Introduction

The art and science of sound system design is one of the great passions of the electronic age. While the proper setup of a media room remains the subject of numerous articles and manufacturer discussions, no serious effort has been made to standardize and demystify the actual process of reproducing great sound; and no beginning to end audio training has existed. Our brothers-in-arms at ISF have had great success defining what video calibration means and today “ISF” means as much as a verb as it does as a name. While it is obvious that there are many opinions about the audio process, the HAA philosophy has been and will continue to be one of collaboration with its members, manufacturers, consumers and the academic community. Along with its long standing goal of supporting its members professionally, the HAA continues to strive to take the collaborative knowledge of a mature industry to create and market a reliable process for audio calibration. This class is our latest step toward disseminating that process and perhaps moving closer to making “HAA” a verb in its own right. Today we begin learning what it means to “HAA Level II” a system.

Learning Objectives

1) Refresh understanding of “Acoustical Goals” as the bull’s-eye of the design/calibration process.
2) Refresh understanding of the “Audio Control Panel” both Low and High frequency versions and review each tools measurement parameters
a. Listener placement
b. Speaker placement
c. Sub-woofer placement
d. Equalization
e. Room acoustical properties
f. Basic calibration elements
3) Understand the overarching importance of the Acoustics Design Review Checklist (ADR) as the prerequisite condition for calibration and its sonic relevance.
4) Introduce the Acoustic Performance Review Checklist (APR) as the calibration process and the sonic relevance of it parameters.
5) Bring sonic results into perspective by listening.

Workshops

Acoustic Design Review Checklist Workshop I

This workshop is designed to allow the team to build the theater from the ground up. Basic layout and design is taught with an emphasis on the Acoustic Design Review Checklist. Students are encouraged to experiment with a variety of layout errors and experience the resulting sonic errors.

Listening Workshop II

The work performed in Workshop I is now reviewed by the group using their most sensitive tools their ears. An array of various reference listening materials is used and each student is required to translate their listening impressions into a series of comments. The basis for judging during this critical listening exercise will be the Acoustical Goals; Clarity, Focus, Envelopment, Dynamics and Response. We'll also take a careful look at how different listening locations in the room sound.

Acoustic Performance Review Checklist Workshop III

This workshop is designed to allow the team to perform advanced measurements on the system assembled in the Workshop I. Students discuss their perceptions of sonic performance versus the actual measurements. Each member of the team is required to perform each measurement and prepare the data for the creation of the Acoustic Performance Review (APR). The APR checklist forms the basis of this "before calibration" report.

Low Frequency Calibration Workshop IV

The nitty gritty of the class begins with the LF Calibration Workshop. Here the students are given an opportunity to experiment with the LF Audio Control panel as the basis for making calibration decisions. Works includes calibration of single and multiple subwoofers using several popular techniques. Also, much attention is placed on the Main LCR speakers including full range settings and using bass management.

Front Sound Stage Calibration Workshop V

The front soundstage is honed here. Experiments will begin with two channel analysis then continue with the introduction of the center channel. The student begins to understand the cause and effect of changing speaker position against the resulting change in soundstage width, depth, cohesiveness and focus. In addition, the resulting change in response is revisited from Workshop IV when soundstage adjustments result in low frequency response changes.

Surround Field Calibration Workshop VI

The surround speakers are brought to center stage with Workshop VI. The lab begins with a demonstration of reference material with the side channels moved in and out of proper position. Experiments are reviewed using mismatched surrounds, dipoles versus monopole speakers. A final experiment demonstrates the proper setup of rear channels for DVDA or SACD recordings. As in Workshop VI, the resulting change in response is revisited from Workshop IV when soundstage adjustments result in low frequency response changes.

Room treatment Calibration Workshop VII

Here the student analyses impulse response measurements from Workshop II and compares them to the result obtained after the many changes over the two days. A variety of strategies for employing standard acoustical absorption are utilized and the resulting change in the impulse response and sound are explored. An introduction to the use of RT60 to determine overall reverberation level is demonstrated including the determination of a necessity for additional treatment. As a final experiment the student is introduced to the correct use of diffusion in a home theater setting and the resulting sonic improvement.

Listening Workshop VIII

Here the student revisits the reference material used in Workshop II and reevaluates the sonic performance of the system. Team discussions will include revised tactics for the calibration process and personal likes and dislikes for the changes. The results of listening tests may result in changes or experiments using techniques learned on earlier Workshops. At the end of the session the team should be, if not in total agreement, at least in consensus on the strategy for calibration to be used during the following days exam.

Acoustic Performance Review Checklist Workshop IX

This final exercise is to allow the collection of "final" acoustical measurements as a comparison to the "before" measurements made initially. The student should understand the creation of the Acoustic Performance Review as a total System Analysis and the basis for a recommendation for further improvements contained in an Advanced Calibration Plan.

Exam

Level II Calibration Exercise

This evaluation tests the teams ability to layout and calibrate a new system. Scheduled to begin and end prior to lunch the third day of training, it will put not only the indivuduals acoustic knowledge to a test but also their ability to work as a team. The results of the exercise will be judged by the creation of a System Analysis which includes each team members personal version of the ADR checklist, APR checklist and an advanced calibration plan. Any differences in opinion amongst team members will be reserved for inclusion in thier personal submission since each report is a privately delivered to the HAA within 10 days of the class. This analysis forms 50% of the final grade toward certification.

Level II Calibration Review

The afternoon of the third day begins with each team returning to the system they worked with for the workshops. Their task will be to complete a System Analysis on this system as a team. The resulting analysis will be returned to the HAA that day and forms 25% of the resulting grade of the team who set up the system.

Level II Calibration Written Test

The final 25% of the exam grade will be provided by the completion of an online test of the subject matter. Students will take the test at their convenience with 30 days of the completion of the Level II class.