The acoustic construction work is completed by making drawings which reflect the intended demands and the detailed field management of the project.
A series of construction process must be performed under a unified command, but even though we use the most current acoustic design and construction technique, it is still difficult to fully control all of the physical phenomena about sound under variable conditions. Therefore, it is necessary to do fine adjustment for the acoustic interior and to make the intended sound fields by the sound measurement and reviewing the course of construction or after the completion. We call this work 'sound tuning'. Listening to the sound with the client, we create higher satisfied acoustic space and the best match concerning an acoustic equipment system and architectural acoustics.
This process is ideal because we can share the sound image with our clients (through the listening experiment using our listening room at the planning stage and sound tuning in the construction site).
On the other hand, as the progress of digital signal processing, various room acoustics index are available to measure, but the physical index correspond to the sound image such as 'localization' or 'Goodness of clear feeling of sound' has not yet established. For instance, even little change on sound absorption material or the reflection surface causes large change on sound image but there isn't much difference in the characteristic of the reverberation time or the impulse response. Moreover it is common that the transmission frequency characteristic remains virtually unchanged even though the 'resolution' will differ significantly by changing the orientation of the monitor speaker.
This implies the acoustic characteristic obtained by the measurement is only one part of the physical value expressing room characteristic and ultimately the human 'ear' plays a primary importance when judging acoustic sound. Therefore we have to check other factors to improve the sound field, if we cannot satisfy audibility even though the acoustic characteristic indicates excellent. The process of finding these factors and improving the sound field is called 'sound tuning'.
With the feedback from various experiences obtained by the sound tuning to the know-how and utilize to the design work. We will introduce part of our sound tuning process in construction site and on completion.
At first, we focus on discussion to achieve the ideal sound field for client spending enough time and sharing the sound image to realize with them. For instance, we will carry out the listening experiment using our listening room.
We consider several things when using our listening room, listening test for selection of equipment systems such as monitor speaker, listening impression test to compare the difference between the setting method and angle of speakers and the study of optimum speaker layout for the surround monitor environment.
Based on these points, we will recognize the direction of acoustic design and determine the fundamental conditions of the sound field.
In some cases, we construct a partial interior with a full scale model in the listening room and then listen and compare the difference of sound quality by changing texture of the sound finish, alignment and the shape.
Through the listening experiment, we can deepen mutual understanding with the actual users concerning important factors of the sound field which they desires such as detailed nuance on audibility like the preference of sound quality as well as the physical characteristic. We think these discussion and listening experiment are the vital process not only for us but also for our clients to create the intended sound field.
In the actual construction situation, it is not always the case which we can carry out an ideal acoustic design /construction due to constraint of the architectural situations or regulations and the relation with the sound / picture equipment and the air conditioning / electrical installation. However, when completing the construction process, we have to realize the aimed sound performances. Therefore we do the confirmation of the acoustic performance along the construction progress and check for problems. This process is called 'Midterm sound tuning'.
At the midterm sound tuning, just before completing acoustic finishes, checking the reverberation time and the characteristic of the transmission frequency by sound measurement and adjusting the position of sound absorption materials or diffusers including the parts covered by the interior finish by listening, we build up the sound tuning in anticipation of the completed sound field. At this point, the construction is still in progress, but sometimes, we bring the client's speakers to the site and check the actual sound listening music sources with the client. We are convinced, this is an important process to create an ideal sound field that confirm the changing 'sound image' with the clients by the slight difference in position of architecture interior and the angle difference of the monitor speaker.
After the interior construction, the wiring work and system equipment installation are followed up and then training and test recording are put into execution. Generally, at this stage, we will make the final sound tuning of the overall system and inspection measurement before the official operation.
In the playback environment, we will execute the measurement by using noise or sweep signal to adjust the transmission frequency characteristic from each channel speaker to listening point and fix the level of the sound based on the balance with respect to each frequency.
In the surround monitor environment, we setup and adjust the monitor system including adjustment of the time alignment and the electric correction such as the base management. When making the final sound tuning, we will take into account all the factors not only the comprehensive characteristic of the monitor system and the transmission route (interior sound field) from the speaker to our ears, but also the electrical system such as the console or amplifier, and each characteristic of the speaker itself.
After achieving a balance based on the acoustic measurement, we make the sound tuning by audibility that does not show up on the physical characteristics with clients. Firstly, we will increase the 'resolution' by adjusting the setting position of the speakers and the acoustic material around them. The Installation angle of the speaker influences the adjustment such as the auditory size of sound image, the definition and the extension feeling, and the sound treatment around the speakers contributes to small adjustments such as the depth and reverberation feeling. Moreover, to bring out the original sound from the speaker, we cannot forget the setting method considering the particular behavior of speaker or the vibration component. We minimize the degradation of the sound quality by using our various know-how for speaker setting.
Our aim is to create a sound space which our clients image to reality, making technical proposal by using two approaches, the physical side and the auditory side as sound.