A horror movie marathon has been planned for Friday the 13th. The hosts have painstakingly themed their home theater for the night, with dim lighting, projections of ghosts, and spiderwebs cast over the seating. Guests arrive, oohing and aahing over the promise of movies that will send shivers up and down their spines.
The theater lights go out, and the movie plays. Everyone takes their seat, anticipating an evening of shrill screams and clutching the armrests for dear life. Except, something is not quite right. The sound is off. There’s a weird echo, and the hosts are experiencing a different kind of horror than expected. The jump scares fall flat, and the music sounds tinny.
What’s happened is pretty standard, the hosts have focused all their time, energy, and home theater budget on the look and feel of the cinema without considering that audio is just as essential. There’s nothing scary about a horror movie without its eerie soundtrack. The same goes for romance movies, action films, and musicals. Poor sound quality takes away the magic of the movie, and dodgy audio wrecks the home cinema experience.
Explore the laws of sound in a home theater
1. Select the right room
For viewers to become fully immersed in the world of a movie, a theater must have excellent acoustics. It needs to be spacious enough to house a proper sound system layout. When it comes to mapping the layout, there are many factors to consider and even specific formulas that help create an optimal sensory experience, e.g. the distance between the speakers and the chairs. Our layout theater blog offers in-depth tips on how the room should be set up for the best sound experience. It’s worth noting that the shape of the theater impacts its performance with irregular shapes providing a better shape for sound than more traditionally shaped spaces.
5 factors to consider when picking a room for acoustic performance
- Don’t use a room with hard surfaces – Theaters with tile and flat wood or walls with glass/windows can create too many audio reflections.
- Try to find a room that does not have vaulted ceilings – Sound can echo from vaulted ceilings, causing audio to change pitch or create poor bass reproduction.
- Irregular or oddly shaped rooms perform better – Theaters that are square or rectangular can cause standing waves, which occurs when sound waves overlap each other. In this case, only the audio wave that has a better frequency is heard, causing important audio cues to be muffled or missed entirely.
- Soften up the room – Carpets, rugs, drapes, cushions, and the right furnishings help to absorb sound reflections and also dampen the audio to create a better listening environment.
- Relocate furniture to a central location – Delving into the layout side of theaters, furniture used for viewing should be pulled away from the walls so that sounds do not bounce off the hard surfaces. Seating should be at the epicenter of the room, as far away from the walls as possible.
2. Source the right audio equipment
While most homes use one box as a go-to for all their audio needs, home theaters require many separate pieces of equipment to fine-tune every single part of the audio experience. The first piece of tech, the power amplifier, sends a strong current to the speakers to create a fuller sound.
Depending on how many speakers a room holds, multiple amplifiers may be needed, especially if the theater goes into a 9.1 surround sound range. Although many theater systems come with built-in systems, these external amplifiers provide better power and support to the audio equipment.
The next piece of tech needed is the preamplifier. This big box is in control of switching audio stations. While the preamplifier is where all the input channels are plugged in, the power amplifier is where the speakers receive their energy.
The two main reasons why the power and preamp should be separated is to provide more flexibility when upgrading tech, as well as getting rid of any interference that is caused by having all the technology together in a single area.
As a quick sidenote, amplifiers always create some distortion. An important measure to check before buying is the Total Harmonic Distortion (THD) that the amp creates. Cheaper systems that typically boast high ratings have a listed THD of 20% or 30%. In this case, the higher the percentage, the worse it is. A 30% THD would be equivalent to the PA system in a 100-year-old grocery store. When looking at the THD rating (often hidden in fine print), look for a rating of 1% or lower.
No theater would be complete without some speakers. We could talk about the different makes all day and show thousands of charts explaining every little detail of each technical stat, but instead, we want to make it simple. Home theaters deserve the best surround sound, so keeping that in mind, the speakers need to fit with the room.
Depending on the size of the space, theaters can go from 5.1 surround sound up to 9.1 surround sound. When it comes to picking the correct speakers, make sure to listen to them in person. No, really! Everybody hears audio differently, so the best way to find the best fit is to take a listen.
Of course, when building a surround sound system, all speakers should be the same brand, and each one should stay in its designated place. (Don’t try to put a speaker labeled left at the front of the theater.)
3. Audio Cables
Excellent quality audio cables have one primary function, to deliver a constant current from the amp to the speakers. Many cables boast superior sound quality, audio enhancements, or sturdy connectors. Don’t fall for these fancy side functions as there are only two critical factors to remember when selecting audio cables.
