POSITIONING LOUDSPEAKERS IN THE ROOM
We will attempt to show you an easy method of obtaining the best sound possible from your new loudspeakers. While positioning your loudspeakers will take some time, this is the most critical step (apart from source and component selection) in determining the sound quality of your system.
Because listening preferences and room environments vary, there is no "ideal" speaker position. Slight variations in placement can have a profound affect on the sound of the speakers. In the end, it is the listener who must decide what position best suits their personal tastes and listening environment.
Before you begin to set up your loudspeakers, read these set up guidelines carefully.
Loudspeaker / Listening Position Relationship:
First, let's consider the relationship between the separation of the two speakers and the distance between the speakers and the listener:
In figure D, the distance between the left and right speakers equals the distance to the listener.
In this position, the stereo image will be emphasized with a heightened sense of the musician location in the sound stage. Shortening D2 and D3 is not recommended as even small amounts of head movement will produce large shifts in the stereo image
In figure E, the distance to the listener is twice the distance between the left and right speakers.
With this configuration, the movement of the listener's head is less restricted and the image is more homogeneous. The sound stage is reduced, however, in width. Lengthening D2 and D3 is not recommended as the image will become monophonic for all but the most emphasized right and left pan locations.
Depending on the number of people that will be listening to the system at any one time, the ideal relationship between the loudspeakers and the listening position will be somewhere in between the positions outlined in figures D and E. Some listening rooms, by limitations of their physical dimensions, may need to have the loudspeakers set up in one of these positions regardless of the listening habits of the owner.
Loudspeaker / Side Wall Relationship:
Distance from Loudspeaker To Side Wall
Each loudspeaker should be an equal distance from the sidewall. If the speakers are not equal, the image will not be centered between the speakers.
Side Wall Construction
Sound waves that travel towards the sidewalls will be partially absorbed and partially reflected by the wall; the amounts of absorption and reflection will depend on the construction of the wall.
In order to have a correct stereo image; the right and left sidewalls should be constructed of the same material. If, for example, the right wall is a highly reflective surface (a glass window) and the left wall is a more absorptive surface, then the reflections off the glass will alter the perceived stereo imaging of the speakers.
The relative absorption/reflection/diffusion characteristics of the sidewalls will have a profound effect on the imaging characteristics of the loudspeakers.Highly reflective sidewalls will artificially increase the perceived width of and depth of the soundstage. Reflective sidewalls create a reverberant environment (long RT60). The slow decay of the previous musical notes in the room creates an echo which an inexperienced listener may perceive as additional width or depth of the soundstage.
The system will always have a characteristic "listening room sound" that will not vary with different recordings rather than accurately recreating the natural acoustics of the original performance which change from recording to recording.
Proper depth and width of the soundstage are created within the recording and then reproduced by the loudspeaker. All Westlake loudspeakers are designed to faithfully reproduce the sound staging information contained in the original recordings.
Sidewalls should be dampened to minimize sidewall reflections and achieve a correct stereo image - see section of owner's manual on creating a dampened stereo environment.
Loudspeaker / Front Wall Relationship:
Speaker Location Relative to Front Wall
The left and rights speakers should be equal distances from the front wall. If the speakers are not equal distances from the front wall, there will be a power imbalance between the right and left speakers.
Distance from Front Wall to Loudspeakers
As sound waves travel in all directions, some sound waves from the loudspeakers will reflect off the front wall back into the listening position - These front wall reflections will arrive at the listener displaced in time with the direct signal from the loudspeakers.
Because this reflected signal is delayed, it will cancel out some portions of the direct sound
and reinforce other parts - the frequency and level of this cancellation being dependant on the location of the loudspeakers relative to the front wall and the absorptive/reflective/diffusive characteristic of the front wall.
There are two locations of the loudspeakers relative to the front wall where the front wall reflection problem can be most easily dealt with:
The loudspeakers can be placed far enough away from the front wall so that the ratio of direct sound to reflected sound is high (the speakers positioned out from the front wall approximately 1/3 of the total length of the room)
In this location, the out of phase reflection is substantially attenuated due to the long distance between the loudspeaker and the front wall (the sound waves need to travel the distance from the loudspeaker to the front wall, be reflected off of the front wall, travel back the distance from the front wall to the loudspeaker before continuing on to the listening position.
The loudspeakers can be placed as close to the front wall as possible (mounting the speakers in the wall, in soffits, being ideal) so that there is no front wall reflection to be dealt wit
When the loudspeakers are mounted in soffits, the front wall is flush with the front baffle of the loudspeaker. The front wall acts as an extended baffle of the loudspeaker (Users should consult with their Westlake dealer or the Westlake Audio technical staff for soffit mounting guidelines).
