Expand the below Frequently Asked Questions on the Kornelius Room report. If you require specific technical assistance, we suggest purchasing a Custom Cinema Design Package where we can engage with you direclty
Distances
The overall dimensions of your room—height, width, and length—affect speaker placement. If your Reference Seating Position (RSP) is towards the back, place the rear height speakers as far back as possible. If your speakers have pivoting tweeters, aim them at the RSP. For reflective walls, position the speaker slightly in from the wall and angle the tweeter to bounce sound off the wall. This can simulate sound coming from above and behind, enhancing the listening experience.
Ensure every listener has a direct line of sight to each speaker. If that’s not feasible, raise the speakers to create an uninterrupted view. In some cases, only raising the tweeter is necessary—this might mean inverting the speaker, but take care with horizontal and vertical sound dispersion.
Front speakers should generally be positioned close to the image area, so sound localization aligns with the picture. In some cases, placing speakers outside the image area may be beneficial, which might require custom design services.
For multiple rows of seating, space the height speakers to provide balanced coverage across all seats. If you focus more on one area, the immersive audio experience in other areas may be compromised. If rear surrounds are too close to the listeners, it might be better to use only one set of surrounds, omitting the rear set.
Amplfication Power
Sound Pressure Level (SPL) is influenced by three factors: distance, amplifier power, and speaker sensitivity. For high-performance home cinemas aiming for 105 dB peaks (concert level is 110 dB), the system should be capable of delivering 90-100 dB at a minimum. To increase SPL by 3 dB, the amplifier needs to double its power. For example, going from 97 dB with 100 watts to 100 dB requires 200 watts.
Speaker damage can occur due to insufficient power, causing the amplifier to clip and potentially blow the speaker. If you’re aiming for cinema-level sound, a custom design may be required. Also, speaker sensitivity plays a critical role in how much SPL reaches the RSP—it’s important to consider this in your setup.
Room Modes
Every room has unique acoustics, with sound frequencies interacting based on the room’s dimensions. Bass frequencies are especially prone to issues. Avoid placing seats in the exact center or thirds of the room, where null points can cause reduced bass response. Ideal seating positions are at the 5th, 7th, or 9th divisions of the room’s length.
For better sound, avoid sitting right up against walls. Sitting at least 1/9th of the room’s length from the rear wall improves bass response. Room correction microphones usually take an average of the room’s acoustic characteristics to level out the system for optimal sound.
Acoustics
Modern immersive audio systems with many speakers create more reverberation in your room, which can cause listening fatigue in rooms with hard surfaces. Use acoustic treatments like absorbers and diffusers to manage this:
- Front Wall: Ideal for absorption, especially behind an acoustically transparent screen.
- Side Walls: Use a mix of absorption and convex diffusion near the front. Diffusion on the rear side walls helps with surround sound envelopment.
- Rear Wall: Use absorption directly behind the seating area, with diffusion above and beside.
- Corners: Bass traps help control low-frequency reverberation in corners.
- Ceiling: Apply both diffusion and absorption, particularly above the listeners.
RT60 refers to reverberation time (how long it takes for sound to decay by 60 dB). A comfortable RT60 is about 0.5 seconds or lower, with 0.3 seconds also being acceptable for smaller rooms.
Construction
Solid construction of walls and ceilings reduces vibrations and improves sound quality. Use double layers of sheetrock with glue and screws where possible, especially with timber or metal framing. Fill wall cavities with glass wool to prevent resonance. If using masonry, resilient mount clips help decouple walls for better isolation.
For custom designs, isolation systems can be incorporated to further minimize sound interference and vibrations.
Screen Size
Screen size is determined by your seating distance. The recommended screen size differs for 16:9 and cinemascope (2.35:1). Larger screens require more ANSI lumens to maintain brightness, especially for HDR content. Consider the natural brightness decay of projectors over time when planning your screen and projector setup.
Custom design services can help calculate screen size based on gain and other factors like projector lens memory for shifting between different aspect ratios.
Viewing
Your seating distance affects how you perceive the screen. There are ideal minimum, recommended, and maximum distances for optimal viewing, which have been studied to ensure a comfortable visual experience.
Subwoofer
Subwoofer placement is key for even bass distribution. For a single subwoofer, position it in the center of the room. If you have multiple subwoofers, place them at ¼ or halfway points along the room. Custom design services can model ideal subwoofer placements based on your room’s dimensions.
CEDIA RP22 guidelines recommend specific subwoofer placements for the best bass response across the seating area.
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