Westlake Audio Loudspeaker Systems - Online Manual

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PROBLEM AREAS IN LISTENING ROOM

Certain areas in all listening rooms are prone to acoustical problems. These are areas where absorptive/diffusive furnishings and room treatment products will be more effective at controlling common acoustical problems.

Direct Sidewall Reflections:

Reflections that originate between the front of the speaker and the listening position are particularly damaging to the perceived imaging of the loudspeakers and need to be dealt with.

To locate the exact area of these reflections, place a small mirror on the suspected wall location. If you can see a loudspeaker in the mirror from the listening position, then you need to treat this surface with some absorptive/diffusive material.

Note:

Sometimes, simply choosing a different set-up can go a long way towards minimizing a particular acoustic problem. In the case of sidewall reflections, consider the two basic set-up variations in a typical rectangular room (see below):

Figure G Figure H

In figure G, the speakers and listener are located on the shorter wall. In some cases (depending on the particular model of speakers and the listening preferences) it may be preferable to locate the speakers on the longer wall (figure H).

As can be seen in the diagrams above, to do this requires a model of loudspeaker that can be listened to at closer distances. Generally speaking, Horizontal speakers (BBSM-F series speakers) will be better suited to listening at closer distances than vertical speakers (BBSM-VNF series speakers) although either configuration may be suited to this arrangement depending on the specific distances and loudspeakers involved.

Floor Reflections:

Carpet, while apparently absorptive, is not effective at attenuating low frequency reflections. Floor reflections are as damaging to the perceived soundstage and bass response as sidewall reflections. Again, a mirror can be used to spot the location of these reflections. Large throw pillows made of a porous cloth material will help control floor reflections and can be moved when the system is not in use.

Figure I

Ceiling Reflections:

Because of the height and potential angles of ceilings, reflections off the ceiling are often moved further out in time making them less problematic than other reflections although these reflections can still cause some potential problems. The lower the ceiling, the more these reflections will cause early, and therefore more damaging, audible effects.

Note:

Again, sometimes altering the basic speaker / listener / room relationship can alter the audibility of ceiling reflections. Consider the diagrams below:

Figure J Figure K

Figure K has the speaker / listener relationship rotated 180 degrees within the room. Rotating the speaker / listener relationship only 90 degrees would produce an asymmetrical listening space and is less desirable for a proper left / right balance.

Corners:

Corners are places where low frequency sound pressure will be potentially very high. Placing absorption material in or in front of the corners can help alleviate the problem of low frequency buildup (long RT60) that occurs due to a lack of absorption in the room


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