Avalon Acoustics AVALON ASCENDANT manual An Optical Analogy

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An Optical Analogy

Let us use an optical analogy to aid our understanding of acoustics. Imagine that you are in a room that is lit only by a candle in its center. There is a uniform amount of light cast in all directions. If a large mirror is held closely to candle, one half of the room becomes darkened, while the other half receives twice as much light. This is because there are effectively two candles now illuminating that half of the room, the real candle, and the virtual (or reflected) candle. The energy that had been sent to both sides of the room has now been concentrated in one side only.

If we repeat the same experiment using a large piece of black cloth instead of a mirror, the results will be somewhat different. The side of the room behind the cloth is darkened, just as before, but the level of light on the side of the candle remains unchanged. This is because the light is absorbed by the cloth, rather than being reflected back into the room.

Thus we can see that the energy can either be absorbed or reflected. A similar situation occurs with sound waves, although we must account for the much greater wavelengths of audible frequencies. Of course no material is a perfect absorber or an absolute reflector. Furthermore, the sonic absorption coefficient of a given material usually varies with frequency.

Basic Room Acoustics

The great majority of all listening rooms are rectangular, with parallel surfaces. The walls and ceiling are typically hard surfaces, which are acoustically reflective. These large areas are the predominating factors in the overall room acoustics, although the other items in the room (furnishings, carpeting, wall hangings, doorways, etc.) will also play a role. Without going into excessive detail, there are four primary areas of potential concern:

1.Standing waves.

2.Flutter echo.

3.Early reflections.

4.Bass reinforcement

The first three items are problems that should be reduced or eliminated. The last item, bass reinforcement, needs to be matched to the entire system for proper tonal balance.

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Contents Page Page Table of Contents Page Introduction Introduction ContentsUnpacking Instructions Opening the Crate Installing the Grilles Orientation of the Felt Anti-Diffraction MaskReplacing Grille Pins Page Wiring Instructions Connecting the Speaker to the AmplifierBreak-in Period Speaker Placement and Symmetry Maximizing PerformanceBreak-in Grille AssembliesToe-in Apex CouplersFirst Reflection Points Corner TreatmentCare of Your Avalon Loudspeakers CabinetWarranty Warranty StatementPage Room Acoustics and Speaker Position IntroductionAn Optical Analogy Standing Waves Avoiding Early Reflections Flutter EchoEarly Reflections Page Bass reinforcement Page Summary of Recommendations Speaker Placement Listening Room Example Accuracy of Bass Reproduction Sensitivity to Time-Related InformationRationale Anechoic Frequency Response vs. In-Room Frequency ResponseMeasurements of Audio Equipment Correlation with Amplifier MeasurementsLoudspeaker Measurements Designing for Accurate Bass ReproductionListening for Size Distortions Listening QualitiesFrequency Response Effects Conclusion Transient Response EffectsFeatures Specifications
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