done in the studio during which hours can be a source of great problems. No matter how clearly it may be stressed that the working hours are 10 am to 10 pm, for example, the situation will always arise when things are going very well or very badly, and where a few extra hours of work after the pre-set deadline could make a good recording great, or perhaps save a disaster. In either case, using a studio where a little flexibility is allowable can be a great comfort to musicians and producers alike, and may be very much taken into account when the decision is made about which studio to use for a recording.

1.3 Confidence in the System

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A professional studio should be able to operate efficiently and smoothly. Not only should the equipment be reliable and well maintained, but all doubts should also be removed as far as possible from the whole recording process. This means that a professional studio needs recording rooms with adequately controlled acoustics and a monitoring situation which allows a reliable assessment to be made of the sounds entering the microphones. This latter requirement means that reasonably flat monitoring systems are needed, in control rooms which allow the flat response to reach the mixing position and any other designated listening regions of the room. The monitoring systems should also have good transparency and resolution of fine detail, and be uncoloured by any disturbances caused by the installed recording equipment. Where doubt exists about the monitored sound, musicians may become insecure and downhearted, and hence will be unlikely to either feel comfortable or perform at their best.

The decay time of the control-room monitoring response should be shorter than that of any of the main recording rooms (dead isolation booths may be an exception), otherwise the recording personnel may not know whether the decay that they are hearing is a part of the recording or a result of the monitoring environment. This subject can arouse many strongly opinionated comments from advocates of some older control room design philosophies, but the fact remains that adequate quality-control monitoring can be difficult to perform in rooms with typically domestic decay times. When recording personnel and musicians realise that they can trust that what they are hearing is no less clear than that which the audiophiles will hear in good conditions, it tends to give them more confidence, and as confidence is often lacking in an insecure artistic world, anything which can boost it is much to be valued.

Despite the fact that very many people now listen to downloaded, data-reduced music via mobile telephones and ear-buds, the majority of musicians still want their recordings to sound good on top-quality systems. (It is simply a question of artistic and professional satisfaction.) Small loudspeakers are effectively de rigueur in studios these days, both as a mixing tool and as a more domestic reference, and they are a very necessary requirement because one obviously wants to know what the likely result of a mix will be in the record buyers’ homes. Nevertheless, it still seems to be incumbent on a professional studio to be able to provide the means to monitor the full range of a recording so that people with good equipment at home will not be disappointed, as they would be wh...