For individualists, the Open Baffle offers freedom for creativity and sound experience
Of course, many of our customers know the basics of good hi-fi sound systems. Then why an article in our magazine about it? On the one hand: we want to inspire career changers, newcomers and returnees to audio technology. Because only a new generation of enthusiastic newcomers will produce the new audio engineers. On the other hand: being able to do something and being able to explain something are two different things. Since we also support our partners in marketing, we are also happy to offer the basics here in our magazine. Very simply and with as little technical language as possible.
The basics: setting up, positioning and aligning loudspeakers
Of course, you and your customers can simply place or hang loudspeakers in the room. Somehow the sound comes from the speaker to the nearest ear. On the other hand, how you place, align, and tune the speakers can make massive differences. And if it's a good sound system, then we want to get as much out of it as possible, right?
Distance between the speakers
Rule of thumb: with standing speaker boxes, you should try to maintain a distance of about 1 metre. However, the perfect distance depends on other factors such as the speaker's radiation angle and the distance from the listener. Depending on the frequency, there are also differences in the directivity pattern. The fact is: if your speakers are too close together, the sound will mix and become muddy. If they are too far apart, there will be a gap between the two halves of the stereo image.
Start at a distance of one metre and vary until the sweet spot is found.
Height of the speakers
Position the speakers so that the tweeter is approximately level with your ears. To achieve an optimal listening height, it is best to use speaker stands. However, it is usually not a problem to place the speakers on furniture if you observe the reflection principle: make sure the speaker cones are flush with the front edge of the furniture (or protrude beyond it). If your speaker is near the back of a shelf, sound will reflect off all surfaces in front of the cone.
Speakers and the proximity to the wall
Place your speakers at least 70-90 centimetres from the nearest wall. This minimises sound reflections that can negatively impact playback clarity. Many speakers have rear-facing bass ports. If you position a rear bass port too close to the wall, the sound waves will be reflected, resulting in a time lag. If your speakers have front-firing bass ports, you should be able to place them a little closer to the wall. Nevertheless: if you have the space, put some space between the walls and your speakers.
Angle of the speakers
Aim your speakers so that they face the listener. More specifically, at a point just behind the listener's head. If you want good sound in a larger listening area, you should decrease the toe-in angle. Angle your speakers up or down a few degrees at a time until you find the sweet spot! By the way: in our magazine you can find more information on loudspeaker angle of radiation.
Arrangement of loudspeakers in the room
Make sure there are no objects between your speakers and your ears. Helpful, if not always feasible in practice: a symmetrical arrangement of speakers and furniture. The aim is to minimise or at least control sound reflections as much as possible - but that is a separate chapter.
Avoiding reflections from speakers (in 5 steps)
When you listen to music, you're (almost always) hearing more than just the sound waves coming straight from the speakers to your ears. You'll also hear reflected sound waves bouncing off your walls and furniture. These sound waves reach your ears slightly later than the direct waves, resulting in a type of distortion that experts call time smearing. This can make your music sound muddy and unclear. A stereo image is also destroyed. So what can you do?
Step 1: What are we up to?
Define the problem areas of reflection. We know from measurements that we have to minimise the time signatures of the reflections so that they are below those of the direct sound. This time signature ratio must be considered for reflections from side walls, ceiling, floor and back wall. We need to minimise the slap echo from the back wall, and the reflections off the side walls need to be addressed. In this way, image shifts and timbre distortions can be avoided.
Step 2: Identify the problem areas
Let's start with the side walls and figure out which areas we need to treat. We know that sidewall reflections need to be controlled. Start with a position at least 30 centimetres behind the back of each speaker, both left and right. Move forward with your measurement towards the listening position until you are one foot behind the listening position. Mark this start and finish area on both side walls. This is the area for applying the room treatment. To be on the safe side, you should extend the treatment from 30 centimetres off the floor to where the side walls meet the ceiling.
Step 3: Determine the appropriate countermeasures
When it comes to reflections, we have two options: Diffusion or absorption. During absorption, the kinetic energy of reflection is converted into heat. So the sound disappears. Diffusion breaks the reflection into multiple small reflections to reduce its signature. These smaller energy signals are not influenced either in time or in their amplitude. Absorption is the recommended treatment for side walls, diffusion works well on front and back walls. Diffusion requires a greater distance between the sound source and the surface for the diffuse waveform to unfold properly.
Step 4: Implement countermeasures
Installing the absorption technology on our side walls is relatively easy. If we use absorbent material that is only absorbent on one side, we can easily attach it according to the product's installation guide. This usually includes a hook or clamp-like assembly. If our material is absorbent on both sides, we need to leave an air space between the wall and the material. Locate your tape marks (step 2) you made on both side walls and fill in the area with the absorbent material. Be careful when selecting materials. Not all absorption technologies are equal.
Step 5: Controlling with a critical ear
Take the time to listen to your installation. Note the position of the image, the accuracy of the timbre, and the overall spatial feeling. Try adding more absorbent material beyond the limits set in step 2. More may be required depending on room size, speaker placement, and listening level. Listen to all kinds of music and take your time because this is a process. You will make most of your decisions in the first 30 days. After this period, the changes will be limited. Then you will know that you did everything right.
Small digression: Upholstered furniture and other details
Rooms usually have several different functions. Therefore, your sound system must be tailored to these purposes. Think about what time of day you use your speaker system the most. Reflective and smooth surfaces, windows and smooth walls are worse for sound than more textured surfaces. This can lead to interesting situations:
the sound is terrible during the day, is it better at night? This is perhaps due to the curtains, which take your windows out of the equation as reflective surfaces.
Similarly, if you've had the same setup for a while, recently put in a new shelving unit and something has changed in the sound.
Challenge: especially small rooms
How should speakers be positioned in small rooms? As an example, let's take a room measuring 3 by 3.50 metres. If you choose to place the speakers along the long wall, you listen in the near field. This means that you are in a listening area where the direct sound from the speaker is louder than the sound reflected back at you. The problem with listening in the near field is that you hardly hear any lower and middle bass. That flattens the sound. In other words:
the problem with smaller rooms is that you don't have much space to hear the full acoustic range of your music at a reasonable distance from the audio source.
Placing your speakers along the longitudinal wall gives you more room to sit. The best place is then directly on the opposite wall. So if you have the opportunity, you should place your speakers against a long wall. You may be in the near field, but the short wall reverberation is further from the speaker. Reverberation is how long a sound lingers after it is originally produced. Reverberation occurs when sounds bounce off multiple times, accumulate, and then die away as the surrounding surfaces absorb them. The reflection distance to the speakers then creates a more dynamic sound. However: If you decide to place your loudspeakers on the longitudinal wall, i.e. the short wall, the so-called sound stage will be narrower and your seating space will be limited. Something to consider: how important is the open soundstage, how important is the bass?