- The thicker, the better – since sound needs a constant current, the thicker the wire, the more reliable the connection will be!
- Gauge size matters – 12 gauge wires are the minimum for most home theaters. The smaller the number gets, the thicker the wire becomes.
One crucial factor to remember from our home theater layout guide is that there needs to be more than one subwoofer. By placing them strategically throughout the space, the bass is evenly distributed, which decreases the loud feedback that usually comes from having one subwoofer. As a general guide, there should be one subwoofer one chair, two subwoofers for one row of chairs, and four subwoofers for multiple rows of chairs. This way, the bass is unified throughout the entire area.
5. Acoustic Treatments
Unfortunately, no matter the room, there will have to be budget put aside for acoustic treatments. It doesn’t matter what shape the room is, this will always be important. Here are a few acoustic treatments that can take any home theater to the next level:
- Foam Panels (audio absorbers) – These panels directly absorb sound so that no bounce back is created. Although if the theater only has audio absorbers, the sound can end up feeling dead.
- Wooden Diffusers – These audio diffusers pair nicely with foam panels to create a balance of absorbing and diffusing sound. The result? No echoing audio, as well as no dead air.
- Sound reduction paint – Of course, no matter how many foam panels are bought, they cannot cover the entire theater. By using sound reduction paint on the walls (and the ceiling), the audio is less likely to bounce.
- Audio panels/acoustic boards – Similar to foam panels, these are the more expensive, design-friendly option. These panels do a great job of absorbing sound while matching the color scheme and aesthetic of the home theater.
- Carpet/rugs – Furnishings and the floor should be kept soft to help absorb any sound waves.
- Sealing any openings – If the home theater has any windows or openings, make sure to seal them with drapes, as well as seal any gaps in doorways.
6. Quality equipment
Every device impacts the sound. Make sure not to cheap out on the DVD/Blu-ray players, as a lower quality Blu-ray player can compromise the audio. Higher end Blu-ray players have 5.1 and 7.1 audio output options, taking full advantage of a surround sound system. Having proper equipment ensures that everything from tone, to quality of voice, is played as it’s meant to be.
7. Sound Control
After following the previous six steps, any home theater should officially be decked out with all the essential audio tools needed for a fully immersive sound experience. The final step is setting up the audio control, this is an important part of the process as most home theaters will serve a variety of purposes.
Some people like to fiddle around with complicated settings and adjust on the fly, but not all home theater owners enjoy getting technical. It’s possible to pre-program different sound settings in an iPad so that everyone can access their preferred sound arrangement with the simple tap of a finger. Pre-settings can include anything from setting a scene to include low music playing before the lights dim and the movie starts, or a lower sound option for those with sensitive ears.
Presetting sound scenes should be integrated with all the other equipment and it’s best to call in a professional to get it right from the start. There are plenty of A/V integrators on the CEDIA list who can assist in making sure audio, lighting, and other a/v equipment work seamlessly.
3. Limit sound reflection in the home theater
Room reflections are one of sound designs worst enemies. When a sound wave hits a wall, it bounces back while the speakers in front continue delivering direct audio. Reflected sound is what the human ear hears best, so while watching a film, many sounds are muffled or distorted.
A solution to this problem is using acoustic absorbers or diffusers. When placed correctly, these acoustic absorbers improve bass, create less reflected audio, and unify tonal quality. Depending on the audio diffuser, it can serve as not only a sound improvement but give the space a unique visual style. Wooden audio absorbers are often favored, and usually, have intricate designs carved into the surface to help control sound. If the theater needs audio diffusers that are hidden from sight, there are also ones made from poly or foam.
4. Seating will impact sound design
It may seem odd, but every aspect of the room plays into sound design. It’s not just the positioning of the seating that’s important but the size of the chair and the height of the headrest. Nobody wants a speaker directly behind their head or just below it. Considering all these factors can be quite a pain for the uninitiated which is why we always recommend getting an A/V integrator because worrying about the details is second nature to them.
No doubt the laws of home theater sound can feel a little overwhelming. We recommend taking a look at some of the CEDIA authorized audio brands for top quality audio equipment and advice. Monitor Audio, Elite AV, Linn, Sony, and Onkyo all have luxury sound equipment that ensures any home theater is equipped to create a fully immersive experience.