When the loudspeakers have a free standing location near the front wall, the speaker should be placed as close to the front wall as possible and absorptive material should be placed on the front wall to attenuate the front wall reflection as much as possible (see section on creating a dampened acoustical environment).
Changes in Bass Response Relative to Loudspeaker Position:
The loudspeaker positioning relative to the front wall will alter the perceived bass response. All enclosed rooms have pressure zones along room boundaries where the bass energy is higher. Small changes in the loudspeaker positioning relative to the front wall will allow the listener to fine-tune the bass response.
Moving the loudspeaker closer to the front wall will increase the perceived bass response as the front wall will reinforce the bass energy of the loudspeaker - The problem of too little bass can be partially remedied by moving the speaker closer to the rear wall.
Moving the speaker away from a front wall will decrease the perceived bass response - The problem of boomy bass or lack of Midbass can be partially solved by moving the speaker away from the front wall.
Listener / Rear Wall Relationship:
The same laws of physics that apply to the relationship between the loudspeaker position and the front wall apply to the selection of the listening position relative to the rear wall. Because of the pressure zones surrounding room boundaries, the distance from the listening position to the rear wall also affects the perceived bass response of the loudspeakers.
As with the relationship between the loudspeakers and the front wall, care must be taken to ensure that the listener does not hear out of phase reflections off the rear wall. The easiest solution is to locate the listening position as close to the rear wall as possible.
While the listening position can be moved 1/3 of the way out into the room to mitigate excessive bass build-up, the possibility of out of phase reflections can be problematic. Near the rear wall, the direct and reflected low frequency energy are in phase.
Listener / Loudspeaker Relationship:
Because a loudspeaker is constructed of multiple transducers, there is a minimum distance at which the individual transducers "sum up" to form what appears to the listener to be a single sound source. The listening seat should not be located closer to the loudspeakers than the following recommended minimum distances as the sound will not appear to come from a single speaker otherwise:
Recommended Listening Distances
Minimum Distance in Feet (cm) Maximum Distance
BBSM-4F 2' (61) 12' (366)
BBSM-6F 3' (92) 18' (549)
BBSM-8F 4' (122) 20' (610)
BBSM-10F 5' (153) 22' (671)
BBSM-12F 6' (183) 25' (762)
BBSM-15F 8' (244) 28' (853)
BBSM-4VNF 4' (122) 12' (366)
BBSM-5VNF 5' (153) 15' (457)
BBSM-6VNF 6' (183) 18' (549)
BBSM-8VNF 8' (244) 20' (610)
BBSM-10VNF 10' (305) 22' (671)
BBSM-12VNF 12' (366) 25' (762)
C-6 3' (92) 12' (366)
C-8 4' (122) 14' (427)
C-10 6' (183) 18' (549)
C-12 8' (244) 22' (671)
The ideal listening height is to have the listener's ear level with the midpoint between the midrange and tweeter. In the case of two-way speakers, the
listener's ear should be half way between the tweeter and the closest woofer.
When possible, a listening chair or couch should be chosen that could accommodate this listening position. If needed, the speakers can be tilted forward or backward slightly as needed to accommodate this position if changing the listening seat is not an option (care should be taken to ensure that the speakers are stable and will not fall over). Cones and other devices that can be placed under the loudspeaker will change the height required at the listening position and should be considered when determining the height of the listening position.
Evaluation of Different Loudspeaker Positions:
Before any listening position is evaluated, care should be taken to ensure that the speakers are equidistant from the listener (D2 and D3 are equal). Small variations in D2 and D3 will cause the signal to be out of phase at the shorter HF wavelengths.
A simple way to determine if D2 and D3 are equal is by using a tape measure:
Figure F - Measuring to Ensure Speakers are Equal Distances From Listener
1. Determine the center of the room (D1) - Mark this line with a string
The listening centerline will ensure that both speakers are equal distances from the center of the room. The string can be used to measure the speakers from the center of the room for each position evaluated.
2. Establish a secure reference point directly behind the listening position
A thumbtack or nail in the wall directly behind the listening position is the best reference point as it will not move when tension is applied to the tape measure.
3. Using a metal tape measure with a slotted right angle end, measure from the reference point behind the listener to the right and left edge of each speaker
(This is why a nail or thumbtack that can hold the slotted end of the tape measure is extremely helpful)
4. Measure and move the loudspeakers until both speakers are equal distances from the listener
After you have measured to ensure that both speakers are equal distances from the listening position, you can begin to listen to various speaker locations.
Remember that after you move the speakers to a new position, you must measure them again to make sure each speaker is an equal distance away from you.
Some Additional Points to Consider:
The best sound and imaging will usually occur when the speakers are focused directly at the listener. The speakers may be angled outward to accommodate additional listeners in a less focused but larger "sweet spot".